Page:NIOSH Manual of Analytical Methods - 5522.pdf/2

 ISOCYANATES: METHOD 5522, Issue 2, dated 15 January 1998 - Page 2 of 6 REAGENTS:

EQUIPMENT:

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

1. Sampler: Midget impinger containing 20 mL sampling medium. 2. Personal sampling pump, 1 to 2 L/min, with flexible tubing. 3. HPLC, fluorescence detector, ex 275 nm, em 320 nm; integrator and column (page5522-1). (Electrochemical detector for confirmation of fluorescent peaks.) 4. Vials, 20-mL, scintillation, and 40-mL opaque, with PTFE-lined caps. 5. Pipets, 20-mL. 6. Cylinders, graduated, 25-mL. 7. Syringes, 25-µL, or fixed sample loop. 8. Volumetric flasks, 10-mL. 9. Fritted glass funnel. 10. Filtering flasks. 11. Sealing bands.

10. 11.

12. 13.

Water, deionized, distilled. Acetonitrile, HPLC grade. Dimethyl sulfoxide (DMSO), HPLC grade.* Sodium acetate trihydrate. Glacial acetic acid, reagent grade. Toluene, HPLC grade. n-Propanol, reagent grade. Heptane, reagent grade. Buffer solution: Dissolve 20.4 g sodium acetate trihydrate in 2 L distilled-deionized water. Add glacial acetic acid to pH 5.5. Mobile phase, acetonitrile and buffer solution. Sampling medium, 450 µg/mL, (a) For sampling in ambient temperatures >60 F: tryptamine, 99+% pure, in DMSO; (b) For ambient temperatures <60 F: 80/20 (v/v) DMSO/ acetonitrile containing tryptamine, 99+% pure. NOTE: Recrystallize tryptamine in acetonitrile before use. (Stable up to 6 mo. in the dark at ambient temperature.) Tryptamine derivatives of isocyanates* (See APPENDIX). Helium. prepurified.
 * See SPECIAL PRECAUTIONS

SPECIAL PRECAUTIONS: Isocyanates are known respiratory irritants. Prepare standards and derivatives in a fume hood. DMSO is readily absorbed into the skin. Wear neoprene latex gloves when handling the solvent, sampling media, and field samples [3]. SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Transfer 20 mL sampling medium to an impinger, and connect to sampling pump with flexible tubing. NOTE: Prepare field blank samples by transferring 20 mL sampling medium to 20-mL vials. 3. Sample at an accurately known flow rate between 1 and 2 L/min for total a sample size of 15 to 360 L. 4. Estimate final impinger volume to the nearest 0.5 mL. Record on sample submittal sheet. NOTE: DMSO is hygroscopic; therefore, final sampling volumes may be greater than 20 mL. 5. Transfer the sample solution to a 40-mL opaque vial for shipment. Secure screw cap with sealing band. 6. Obtain a bulk sample (1 to 2 mL) and the material safety data sheet for each component of the formulation. SAMPLE PREPARATION: 7. Transfer an aliquot of each sample to a HPLC autosampler vial.

CALIBRATION AND QUALITY CONTROL: 8. Calibrate daily with at least six working standards in the range of interest. a. Prepare working standards containing 0.05 to 10.0 µg/mL of the appropriate monomeric tryptamine derivative in the sampling medium. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition