Page:NIOSH Manual of Analytical Methods - 3514.pdf/3

 ETHYLENIMINE: METHOD 3514, Issue 2, dated 15 August 1994 - Page 3 of 4 SAMPLE PREPARATION: 5. 6. 7. 8. 9. 10.

Transfer sample solution to a 60-mL separatory funnel. Rinse bubbler with 4 mL of chloroform, and add rinse to separatory funnel. Cap and shake funnel for 15 seconds. Allow the phases to separate. Collect chloroform extract in a 10-mL volumetric flask. Repeat steps 6 and 7, and collect chloroform extract in the same volumetric flask. Dilute solution in the volumetric flask to 10 mL with chloroform.

CALIBRATION AND QUALITY CONTROL: 11.

12.

Calibrate daily with working standards over the range of 1.4 to 3681 µg of 4-(1-aziridinyl)-1,2naphthoquinone per sample. Express the quantities of 4-(1-aziridinyl)-1,2-naphthoquinone in terms of the corresponding quantities of ethylenimine (1 µg of 4-(1-aziridinyl)-1,2naphthoquinone corresponds to 0.216 µg of ethylenimine). The corresponding range is 0.3 to 795 µg of ethylenimine per sample. a. Dilute portions of the calibration stock solution to prepare a series of working standards in the range of 0.3 to 795 µg of ethylenimine per sample (0.03 to 79.5 µg/mL). b. Analyze according to steps 13 and 14. c. Prepare a calibration graph (peak area or peak height versus µg of ethylenimine per sample). Determine recovery from bubblers. a. Dilute portions of recovery stock solution with chloroform to prepare a series of spiking solutions in the range of interest. b. Add known quantities of ethylenimine in spiking solutions to bubblers containing 15-mL quantities of Folin's reagent. Prepare five samples at each of three levels over the range of interest. c. Prepare sample solutions (steps 5 through 10) and analyze (steps 13 and 14). d. Calculate recovery, R (µg of ethylenimine found divided by µg of ethylenimine applied). e. Prepare a graph of recovery versus µg of ethylenimine found.

MEASUREMENT: 13. 14.

Set the liquid chromatograph according to manufacturer's instructions and to conditions on page 1. Analyze sample solutions with standards.

CALCULATIONS: 15. 16.

Determine the quantities of ethylenimine in the sample corrected for Recovery, W (µg), and the average media blank, B (µg), from the calibration graph. Calculate the concentration, C (mg/m 3), of ethylenimine in the air volume sampled, V (L):

EVALUATION OF METHOD: This method is based on Method P&CAM 300, which was evaluated with controlled atmospheres of ethylenimine [3]. Overall precision ( SˆrT) was 0.069 (52 samples, pooled) for 2.6- to 39-L samples at 0.16 to 21 mg/m 3; SˆrT includes an assumed pump error of 0.05. Independent concentrations of ethylenimine vapor in the controlled atmospheres (referred to as "taken" values) were calculated from the measured total air flow and the delivery rate of the syringe pump. Recoveries with controlled atmospheres NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94