Page:NIOSH Manual of Analytical Methods - 1501.pdf/2

 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