Page:NIOSH Manual of Analytical Methods - 2553.pdf/2

 KET ON ES II: MET HO D 255 3, Issue 1, dated 15 M arch 200 3 - Page 2 o f 4 REAGENTS:

EQUIPMENT:

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

1. Sam pler: glass tube, 7 cm long, 6-mm OD, 4mm ID, flame-sealed ends, containing two sec tions o f Anaso rb C MS (front = 150 m g; back = 75 mg) separated by a 2-mm urethane plug. A silylated glass wool plug precedes the front section and a 3-mm urethane plug follows the back se ction. Tubes are com m ercially available (S KC # 226-12 1). 2. Personal sa m pling pum p, 0.01 to 0.2 L/m in, with flexible connecting tubing. 3. Gas chromatograph, FID, integrator, and Rtx200 fused silica capillary column. 4. GC autosam pler vials, 2-m L glass, with PTF Elined crimp caps. 5. Syringes, 10-µL, 25-µL, and 1-mL. 6. Pipets, 3-mL and 5-m L, with pipet bulb. 7. Volumetric flasks, 250-mL and 10-mL.

2-Hep tanone, reagen t grade (98% ). 3-Hep tanone, reagen t grade (98% ). Mes ityl oxide, reagent grade (98% ). 5-Methyl-3-heptanone, reagent grade (97% ). Cam phor, reagent grade (99% ). Ca rbon disulfide, low b enze ne g rade .* Iso propanol. Helium, prepurified and filtered. Hydrogen, prepurified and filtered. Air, compressed and filtered. Desorption solvent: 2% isopropanol in carbon disulfide (v/v). 12. DE s tock solution: Add kn own am ount of analyte to desorption solvent in 10-m L volumetric flask.


 * See SPECIAL PRECAUTIONS

SPECIAL PRECAUTIONS: Carbon disulfide is tox ic and a fire/explosion haza rd (flas h po int = -30 °C). Isop ropa nol is flam m able. All work sho uld be perform ed in a ventilated fum e ho od.

SAMPLING: 1. 2. 3. 4.

Calibrate each personal sampling pump with a representative sampler in line. Break the ends of the sampler imm ediately prior to sampling. Attach sampler to personal sampling pump with flexible tubing. Sam ple at a known flow rate between 0.01 and 0.2 L/min for a total sample size of 1 to 25 L. Ca p the sam plers and pac k secu rely for shipm ent.

SAMPLE PREPARATION: 5. 6. 7.

Place the front (include the initial glass wool plug) and back sorbent sections of the sampler in separate vials. Discard the foam plugs. Add 1.0 mL of the 2% isopropanol/carbon disulfide desorption solvent to each vial. Securely attach crim p caps to each vial. Allow to desorb for 30 m inutes with oc cas ional agitation.

CALIBRATION AND QUALITY CONTRO L: 8.

9.

Ca librate daily with at leas t six wo rking standa rds to cover the an alytical range. If nece ssa ry, additional standards may be added to extend the calibration curve. a. Add known amounts of each analyte to the desorption solvent solution in 10-mL volumetric flasks and dilute to the m ark. Mix well. b. Analyze together with samp les and blanks (steps 11 and 12). c. Prepare c alibration graph (pe ak area versus µg analyte). Determine desorption efficiency (DE) at least once for each lot of Anasorb CMS used for sampling in the calibration rang e (ste p 8). a. Prepare three tubes at each of five levels plus three media blanks.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition