Page:NIOSH Manual of Analytical Methods - 1451.pdf/3

METHYL CELLOSOLVE ACETATE: METHOD 1451, dated 15 August 1994 - Page 3 of 3 a. b.

10.

Remove and discard back sorbent section of a media blank sampler. Inject a known amount of calibration stock solution directly onto front sorbent section with a microliter syringe. c. Cap the tube. Allow to stand overnight. d. Desorb (steps 5 through 7) and analyze together with working standards (steps 11 and 12). e. Prepare a graph of DE vs. µg methyl cellosolve acetate. Analyze three quality control blind spikes and three analyst spikes to insure 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 1451-1. 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 eluent, reanalyze, and apply the appropriate dilution factor in calculations. Measure peak area. If internal standard is used, divide the peak area of analyte by the peak area of internal standard on the same chromatogram.

CALCULATIONS: 13.

14.

Determine the mass, µg (corrected for DE) of analyte found in the sample front (W f) and back (W b) sorbent sections, and in the average media blank front (B f) and back (B b) sorbent sections. NOTE: If W b > W f/10, report breakthrough and possible sample loss. Calculate concentration, C, of methyl cellosolve acetate in the air volume sampled, V (L):

EVALUATION OF METHOD: This method was validated over the range 51 to 214 mg/m 3 at 23 °C and pressure of 762 mm Hg using 20-L samples [2]. Overall sampling and measurement precision, SˆrT, was 0.078, with average recovery of 99.8% [2]. Sample stability of methyl cellosolve acetate on charcoal was determined by OSHA to be at least 15 days at 0 °C [1].

REFERENCES: [1] [2] [3]

OSHA Manual of Analytical Methods, Method 53, U.S. Occupational Safety and Health Administration, Salt Lake City, Utah (1985). NIOSH Manual of Analytical Methods, 2nd. ed., V. 2, S39, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-157-B (1977). Analytical Report for Organics on Charcoal Tubes, Data Chem Sequence # 6227, Unpubl. NIOSH (1988).

METHOD REVISED BY: Rosa J. Key-Schwartz, Ph.D., NIOSH/DPSE.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94