Page:NIOSH Manual of Analytical Methods - 2531.pdf/3

 GLUTARALDEHYDE: METHOD 2531, Issue 2, dated 15 August 1993 - Page 3 of 5 SAMPLE PREPARATION: 4. 5. 6. 7. 8.

Score each sampler with a file in back of the back sorbent section. Break sampler at score line. Remove and place back glass wool plug and back sorbent section in a vial. Transfer front section with remaining glass wool plugs to a second vial. Add 2.0 mL toluene to each vial. Screw cap tightly onto each vial. Agitate vials in an ultrasonic bath for 60 min. NOTE: Desorption efficiency is affected by the amount of time that the vials are allowed to spend in the ultrasonic bath. A minimum of 60 min residence time in the ultrasonic bath is required to ensure adequate desorption.

CALIBRATION AND QUALITY CONTROL: 9.

10.

11.

Prepare glutaraldehyde oxazolidine standard solutions. a. Add known amounts of glutaraldehyde oxazolidine stock solution (equivalent to the range of the samples) to toluene in 10-mL volumetric flasks and dilute to the mark. b. Analyze (steps 12 and 13) with samples and blanks for qualitative identification of derivative peaks. Calibrate daily with at least five working standards covering the range of the samples. a. Weigh 120-mg portions of unused sorbent from media blanks into vials. b. Add aliquiots of glutaraldehyde stock solution or dilutions thereof. Cap vials and allow them to stand overnight at room temperature. c. Desorb (steps 7 and 8) and analyze (steps 12 and 13) with samples and blanks. d. Prepare calibration graph (combined peak area vs. µg glutaraldehyde). NOTE: Because the working standards are prepared on media blanks, no additional blank correction or desorption efficiency correction is necessary. Check desorption efficiency occasionally in the range of interest (see APPENDIX D). Analyze three quality control blind spikes to ensure that the calibration graph is in control.

MEASUREMENT: 12.

13.

Set gas chromatograph to manufacturer's recommendations and to conditions given on page 2531-1. Inject 1-µL sample aliquot. NOTE: If the amount of oxazolidine in the aliquot exceeds the capacity of the column, dilute the sample with toluene and apply the appropriate dilution factor in calculations. Measure total peak area of the two analyte peaks. NOTE: On the recommended column, the oxazolidine derivative gives two peaks, since the diastereoisomers are resolved. t r for the glutaraldehyde derivative = 9.4 and 9.7 min; and t r for 2-(hydroxymethyl)piperidine = 2.6 min for these conditions.

CALCULATIONS: 14.

15.

Determine the mass, µg, of glutaraldehyde found in the sample front (W f) and back (W b) sorbent sections. NOTE: If W b > W f/10, report breakthrough and possible sample loss. Calculate concentration, C, of glutaraldehyde in the air volume sampled, V (L):

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/93