Page:NIOSH Manual of Analytical Methods - 2555.pdf/2

 KET ON ES I: MET HO D 255 5, Issue 1, dated 15 M arch 200 3 - Page 2 o f 5 REAGENTS:

EQUIPMENT:

1. 2. 3. 4. 5. 6.

1. Sam pler: glass tube, 7 cm long, 6-mm OD, 4mm ID, flame-sealed ends with plastic caps, containing two sections of Anasorb CMS (150 m g/ 75 m g) separated b y a 2-mm urethane plug. A silylated glass wool plug precede s the front section and a 3-m m urethane foam plug follows the back section. Tu bes are c om m ercially available. 2. Personal sampling pump, 0.01 to 0.2 L/min, connected with flexible tubing. 3. Gas chromatograph equipped with FID, integrator and capillary colum n (page 25 55-1). 4. Autosampler vials, 2-mL, glass, with PTFElined crimp caps. 5. Syringes, 10-µL, 25-µL, and 1-mL. 6. Pipettes, 3-mL and 5-mL. 7. Volumetric flasks, 10-mL. 8. Bagge d refrigera nt, Blue -ice or equ ivalent.

Ca rbon disulfide (G C grade ).* Analytes, reage nt gra de.* Helium, prepurified and filtered. Hydrogen, prepurified and filtered. Air, compressed, purified, filtered. Ca libration s tock solution: Ad d know n am oun ts of analytes to carbon disulfide in 10-m L volum etric flas k.


 * See SPECIAL PRECAUTIONS

SPECIAL PRECAUTIONS: Carbon disulfide is toxic, explosive, and a fire hazard (FP = -30°C). W ork with carbon disulfide in a well ventilated hood. Analytes should be handled in a fume hood. Use protective clothing and eyew ear.

SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Break the ends of the sampling tube imm ediately before sampling. Attach sampling tube to personal sampling pump with flexible tubing. 3. Sa m ple at an accu rately know n flow rate between 0.01 a nd 0.2 L/m in for a total sam ple size of 3 L for acetone and 10 L for all other analytes. 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. Place the glass wool preceding the front section into the vial containing the front sorbent sec tion. Discard the urethane foam plugs. 6. Ad d 1.0 m L of carbon disulfide into each vial. Attach crim p caps to each vial. 7. Allow to stand fo r 30 m inutes with oc cas ional agitation.

CALIBRATION AND QUALITY CONTRO L: 8. Ca librate daily with at least six working s tandards from below the LOD to 10 times the LOQ. If nec ess ary, additional stand ards m ay be a dde d to exten d the calibra tion cu rve. a. Add known amounts of analytes to carbon disulfide solvent in a 10 -m L volum etric flas k and d ilute to the mark. Prepare additional standards by serial dilution in 10-mL volumetric flasks. b. Analyze together with samp les and blanks (steps 11 and 12). c. Prepare c alibration graph (pe ak area vs µg ana lyte). 9. Determine desorption efficiency (DE) at least once for each lot of Anasorb CMS used for sampling in the calibration ranges (step 8). a. Prepare three tubes at each of five levels plus three media blanks.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition