Document prvbZqYRDy1NYbRXJ8wv4ved

3M COMPANY OCCUPATIONAL HEALTH & SAFETY PRODUCTS LABORATORY Organic Vapor Analytical Method No. 2 January, 1979 DETERMINATION OF SELECTED ORGANIC VAPORS IN AIR SCOPE This is a procedure which covers the method of collecting and analyzing samples to determine the amount of a particular organic vapor(s) present in the air. More specifically, this procedure is to be used for those organic vapors which can be collected by 3M Organic Vapor Monitors and desorbed with carbon disulfide or other suitable solvents, a provisional list of organic vapors thet be determined is given in Table 1. Also included in this Table is a suggested analytical column and desorption solvent. A cali bration curve is generated for each compound of interest so that concentration ranges and sensitivities are known. Interferences will be treated in the Discussion Section. can SUMMARY OF METHOD The organic vapors are adsorbed on high activity charcoal, desorbed with carbon disulfide and quantitated using a gas chromatograph equipped with a flame ionization detector. APPARATUS Organic Vapor Monitor - 3M brand No. 3500 and No. 3502 or equiva lent. Additional information: The sample layer equals 160 mg. petroleum based charcoal. Features: Sampling rate determined by natural molecular diffusion. Gas Chromatograph - Hewlett Packard, Model 5840A, or equivalent, equipped with a flame ionization detector - available from Hewlett Packard, 2400 North Prior, Roseville, Minnesota 55113. Analytical Columns and Parameters - A list of suggested columns is given in Table 1. Column parameter should always be adjusted to produce sharp syimetrical peaks with as much resolution as possible from interfering components. Carrier gas flow rates are nominally set at 25 cm /min. for packed columns 1/8 inch in diameter. 3M 005075 3M Company Occupational Health & Safety Products Laboratory Page 2 Vials - Equipped with Teflon lined caps. Vials t Size -3.2 rrm x 1.1 mm volume - 1 ml. Part No. 3-3123 Cap Crimper - Part No. 3-3195 available from Supelco REAGENTS Carbon Disulfide - Spectroquality or equivalent. Solvents - Preferably chromatoquality for all compounds listed in Table 1. Gas Chromatograph Supplies - Pressurized bottles of: 1. Helium for carrier gas use must meet or exceed laboratory Grade D 99.995% pure. 2. Nitrogen for carrier gas use must meet or exceed laboratory Grade E 99.98% pure. 3. Hydrogen for flame detector must meet or exceed Grade A 99.8% pure. 4. Air for flame detector must meet or exceed industrial Grade Type 1. Caution: High pressure containers are hazardous and should be handled with care. Do not store in extreme heat. Calibration Standards - A series of standard solutions are prepared for each solvent to be determined. A microliter syringe is used to inject an appropriate amount of a particular compound into a known volume of carbon disulfide or other suitable solvent. Nominally 10, 25, and 50 mL glass - stoppered volumetric flasks are used. For the more volatile compounds, known amounts are added to measured quantities of solvent contained in vials equipped with Teflon - lined caps. The vials are immediately inverted and left in that position until used. These solutions are used to prepare a reference calibration curve for the particular organic vapor of interest. Normally 2 uL of each of the standard solutions are injected into a gas chromatograph and the peak area for each con centration is recorded. A best fit line is calculated by the regression technique to correlate peak area with the weight of component(s) present. It is recommended that the calibration and monitor samples be the same size (2 uL) to avoid possible column overloading as well as factorial errors. An alternate method to the regression line is to average the resultant sensitivity factors of three individually prepared standards Sensitivity factors are determined by the ratio of weight to area units. 3H 005076 3M Company Occupational Health & Safety Products Laboratory Page 3 Caution: Carbon disulfide is toxic and should be handled in a hood. Standard solutions should be used as soon as possible. They may be stored in the laboratory refrigerator for no more than five days. SAMPLING The monitor is removed from the package and the exposure start time is recorded on the back of the badge. When personal sampling is being performed, the monitor should be attached near the breathing zone. For area sampling, the monitor should NOT be placed in a corner or along a wall where stagnant air may exist. At the conclusion of the sampling period, the badge is removed and the retaining ring along with the membrane are discarded. The elutriation cap is then immediately snapped on terminating monitor exposure and the end time is recorded on the back of the badge. The following information must be recorded for each sample: 1. Monitor number 2. Date exposed 3. Employee or Area I.D. 4. Organic vapor of interest along with suspected con taminants which could cause interference 5. Temperature and relative humidity of the monitored environment if considered extreme 6. Any comments or unusual circumstances SAMPLE ANALYSIS Using a repipet or a syringe, add 1.5 mL of the desorption reagent to each monitor through the center port (the port is immediately resealed). After 30 minutes, with occasional gentle agitation, the eluent is decanted into a marked auto-sampler vial where a 2 uL sized sample is automatically introduced into the gas chromatograph. Alternatively, a 2 uL aliquot is removed from the center port for manual injection. The resultant analysis is recorded on a chromatogram where area units of the desired component(s) are correlated with the amount (weight) present during the sampling period. The weight found is recorded and converted to mg/m3 and/or/ ppm. If the total collected weight is determined to be greater than 16 milligrams, for strongly adsorbed materials, the monitor may have been overposed. In some cases over-exposure could occur at lower concentrations. Referring to the qualification data sheets for upper capacity limits will help determine if the monitor has been overexposed. 3M 005077 3M Company Occupational Health & Safety Products Laboratory Page 4 CALCULATION The relationship between environmental contaminant concentrations and the weight of material collected by the monitor is given by equation (1). (1) M = D A C t where M = total mass of collected contaminant L (ng) D = molecular diffusion coefficient (cm /min) A = diffusion path area (cm; L = diffusion path length (cm) C = environmental contaminant concentration (ng/cm = mg/in ) t = sampling time (min) When the (D A/L) term has been experimentally determined to be some value (K), equation (1) may be changed to equation (2) (2) M = KC t 3 where K = sampling rate (cm /min); the time- weighted exposure level is then calculated by solving equation (2) the (C) term. (3) mg = * corrected nanograms found_____________ ^ ~3 recovery coefficient x sampling rate (cm/min) x sampling time (min) (4) ppm = mg x 22.41/mole x TK x 760 mm Hg 3 M.W. g/mole 2^73K p nun Ho mp where M.W. = molecular weight of the organic vapor TK = ambient temperature in degrees Kelvin P = ambient atmospheric pressure in mm of Hg DISCUSSION Experience teaches that a single contaminant is rarely found by itself in a given industrial atmosphere. Depending on the number and nature of the contaminating organic vapors, it is possible that interferences may occur. To help insure the accuracy of an analytical result, a sample may be analyzed on two chemically different natured columns (Carbowax vs SE-30). If the results are essentially the same for both columns, there is a good chance no interferences are present. However, no absolute identification can be made for any contaminant(s) by retention time only, regardless of the number of analytical columns used. ^Corrected nanograms - (sample area - blank area)calibration factor. 3M 005078 3M Company Occupational Health & Safety Products Laboratory Page 5 It is good analytical practice to run a bulk sample of the solvents being used in the surrounding area. These samples will give the analyst some insight to the possible airborne matrix. REFERENCES 1) Gilliland, E. R., Diffusion Coefficients in Gaseous Systems, Ind. and Eng. Chemistry, June, 1934 2) Procedure for Organic Solvents in Air from NIOSH Manual of Analytical Methods H. E. Mullins /ss 3H 005079 5 TABLE 1 COMPOUNDS AND SUGGESTED METHODS Organic Vapor Acetone Acrylonitrile Allyl Alcohol Allyl Chloride Benzene Benzyl Chloride Bromoform Butadiene 2-Butanone (MEK) ^-Butoxy Ethanol ~utyl Acetate Butyl Alcohol Carbon Disulfide Carbon Tetrachloride Chlorobenzene Chlorobromomethane Chloroform Chlorotoluene Cumene Cyclohexane Cyclohexanol Molecular Weight (g/mole) 58.1 53.1 58.1 76.5 78.11 126.6 252.8 54.1 72.1 118.2 116.2 74.1 76.1 153.8 112.6 129.4 119.4 126.6 120.2 84.2 100.2 Density (q/mL) 0.79 0.81 0.85 0.94 0.88 1.10 2.9 Gas 0.81 0.90 0.88 0.81 1.26 1.59 1.10 1.99 1.48 1.07 0.86 0.78 0.96 Desorption Solution A A B C A A A A A D A E C A A A A A A A B Analyt Colui I I II III IV, II II IV II II VI II VII II II II IV II II III II 3M 005080 Organic ^^apor Molecular Weight (g/mole) Cyclohexone 98.1 Cyclohexane 82.1 Decane Diacetone Alcohol 142.3 116.2 m-Dichlorobenzene 1,1-Dichloroethane 147.0 99.0 1,2-Dichloroethane 99.0 1,2-Dichloroethylene 97.0 Difluorodibromomethane 209.8 Diisobutyl Ketone 142.2 Dioxane 88.1 Dipropylene Glycol Methyl Ether 148.2 Epichlorohydrin 92.5 2-Ethoxyethyl Acetate 132.2 Ethyl Acetate 88.1 Ethyl Acrylate Ethyl Alcohol Ethyl Benzene 100.1 46.1 106.2 Ethyl Bromide Ethyl Butyl Ketone 109.0 114.2 Ethylene Chlorohydrin Ethylene Dibromide 80.5 187.9 Ethylene Dichloride Ethyl Ether 99.0 74.1 yl Formate Glycidol 74.1 74.1 r-4 00 o Density (q/mL) 0.95 0.81 0.73 0.93 1.29 1.18 1.26 1.28 gas 1.03 0.95 Desorption Solution A A A B A A A A F A A A 1.18 0.98 0.90 0.94 0.80 0.87 1.45 0.82 1.20 2.17 1.26 0.73 0.92 1.11 A A A A G A F H B A A I A J Analytica Column II III IV II II I, II I, II II II II IV II II VI VI VI II II II II II II VIII III IV II 3M 005081 Organ ic ^^apor Molecular Weight (q/mole) Density (g/mL) Desorption Solution Heptane Hexane Hexanone Isoamyl Acetate 100.2 86.2 100.2 130.2 0.68 0.66 0.80 0.88 A A A A Isoamyl Alcohol 88.2 0.81 B Isobutyl Acetate 116.2 0.87 A Isobutyl Alcohol 74.1 0.81 E Isopropyl Acetate Isopropyl Alcohol Isooctane Mesityl Oxide 102.1 60.1 114.2 98.1 0.87 0.79 .70 0.86 A G A H Methyl Acetate thyl Acrylate Methyl Bromide Methyl Cellosolve Methyl Cellosolve Acetate 74.1 86.1 94.9 76.1 118.1 0.93 0.96 1.73 0.97 1.0 A A A D A Methyl Chloroform Methyl Cyclohexane Methylene Chloride Methyl Ethyl Ketone Methyl Isobutyl Ketone Nitrobenzene Octane Pentane (See 1,1 ,1-Trichloroethane) 98.2 0.77 A 84.9 1.33 A (See 2 - Butanone) 100.2 123.1 .80 1.20 A, H A 114.2 0.70 A 72.2 0.63 A Analytical Column VIII IV II VI II VI II VI II IV II IV VI II II VI IV IV I I IX IX 3M 005082 Organic /apor Perchloroethylene n-Propyl Acetate iso-Propyl Acetate iso-Propyl Benzene Molecular Weight (g/nvole) Density (g/mL) Desorption Solution (See Tetrachloroethylene) 102.1 .84 A 102.1 .87 A (See Cumene) Stoddard Solvent Styrene 1,1,2,2-Tetrachloroethane 148 104.1 167.9 0.78 0.91 1.59 A A A Tetrachloroethylene Toluene 1,1,1-Trichloroethane , 1,2-Trichloroethane Trichloroethylene Turpentine Vinyl Chloride Vinyl Toluene Xylene 165.9 92.1 133.4 133.4 131.4 256.0 62.5 118.1 106.2 1.63 .87 1.35 1.44 1.47 0.85 Gas 0.89 0.86 A A A A A A A A A Desorption Solution Key A Carbon disulfide B Carbon disulfide containing 5% 2-propanol C Benzene D Methylene chloride containing 5% methanol E Carbon disulfide containing 1% 2-propanol F Isopropyl alcohol G Carbon disulfide containing 1% 2-butanol H Carbon disulfide containing 1% methanol I Ethyl acetate Tetrahydro furan Analytical Column VI VI X II II VIII IV VIII VIII VIII X III II IV 3H 005083 zialytical Columns Key X 15% carbowax 20m, Chromosorb W, 7.5 ft. x 1/8 in. SS II 10% FFAP, Chromosorb W AW, 10 ft. x 1/8 in. SS III Porapak Q, 6 ft. x 1/8 in. SS IV 10% FFAP, Chromosorb W AW, 20 ft. x 1/8 in. SS V 25% CEF, Chromosorb P AW, 10 ft. x 1/8 in. SS VI 5% FFAP, Supelcoport, 10 ft. x 1/8 in. SS VII 5% OV-17, Supelcoport, 6 ft. x 4 nan glass VIII 10% OV-101, Supelcoport, 10 ft. x 1/8 in. SS IX 10% SP-2100, Supelcoport, 10 ft. x 1/8 in. SS X 1.5% OV-101, Supelcoport, 6 ft. x 1/8 in. SS 3H 005084