Page:NIOSH Manual of Analytical Methods - 2533.pdf/2

 TETRAETHYL LEAD (as Pb): METHOD 2533, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS: 1. 2. 3.

4.

EQUIPMENT:

Pentane (reagent grade). Tetraethyl lead.* XAD-2 resin (Rohm & Haas Co.)(optional, if commercial tubes are used). Extract, in order, for 24 h each in Soxhlet or Giant extractor with: water, methanol, diethylether, and npentane. Dry 24 h under vacuum (0.1 to 1 kPa) at low heat. Calibration stock solution, 2 mg/mL (as Pb). Dissolve 31.2 mg tetraethyl lead (ca. 19 µL) in pentane to make 10 mL solution. Prepare in duplicate.



1. Sampler: glass tubes, 10-cm long, 6-mm OD, and 4-mm ID with plastic caps, containing two sections of 20/50 mesh XAD-2 resin (front = 100 mg, back = 50 mg), separated and contained by silylated glass wool plugs. Tubes are commercially available. 2. Personal sampling pump, 0.01 to 1.0 L/min, with flexible connecting tubing. 3. Gas chromatograph, with photoionization detector, integrator, and column. 4. Vials, 2-mL, glass, with PTFE-lined caps. 5. Volumetric flasks, 10-mL. 6. Syringe, 10-µL, readable to 0.1 µL. 7. Pipet, 1 mL, with bulb.

See SPECIAL PRECAUTIONS.

SPECIAL PRECAUTIONS: Tetraethyl lead is extremely poisonous. Acute or chronic poisoning may occur if inhaled or absorbed through skin [3].

SAMPLING: 1. 2. 3. 4.

Calibrate each personal sampling pump with a representative sampler in line. Break 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 1 L/min for a total sample size of 30 to 200 L. Cap the samplers. Pack securely for shipment.

SAMPLE PREPARATION: 5. 6.

7.

Place the front and back sorbent sections of the sampler tube in separate vials. Discard the glass wool plugs. Add 1.0 mL pentane to each vial. Cap each vial. NOTE: A suitable internal standard, such as 0.1% (v/v) dodecane, may be added to samples, blanks, and working standards at this step [2]. Allow to stand 30 min with occasional agitation.

CALIBRATION AND QUALITY CONTROL: 8.

Calibrate daily with at least six working standards. a. Add known amounts of calibration stock solution to pentane in 10-mL volumetric flasks and dilute to the mark. Use serial dilutions as needed to obtain tetraethyl lead (as Pb) concentrations in the range 0.1 to 30 µg/mL. b. Analyze with samples and blanks (steps 11 and 12). c. Prepare calibration graph [peak area vs. µg tetraethyl lead (as Pb)].

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