Prepare standards to span the 0-

to 400- or 400- to 1000-ppm range. If any samples span both concentration ranges, prepare a calibration curve for each range. A set of three bulbs containing colorimetric reagent but no CO should serve as a reagent blank and be taken through the analysis procedure. Calculate the average absorbance for each set (3 bulbs) of standards using Equation 10A-1 and Table 10A-1. Construct a graph of average absorbance for each standard against its corresponding concentration in ppm. Draw a smooth curve through the points. The curve should be linear over the two concentration ranges discussed In Section 1.3.1. 6. Calculations Carry out calculations retaining at least one extra decimal figure beyond that of the acquired data. Round off figures after final calculation. 6.1 Nomenclature. A=Sample absorbance, uncorrected for the reagent blank. A,=Absorbance of the reagent blank. A,=Average sample absorbance per liter, units/liter. B.=Moisture content In the bag sample. C=CO concentration in the stack gas, dry basis, ppm. C₂=CO concentration of the bag sample, dry basis, ppm. Cg=CO concentration from the calibration curve, ppm. F=Volume fraction of CO₂ in the stack. n=Number of reaction bulbs used per bag sample. Pt pressure. mm Hg. P.=Residual pressure in the sample bulb after evacuation. mm Hg. Pw=Vapor pressure of H 20 in the bag (from Table 10A-2), mm Hg. V6=Volume of the sample bulb, liters. V-Volume of reagent added to the sample bulb, 0.0100 liter. 6.2 Average Sample Absorbance per Liter. Average the three absorbance values for each bulb set. Then calculate A, for each set of gas bulbs using Equation 10A-1. Use A, to determine the CO concentration from the calibration curve (C₂) NOTE: A and A, must be at the same wavelength. 6.3 CO Concentration in the Bag. Calculate C₆ using Equations 10A-2 and 10A-3. If condensate is visible in the Tedlar bag, calculate B. using Table 10A-2 and the temperature and barometric pressure in the analysis room. If condensate is not visible, calculate Bw using the temperature and barometric pressure recorded at the sampling site. EC16NO91.168 EC16NO91.169 METHOD 10 B 40 CFR PART 60 APPENDIXA Pt. 60, App. A, Meth. 10B EC16NO91.170 6.4 CO Concentration in the Stack. EC16NO91.171 EC01JN92.185 7. BIBLIOGRAPHY 1. Butler. F.E., J.E. Knoll, and M.R. Midgett. Development and Evaluation of Methods for Determining Carbon Monoxide Emissions. Quality Assurance Division. Environmental Monitoring Systems Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711. June 1985. 33 p. 2. Ferguson. B.B., R.E. Lester. and W.J. Mitchell. Field Evaluation of Carbon Monoxide and Hydrogen Sulfide Continuous Emission Monitors at an Oil Refinery. U.S. Environmental Protection Agency. Research Triangle Park, NC. Publication No. EPA-600/ 4-82-054. August 1982. 100 p. 3. Lambert, J.L., and R.E. Welns. Induced Colorimetric Method for Carbon Monoxide. Analytical Chemistry. 46(7):929-930. June 1974. 4. Levaggi. D.A., and M. Feldstein. The Colorimetric Determination of Low Concentrations of Carbon Monoxide. Industrial Hygiene Journal. 25.64-66. January-February 1964. 5. Repp. M. Evaluation of Continuous Monitors for Carbon Monoxide in Stationary Sources. U.S. Environmental Protection Agency. Research Triangle Park, NC. Publication No. EPA-600/2-77-063. March 1977. 155 p. 6. Smith, F., D.E. Wagoner, and R.P. Donovan. Guidelines for Development of a Quality Assurance Program: Volume VIII-Determination of CO Emissions from Stationary Sources by NDIR Spectrometry. U.S. Envlronmental Protection Agency. Research Triangle Park, NC. Publication No. EPA-850/4- 74-005-h. February 1975. 96 p. METHOD 10B-DETERMINATION OF CARBON MONOXIDE EMISSIONS FROM STATIONARY SOURCES 1. Applicability and Principle 1.1 Applicability. This method applies to the measurement of carbon monoxide (CO) emissions at petroleum refineries and from other sources when specified in an applicable subpart of the regulations. Environmental Protection Agency, EPA Pt. 60, App. A, Meth. 10B 1.2 Principle. An integrated gas sample is extracted from the sampling point and analyzed for CO. The sample is passed through a conditioning system to remove interferences and collected in a Tedlar bag. The CO is separated from the sample by gas chromatography (GC) and catalytically reduced to methane (CH4) prior to analysis by flame ionization detection FID. The analytical portion of this method is Identical to applicable sections in Method 25 detailing CO measurement. The oxidation catalyst required in Method 25 is not needed for sample analysis. Complete Method 25 analytical systems are acceptable alternatives when calibrated for CO and operated by the Method 25 analytical procedures. NOTE: Mention of trade names or commercial products in this method does not constitute the endorsement or recommendation for use by the Environmental Protection Agency. 1.3 Interferences. Carbon dioxide (CO₂) and organics potentially can interfere with the analysis. Carbon dioxide is primarily removed from the sample by the alkaline permanganate conditioning system; any residual CO₂ and organics are separated from the CO by GC. 2. Apparatus 2.1 Sampling. Same as in Method 10A, section 2.1. 2.2 Analysis. 2.2.1 Gas Chromatographic (GC) Analyzer. A semicontinuous GC/FID analyzer capable of quantifying CO in the sample and containing at least the following major components. 2.2.1.1 Separation Column. A column that separates CO from CO₂ and organic compounds that may be present. A 1/8-in. OD stainless-steel column packed with 5.5 ft of 60/80 mesh Carbosieve S-II (available from Supelco) has been used successfully for this purpose. The column listed in Addendum 1 of Method 25 is also acceptable. 2.2.1.2 Reduction Catalyst. Same as in Method 25, section 2.3.2. 2.2.1.3 Sample Injection System. Same as in Method 25, section 2.3.4, equipped to accept a sample line from the Tedlar bag. 2.2.1.4 Flame Ionization Detector. Linearlty meeting the specifications In section 2.3.5.1 of Method 25 where the linearity check is carried out using standard gases containing 20-, 200-, and 1.000-ppm CO. The minimal instrument range shall span 10 to 1,000 ppm CO. 2.2.1.5 Data Recording System. Same as in Method 25, section 2.3.6. 3. Reagents 3.1 Sampling. Same as in Method 10A, section 3.1. 3.2 Analysis. 3.2.1 Carrier, Fuel, and Combustion Gases. Same as in Method 25, sections 3.2.1, 3.2.2. and 3.2.3. 3.2.2 Linearity and Calibration Gases. Three standard gases with nominal CO concentrations of 20-, 200-, and 1,000-ppm CO in nitrogen. 3.2.3 Reduction Catalyst Efficiency Check Calibration Gas. Standard CH₄ gas with a concentration of 1,000 ppm in air. 4. Procedure 4.1 Sample Bag Leak-checks, Sampling, and CO₂ Measurement. Same as in Method 10A, sections 4.1. 4.2. and 4.3. 4.2 Preparation for Analysis. Before putting the GC analyzer into routine operation, conduct the calibration procedures listed In section 5. Establish an appropriate carrier flow rate and detector temperature for the specific instrument used. 4.3 Sample Analysis. Purge the sample loop with sample, and then inject the sample. Analyze each sample in triplicate, and calculate the average sample area (A). Determine the bag CO concentration according to section 6.2. 5. Callbration 5.1 Carrier Gas Blank Check. Analyze each new tank of carrier gas with the GC analyzer according to section 4.3 to check for contamination. The corresponding concentration must be less than 5 ppm for the tank to be acceptable for use. 5.2 Reduction Catalyst Efficiency Check. Prior to initial use, the reduction catalyst shall be tested for reduction efficiency. With the heated reduction catalyst bypassed, make triplicate Injections of the 1,000-ppm CH4 gas (section 3.2.3) to calibrate the analyzer. Repeat the procedure using 1.000-ppm CO (section 3.2.2) with the catalyst in operation. The reduction catalyst operation is acceptable if the CO response is within 5 percent of the certified gas value. 5.3 Analyzer Linearity Check and Calibration. Perform this test before the system is first placed into operation. With the reduction catalyst In operation, conduct a linearlty check of the analyzer using the standards specified in section 3.2.2. Make triplicate injections of each calibration gas, and then calculate the average response factor (area/ppm) for each gas. as well as the overall mean of the response factor values. The instrument linearity is acceptable if the average response factor of each calibration gas is within 2.5 percent of the overall mean value and if the relative standard deviation (calculated in section 6.9 of Method 25) for each set of triplicate injections Is less than 2 percent. Record the overall mean of the response factor values as the calibration response factor (R). Pt. 60, App. A, Meth. 11 40 CFR Ch. I (7-1-99 Edition) 6. Calculations Carry out calculations retaining at least one extra decimal figure beyond that of the acquired data. Round off results only after the final calculation. 6.1 Nomenclature. A=Average sample area. B.=Moisture content In the bag sample, fraction. C=CO concentration in the stack gas, dry basis, ppm. Cb=CO concentration in the bag sample, dry basis, ppm. F=Volume fraction of CO2 in the stack, fraction. Pta-Barometric pressure, mm Hg. Pw=Vapor pressure H2O in the bag (from Table 10-2, Method 10A). mm Hg. R=Mean calibration response factor. area/ ppm. 6.2 CO Concentration in the Bag. Calculate C₃ using Equations 10B-1 and 10B-2. If condensate is visible in the Tedlar bag, calculate Bw using Table 10A-1 of Method 10A and the temperature and barometric pressure in the analysis room. If condensate is not visible, calculate B W using the temperature and barometric pressure at the sampling site. EC18NO91.172 EC16NO91.173 6.3 CO Concentration in the Stack. C=C₆(1 Eq. 10B-3 1. Butler. F.E, J.E. Knoll, and M.R. Midgett. Development and Evaluation of Methods for Determining Carbon Monoxide Emissions. Quality Assurance Division. Environmental Monitoring Systems Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711. June 1985. 33p. 2. Salo, A.E., S. Witz, and R.D. MacPhee. Determination of Solvent Vapor Concentrations by Total Combustion Analysis: A Comparison of Infrared with Flame Ionization Detectors. Paper No. 75-33.2. (Presented at the 68th Annual Meeting of the Air Pollution Control Association. Boston, MA. June 15. 1975.) 14 p. 3. Salo. A.E., W.L. Oaks, and R.D. MacPhee. Measuring the Organic Carbon Content of Source Emissions for Air Pollution Control. Paper No. 74-190. (Presented at the 67th Annual Meeting of the Air Pollution 7. Bibliography Control Association. Denver, CO. June 9, 1974.) 25 p. METHOD 11-DETERMINATION OF HYDROGEN SULFIDE CONTENT OF FUEL GAS STREAMS IN PETROLEUM REFINERIES 1. Principle and Applicability 1.1 Principle. Hydrogen sulfide (H2S) is collected from a source in a series of midget impingers and absorbed In pH 3.0 cadmium sulfate (CdSO4) solution to form cadmium sulfide (CdS). The latter compound is then measured iodometrically. An impinger containing hydrogen peroxide is Included to remove SO₂ as an interfering species. This method is a revision of the H₂ S method originally published in the FEDERAL REGISTER, Volume 39, No. 47, dated Friday, March 8, 1974. 1.2 Applicability. This method is applicable for the determination of the hydrogen sulfide content of fuel gas streams at petroleum refineries. 2. Range and Sensitivity The lower limit of detection is approximately 8 mg/m3 (6 ppm). The maximum of the range is 740 mg/m3 (520 ppm). 3. Interferences Any compound that reduces iodine or oxidizes iodide ion will Interfere in this procedure, provided it is collected In the cadmium sulfate Impingers. Sulfur dioxide in concentrations of up to 2,600 mg/m 3 is eliminated by the hydrogen peroxide solution. Thiols precipitate with hydrogen sulfide. In the absence of H₂S, only co-traces of thiols are collected. When methane- and ethanethiols at a total level of 300 mg/m3 are present in addition to H 2S, the results vary from 2 percent low at an H₂S concentration of 400 mg/m3 to 14 percent high at an H2S concentration of 100 mg/m 3. Carbon oxysulfide at a concentration of 20 percent does not interfere. Certain carbonyl-containing compounds react with iodine and produce recurring end points. However. acetaldehyde and acetone at concentrations of 1 and 3 percent, respectively, do not interfere. Entrained hydrogen peroxide produces a negative Interference equivalent to 100 percent of that of an equimolar quantity of hydrogen sulfide. Avoid the ejection of hydrogen peroxide into the cadmium sulfate impingers. 4. Precision and Accuracy Collaborative testing has shown the within-laboratory coefficient of variation to be 2.2 percent and the overall coefficient of variation to be 5 percent. The method blas was shown to be 4.8 percent when only H₂S was present. In the presence of the Interferences cited in section 3, the blas was positive at low H₂S concentration and negative at higher concentrations. At 230 mg H₂S/m 3. the level of the compliance standard. the bias METHOD 23 40 CFR PART 60 APPENDIXA EC01JN92.248 METHOD 23-DETERMINATION OF POLY- CHLORINATED DIBENZO-P-DIOXINS AND POLY- CHLORINATED DIBENZOFURANS FROM STA- TIONARY SOURCES 1. Applicability and Principle 1.1 Applicability. This method is applicable to the determination of polychlorinated dibenzo-p-dioxins (PCDD's) and polychlorinated dibenzofurans (PCDF's) from stationary sources. 1.2 Principle. A sample is withdrawn from the gas stream isokinetically and collected in the sample probe, on a glass flber filter, and on a packed column of adsorbent material. The sample cannot be separated into a particle vapor fraction. The PCDD's and PCDF's are extracted from the sample, separated by high resolution gas chromatography. and measured by high resolution mass spectrometry. 2. Apparatus 2.1 Sampling. A schematic of the sampling train used in this method is shown in Figure 23-1. Sealing greases may not be used in assembling the train. The train is identical to that described in section 2.1 of Method 5 of this appendix with the following additions: EC01JN92.249 2.1.1 Nozzle. The nozzle shall be made of nickel. nickel-plated stainless steel, quartz, or borosilicate glass. 2.1.2 Sample Transfer Lines. The sample transfer lines, If needed, shall be heat traced, heavy walled TFE (1/2 in. OD with 1/8 in. wall) with connecting fittings that are capable of forming leak-free. vacuum-tight connections without using sealing greases. The line shall be as short as possible and must be maintained at 120 °C. 2.1.1 Filter Support. Teflon or Tefloncoated wire. 2.1.2 Condenser. Glass, coll type with compatible fittings. A schematic diagram is shown in Figure 23-2. 2.1.3 Water Bath. Thermostatically controlled to maintain the gas temperature exiting the condenser at < 20 °C (68 °F). 2.1.4 Adsorbent Module. Glass container to hold the solid adsorbent. A shematic diagram is shown in Figure 23-2. Other physical configurations of the resin trap/condenser assembly are acceptable. The connecting flttings shall form leak-free. vacuum tight seals. No sealant greases shall be used in the sampling train. A coarse glass frit is included to retain the adsorbent. 2.2 Sample Recovery. 2.2.1 Fitting Caps. Ground glass, Teflon tape, or aluminum foil (Section 2.2.6) to cap off the sample exposed sections of the train. 2.2.2 Wash Bottles. Teflon, 500-ml. 2.2.3 Probe-Liner Probe-Nozzle, and Filter-Holder Brushes. Inert bristle brushes with precleaned stainless steel or Teflon handles. The probe brush shall have extensions of stainless steel or Teflon, at least as long as the probe. The brushes shall be properly sized and shaped to brush out the nozzle, probe liner. and transfer line, if used. EC01JN92.250 2.2.4 Filter Storage Container. Sealed filter holder, wide-mouth amber glass jar with Teflon-lined cap, or glass petri dish. 2.2.5 Balance. Triple beam. 2.2.6 Aluminum Foil. Heavy duty, hexanerinsed. 2.2.7 Metal Storage Container. Air tight container to store silica gel. Pt. 60, App. A, Meth. 23 2.2.8 Graduated Cylinder. Glass, 250-ml with 2-ml graduation. 2.2.9 Glass Sample Storage Container. Amber glass bottle for sample glassware washes, 500- or 1000-ml, with leak free Teflonlined caps. 2.3 Analysis. 2.3.1 Sample Container. 125- and 250-ml flint glass bottles with Teflon-lined caps. 2.3.2 Test Tube. Glass. 2.3.3 Soxhlet Extraction Apparatus. Capable of holding 43 X 123 mm extraction thimbles. 2.3.4 Extraction Thimble. Glass, precleaned cellulosic, or glass fiber. 2.3.5 Pasteur Pipettes. For preparing liquid chromatographic columns. 2.3.6 Reacti-vials. Amber glass, 2-ml, silanized prior to use. 2.3.7 Rotary Evaporator. Bucht/Brinkman RF-121 or equivalent. 2.3.8 Nitrogen Evaporative Concentrator. N-Evap Analytical Evaporator Model III or equivalent. 2.3.9 Separatory Funnels. Glass, 2-liter. 2.3.10 Gas Chromatograph. Consisting of the following components: 2.3.10.1 Oven. Capable of maintaining the separation column at the proper operating temperature ± °C and performing programmed increases in temperature at rates of at least 40 °C/min. 2.3.10.2 Temperature Gauge. To monitor column oven, detector, and exhaust temperatures ±1 °C. 2.3.10.3 Flow System. Gas metering system to measure sample. fuel, combustion gas, and carrier gas flows. 2.3.10.4 Capillary Columns. A fused silica column, 60 X 0.25 mm inside diameter (ID). coated with DB-5 and a fused silica column. 30 m x 0.25 mm ID coated with DB-225. Other column systems may be used provided that the user is able to demonstrate using calibration and performance checks that the column system is able to meet the specifications of section 6.1.2.2. 2.3.11 Mass Spectrometer. Capable of routine operation at a resolution of 1:10000 with a stability of ±5 ppm. 2.3.12 Data System. Compatible with the mass spectrometer and capable of monitoring at least five groups of 25 ions. 2.3.13 Analytical Balance. To measure within 0.1 mg. 3. Reagents 3.1 Sampling. 3.1.1 Filters. Glass fiber filters, without organic binder, exhibiting at least 99.95 percent efficiency (<0.05 percent penetration) on 0.3-micron dioctyl phthalate smoke particles. The filter efficiency test shall be conducted in accordance with ASTM Standard Method D 2986-71 (Reapproved 1978) (incorporated by reference-see $60.17). 3.1.1.1 Precleaning. All filters shall be cleaned before their initial use. Place a glass extraction thimble and 1 g of silica gel and a plug of glass wool into a Soxhlet apparatus, charge the apparatus with toluene, and reflux for a minimum of 3 hours. Remove the toluene and discard it. but retain the silica gel. Place no more than 50 filters in the thimble onto the silica gel bed and top with the cleaned glass wool. Charge the Soxhlet with toluene and reflux for 16 hours. After extraction. allow the Soxhlet to cool, remove the filters. and dry them under a clean N₂ stream. Store the filters In a glass petri dish sealed with Teflon tape. 3.1.2 Adsorbent Resin. Amberlite XAD-2 resin. Thoroughly cleaned before Initial use. 3.1.2.1 Cleaning Procedure. This procedure may be carried out in a giant Soxhlet extractor. An all-glass filter thimble containing an extra-course frit is used for extraction of XAD-2. The frit is recessed 10-15 mm above a crenelated ring at the bottom of the thimble to facilitate drainage. The resin must be carefully retained in the extractor cup with a glass wool plug and a stainless steel ring because it floats on methylene chloride. This process involves sequential extraction in the following order. 40 CFR Ch. I (7-1-99 Edition) Solvent Procedure Water Initial rinse: Place resin in a beaker, rinse once with water, and discard. Fill with water a second time, let stand overnight, and discard. Water Extract with water for 8 hours. Methanol Extract for 22 hours. Methylene Chloride Extract for 22 hours. Toluene Extract for 22 hours. 3.1.2.2 Drying. 3.1.2.2.1 Drying Column. Pyrex pipe, 10.2 cm ID by 0.6 m long, with suitable retainers. 3.1.2.2.2 Procedure. The adsorbent must be dried with clean inert gas. Liquid nitrogen from a standard commercial liquid nitrogen cylinder has proven to be a reliable source of large volumes of gas free from organic contaminants. Connect the liquid nitrogen cylinder to the column by a length of cleaned copper tubing, 0.95 cm ID, colled to pass through a heat source. A convenient heat source is a water-bath heated from a steam line. The final nitrogen temperature should only be warm to the touch and not over 40 °C. Continue flowing nitrogen through the adsorbent until all the residual solvent is removed. The flow rate should be sufficient to gently agitate the particles but not so excessive as the cause the particles to fracture. 3.1.2.3 Quality Control Check. The adsorbent must be checked for residual toluene. 3.1.2.3.1 Extraction. Weigh 1.0 g sample of dried resin into a small vial, add 3 ml of toluene, cap the vial, and shake it well. Environmental Protection Agency, EPA 3.1.2.3.2 Analysis. Inject a 2 µl sample of the extract into a gas chromatograph operated under the following conditions: Column: 6 ft X 1/8 in stainless steel containing 10 percent OV-101 on 100/120 Supelcoport. Carrier Gas: Helium at a rate of 30 ml/min. Detector: Flame ionization detector operated at a sensitivity of 4 10-" A/mV. Injection Port Temperature: 250 °C. Detector Temperature: 305 °C. Oven Temperature: 30 °C for 4 min; programmed to rise at 40 °C/min until it reaches 250 °C: return to 30 °C after 17 minutes. Compare the results of the analysis to the results from the reference solution. Prepare the reference solution by injection 2.5 al of methylene chloride into 100 ml of toluene. This corresponds to 100 µg of methylene chloride per 8 of adsorbent. The maximum acceptable concentration is 1000 µg/g of adsorbent. If the adsorbent exceeds this level. dry- Ing must be continued until the excess methylene chloride is removed. 3.1.2.4 Storage. The adsorbent must be used within 4 weeks of cleaning. After clean- Ing, it may be stored in a wide mouth amber glass container with a Teflon-lined cap or placed in one of the glass adsorbent modules tightly sealed with glass stoppers. If precleaned adsorbent is purchased in sealed containers, it must be used within 4 weeks after the seal is broken. 3.1.3 Glass Wool. Cleaned by sequential immersion In three aliquots of methylene chloride, dried in a 110 °C oven, and stored in a methylene chloride-washed glass Jar with a Teflon-lined screw cap. 3.1.4 Water. Deionized distilled and stored in a methylene chloride-rinsed glass container with a Teflon-lined screw cap. 3.1.5 Silica Gel. Indicating type. 6 to 16 mesh. If previously used, dry at 175 °C (350 °F) for two hours. New silica gel may be used as received. Alternately other types of desiccants (equivalent or better) may be used, subject to the approval of the Administrator. 3.1.6 Chromic Acid Cleaning Solution. Dissolve 20 g of sodium dichromate in 15 ml of water, and then carefully add 400 ml of concentrated sulfuric acid. 3.2 Sample Recovery. 3.2.2 Acetone. Pesticide quality. 3.2.2 Methylene Chloride. Pesticide qualtity. 3.2.3 Toluene. Pesticide quality. 3.3 Analysis. 3.3.1 Potassium Hydroxide. ACS grade. 2- percent (weight/volume) in water. 3.3.2 Sodium Sulfate. Granulated. reagent grade. Purify prior to use by rinsing with methylene chloride and oven drying. Store the cleaned material in a glass container with a Teflon-lined screw cap. 3.3.3 Sulfuric Acid. Reagent grade. 3.3.4 Sodium Hydroxide. 1.0 N. Weigh 40 g of sodium hydroxide into a 1-liter volumetric flask. Dilute to 1 liter with water. 3.3.5 Hexane. Pesticide grade. 3.3.6 Methylene Chloride. Pesticide grade. 3.3.7 Benzene. Pesticide Grade. 3.3.8 Ethyl Acetate. 3.3.9 Methanol. Pesticide Grade. 3.3.10 Toluene. Pesticide Grade. 3.3.11 Nonane. Pesticide Grade. 3.3.12 Cyclohexane. Pesticide Grade. 3.3.13 Basic Alumina. Activity grade 1. 100-200 mesh. Prior to use, activate the alumina by heating for 16 hours at 130 °C before use. Store in a desiccator. Pre-activated alumina may be purchased from a supplier and may be used as received. 3.3.14 Silica Gel. Bio-Sil A, 100-200 mesh. Prior to use, activate the silica gel by heating for at least 30 minutes at 180 °C. After cooling, rinse the silica gel sequentially with methanol and methylene chloride. Heat the rinsed silica gel at 50 °C for 10 minutes, then increase the temperature gradually to 180 °C over 25 minutes and maintain it at this temperature for 90 minutes. Cool at room temperature and store in a glass container with a Teflon-lined screw cap. 3.3.15 Silica Gel Impregnated with Sulfuric Acid. Combine 100 g of silica gel with 44 g of concentrated sulfuric acid in a screw capped glass bottle and agitate thoroughly. Disperse the solids with a stirring rod until a uniform mixture is obtained. Store the mixture in a glass container with a Teflonlined screw cap. 3.3.16 Silica Gel Impregnated with Sodium Hydroxide. Combine 39 g of 1 N sodium hydroxide with 100 g of silica gel in a screw capped glass bottle and agitate thoroughly. Disperse solids with a stirring rod until a unlform mixture is obtained. Store the mixture in glass container with a Teflon-lined screw cap. 3.3.17 Carbon/Celite. Combine 10.7 g of AX-21 carbon with 124 g of Celite 545 in a 250- ml glass bottle with a Teflon-lined screw cap. Agitate the mixture thoroughly until a uniform mixture is obtained. Store in the glass container. 3.3.18 Nitrogen. Ultra high purity. 3.3.19 Hydrogen. Ultra high purity. 3.3.20 Internal Standard Solution. Prepare a stock standard solution containing the isotopically labelled PCDD's and PCDF's at the concentrations shown in Table 1 under the heading "Internal Standards" in ID ml of nonane. 3.3.21 Surrogate Standard Solution. Prepare a stock standard solution containing the isotopically labelled PCDD's and PCDF's at the concentrations shown In Table 1 under the heading "Surrogate Standards" in 10 ml of nonane. 3.3.22 Recovery Standard Solution. Prepare a stock standard solution containing the isotopically labelled PCDD's and PCDF's Pt. 60, App. A, Meth. 23 at the concentrations shown in Table 1 under the heading "Recovery Standards" in 10 ml of nonane. 4. Procedure 4.1 Sampling. The complexity of this method is such that, in order to obtain rellable results, testers should be trained and experienced with the test procedures. 4.1.1 Pretest Preparation. 4.1.1.1 Cleaning Glassware. All glass components of the train upstream of and including the adsorbent module, shall be cleaned as described in section 3A of the "Manual of Analytical Methods for the Analysis of Pesticides in Human and Environmental Samples." Special care shall be devoted to the removal of residual silicone grease sealants on ground glass connections of used glassware. Any residue shall be removed by soaking the glassware for several hours in a chromic acid cleaning solution prior to cleaning as described above. 4.1.1.2 Adsorbent Trap. The traps must be loaded in a clean area to avoid contamination. They may not be loaded in the field. Fill a trap with 20 to 40 g of XAD-2. Follow the XAD-2 with glass wool and tightly cap both ends of the trap. Add 100 µl of the surrogate standard solution (section 3.3.21) to each trap. 4.1.1.3 Sample Train. It is suggested that all components be maintained according to the procedure described in APTD-0576. 4.1.1.4 Silica Gel. Weigh several 200 to 300 g portions of silica gel in an air tight container to the nearest 0.5 g. Record the total weight of the silica gel plus container, on each container. As an alternative. the silica gel may be weighed directly in its impinger or sampling holder Just prior to sampling. 4.1.1.5 Filter. Check each filter against light for irregularities and flaws or pinhole leaks. Pack the filters flat in a clean glass container. 4.1.2 Preliminary Determinations. Same as section 4.1.2 of Method 5. 4.1.3 Preparation of Collection Train. 4.1.3.1 During preparation and assembly of the sampling train, keep all train openings where contamination can enter, sealed until just prior to assembly or until sampling is about to begin. NOTE: Do not use sealant grease in assembling the train. 4.1.3.2 Place approximately 100 ml of water in the second and third impingers, leave the first and fourth impingers empty. and transfer approximately 200 to 300 g of preweighed silica gel from its container to the fifth impinger. 4.1.3.3 Place the silica gel container in a clean place for later use in the sample recovery. Alternatively. the weight of the silica gel plus impinger may be determined to the nearest 0.5 g and recorded. 4.1.3.4 Assemble the train as shown in Figure 23-1. 4.1.3.5 Turn on the adsorbent module and condenser coil recirculating pump and begin monitoring the adsorbent module gas entry temperature. Ensure proper sorbent temperature gas entry temperature before proceeding and before sampling is initiated. It is extremely important that the XAD-2 adsorbent resin temperature never exceed 50 °C because thermal decomposition will occur. During testing. the XAD-2 temperature must not exceed 20 °C for efficient capture of the PCDD's and PCDF's. 4.1.4 Leak-Check Procedure. Same as Method 5, section 4.1.4. 4.1.5 Sample Train Operation. Same as Method 5, section 4.1.5. 4.2 Sample Recovery. Proper cleanup procedure begins as soon as the probe is removed from the stack at the end of the sampling period. Seal the nozzle end of the sampling probe with Teflon tape or aluminum foll. When the probe can be safely handled, wipe off all external particulate matter near the tip of the probe. Remove the probe from the train and close off both ends with aluminum foll. Seal off the Inlet to the train with Teflon tape, a ground glass cap. or aluminum foll. Transfer the probe and impinger assembly to the cleanup area. This area shall be clean and enclosed so that the chances of losing or contaminating the sample are minimized. Smoking. which could contaminate the sample, shall not be allowed in the cleanup area. Inspect the train prior to and during disassembly and note any abnormal conditions, e.g., broken filters, colored Impinger liquid, etc. Treat the samples as follows: 4.2.1 Container No. 1. Either seal the filter holder or carefully remove the filter from the filter holder and place it in its identified container. Use a pair of cleaned tweezers to handle the filter. If It is necessary to fold the filter. do so such that the particulate cake is inside the fold. Carefully transfer to the container any particulate matter and filter fibers which adhere to the filter holder gasket. by using a dry inert bristle brush and a sharp-edged blade. Seal the container. 4.2.2 Adsorbent Module. Remove the module from the train, tightly cap both ends, label it. cover with aluminum foil. and store it on ice for transport to the laboratory. 4.2.3 Container No. 2. Quantitatively recover material deposited in the nozzle, probe transfer lines, the front half of the filter holder, and the cyclone, if used. first. by brushing while rinsing three times each with acetone and then. by rinsing the probe three times with methylene chloride. Collect all the rinses in Container No. 2. Environmental Protection Agency, EPA Rinse the back half of the filter holder three times with acetone. Rinse the connecting line between the filter and the condenser three times with acetone. Soak the connecting line with three separate portions of methylene chloride for 5 minutes each. If using a separate condenser and adsorbent trap, rinse the condenser in the same manner as the connecting line. Collect all the rinses in Container No. 2 and mark the level of the liquid on the container. 4.2.4 Container No. 3. Repeat the methylene chloride-rinsing described in Section 4.2.3 using toluene as the rinse solvent. Collect the rinses in Container No. 3 and mark the level of the liquid on the container. 4.2.5 Impinger Water. Measure the liquid in the first three impingers to within +1 ml by using a graduated cylinder or by weighing it to within ±0.5 g by using a balance. Record the volume or weight of liquid present. This information is required to calculate the moisture content of the effluent gas. Discard the liquid after measuring and recording the volume or weight. 4.2.7 Silica Gel. Note the color of the indicating silica gel to determine if It has been completely spent and make a mention of its condition. Transfer the silica gel from the fifth impinger to its original container and seal. 5. Analysis All glassware shall be cleaned as described in section 3A of the "Manual of Analytical Methods for the Analysis of Pesticides in Human and Environmental Samples." All samples must be extracted within 30 days of collection and analyzed within 45 days of extraction. 5.1 Sample Extraction. 5.1.1 Extraction System. Place an extraction thimble (section 2.3.4). 1 g of silica gel, and a plug of glass wool into the Soxhlet apparatus, charge the apparatus with toluene, and reflux for a minimum of 3 hours. Remove the toluene and discard it, but retain the silica gel. Remove the extraction thimble from the extraction system and place it in a glass beaker to catch the solvent rinses. 5.1.2 Container No. 1 (Filter). Transfer the contents directly to the glass thimble of the extraction system and extract them simultaneously with the XAD-2 resin. 5.1.3 Adsorbent Cartridge. Suspend the adsorbent module directly over the extraction thimble in the beaker (See section 5.1.1). The glass frit of the module should be in the up position. Using a Teflon squeeze bottle containing toluene, flush the XAD-2 into the thimble onto the bed of cleaned silica gel. Thoroughly rinse the glass module catching the rinsings in the beaker containing the thimble. If the resin is wet, effective extraction can be accomplished by loosely packing the resin in the thimble. Add the XAD-2 glass wool plug into the thimble. 5.1.4 Container No. 2 (Acetone and Methylene Chloride). Concentrate the sample to a volume of about 1-5 ml using the rotary evaporator apparatus, at a temperature of less than 37 °C. Rinse the sample container three times with small portions of methylene chloride and add these to the concentrated solution and concentrate further to near dryness. This residue contains particulate matter removed In the rinse of the train probe and nozzle. Add the concentrate to the filter and the XAD-2 resin in the Soxhlet apparatus described in section 5.1.1. 5.1.5 Extraction. Add 100 µ1 of the internal standard solution (Section 3.3.20) to the extraction thimble containing the contents of the adsorbent cartridge, the contents of Container No. 1. and the concentrate from section 5.1.4. Cover the contents of the extraction thimble with the cleaned glass wool plug to prevent the XAD-2 resin from floating into the solvent reservoir of the extractor. Place the thimble in the extractor, and add the toluene contained in the beaker to the solvent reservoir. Pour additional toluene to fill the reservoir approximately 2/3 full. Add Teflon boiling chips and assemble the apparatus. Adjust the heat source to cause the extractor to cycle three times per hour. Extract the sample for 16 hours. After extraction. allow the Soxhlet to cool. Transfer the toluene extract and three 10-ml rinses to the rotary evaporator. Concentrate the extract to approximately 10 ml. At this point the analyst may choose to split the sample in half. If so, split the sample, store one half for future use, and analyze the other according to the procedures in sections 5.2 and 5.3. In either case, use a nitrogen evaporative concentrator to reduce the volume of the sample being analyzed to near dryness. Dissolve the residue in 5 ml of hexane. 5.1.6 Container No. 3 (Toluene Rinse). Add 100 µl of the Internal Standard solution (section 3.3.2) to the contents of the container. Concentrate the sample to a volume of about 1-5 ml using the rotary evaporator apparatus at a temperature of less than 37 °C. Rinse the sample container apparatus at a temperature of less than 37 °C. Rinse the sample container three times with small portions of toluene and add these to the concentrated solution and concentrate further to near dryness. Analyze the extract separately according to the procedures in sections 5.2 and 5.3, but concentrate the solution In a rotary evaporator apparatus rather than a nitrogen evaporative concentrator. 5.2 Sample Cleanup and Fractionation. 5.2.1 Silica Gel Column. Pack one end of a glass column, 20 mm X 230 mm, with glass wool. Add in sequence. 1 g silica gel. 2 g of sodium hydroxide Impregnated silica gel, 1 g silica gel. 4 g of acid-modified silica gel. and I g of silica gel. Wash the column with 30 ml of hexane and discard it. Add the sample extract, dissolved in 5 ml of hexane to the column with two additional 5-ml rinses. Elute the column with an additional 90 ml of hexane and retain the entire eluate. Concentrate this solution to a volume of about 1 ml using the nitrogen evaporative concentrator (section 2.3.7). 5.2.2 Basic Alumina Column. Shorten a 25- ml disposable Pasteur pipette to about 16 ml. Pack the lower section with glass wool and 12 g of basic alumina. Transfer the concentrated extract from the silica gel column to the top of the basic alumina column and elute the column sequentially with 120 ml of 0.5 percent methylene chloride in hexane followed by 120 ml of 35 percent methylene chloride in hexane. Discard the first 120 ml of eluate. Collect the second 120 ml of eluate and concentrate it to about 0.5 ml using the nitrogen evaporative concentrator. 5.2.3 AX-21 Carbon/Celite 545 Column. Remove the botton 0.5 in. from the tip of a 9-ml disposable Pasteur plpette. Insert a glass fiber filter disk in the top of the pipette 2.5 cm from the constriction. Add sufficient carbon/celite mixture to form a 2 cm column. Top with a glass wool plug. In some cases AX-21 carbon fines may wash through the glass wool plug and enter the sample. This may be prevented by adding a celite plug to the exit end of the column. Rinse the column in sequence with 2 ml of 50 percent benzene in ethyl acetate, 1 ml of 50 percent methylene chloride in cyclohexane, and 2 ml of hexane. Discard these rinses. Transfer the concentrate in 1 ml of hexane from the basic alumina column to the carbon/celite column along with 1 ml of hexane rinse. Elute the column sequentially with 2 ml of 50 percent methylene chloride in hexane and 2 ml of 50 percent benzene in ethyl acetate and discard these eluates. Invert the column and elute in the reverse direction with 13 ml of toluene. Collect this eluate. Concentrate the eluate in a rotary evaporator at 50 °C to about 1 ml. Transfer the concentrate to a Reacti-vial using a toluene rinse and concentrate to a volume of 200 µl using a stream of N2. Store extracts at room temperature. shielded from light. until the analysis is performed. 5.3 Analysis. Analyze the sample with a gas chromatograph coupled to a mass spectrometer (GC/MS) using the instrumental parameters in sections 5.3.1 and 5.3.2. Immediately prior to analysis. add a 20 µl aliquot of the Recovery Standard solution from Table 1 to each sample. A 2 μl aliquot of the extract is injected Into the GC. Sample extracts are first analyzed using the DB-5 capillary column to determine the concentration of each isomer of PCDD's and PCDF's (tetra-through octa-). If tetra-chlorinated dibenzofurans are detected in this analysis. then analyze another aliquot of the sample In a separate run, using the DB-225 column to measure the 2,3,7.8 tetra-chloro dibenzofuran Isomer. Other column systems may be used. provided that the user is able to demonstrate using calibration and performance checks that the column system is able to meet the specifications of section 6.1.2.2. 5.3.1 Gas Chromatograph Operating Conditions. 5.3.1.1 Injector. Configured for capillary column, splitless, 250 °C. 5.3.1.2 Carrier Gas. Helium, 1-2 ml/min. 5.3.1.3 Oven. Initially at 150 °C. Raise by at least 40 °C/min to 190 °C and then at 3 °C/ min up to 300 °C. 5.3.2 High Resolution Mass Spectrometer. 5.3.2.1 Resolution. 10000 m/e. 5.3.2.2 Ionization Mode. Electron impact. 5.3.2.3 Source Temperature 250 °C. 5.3.2.4 Monitoring Mode. Selected ion monitoring. A list of the various ions to be monitored is summarized in Table 3. 5.3.2.5 Identification Criteria. The following identification criteria shall be used for the characterization of polychlorinated dibenzodioxins and dibenzofurans. 1. The integrated ion-abundance ratio (M/ M+2 or M+2/M+4) shall be within 15 percent of the theoretical value. The acceptable ionabundance ratio ranges for the identification of chlorine-containing compounds are given in Table 4. 2. The retention time for the analytes must be within 3 seconds of the corresponding 13C-labeled internal standard, surrogate or alternate standard. 3. The monitored ions, shown in Table 3 for a given analyte. shall reach their maximum within 2 seconds of each other. 4. The identification of specific Isomers that do not have corresponding 13C-labeled standards is done by comparison of the relative retention time (RRT) of the analyte to the nearest Internal standard retention time with reference (i.e., within 0.005 RRT units) to the comparable RRT's found in the continuing calibration. 5. The signal to noise ratio for all monitored ions must be greater than 2.5. 6. The confirmation of 2, 3, 7. 8-TCDD and 2, 3. 7. 8-TCDF shall satisfy all of the above identification criteria. 7. For the identification of PCDF's, no signal may be found in the corresponding PCDPE channels. 5.3.2.6 Quantification. The peak areas for the two lons monitored for each analyte are summed to yield the total response for each analyte. Each Internal standard is used to quantify the Indigenous PCDD's or PCDF's in its homologous series. For example, the 13C₁₂-2,3,7,8-tetra chlorinated dibenzodioxin is used to calculate the concentrations of all other tetra chlorinated Isomers. Recoveries of the tetra- and penta- Internal standards are calculated using the Recoveries of the hexa- through octa- Internal standards are calculated using 13C12 Environmental Protection Agency, EPA 1,2,3,7,8,9-HxCDD. Recoveries of the surrogate standards are calculated using the corresponding homolog from the internal standard. 6. Calibration Same as Method 5 with the following additions. 6.1 GC/MS System. 6.1.1 Initial Calibration. Calibrate the GC/ MS system using the set of five standards shown in Table 2. The relative standard deviation for the mean response factor from each of the unlabeled analytes (Table 2) and of the Internal, surrogate, and alternate standards shall be less than or equal to the values in Table 5. The signal to noise ratio for the GC signal present in every selected ion current profile shall be greater than or equal to 2.5. The ion abundance ratios shall be within the control limits in Table 4. 6.1.2 Daily Performance Check. 6.1.2.1 Calibration Check. Inject on µl of solution Number 3 from Table 2. Calculate the relative response factor (RRF) for each compound and compare each RRF to the corresponding mean RRF obtained during the initial calibration. The analyzer performance is acceptable If the measured RRF's for the labeled and unlabeled compounds for the daily run are within the limits of the mean values shown in Table 5. In addition, the ionabundance ratios shall be within the allowable control limits shown in Table 4. 6.1.2.2 Column Separation Check. Inject a solution of a mixture of PCDD's and PCDF's that documents resolution between 2,3,7,8- TCDD and other TCDD isomers. Resolution is defined as a valley between peaks that is less than 25 percent of the lower of the two peaks. Identify and record the retention time windows for each homologous series. Perform a similar resolution check on the confirmation column to document the resolution between 2,3,7.8 TCDF and other TCDF isomers. 6.2 Lock Channels. Set mass spectrometer lock channels as specified in Table 3. Monitor the quality control check channels specified in Table 3 to verify instrument stability during the analysis. 7. Quality Control 7.1 Sampling Train Collection Efficiency Check. Add 100 µl of the surrogate standards in Table 1 to the absorbent cartridge of each train before collecting the field samples. 7.2 Internal Standard Percent Recoveries. A group of nine carbon labeled PCDD's and PCDF's representing, the tetra-through octachlorinated homologues, is added to every sample prior to extraction. The role of the internal standards is to quantify the native PCDD's and PCDF's present in the sample as well as to determine the overall method efficiency. Recoveries of the internal standards must be between 40 to 130 percent for the tetra-through hexachlorinated compounds while the range is 25 to 130 percent for the higher hepta- and octachlorinated homologues. 7.3 Surrogate Recoveries. The five surrogate compounds In Table 2 are added to the resin in the adsorbent sampling cartridge before the sample is collected. The surrogate recoveries are measured relative to the internal standards and are a measure of collection efficiency. They are not used to measure native PCDD's and PCDF's. All recoveries shall be between 70 and 130 percent. Poor recoveries for all the surrogates may be an indication of breakthrough in the sampling train. If the recovery of all standards is below 70 percent. the sampling runs must be repeated. As an alternative, the sampling runs do not have to be repeated if the final results are divided by the fraction of surrogate recovery. Poor recoveries of isolated surrogate compounds should not be grounds for rejecting an entire set of the samples. 7.4 Toluene QA Rinse. Report the results of the toluene QA rinse separately from the total sample catch. Do not add it to the total sample. 8. Quality Assurance 8.1 Applicability. When the method is used to analyze samples to demonstrate compliance with a source emission regulation. an audit sample must be analyzed, subject to availability. 8.2 Audit Procedure. Analyze an audit sample with each set of compliance samples. The audit sample contains tetra through octa isomers of PCDD and PCDF. Concurrently, analyze the audit sample and a set of compliance samples in the same manner to evaluate the technique of the analyst and the standards preparation. The same analyst, analytical reagents, and analytical system shall be used both for the compliance samples and the EPA audit sample. 8.3 Audit Sample Availability. Audit samples will be supplied only to enforcement agencies for compliance tests. The availability of audit samples may be obtained by writing: Source Test Audit Coordinator (MD- 77B). Quality Assurance Division. Atmospheric Research and Exposure Assessment Laboratory. U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, or by calling the Source Test Audit Coordinator (STAC) at (919) 541-7834. The request for the audit sample must be made at least 30 days prior to the scheduled compliance sample analysis. 8.4 Audit Results. Calculate the audit sample concentration according to the calculation procedure described in the audit instructions included with the audit sample. Fill in the audit sample concentration and the analyst's name on the audit response form included with the audit Instructions. Pt. 60, App. A, Meth. 23 40 CFR Ch. I (7-1-99 Edition) Send one copy to the EPA Regional Office or the appropriate enforcement agency and a second copy to the STAC. The EPA Regional office or the appropriate enforcement agency will report the results of the audit to the laboratory being audited. Include this response with the results of the compliance samples in relevant reports to the EPA Regional Office or the appropriate enforcement agency. 9. Calculations Same as Method 5. section 6 with the following additions. 9.1 Nomenclature. A=Integrated ion current of the noise at the retention time of the analyte. A*α=Integrated ion current of the two lons characteristic of the internal standard 1 in the calibration standard. A lon current of the two ions characteristic of compound i In the Jth calibration standard. A"aj=Integrated ion current of the two ions characteristic of the internal standard 1 in the Jth callbration standard. A ion current of the two ions characteristic of surrogate compound 1 in the calibration standard. A,=Integrated ion current of the two ions characteristic of compound 1 in the sample. A'₁=Integrated ion current of the two ions characteristic of internal standard i in the sample. An=Integrated ion current of the two lons characteristic of the recovery standard. As=Integrated ion current of the two lons characteristic of surrogate compound 1 in the sample. C=Concentration of PCDD or PCDF 1 in the sample, pg/M 3. CT=Total concentration of PCDD's or PCDF's in the sample, pg/M 3. ma=Mass of compound 1 in the calibration standard injected into the analyzer, pg. mm-Mass of recovery standard in the callbration standard injected into the analyzer. pg. m=Mass of surrogate compound in the calibration standard, pg. RRF;=Relative response factor. RRF₂=Recovery standard response factor. RRF,=Surrogate compound response factor. 9.2 Average Relative Response Factor. EC16NO91.219 EC16NO91.220 9.3 Concentration of the PCDD's and PCDF's. 9.4 Recovery Standard Response Factor. EC16NO91.221 9.5 Recovery of Internal Standards (R*). EC16NO91.222 9.6 Surrogate Compound Response Factor. EC16NO91.223 9.7 Recovery of Surrogate Compounds (R,). EC16NO91.224 9.8 Minimum Detectable Limit (MDL). EC16NO91.225 9.9 Total Concentration of PCDD's and PCDF's in the Sample. EC16NO91.226 Any PCDD's or PCDF's that are reported as nondetected (below the MDL) shall be counted as zero for the purpose of calculating the total concentration of PCDD's and PCDF's in the sample. 10. Bibliography 1. American Society of Mechanical Engineers. Sampling for the Determination of Chlorinated Organic Compounds in Stack Emissions. Prepared for U.S. Department of Energy and U.S. Environmental Protection Agency. Washington DC. December 1984. 25 p. 2. American Society of Mechanical Englneers. Analytical Procedures to Assay Stack Effluent Samples and Residual Combustion Products for Polychlorinated Dibenzo-p- Dioxins (PCDD) and Polychlorinated Dibenzofurans (PCDF). Prepared for the U.S. Department of Energy and U.S. Environmental Protection Agency. Washington, DC. December 1984. 23 p. 3. Thompson, J. R. (ed.). Analysis of Pesticide Residues in Human and Environmental Samples. U.S. Environmental Protection Agency. Research Triangle Park, NC. 1974. Environmental Protection Agency, EPA Pt. 60, App. A, Meth. 23 4. Triangle Laboratories. Case Study: Analysis of Samples for the Presence of Tetra Through Octachloro-p-Dibenzodioxins and Dibenzofurans. Research Triangle Park. NC. 1988. 26 p. 5. U.S. Environmental Protection Agency. Method 8290-The Analysis of Polychlorinated Dibenzo-p-dioxin and Polychlorinated Dibenzofurans by High-Resolution Gas Chromotography/High-Resolution Mass Spectrometry. In: Test Methods for Evaluating Solid Waste. Washington, DC. SW-846. TABLE 1-COMPOSITION OF THE SAMPLE FOR- TIFICATION AND RECOVERY STANDARDS SOLU- TIONS Analyte Concentration (pg/ul) Internal Standards: 13 C₁₂-2,3,7,8-TCDD 100 13 C₁₂-1,2,3,7,8-PeCDD 100 13 C₁₂-1,2,3,6,7,8-HxCDD 100 13 C₁₂-1,2,3,4,6,7,8-HpCDD 100 13 C12-OCDD 100 13 C₁₂-2,3,7,8-TCDF 100 13 C₁₂-1,2,3,7,8-PeCDF 100 13 100 13 Ct-1,2,3,4,6,7,8-HpCDF 100 Surrogate Standards: 37 Cl-2,3.7,8-TCDD 100 TABLE 1-COMPOSITION OF THE SAMPLE FOR- TIFICATION AND RECOVERY STANDARDS SOLU- TIONS-Continued Concentra- Analyte tion (pg/µl) 13 C₁₂-1,2,3,4,7,8-HxCDD 100 13 C₁₂-2,3,4,7,8-PeCDF 100 13 Cr₂1,2,3,4,7,8-HxCDF 100 13 C₁₂₁,2,3,4,7,8,9-HpCDF 100 Recovery Standards: 13 C₁₂₁,2,3,4-TCDD 500 13 Ci-1,2,3,7,8,9-HxCDD 500 TABLE 2-COMPOSITION OF THE INITIAL CALIBRATION SOLUTIONS TABLE 3-ELEMENTAL COMPOSITIONS AND EXACT MASSES OF THE IONS MONITORED BY HIGH RESOLUTION MASS SPECTROMETRY FOR PCDD's AND PCDF's Concentrations (pg/uL) Compound Solution No. 1 2 3 4 5 Alternate Standard: 13 C₁₂-1,2,3,7,8,9- HxCDF 2.5 5 25 250 500 Recovery Standards: 13 Ctr1,2,3,4-TCDD 100 100 100 100 100 13 C₁₂₁,2,3,7,8,9- HxCDD 100 100 100 100 100 Descriptor No. Accurate mass lon type Elemental composition Analyte 2 292.9825 LOCK CF,, PFK 303.9016 M C12H2CLO TCDF 305.8987 M+2 TCDF 315.9419 M TCDF (S) 317.9389 M+2 TCDF (S) 319.8965 M C12H45CIO₂ TCDD 321.8936 M+2 TCDD 327.8847 M C12H27CLO₂ TCDD (S) 330.9792 QC CF13 PFK 331.9368 M TCDD (S) 333.9339 M+2 TCDD (S) 339.8597 M+2 PECDF 341.8567 M+4 PeCDF 351.9000 M+2 PeCDF (S) 353.8970 M+4 PeCDF (S) 355.8546 M+2 PeCDD 357.8516 M+4 PeCDD 367.8949 M+2 PeCDD (S) 369.8919 M+4 "CuH3"Ch" Cl₂O₂ PeCDD (S) 375.8364 M+2 HxCDPE 409.7974 M+2 HpCPDE 3 373.8208 M+2 HxCDF 375.8178 M+4 HxCDF 383.8639 M HxCDF (S) 385.8810 M+2 HxCDF (S) 389.8157 M+2 HxCDD 391.8127 M+4 HxCDD 392.9760 LOCK CF15 PFK 401.8559 M+2 HxCDD (S) 403.8529 M+4 HxCDD (S) 445.7555 M+4 OCDPE 430.9729 QC CF,, PFK 4 407.7818 M+2 C HpCDF 409.7789 M+4 HpCDF Pt. 60, App. A, Meth. 24 TABLE 3-ELEMENTAL COMPOSITIONS AND EXACT MASSES OF THE IONS MONITORED BY HIGH RESOLUTION MASS SPECTROMETRY FOR PCDD's AND PCDF's-Continued Descriptor No. Accurate mass Ion type Elemental composition Analyte 417.8253 M 13C12H35Cl70 HpCDF (S) 419.8220 M+2 HpCDF (S) 423.7766 M+2 HpCDD 425.7737 M+4 HpCDD 435.8169 M+2 HpCDD (S) 437.8140 M+4 HpCDD (S) 479.7165 M+4 NCPDE 430.9729 LOCK CF17 PFK 441.7428 M+2 C123Ch3TCIO OCDF 443.7399 M+4 OCDF 457.7377 M+2 OCDD 459.7348 M+4 OCDD 469.7779 M+2 OCDD (S) 471.7750 M+4 OCDD (S) 513.6775 M+4 DCDPE 442.9728 QC C1057 PFK (a) The following nuclidic masses were used: H = 1.007825 C - 12.000000 13C = 13.003355 F = 18.9984 O = 15.994915 35CI = 34.968853 37CI = 36.965903 S = Labeled Standard QC = Ion selected for monitoring instrument stability during the GC/MS analysis. TABLE 4-ACCEPTABLE RANGES FOR ION- ABUNDANCE RATIOS OF PCDD's AND PCDF's No. of Theo- Control limits chiorine Ion type retical atoms ratio Lower Upper 4 M/M+2 0.77 0.65 0.89 5 M+2/M+4 1.55 1.32 1.78 6 M+2/M+4 1.24 1.05 1.43 6= M/M+2 0.51 0.43 0.59 7b M/M+2 0.44 0.37 0.51 7 M+2/M+4 1.04 0.88 1.20 8 M+2/M+4 0.89 0.76 1.02 *Used only for 13C-HxCDF. Used only for 13C-HpCDF. TABLE 5-MINIMUM REQUIREMENTS FOR INITIAL AND DAILY CALIBRATION RESPONSE FACTORS Relative response factors Compound Initial calibra- Daily calibration RSD tion % difference Unlabeled Analytes: 2,3,7,8-TCDD 25 25 2,3,7,8-TCDF 25 25 1,2,3,7,8-PeCDD 25 25 1,2,3,7,8-PeCDF 25 25 2,3,4,7,8-PeCDF 25 25 1,2,4,5,7,8-HxCDD 26 25 1,2,3,6,7,8-HxCDD 25 25 1,2,3,7,8,9-HxCDD 25 25 1,2,3,4,7,8-HxCDF 25 25 1,2,3,6,7,8-HxCDF 25 25 1,2,3,7,8,9-HxCDF 25 25 2,3,4,6,7,8-HxCDF 25 25 1,2,3,4,6,7,8-HpCDD 25 25 1,2,3,4,6,7,8-HpCDF 25 25 OCDD 25 25 TABLE 5-MINIMUM REQUIREMENTS FOR INITIAL AND DAILY CALIBRATION RESPONSE FAC- TORS-Continued Relative response factors Compound Initial calibra- Daily calibration RSD tion % difference OCDF 30 30 Internal Standards: 13C₁ᵣ⁻2,3,7,8-TCDD 25 25 ³C₁-1,2,3,7,8-PeCDD 30 30 25 25 13C₁₂-1,2,3,4,6,7,8- HpCDD 30 30 13C₁₂-OCDD 30 30 13C₁₂-2,3,7,8-TCDF 30 30 13C₁₃⁻1,2,3,7,8-PeCDF 30 30 30 30 13C₁₂-1,2,3,4,6,7,8- HpCDF 30 30 Surrogate Standards: "CL-2,3,7,8-TCDD 25 25 : 25 25 25 25 25 25 13C₁₁⁻1,2,3,4,7,8,9- HpCDF 25 25 Alternate Standard: 25 25 METHOD 24-DETERMINATION OF VOLATILE MATTER CONTENT. WATER CONTENT. DEN- SITY, VOLUME SOLIDS, AND WEIGHT SOLIDS OF SURFACE COATINGS 1. Applicability and Principle METHOD 26 40 CFR PART 60 APPENDIXA Pt. 60, App. A, Meth. 26 40 CFR Ch. I (7-1-99 Edition) 6. Operational Checks and Calibration Maintain a record of performance of each item. 6.1 Use the procedures in Section 6.1.1 to calibrate the headspace analyzer and FID and check for linearity before the system is first placed in operation, after any shutdown longer than 6 months, and after any modification of the system. 6.1.1 Calibration and Linearity. Use the procedures in Section 6.2.1 of Method 18 of Part 60, Appendix A. to prepare the standards and calibrate the flowmeters, using propane as the standard gas. Fill the calibration standard vials halfway (+5 percent) with deionized water. Purge and fill the airspace with calibration standard. Prepare a minimum of three calibration standards in triplicate at concentrations that will bracket the applicable cutoff. For a cutoff of 5.2 kPa. prepare nominal concentrations of 30,000, 50,000. and 70,000 ppm as propane. For a cutoff of 27.6 kPa, prepare nominal concentrations of 200,000. 300,000, and 400,000 ppm as propane. 6.1.1.1 Use the procedures in Section 5.2.3 to measure the FID response of each standard. Use a linear regression analysis to calculate the values for the slope (k) and the y- Intercept (b). Use the procedures in Sections 7.2 and 7.3 to test the calibration and the linearity. 6.1.2 Daily FID Calibration Check. Check the calibration at the beginning and at the end of the daily runs by using the following procedures. Prepare two calibration standards at the nominal cutoff concentration using the procedures in Section 6.1.1. Place one at the beginning and one at the end of the daily run. Measure the FID response of the daily callbration standard and use the values for k and b from the most recent calibration to calculate the concentration of the daily standard. Use an equation similar to 25E-2 to calculate the percent difference between the daily standard and C R. If the difference is within 5 percent. then the previous values for k and b may be used. Otherwise, use the procedures in Section 6.1.1 to recalibrate the FID. 7. Calculations 7.1 Nomenclature. A at Measurement of the area under the response curve, counts. b = y-intercept of the linear regression line. C. = Measured vapor phase organic concentration of sample. ppm as propane. Cms - Average measured vapor phase organic concentration of standard. ppm as propane. Cm - Measured vapor phase organic concentration of standard, ppm as propane. C. = Calculated standard concentration, ppm as propane. k = Slope of the linear regression line. Phar = Atmospheric pressure at analysis conditions, mm Hg (in. Hg). P* = Organic vapor pressure in the sample, kPa (psi). B = 1.333 X 10-7 kPa/[(mm Hg)(ppm)]. (4.91 X 10-7 psi/[(in. Hg)(ppm)]) 7.2 Linearity. Use the following equation to calculate the measured standard concentration for each standard vial. Cm=kA+b Eq. 25E-1 7.2.1 Calculate the average measured standard concentration (Cma) for each set of triplicate standards and use the following equation to calculate the percent difference (PD) between Cms and Ca. ER06DE94.001 The instrument linearity is acceptable if the percent difference is within five for each standard. 7.3 Relative Standard Deviation (RSD). Use the following equation to calculate the RSD for each triplicate set of standards. ER06DE94.002 The calibration is acceptable if the RSD is within five for each standard concentration. 7.4 Concentration of organics in the headspace. Use the following equation to calculate the concentration of vapor phase organics in each sample. C.=kA+b Eq. 25E-4 7.5 Vapor Pressure of Organics in the Headspace Sample. Use the following equation to calculate the vapor pressure of organics in the sample. P* = ß Phar C. Eq. 25E-5 METHOD 26-DETERMINATION OF HYDROGEN CHLORIDE EMISSIONS FROM STATIONARY SOURCES J. Applicability, Principle, Interferences, Precision, Blas, and Stability 1.1 Applicability. This method is applicable for determining emissions of hydrogen halides (HX) [hydrogen chloride (HCI), hydrogen bromide (HBr). and hydrogen fluoride (HF)] and halogens (X2) [chlorine (CI 2) and bromine (Br₂)] from stationary sources. Sources, such as those controlled by wet scrubbers, that emit acid particulate matter must be sampled using Method 26A. NOTE: Mention of trade names or specific products does not constitute endorsement by the Environmental Protection Agency.] 1.2 Principle. An integrated sample is extracted from the source and passed through Environmental Protection Agency, EPA a prepurged heated probe and filter into dilute sulfuric acid and dilute sodium hydrox- Ide solutions which collect the gaseous hydrogen halides and halogens, respectively. The filter collects other particulate matter including halide salts. The hydrogen halides are solubilized in the acidic solution and form chloride (CI- ), bromide (Br⁻). and fluoride (F⁻) ions. The halogens have a very low solubility in the acidic solution and pass through to the alkaline solution where they are hydrolyzed to form a proton (H-), the halide ion, and the hypohalous acid (HCIO or HBrO). Sodium thiosulfate is added In excess to the alkaline solution to assure reaction with the hypohalous acid to form a second halide ion such that 2 halide ions are formed for each molecule of halogen gas. The halide lons in the separate solutions are measured by ion chromatography (IC). 1.3 Interferences. Volatile materials, such as chlorine dioxide (C1O2) and ammonium chloride (NH4CI), which produce halide ions upon dissolution during sampling are potential Interferents. Interferents for the halide measurements are the halogen gases which disproportionate to a hydrogen halide and a hydrohalous acid upon dissolution in water. However, the use of acidic rather than neutral or basic solutions for collection of the hydrogen halides greatly reduces the dissolution of any halogens passing through this SOlution. The simultaneous presence of HBr and CL2 may cause a positive blas in the HCL result with a corresponding negative bias in the Cl₂ result as well as affecting the HBr/Br₂ split. High concentrations of nitrogen oxides (NOx) may produce sufficient nitrate (NO₃ -) to interfere with measurements of very low Br - levels. 1.4 Precision and Bias. The within-laboratory relative standard deviations are 6.2 and 3.2 percent at HCI concentrations of 3.9 and 15.3 ppm, respectively. The method does not exhibit a bias to Cl₂ when sampling at concentrations less than 50 ppm. 1.5 Sample Stability. The collected Clsamples can be stored for up to 4 weeks. 1.6 Detection Limit. The analytical detection limit for Cl- is 0.1 µg/ml. Detection lim- Its for the other analyses should be similar. 2. Apparatus 2.1 Sampling. The sampling train is shown in Figure 26-1. and component parts are discussed below. 2.1.1 Probe. Borsilicate glass, approximately 3/8-in. (9-mm) I.D. with a heating system to prevent moisture condensation. A Teflon-glass filter in a mat configuration shall be installed behind the probe to remove particulate matter from the gas stream (see section 2.1.5). A glass wool plug should not be used to remove particulate matter since a negative blas in the data could result. 2.1.2 Three-Way Stopcock. A borosilicate glass three-way stopcock with a heating system to prevent molsturecondensation. The heated stopcock should connect to the outlet of the heated filter and the inlet of the first impinger. The heating system shall be capable of preventing condensation up to the inlet of the first Impinger. Silicone grease may be used, if necessary. to prevent leakage. ER22AP94.011 2.1.3 Impingers. Four 30-ml midget impingers with leak-free glass connectors. Silicone grease may be used, If necessary, to prevent leakage. For sampling at high moisture sources or for sampling times greater than 1 hour, a midget impinger with a shortened stem (such that the gas sample does not bubble through the collected condensate) should be used in front of the first impinger. 2.1.4 Drying Tube or Impinger. Tube or impinger, of Mae West design. filled with 6- to 16-mesh indicating type silica gel, or equivalent, to dry the gas sample and to protect the dry gas meter and pump. If the sillca gel has been used previously, dry at 175 °C (350 °F) for 2 hours. New silica gel may be used as received. Alternatively, other types of desiccants (equivalent or better) may be used. 2.1.5 Filter. When the stack gas temperature exceeds 210 °C (410 °F) and the HCI concentration is greater than 20 ppm, a quartzfiber filter may be used. 2.1.6 Filter Holder and Support. The filter holder should be made of Teflon or quartz. The filter support shall be made of Teflon. All-Teflon filter holders and supports are available from Savillex Corp., 5325 Hwy 101. Minnetonka, MN 55345. 2.1.7 Sample Line. Leak-free, with compatible fittings to connect the last Impinger to the needle valve. 2.1.8 Rate Meter. Rotameter, or equivalent, capable of measuring flow rate to within 2 percent of the selected flow rate of 2 11- ters/min. 2.1.9 Purge Pump, Purge Line, Drying Tube, Needle Valve, and Rate Meter. Pump capable of purging the sampling probe at 2 11- ters/min. with drying tube, filled with silica gel or equivalent, to protect pump, and a rate meter capable of measuring 0 to 5 liters/ min. 2.1.10 Stopcock Grease, Valve, Pump. Volume Meter, Barometer. and Vacuum Gauge. Same as in Method 6. Sections 2.1.4, 2.1.7, 2.1.8, 2.1.10, 2.1.11, and 2.1.12. 2.1.11 Temperature Measuring Devices. Temperature measuring device to monitor the temperature of the probe and a thermometer or other temperature measuring device to monitor the temperature of the sampling system from the outlet of the probe to the Inlet of the first Impinger. 2.1.12 Ice Water Bath. To minimize loss of absorbing solution. 2.2 Sample Recovery. 2.2.1 Wash Bottles. Polyethylene or glass, 500-ml or larger, two. 2.2.2 Storage Bottles. 100- or 250-ml. highdensity polyethylene bottles with Teflon ® screw cap liners to store Impinger samples. 2.3 Sample Preparation and Analysis. The materials required for volumetric dilution and chromatographic analysis of samples are described below. 2.3.1 Volumetric Flasks. Class A, 100-ml size. 2.3.2 Volumetric Pipets. Class A. assortment. To dilute samples Into the calibration range of the instrument. Environmental Protection Agency, EPA 2.3.3 Ion Chromatograph. Suppressed or nonsuppressed. with a conductivity detector and electronic Integrator operating in the peak area mode. Other detectors, strip chart recorders, and peak height measurements may be used. 3. Reagents Unless otherwise indicated, all reagents must conform to the specifications established by the Committee on Analytical Reagents of the American Chemical Society (ACS reagent grade). When such specifications are not available. the best available grade shall be used. 3.1 Sampling. 3.1.1 Water. Delonized, distilled water that conforms to ASTM Specification D 1193- 77, Type 3. 3.1.2 Acidic Absorbing solution, 0.1 N Sulfuric Acid (H₂SO₄). To prepare 100 ml of the absorbing solution for the front impinger pair, slowly add 0.28 ml of concentrated H2SO4 to about 90 ml of water while stirring, and adjust the final volume to 100 ml using additional water. Shake well to mix the solution. 3.1.3 Alkaline Absorbing Solution. 0.1 N Sodium Hydroxide (NaOH). To prepare 100 ml of the scrubber solution for the back pair of impingers, dissolve 0.40 g of solid NaOH in about 90 ml of water, and adjust the final SOlution volume to 100 ml using additional water. Shake well to mix the solution. 3.1.4 Sodium Thiosulfate (Na₂S₂O₃.5H₂O) 3.2 Sample Preparation and Analysis. 3.2.1 Water. Same as in Section 3.1.1. 3.2.2 Absorbing Solution Blanks. A separate blank solution of each absorbing reagent should be prepared for analysis with the field samples. Dilute 30 ml of each absorbing solution to approximately the same final volume as the field samples using the blank sample of rinse water. 3.2.3 Halide Salt Stock Standard Solutions. Prepare concentrated stock solutions from reagent grade sodium chloride (NaCl). sodium bromide (NaBr). and sodium fluoride (NaF). Each must be dried at 110 °C for two or more hours and then cooled to room temperature in a desiccator immediately before weighing. Accurately weigh 1.6 to 1.7 g of the dried NaCl to within 0.1 mg. dissolve in water, and dilute to 1 liter. Calculate the exact Cl- concentration using Equation 26-1. µg Cl⁻/ml = g of NaCl x 103 x 35.453/58.44 Eq. 26-1 In a similar manner, accurately weigh and solubilize 1.2 to 1.3 g of dried NaBr and 2.2 to 2.3 g of NaF to make 1-liter solutions. Use Equations 26-2 and 26-3 to calculate the Br - and F- concentrations. µg Br-/ml = g of NaBr X 103 X 79.904/102.90 Eq. 26-2 µg F-/ml = g of NaF x 103 X 18.998/41.99 Eq. 26-3 Alternately, solutions containing a nominal certified concentration of 1000 mg/l NaCl are commercially available as convenient stock solutions from which standards can be made by appropriate volumetric dilution. Refrigerate the stock standard solutions and store no longer than one month. 3.2.4 Chromatographic Eluent. Effective eluents for nonsuppressed IC using a resinor silica-based weak ion exchange column are a 4 mM potassium hydrogen phthalate solution, adjusted to pH 4.0 using a saturated sodium borate solution, and a 4 mM 4-hydroxy benzoate solution, adjusted to pH 8.6 using 1 N NaOH. An effective eluent for suppressed ion chromatography is a solution containing 3 mM sodium bicarbonate and 2.4 mM sodium carbonate. Other dilute solutions buffered to a similar pH and containing no interfering ions may be used. When using suppressed ion chromatography. If the "water dip" resulting from sample injection interferes with the chloride peak, use a 2 mM NaOH/2.4 mM sodium bicarbonate eluent. 4. Procedure 4.1 Sampling. 4.1.1 Preparation of Collection Train. Prepare the sampling train as follows: Pour 15 ml of the acidic absorbing solution into each one of the first pair of impingers, and 15 ml of the alkaline absorbing solution Into each one of the second pair of impingers. Connect the impingers in series with the knockout Impinger first, If used, followed by the two impingers containing the acidic absorbing solution and the two impingers containing the alkaline absorbing solution. Place a fresh charge of silica gel, or equivalent, in the drying tube or impinger at the end of the impinger train. 4.1.2 Adjust the probe temperature and the temperature of the filter and the stopcock. i.e., the heated area in Figure 26-1 to a temperature sufficient to prevent water condensation. This temperature should be at least 20°C above the source temperature, but not greater than 120 °C. The temperature should be monitored throughout a sampling run to ensure that the desired temperature is maintained. 4.1.3 Leak-Check Procedure. A leak-check prior to the sampling run is optional; however, a leak-check after the sampling run is mandatory. The leak-check procedure is as follows: Temporarily attach a suitable (e.g., 0-40 cc/min) rotameter to the outlet of the dry gas meter and place a vacuum gauge at or near the probe inlet. Plug the probe inlet, pull a vacuum of at least 250 mm Hg (10 in. Hg). and note the flow rate as Indicated by the rotameter. A leakage rate not in excess of 2 percent of the average sampling rate is acceptable. (NOTE: Carefully release the probe inlet plug before turning off the Pt. 60, App. A, Meth. 26 pump.) It is suggested (not mandatory) that the pump be leak-checked separately, either prior to or after the sampling run. If done prior to the sampling run, the pump leakcheck shall precede the leak-check of the sampling train described immediately above; if done after the sampling run, the pump leak-check shall follow the train leak-check. To leak-check the pump, proceed as follows: Disconnect the drying tube from the probeimpinger assembly. Place a vacuum gauge at the inlet to either the drying tube or pump, pull a vacuum of 250 mm (10 in.) Hg, plug or pinch off the outlet of the flowmeter, and then turn off the pump. The vacuum should remain stable for at least 30 sec. Other leakcheck procedures may be used, subject to the approval of the Administrator, U.S. Environmental Protection Agency. 4.1.4 Purge Procedure. Immediately before sampling, connect the purge line to the stopcock. and turn the stopcock to permit the purge pump to purge the probe (see Figure 1A of Figure 26-1). Turn on the purge pump. and adjust the purge rate to 2 liters/ min. Purge for at least 5 minutes before sampling. 4.1.5 Sample Collection. Turn on the sampling pump. pull a slight vacuum of approximately 25 mm Hg (1 in. Hg) on the impinger train. and turn the stopcock to permit stack gas to be pulled through the impinger train (see Figure IC of Figure 26-1). Adjust the sampling rate to 2 liters/min, as indicated by the rate meter, and maintain this rate to within 10 percent during the entire sampling run. Take readings of the dry gas meter volume and temperature, rate meter, and vacuum gauge at least once every 5 minutes during the run. A sampling time of 1 hour is recommended. Shorter sampling times may introduce a significant negative blas in the HCI concentration. At the conclusion of the sampling run, remove the train from the stack, cool, and perform a leak-check as described in section 4.1.2. 4.2 Sample Recovery. Disconnect the impingers after sampling. Quantitatively transfer the contents of the acid impingers and the knockout impinger, if used. to a leak-free storage bottle. Add the water rinses of each of these impingers and connecting glassware to the storage bottle. Repeat this procedure for the alkaline impingers and connecting glassware using a separate storage bottle. Add 25 mg sodium thiosulfate per the product of ppm of halogen anticipated to be in the stack gas times the dscm stack gas sampled. [Note: This amount of sodium thiosulfate includes a safety factor of approximately 5 to assure complete reaction with the hypohalous acid to form a second C1- ion in the alkaline solution.] Save portions of the absorbing reagents (0.1 N H2SO4 and 0.1 N NaOH) equivalent to the amount used in the sampling train (these are the absorbing solution blanks described in Section 3.2.2); dilute to the approximate volume of the corresponding samples using rinse water directly from the wash bottle being used. Add the same amount of sodium thiosulfate solution to the 0.1 N NaOH absorbing solution blank. Also, save a portion of the rinse water used to rinse the sampling train. Place each in a separate, prelabeled storage bottle. The sample storage bottles should be sealed, shaken to mix, and labeled. Mark the fluid level. 4.3 Sample Preparation for Analysis. Note the liquid levels in the storage bottles and confirm on the analysis sheet whether or not leakage occurred during transport. If a noticeable leakage has occurred, either void the sample or use methods, subject to the approval of the Administrator, to correct the final results. Quantitatively transfer the sample solutions to 100-ml volumetric flasks, and dilute to 100 ml with water. 4.4 Sample Analysis. 4.4.1 The IC conditions will depend upon analytical column type and whether suppressed or nonsuppressed IC is used. An example chromatogram from a nonsuppressed system using a 150-mm Hamilton PRP-X100 anion column, a 2 ml/min flow rate of 4 mM 4-hydroxy benzoate solution adjusted to a pH of 8.6 using 1 N NaOH, a 50-µ 1 sample loop, and a conductivity detector set on 1.0 µS full scale is shown in Figure 26-2. 4.4.2 Before sample analysis, establish a stable baseline. Next, Inject a sample of water, and determine If any CI- Br-, or F- appears In the chromatogram. If any of these ions are present, repeat the load/injection procedure until they are no longer present. Analysis of the acid and alkaline absorbing solution samples requires separate standard calibration curves: prepare each according to