Document Gm1zBen6gQ1ORoL2zL4Okx80n

THE DOW CHEMICAL COMPANY MIDLAND. MCHKIAN 4MM October 16, 1985 INDUSTRIAL HYGIENE MONITORING METHOD Monitoring Ethanol amines in Air ML-IHM-84-07 QA-2460 1. SCOPE 1.1 Analyte(s): Monoethanol amine (MEA), diethanolamine (DEA), and triethanolamine (TEA) 1.2 Matrix: air 1.3 Procedure: adsorption on precleaned alumina adsorbent tubes at 100 mL/minute for <7 hours; solvent desorption In MIlliQ-purifled water; analysis by mobile" phase Ion chromatography (MPIC) with conductimetric detection. 1.4 Exposure Guidelines: Compound TLV-TWA3 TLV-STEL Source MEA 3 6 ACGIHa TLVs, 1984 DEA 3 * ACGIH TLVs, 1984 TEA None assigned 1.5 Compound MEA DEA TEA Validation Range, Percent Recovery, and Total Relative Precision: Validation Range h (ug/sample) (ppm(v/v))D Average Percent Recovery (Rn) Total Relative Precision (RPj) 13-317 45-600 79-940 0.12-3.0 0.25-3.3 0.31-3.7 93.1 17.25 92.7 15.0% 89.4 21.0% number of determinations (n) * 35 aTLV- Threshold Limit Value TWA - 8-hour Time-Weighted Average STEL - Short Term Exposure Limit ACGIH - American Conference of Governmental Industrial . Hygienists - TLVs. "based on a 42 liter air sample Page 1 of 10 do 073863 CONFTDFNTTAl October 16, 1985 Page 2 of 10 ML-IHM-84-07 1.6 Effect of Humidity: Humidity does not significantly affect recovery or breakthrough of these compounds from adsorbent tubes. 1.7 Effect of Sample Storage: Sample tubes can be stored up to 29 days at room temperature (25C) without affecting recoveries and without sig nificant migration of the compounds In the tube. 1.8 Validation Date: March 20, 1982 1.9 Physical Properties of Compound(s): Compound Molecular Weight Boiling Point (8C) 760 mm Hg Density (g/mL) 20C MEA 61.08 171 DEA 105.14 270 TEA 149.14 340 1.022 1.097 1.266 SAFETY 2.1 Each analyst should be acquainted with potential hazards of the reagents, products, and solvents before commencing laboratory work. SOURCES OF INFORMATION INCLUDE: MATERIAL SAFETY DATA SHEETS, LITERATURE, AND OTHER RELATED DATA. Safety information on non-Dow products should be requested from the supplier. Disposal of reagents, reactants and solvents must be in compli ance with local, state and federal laws and regulations. 2.2 Hexanesulfonic acid is toxic and corrosive. Wear chemical workers' goggles and gloves to prevent eye and skin contact. 2.3 Boric acid can be harmful when absorbed through the skin. Avoid skin and eye contact. 2.4 Sodium hydroxide is a corrosive and strong base. Wear chemical workers' goggles and gloves to prevent eye and skin contact. 3. PRINCIPLE 3.1 A measured volume of air is drawn through a glass tube containing alumina, especially precleaned for this work (see Section 6.5, Reagents). The ethanolamines are adsorbed on the sorbent. After sampling, the adsorbent sections are desorbed with Mill IQ-purified water and the extract is analyzed by MPIC and conductimetric detection. Quantitation is based upon direct com parison of peak heights with external standards. DO 073864 OONFTDPNTTAl October 16, 1985 Page 3 of 10 ML-IHM-84-07 4. INTERFERENCES 4.1 Inorganic cations such as Na+, K+, Mg++, Ca++ will interfere if the alumina is not cleaned prior to its use. 4.2 Other amines, such as methylamines will interfere if present. 5. APPARATUS 5.1 1C Detector: WESCAN conductivity meter. Model 212, and Model 219-200 microcell, available from WESCAN Industries, Inc, Santa Clara, CA 95050 or equivalent. 5.2 Pump, capable of 2 mL/min and 500 psig pressure such as Waters Associates, Model 6000A. 5.3 Guard Column: Dionex MPIC SI #35320 available from Dionex Corporation, Sunnyvale, CA 94086. 5.4 Separating Column: Dionex MPIC SI #35321 available from Dionex Corporation, Sunnyvale, CA. 5.5 Suppressor: 4 x 240 mm AGI-10 resin, 200-400 mesh In the borate form, prepared from AGI-10 resin in the chloride form which was converted first to the hydroxide form with 1.0 N NaOH (about one hour) plus a water rinse and second to the borate form with 0.5 M H-BO- (boric acid) for at least one hour and a water rinse. 5.6 Syringe: 100 uL, Hamilton 710 SNR or equivalent, available from VWR Scientific, Midland, MI 48640. 5.7 Injection Valve: Rheodyne Model 7125 or 7120 with 100 vl looo, Rheodyne, Inc., 2809 Tenth Street, Berkeley, CA 94710, or equivalent. 5.8 Recorder, such as Sargent-Welch Model SRG-2, 1 millivolt full scale, available from Sargent-Welch Scientific Co., 8560 W. Chicago Ave., Detroit, MI 48204. 5.9 Mechanical shaker (wrist-action) available from Burrell Corpora tion, 2223 Fifth Avenue, Pittsburgh, PA 15219. 5.10 Filter: Gelman ACRODISC-CR, 0.45 urn pore size, available from Fisher Scientific, 711 Forbes Avenue, Pittsburgh, PA 15219. 5.11 Portable battery operated pumps, capable of pumping at flow rates of 50-200 mL/minute. The Si pin Model SP1 available from Anatole 0. Sipin Company, Inc., 425 Park Avenue South, New York, NY 10016 was shown to be satisfactory. This pump is also distributed by Argus Supply Company, 15075 East Eleven Mile Road, Roseville, MI 48066. DO 073865 CONF TDFNTTAL October 16, 1985 Page 4 of 10 ML-IHM-84-07 5.12 Alumina tubes containing precleaned alumina (see reagents). 6. REAGENTS 6.1 Ethanolamines (99.0% MEA, 98.5% DEA, 98.0% TEA) available from J. T. Baker, Phillipsburg, NJ 08865. 6.2 0.1M hexanesulfonic acid, available from Dionex Corp., Sunnyvale, CA 94806. 6.3 Mobile Phase: Transfer 50 mL of 0.1M hexanesulfonic acid into a one liter volumetric flask and dilute to volume with Milli-Q or deionized water. 6.4 Alumina 20/40 mesh available in bulk from SKC, Inc'., Eighty Four, PA 15330, stock number 226-11-01. 6.5 Cleaning of Alumina: Add approximately 100 g of alumina to a 1000 mL beaker containing about 800 mL of deionized water. Place the beaker on a hot plate and extract the alumina with the water boiling for about 15 minutes. Oecant the hot water and wash the alumina several times with deionized water. Repeat this cleaning procedure twice more (total of three times) and filter the alumina. Reactivate In an air oven at about 150C for about 3 hours. 6.6 Preparation of Sampling Tube: Take a disposable plpet f 10.5 cm long), place a small amount of glass wool in the end and fill 1/3 ofthe tube with cleaned alumina. This is the back section of the sampling tube. Put glass wool on top of the back section and fill another 2/3 of the tube with alumina. This is the front section of the tube. Cover the top of the front section with glass wool. These prepared tubes are almost equivalent to the SKC tybes.^Cataj^g number 226-18. The SKC tubes do not contain alumina free of Na , Ca , Mg , etc. 6.7 Sodium hydroxide solution, approximately 1 N. Place 40 g of sodium hydroxide pellets in a polyethylene bottle and dissolve to one liter. 6.8 AGI-X10 resin available from 8io-Rad Laboratories, Griffin, Richmond, CA 94804. 32nd & 6.9 Boric acid, 0.5 M in MilliQ-purified water. 7. SAMPLING PROCEDURE 7.1 6.5, 6.6. The recommended field sampling tube is described in Sections 6.4, 7.2 As a guideline, suitable sampling pumps are those having stable low flow rates, 10%, at 100 mL/min., for sampling periods of up to 8 hours. DO 073866 CONFTDFNTTAI October 16, 1985 Page 5 of 10 ML-IHM-84-07 7.3 Carefully calibrate all sampling pumps with a tube in the proper sampling position. The precision of determining the total air volume sampled should be 5% relative. 7.4 Do not use sampling tubes with plastic or rubber tubing upstream of the alumina. Absorption by the tube may introduce sampling errors. 7.5 Attach the alumina tube to a calibrated personal sampling pump by means of a piece of rubber or plastic tubing with the back section of the alumina next to the pump. 7.6 Put the alumina tube in an appropriate holder to prevent injuries from the glass tube. 7.7 Attach the alumina tube in a vertical position as near to the breathing zone of the person being sampled as possible. 7.8 Turn on the sampling pump which has been calibrated for the desired flow. Sample up to 7 hr at 100 mL/min. 7.9 Record the time, flow rate, temperature, and barometric pressure when the pump was started. The register reading should be recorded just before the pump is started if a pump incorporating a counter is used. 7.10 At the end of the sampling period, check the flow rate or record register reading if using a pump Incorporating a counter. 7.11 Remove the alumina tube from the protective holder and pump. CaD the ends of the tube with the polyethylene caps. 7.12 Sample tubes can be stored up to 29 days at room temperature (25C), or refrigerator temperature (4C) without affecting recoveries and without detectable migration of the components in the tube. 8. DESORPTION AND ANALYSIS 8.1 Following collection, desorb the alumina of the front section with 10 mL of MilliQ-purified water and the back section with 5 ml of MilliQ-purified water. Shake on a mechanical shaker for about 45 minutes. 8.2^ Filter a portion of the extract into a clean vial using a Gelman Acrodisc filter, 0.45 urn pore size. 8.3 solution. Using a 100 uL syringe (see 5.61 fill the loop with filtered DO 073887 CONFIDENTIAL October 16, 1985 Page 6 of 10 ML-IHM-84-07 8.4 Inject the sample and obtain a chromatogram under the conditions described in 8.5, 8.5 Liquid Chromatographic Conditions: Column: Pre-column: Mobile phase: Injection size: Flow rate: Detector: Column temperature: Recorder: Chart speed: Dionex MPIC SI #35321 Dionex MPIC SI #35321 0.005 M hexanesulfonlc acid 100 uL 0.9 mU/mln Conductivity Ambient Sargent-Welch SRG-2 0.2 cm/mln 9. CALIBRATION 9.1 Prepare four mixed standard solutions containing the ethanol amines of Interest in alumina extract with water (Section 9.4). The concen trations should range approximately from: 1,5 vg/mL to 30 ug/mL for MEA, (0.1-3 ppm v/v) 45 ug/mL to 60 ug/mL for DEA, (0.3-3 ppm v/v) 80 ug/mL to 950 ug/mL for TEA, (0.3-4 ppm v/v) 9.2 8.5. Analyze the standard solutions under the conditions described in 9.3 Determine the response factor (concentration/area or peak height) for each component in the standard solution. The response factors should agree to within 1% relative. If they do not, recalibration should be done. 9.4 The standards for the calibration and analysis are prepared in aqueous alumina extract (same ratio of alumina-water applied to extract the sample) to simulate the background of the samples. DO 073868 CONFIDENTIAL October 16, 1985 Page 7 of 10 ML-IHM-84-07 10. CALCULATIONS 10.1 If manual calculations are used, calculate the response factor, RF, for each component as follows: A RF *----B where: RF = response factor in ug/mL/area or ug/mL/peak height unit A = concentration of the calibration standard (ug/mL) B = area or peak height of the calibration standard 10.2 Calculate the amount of each component in the extracting solvent (10 mL or 5 mL) using the respective response factor and the area or the peak height of the peak of interest. C - RF x D x V where: C - total micrograms (ug) of amine in the sample solution RF * response factor D = area or peak height of amine V = volume of sample solution (10 mL for front section, 5 mL for back section) 10.3 Calculate the molar volume of gas or vapor component at ambient condition as follows: 760 T+273 Vm * 24.45 x -----x--------- P 298 where Vm * molar volume of gas or vapor component sampled at ambient conditions P = barometric pressure (mm Hg) T = temperature (C) of air sampled 24.45 * volume of 1 mole of gas or vapor component at 25C and 760 mmHg (liters) ^ 10.4 Calculate the concentration of each component in air from the total micrograms found in the desorption solution C x Vm E =---------Vs x M where E = concentration of amine in air (ppm (v/v)) C = total amount of amine in sample solution (ug) Vm = molar volume of gas or vapor component at ambient conditions Vs * volume of air sampled at ambient conditions" M = molecular weight of amine (see 1.9) DO 073869 OONFIDFNTTAl October 16, 1985 Page 8 of 10 ML-IHM-84-07 10.5 If a positive response is observed in the solvent or reagent blank, this amount must be subtracted from the values found in the actual samples to obtain the real concentration in the air. 10.6 Using the validation data, correct sample concentrations based on the method recovery E x 100 E' =---------------- % Recovery where E' = corrected concentration of component in air % Recovery * the appropriate recovery value from Section 1.5 expressed as % 11. RECOVERY AND TOTAL RELATIVE PRECISION (RPy) 11.1 The average percent recovery and total relative precision at the 952 confidence level are listed in Section 1.5. The concentration ranges at which the recovery work was done are listed In Section 1.5. These data are based on 35 determinations for each component. 11.2 The total relative precision (RP-p) includes the precision of a single value, the relative precision of the recovery factor, and an estimated relative precision of the sampling pump of 52. 11.3 The analytical limit of detection for these compounds is listed below along with the limit of detection for a 42 liter air sample: Compound LOD (ug/mL) LOD (ppm (v/v), assuming 5 mL desorption volume and 42 liter air sample) MEA 1.3 DEA 4.5 TEA 8.0 0.06 0.12 0.16 11.4 The limits of detection and quantitation which are reported in this method represent conditions achieved in a research laboratory. Results obtained under field conditions and/or In multiple laboratory comparisons may differ and further testing would be required to establish practical limits under these conditions. 11.7 Under the collection conditions described in Section 7, there is no significant breakthrough of any of the components. However, since It is not always possible to sample within these guidelines, all back sections should be analyzed separately to assure no breakthrough occurred. D 073870 OONF TDF-NT I A!. Page 9 of 10 ML-IHM-84-07 "The information herein is presented in good faith, but no warranty, expressed or implied, is given nor is freedom from any patent owned by The Dow Chemical Company or by others to be inferred. In the hands of qualified personnel, the procedures are expected to yield results of sufficient accuracy for their intended purposes; but recipients are cautioned to confirm the reliability of their techniques, equipment and standards by appropriate tests. Anyone wishing to reproduce or publish the material in whole or in part should request written permission from The Dow Chemical Company." DO 070871 CONFIDENTIAL Page 10 of 10 ML-IHM-84-07 Figure 1. Ethanol amines by Mobile Phase Ion Chromatography Column: Pre-column: Mobile phase: Injection Isze: Flow rate: Detector: Column temperature: Recorder: Chart speed: Dionex MPIC SI #35321 Dionex MPIC SI #35321 0.005 M hexanesulfonic acid 100 UL 0.9 mL/min Conductivity Ambient Sargent-Welch SRG-2 0.2 cm/min Sample .>a S tar.dard :a 1!IA DEA te; W1 DEA I II tea DETECTOR RESPONSE ______ _ ,,,, `___________i _l 0 10 20 V MINUTES j__________ !__________L 0 lo 20 DO 073872 CONFTDFNTTAl