Page:NIOSH Manual of Analytical Methods - 1452.pdf/2

 ETHYL FORMATE: METHOD 1452, Issue 1, dated 15 August 1994 - Page 2 of 3 REAGENTS: 1. 2.

3. 4. 5.

EQUIPMENT:

Ethyl formate, ACS reagent grade. Eluent: carbon disulfide, chromatographic quality, with 0.1% v/v n-nonane, ACS reagent grade (optional internal standard). Helium, purified. Hydrogen, prepurified. Air, compressed, filtered.



SPECIAL PRECAUTIONS

1. Sampler: glass tube, 7 cm long, 6-mm OD, 4mm ID flame-sealed ends with plastic caps, containing two sections of 20/40 mesh of activated (600 °C) coconut shell charcoal (front = 100 mg; back = 50 mg) separated by a 2-mm urethane foam plug. A silylated glass wool plug precedes the front section and a 3mm urethane foam plug follows the back section. Pressure drop across the tube must be less than 3.4 kPa at 1 L/min airflow. Tubes are commercially available. 2. Personal sampling pump, 0.01 to 0.2 L/min, with flexible connecting tubing. 3. Gas chromatograph, FID, integrator, and column. 4. Vials, glass, 2-mL, PTFE-lined caps. 5. Syringe, 10-µL and other convenient sizes for preparing standards. 6. Flasks, volumetric, 10-mL. 7. Pipet, 1-mL graduated in 0.1 mL increments with bulb.

SPECIAL PRECAUTIONS: Carbon disulfide is toxic and a serious fire and explosion hazard (flash point = -30 °C); work with it only in a hood. SAMPLING: 1. 2. 3. 4. 5.

Calibrate each personal sampling pump with a representative sampler in line. Break the ends of the sampler immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. Sample at an accurately known flow rate between 0.01 and 0.2 L/min for a sample size of 0.3 to 10 L. Replace the caps on the sampling tube and pack securely for shipment. Obtain a small quantity (5 mL) of the bulk material in a glass container with a Teflon-lined cap. Ship to the laboratory in a separate container from the charcoal tube samples.

SAMPLE PREPARATION: 6. 7. 8.

Place the front and back sorbent sections of the sampler tube in separate vials. Discard the glass wool and foam plugs. Add 1.0 mL eluent to each vial. Attach cap to each vial. Allow to stand for 30 min. with occasional agitation.

CALIBRATION AND QUALITY CONTROL: 9.

Calibrate daily with at least six working standards covering the range 0.01 to 6 mg/sample. a. Add known amounts of ethyl formate to eluent in 10-mL volumetric flasks with a concentration equal to 70% of that of the highest standard. b. Analyze together with the samples (steps 12 and 13). NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94