Page:NIOSH Manual of Analytical Methods - 1301.pdf/3

 KETONES II: METHOD 1301, Issue 2, dated 15 August 1994 - Page 3 of 5 a. Remove and discard back sorbent section of a media blank sampler. b. Inject a known amount of analyte 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. mg analyte recovered. Analyze three quality control blind spikes and three analyst spikes to insure that the calibration graph and DE graph are in control.

10.

MEASUREMENT: 11.

Set gas chromatograph according to manufacturer's recommendations and to conditions given on page 1301-1. 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 CS 2, reanalyze, and apply the appropriate dilution factor in calculations. Measure peak area.

12.

CALCULATIONS: 13.

Determine the mass, mg (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 analyte in the air volume sampled, V (L):

14.

EVALUATION OF METHOD: Laboratory testing with spiked samples and samples collected from atmospheres generated by syringe pump/air dilution and verified by FID continuous monitor [2]. Results were:

S/A Breakthrough 1 Overall Range Precision ˆ rT (mg/m 3) (L) S

Method [1,2]

Range (mg per sample)

DE 2-

Sr

Camphor

S10

0.02 to 0.40

0.97

0.018

6 to 25

>48

Mesityl oxide

S12

0.10 to 3.0

0.81

0.014

45 to 210

5-Methyl-3-heptanone

S13

0.15 to 4.0

0.90

0.014

Methyl-(n-amyl)-ketone

S15

0.5 to 10.0

0.82

Ethyl butyl ketone

S16

0.25 to 7.0

0.94

Compound

1 2

Bias (%)

Accuracy (±%)

0.074

0.9

10.5

>48

0.071

7.0

22.8

60 to 270

>36

0.10

13.1

31.0

0.012

200 to 925

>36

0.066

4.9

15.0

0.022

100 to 460

>24

0.086

-3.1

26.3

5% breakthrough, 0.2 L/min at high end of concentration range in dry air. Averaged over mass range shown.

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