Page:NIOSH Manual of Analytical Methods - 5500.pdf/2

 ETHYLENE GLYCOL: METHOD 5500, Issue 2, dated 15 August 1993 - Page 2 of 3 REAGENTS: 1. 2.

3. 4. 5. 6.

EQUIPMENT:

Ethylene glycol. 2-Propanol/water, 2% (v/v). Add 2 volumes 2-propanol to 98 volumes freshly distilled water. Helium or nitrogen, purified. Hydrogen, prepurified. Air, filtered. Calibration stock solution, 10 mg/mL, in 2% 2-propanol/water.

1. Sampler: 13-mm glass fiber filter, free of binders, in filter holder (Cat. No. SX00 013 00, Millipore Corp. or equivalent) followed by glass tube, 8 cm long, 8-mm OD, 6-mm ID; two sections of 20/40 mesh silica gel (d = 0.72 g/cm 3; surface area, 720 to 760 m 2/g) separated by 3-mm urethane foam plug (front = 520 mg; backup = 260 mg). Filter holder and glass tube connected with two short pieces of plastic tubing. One piece (7 mm long) fits tightly around outlet of filter holder; other piece fits over first piece and inlet of glass tube. 2. Personal sampling pump, 0.2 L/min, with flexible connecting tubing. 3. Gas chromatograph, FID, integrator and column (page 5500-1). 4. Vials, glass, 1-mL, rubber caps. 5. Syringes, 10-µL, readable to 0.1 µL. 6. U-tube, glass, 25 cm x 15-mm ID. 7. Constant temperature bath, 75 °C. 8. Volumetric flasks, 10-mL

SPECIAL PRECAUTIONS: None. SAMPLING: 1. 2. 3. 4.

Calibrate each personal sampling pump with a representative sampler in line. Sample at 0.2 L/min for a total sample size of 0.3 to 60 L. Immediately after sampling, disassemble the sampler and transfer the filter to a vial containing 1 mL 2% 2-propanol/water. Seal the vial. Seal the ends of the silica gel tubes with plastic caps. Pack securely for shipment.

SAMPLE PREPARATION: 5. 6.

Transfer front and backup sections of silica gel to separate vials. Add 1 mL 2% 2-propanol/water to each vial. Place samples in ultrasonic bath for 15 to 30 minutes.

CALIBRATION AND QUALITY CONTROL: 7.

8.

Calibrate daily with at least six working standards over the range 0.001 to 1 mg ethylene glycol per sample. a. Add known amounts of calibration stock solution to 2% 2-propanol/water in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with samples and blanks (steps 10 through 12). c. Prepare calibration graph (peak area or height vs. mg ethylene glycol). Determine recovery from filters in the calibration range (step 7). Prepare three filters at each of three levels plus three media blanks. a. Place a filter in a clean vial. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/93