HYD RO CAR BO NS, AR OM ATIC : MET HO D 150 1, Issue 3, dated 15 M arch 200 3 - page 2 of 7 REAGENTS:
EQUIPMENT:
1. Ca rbon disulfide*, low ben zene , chrom ato graphic quality. 2. Analytes, reagent grade. 3. Helium, prepurified and filtered. 4. Hydrogen, prepurified and filtered. 5. Air, prepurified and filtered.
1. Sam pler: glass tube, 7 cm long, 6-mm OD, 4mm ID, flame-sealed ends, containing two sectio ns of a ctivate d coconut s hell charcoal (front = 100 mg, back = 50 mg) separated by a 2-mm urethane foam plug. A silylated glass wool plug precedes the front section and a 3mm urethane foam plug follows the back section. Tubes are comm ercially available. 2. Personal sampling pump, 0.01 to 1.0 L/min (Table 3), with flexible connecting tubing. 3. Gas chromatograph, FID, integrator, and colum ns (page 1501-1). 4. Autosampler vials, glass, 1.8 mL, with PTFElined caps. 5. Pipets, 1-mL, and pipet bulb. 6. Syringes, 10-µL, 25-µL, and 250-µL. 7. Volumetric flasks, 10-mL.
- See SPECIAL PRECAUTIONS
SPECIAL PRECAUTIONS: Carbon disulfide is toxic and extrem ely flam m able (flash point = -30°C), ben zene is a su spe ct ca rcinogen . Prep are s tand ards and sam ples in a we ll ventilated hoo d.
SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Break the ends of the sampler imm ediately before sampling. Attach sampler to personal sam pling pum p with flexible tubing. 3. Sa m ple at an accurately known flow rate between 0.01 and 0.2 L/min for a total sample size as shown in Table 3. 4. Ca p the sam plers with plastic (not rub ber) cap s and pa ck sec urely for shipm ent.
SAMPLE PREPARATION: 5. Place the front and back sorbent sections of the sampler tube in separate vials. Include the glass wool plug in the vial along with the front sorb ent section . 6. Ad d 1.0 m L eluent to each vial. Attach crim p cap to each vial im m ediate ly. 7. Allow to stand at least 30 min with occasional agitation.
CALIBRATION AND QUALITY CONTRO L: 8. Calibrate daily with at least six working standards from below the LOD to 10 times the LO Q. If necess ary, add itional standa rds m ay be a dde d to exten d the calibra tion cu rve. a. Add known a m oun ts of a nalytes to carbon disulfide so lvent in 10-m L volum etric flas ks and dilute to the mark. Prepare additional standards by serial dilution in 10-mL volumetric flasks. b. Analyze together with samp les and blanks (steps 11 through 12). c. Prepare c alibration graph (pe ak area of analyte vs. µg analyte per sam ple).
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
