PHENYLHYDRAZINE: METHOD 3518, Issue 1, dated 15 August 1994 - Page 3 of 4 9.
10.
Calibrate daily with at least six working standards. a. Transfer 15 mL 0.1 M HCl to a 50-mL volumetric flask. b. Pipet 1 to 10 mL of phenylhydrazine hydrochloride stock solution into the volumetric flask. c. Continue preparation as with samples (steps 7 and 8). d. Analyze together with samples and blanks (steps 11 and 12). e. Prepare calibration graph (absorbance vs. mg phenylhydrazine hydrochloride per sample). Analyze three quality control blind spikes and three analyst spikes to ensure that calibration graph is in control.
MEASUREMENT: 11. 12.
Set spectrophotometer according to manufacturer's recommendations and to conditions given on p. 3518-1. Fill 1-cm cuvette with sample from 10-mL volumetric flask. Read sample absorbance at 730 nm against a reagent blank prepared in the same manner as the samples (steps 9.a, 7, and 8).
CALCULATIONS: 13. 14.
Calculate the mass, mg, of phenylhydrazine hydrochloride in each sample (W) and average field blank (B). Calculate the concentration, C, of phenylhydrazine in the air volume sampled, V (L):
EVALUATION OF METHOD: This method was validated over the range 10.37 to 44.8 mg/m 3 at 22 °C and 761 mm Hg using 100-L samples [1,2]. The average recovery was 95%, while the recovery from samples after five days storage was 100% [1]. Sample stability during storage was evaluated at a level of 4.4 mg phenylhydrazine per sample [1].
REFERENCES: [1] [2] [3] [4] [5] [6] [7]
Documentation of the NIOSH Validation Tests, S160, U.S. Department of Health, Education, and Welfare; Publ. (NIOSH) 77-185 (1977). NIOSH Manual of Analytical Methods, 2nd. ed., V. 3, S160, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-157-C (1977). Feinsilver, L. Perregrino, J.A., and Smith, C.J. Jr., "Estimation of Hydrazine and Three of Its Methyl Derivatives," Am. Ind. Hyg. Assoc. J., 20, 26 (1959). Murty, N.K., Rao, V.J., and Rao, N.V.S., "Detection and Determination of Phenylhydrazine," Talanta, 31 (6), 466 (1984). Hasan, T., "Resin Bead Detection and Spectrophotometric Determination of Phenylhydrazine Using Inorganic Reagents," Anal. Lett., 21 (4), 633 (1988). NIOSH Criteria for a Recommended Standard: Occupational Exposure to Hydrazines, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 78-172 (1978). NIOSH/OSHA Occupational Health Guidelines for Occupational Hazards, U.S. Department of Health and Human Services, Publ. (NIOSH) 81-123 (1981), available as GPO Stock #017-03300337-8 from Superintendent of Documents, Washington, DC 20402.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
