EPICHLOROHYDRIN: METHOD 1010, Issue 2, dated 15 August 1994 - Page 3 of 4
a. b. c. d. e. 10.
the calibration range (step 8). Prepare three tubes at each of five levels plus three media blanks. Remove and discard back sorbent section of a media blank sampler. Inject a known amount of epichlorohydrin (or a solution of epichlorohydrin) directly onto front sorbent section with a microliter syringe. Cap the tube. Allow to stand overnight. Desorb (steps 5 through 7) and analyze together with working standards (steps 11 and 12). Prepare a graph of DE vs. µg epichlorohydrin recovered. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and DE graph are in control.
MEASUREMENT: 11.
12.
Set gas chromatograph according to manufacturer's recommendations and to conditions given on page 1010-1. Inject sample aliquot manually using solvent flush technique or with autosampler. NOTE: If peak area is above the linear range of the working standards, dilute with CS2, reanalyze, and apply the appropriate dilution factor in calculations. Measure peak area.
CALCULATIONS: 13.
14.
Determine the mass, µg (corrected for DE) of epichlorohydrin found in the sample front (Wf) and back (Wb) sorbent sections, and in the average media blank front (Bf) and back (Bb) sorbent sections. NOTE: If Wb > Wf/10, report breakthrough and possible sample loss. Calculate concentration, C, of epichlorohydrin in the air volume sampled, V (L):
C
(Wf
Wb
Bf V
Bb )
, mg/m 3.
EVALUATION OF METHOD: Method S118 was issued on May 9, 1975 and validated over the range 11.7 to 43.1 mg/m3 using approximately 20-L sample volumes [2] of a generated atmosphere of epichlorohydrin. During sampling, a total hydrocarbon analyzer was used to independently verify the analyte concentration. Epichlorohydrin at the OSHA standard, 0.38 mg, was stable on coconut charcoal for six days at ambient temperature. Over the analytical range, the average DE was 0.905. Breakthrough of the front section occurred at 44.4 L while sampling 43.1 mg/m3 at 0.185 L/min. Epichlorohydrin was also sampled at 40 µg/L for 49 L without breakthrough to the back section using 80% relative humidity [1]. In this later evaluation, epichlorohydrin on lot 105, PCB 20/40, charcoal was found to be stable for at least two weeks. A DE of 0.82 was used to correct results of 8.1 and 11.6 µg per tube.
REFERENCES: [1] Hill, R.J., Jr., J.A. Arnold and W.J. Woodfin. Collection and Determination of Epichlorohydrin in Air, NIOSH, Method evaluation report (unpublished, 1976). [2] Documentation of the NIOSH Validation Tests, S118, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-185 (1977). 3] NIOSH Manual of Analytical Methods, 2nd ed., Vol. 2, S118, U.S. Department of Health, Education, NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
