SULFUR DIOXIDE Formula: SO 2 ; MW 64.06; CAS [7446-09-5]; a major air pollutant; produced when soft coals, oils, and automobile fuels burn; used as a fumigating and bleaching agent; colorless gas with a strong suffocating odor; liquefies at –10°C; solidifies at –72°C; soluble in water (8.5% at 25°C), alcohol, ether, and chloro- form; highly toxic and a strong irritant. AIR ANALYSIS Air drawn through two 0.8 µ m cellulose ester membranes: (1) the front filter to collect any interfering particulate sulfate and sulfite in the air, and (2) the back filter, treated with KOH to trap SO 2 ; SO 2 converted to K 2 SO 3 on the back filter; this filter treated with 10 mL mixture solution of 3 mmol NaHCO 3 and 2.4 mmol Na 2 CO 3 ; K 2 SO 3 dissociates into SO 3 2– anion, which is then determined by ion chromatography (NIOSH Method 6004, 1989); recommended flow rate 1 L/min; sample volume 100 L. • Use SO 3 2– calibration standard to determine the mass of SO 3 2– ; a blank analysis performed on the media blanks for background correction. • Multiply SO 3 2– concentration by the stoichiometric factor 0.8 to calculate the concentration of SO 2 . • Bicarbonate-carbonate eluant of the back filter may also be oxidized with a drop of 30% H 2 O 2 to SO 4 2– ; SO 4 2– formed measured by ion chromatog- raphy; to calculate the concentration of SO 2 , multiply the mass of SO 4 2– found in the analysis, multiplied by the stoichiometric factor 0.667. Alternatively, air drawn through an impinger solution containing 0.3 N H 2 O 2 ; SO 2 converted to SO 4 2– which is measured by titration with NaOH or barium per- chlorate (NIOSH Method S308, 1978). Alternatively, air drawn though a solid sorbent tube containing molecular sieve 5A; SO 2 adsorbed on this trap desorbed on heating under He purge; transported onto GC column and determined by GC/MS. • Characteristic mass for SO 2 is 64. 3.64 © 1997 by CRC Press LLC © 1997 by CRC Press LLC 412 HANDBOOK OF ENVIRONMENTAL ANALYSIS A passive colorimetric dosimeter tube may also be used for direct measurement; SO 2 diffuses into the tube; color changes (red-purple to yellow in Vapor Guard tube); concentration determined from the length of stain. •Temperature and relative humidity may affect measurement; tubes should be used between 15 and 40°C. (1 ppm SO 2 = 2.62 mg/m 3 at NTP) © 1997 by CRC Press LLC © 1997 by CRC Press LLC 412 TETRACHLORETHYLENE Synonyms: perchloroethylene, tetrachloroethene, ethylene tetrachloride; For- mula: Cl 2 C=CCl 2 ; MW 165.82; CAS [127-18-4]; used in dry cleaning and metal degreasing; colorless liquid with ether-like odor; boils at 121°C; freezes at –22°C; vapor pressure 19 torr at 25°C; density 1.62 g/mL at 20˚C; insoluble in water; miscible with organic solvents. ANALYSIS OF AQUEOUS AND NONAQUEOUS SAMPLES Aqueous samples extracted by purge and trap method; analyte thermally desorbed out of trap and swept onto a GC column for separation from other volatile compounds; detected by HECD, ECD, FID, or MSD. Soils, solid wastes, or sludges mixed with water or methanol; the aqueous extract or a solution of methanol extract spiked into water; subjected to purge and trap concentration and analyzed as above. Methanol or hexane extract may be directly injected for GC (ECD or FID) or GC/MS determination. • Characteristic masses for GC/MS identification: 164, 129, 131, and 166. • Limit of detection: in the range 0.05 µ g/L when detected by HECD for a 5-mL sample aliquot (subject to matrix interference). • Recommended surrogate/IS: 2-bromo-1-chloropropane and 1,4-dichloro- butane. • Samples collected in glass/plastic containers without headspace, refriger- ated, and analyzed within 14 days. See Halogenated Hydrocarbons, Chapter 2.9 for GC columns and conditions and a further discussion. AIR ANALYSIS Adsorbed over coconut charcoal (100 mg/50 mg); desorbed with CS 2 and analyzed by GC-FID (NIOSH Method 1003, 1987); recommended flow rate 100 mL/min; sample volume 3 L. 3.65 © 1997 by CRC Press LLC © 1997 by CRC Press LLC 414 HANDBOOK OF ENVIRONMENTAL ANALYSIS Adsorbed over Tenax (~2 g) in a cartridge; desorbed by heating under He purge; transferred into a cold trap and then to the front of a GC column at –70°C; column heated; analyte detected by ECD or MSD (U.S. EPA Method TO-1); recommended flow rate 100 mL/min; sample volume 10 L. Adsorbed over carbon molecular sieve (~400 mg) in a cartridge; heated at 350°C under He purge; transferred into a cryogenic trap and flash evaporated onto a capillary column GC/MS (U.S. EPA Method TO-2); recommended flow rate 1 L/min; sample volume 100 L. Collected in a trap in liquid argon; the trap removed and heated; sample transferred to a precooled GC column for ECD or FID detection (U.S. EPA Method TO-3). Collected in a SUMMA passivated canister under pressure using an additional pump or at subatmospheric pressure by initially evacuating the canister; the air transferred into cryogenically cooled trap attached to a GC column; the trap heated; the analyte separated on the column for detection by ECD or GC/MS (U.S. EPA Method TO-14). (1 ppm tetrachloroethylene in air = ~6.8 mg/m 3 at NTP) © 1997 by CRC Press LLC © 1997 by CRC Press LLC 414 TETRAETHYLLEAD Synonym: tetraethylplumbane, lead tetraethyl; Formula: Pb(C 2 H 5 ) 4 ; MW 323.47; CAS [78-00-2]; used in motor gasoline as an additive to prevent “knock- ing”; such an application, however, is currently curtailed because of environmen- tal pollution; boils at 200°C; vapor pressure 0.2 torr at 20°C; density 1.653 g/mL at 20°C; insoluble in water; slightly soluble in alcohols; dissolves in benzene, toluene, hexane, petroleum ether, and gasoline; highly toxic (Patnaik, 1992). ANALYSIS OF AQUEOUS AND NONAQUEOUS SAMPLES Aqueous samples may be microextracted with toluene, benzene, or hexane and the extract analyzed by GC/MS. • The m/z of primary characteristic ion 237; the secondary ions for compound identification 295, 208, 235, and 266 (electron impact ionization); peak intensity ratios for m/z 237:295:208 = 100:73:61 (Hites, 1992). • GC column: a fused silica capillary column such as DB-5, SPB-5, Rtx-5, or equivalent. Soils, sediments, or other nonaqueous matrices mixed with anhydrous Na 2 SO 4 and extracted by sonication; the solvent extract analyzed as above by GC/MS. • If lead analysis is performed by AA spectrophotometry, following acid digestion of samples, then the stoichiometric calculation for tetraethyllead (TEL) may be done as follows: conc. of TEL = conc. of Pb × 1.56 (assuming all Pb in sample occurs as TEL; such an assumption, however, could be erroneous.) 3.66 © 1997 by CRC Press LLC © 1997 by CRC Press LLC TETRAETHYL PYROPHOSPHATE Synonyms: pyrophosphoric acid tetraethyl ester, TEPP; Formula: C 8 H 20 O 7 P 2 ; Structure: MW 290.19; CAS [107-49-3]; an organophosphorus pesticide; colorless liquid; hygroscopic; boiling point 124°C at 1 mm Hg; vapor pressure 0.00047 torr at 20°C; decomposes at 170 to 213°C; density 1.185 g/ml at 20°C; miscible with most organic solvents; miscible with water but rapidly hydrolyzed; highly toxic. ANALYSIS OF AQUEOUS AND NONAQUEOUS SAMPLES Aqueous samples (TEPP unstable) extracted serially with methylene chloride; the extract concentrated and analyzed by GC/MS. • Characteristic masses for GC/MS identifications: 99, 155, 127, 81, and 109. • GC column: a fused silica capillary column, such as DB-5 or equivalent. Soil, sediment, or solid waste sample mixed with anhydrous Na 2 SO 4 ; sonicated or Soxhlett extracted with methylene chloride; extract concentrated and analyzed by GC/MS as above. AIR ANALYSIS Air drawn through a solid sorbent tube containing Chromosorb 102 (100 mg/ 50 mg); analyte desorbed with 1 ml toluene (on 60 min standing); toluene extract analyzed by GC-FPD (NIOSH method 2504, 1984); recommended flow rate 0.1 L/min; sample volume 20 L. CH 3 CH 2 O P O CH 2 CH 3 O OP O O O CH 2 CH 3 CH 2 CH 3 3.67 © 1997 by CRC Press LLC © 1997 by CRC Press LLC 418 HANDBOOK OF ENVIRONMENTAL ANALYSIS • GC column: Super-Pak 20M or equivalent. • Calibration standards are made from TEPP in toluene. • The working range of the method was determined to be 0.025 to 0.15 mg/m 3 for a 40 L sample. (1 ppm TEPP in air = 11.86 mg/m 3 at NTP) © 1997 by CRC Press LLC © 1997 by CRC Press LLC 418 . phenylmethane. Formula: C 7 H 8 ; Structure: MW 92.15; CAS [1 08- 88- 3]; occurs in gasoline, petroleum solvents, and coal-tar distillates; used as a solvent and in many organic syntheses; colorless liquid. coals, oils, and automobile fuels burn; used as a fumigating and bleaching agent; colorless gas with a strong suffocating odor; liquefies at –10°C; solidifies at –72°C; soluble in water (8. 5% at 25°C),. to 60% in 15 min; 5 min isocratic; flow rate 1.5 mL/min. •For quantitation, prepare a calibration standard, plotting the concentration of urea derivative of each reference standard against peak