Page:NIOSH Manual of Analytical Methods - 2562.pdf/2

 1,1,2,2-TET RAC HLO RO ETH ANE : MET HO D 256 2, Issue 1, dated 15 M arch 200 3 - Page 2 o f 4 REAGENTS:

EQUIPMENT:

1. Carbon disulfide (CS 2), chrom ato graphic qua lity.* 2. 1,1,2,2-T etrac hloroetha ne, re age nt gra de.* 3. Desorption efficiency (DE) stock solution, 12.7 mg/mL. Dilute 80 µL of 1,1,2,2-tetrachloroethane to 10 mL with CS 2. 4. Helium, purified 5. Hydrogen, prepurified 6. Air, filtered, compressed

1. Sam pler: glass tube, 7 cm long, 6-mm OD, 4-m m ID, glass-sealed ends with plastic caps, containing two sections of 100/50 An asorb CMS (front = 100 mg; back = 50 mg) separated by a 2-m m glass wool plug. Another glass wool plug precedes the front section and a 3-mm urethane foam plug follows the back section. (SKC 226121, or equivalent). 2. Personal sa m pling pum p, 0.01 to 0.2 L/m in, with flexible connecting tubing. 3. Gas chrom atograph, flam e ionization detector, integrator, and column. 4. Vials, 2-mL, PTFE-lined caps. 5. Syringes, 10-µL, rea dab le to 0.1 µL, 25-µL, read able to 0.5 µ L, and 10 00-µ L, rea dab le to 1 µL. 6. Volumetric flasks, 10-mL. 7. Pipet, TD, 1-mL.


 * See SPECIAL PRECAUTIONS

SPE CIAL PRECAUTIONS: 1,1,2,2-Tetrachloroethane is a powerful narcotic, liver poison, and suspected carcinogen, and can be abso rbed throu gh the sk in [3, 4]. Carbon disulfide is toxic and a serious fire and explosion hazard (flash point = - 30 °C). W ork with these substances only in a hood. SAMPLING: 1. 2. 3. 4.

Calibrate each personal sampling pump with a representative sampler in line. Break ends of the sampler imm ediately before sampling. Attach sampler to personal sampling pump with flexible tubing. Sam ple at a n ac curately kn own flow ra te betwee n 0.01 an d 0.2 L/m in for a total sam ple size of 3 to 30 L. Ca p the sam plers. Pac k secu rely for shipm ent.

SAMPLE PREPARATION: 5. 6. 7.

Place front and back sorbent sections of the sampler tube in separate vials. Discard glass wool plugs. Add 1.0 mL CS 2 to each vial. C ap each vial. Allow to stand 30 min with occasional agitation.

CALIBRATION AND QUALITY CONTRO L: 8.

9.

Calibrate daily with at least six working standards from below the LOD to 10x the LOQ. a. Add a specific amount of 1,1,2,2-tetrachloroethane to CS 2 in 10-m L volum etric flas ks and dilute to th e m ark. Us e serial dilutions as needed to obta in 1,1,2 ,2-tetrachloroeth ane concentratio ns in the ran ge needed. Additional standards m ay be added to exte nd the calibra tion curve, if necess ary. b. Analyze with calibration standards, sam ples, and blanks (s teps 11 and 12). c. Prepare c alibration graph (pe ak area vs. µg 1,1,2,2-tetrachloroethane). Determine desorption efficiency (DE) at least once for each lot of sorbent used for sampling in the range of interest. Prepare three tubes at each of five concentrations plus three media blanks. a. Rem ove and disca rd back sorbent sec tion of a med ia blank sam pler. b. Injec t a kn own am oun t (2 to 25 µL ) of D E sto ck solution, or a serial dilution thereof, directly onto the front sorbent section with a microliter syringe. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition