Page:NIOSH Manual of Analytical Methods - 2510.pdf/2

 1-OCTANETHIOL: METHOD 2510, Issue 2, dated 15 August 1994 - Page 2 of 3 REAGENTS: 1. 2. 3.

4. 5. 6.

EQUIPMENT:

Acetone*. 1-Octanethiol, ≥97% purity.* Calibration stock solution, 0.843 µg/µL. Dissolve 10 µL 1-octanethiol in 10 mL acetone. Prepare fresh daily. Nitrogen or helium, purified. Hydrogen, prepurified. Air, filtered.



See SPECIAL PRECAUTIONS.

1. Sampler: glass tube, 8.5 cm long, 6-mm OD, 4-mm ID, sealed with PTFE tape and plastic caps containing front (100-mg) and rear (50-mg) sections of 60/80 mesh Tenax-GC, separated and held in place by three silanized glass wool plugs. (Tenax-GC pretreatment: Sohxlet extraction for 6 hrs with acetone/methanol, 6 hrs with methanol, then drying under vacuum.) Typical pressure drop across tube is 2.4 kPa at 0.05 L/min flow. Similar commercially available tubes, e.g., SKC #226-35-03, are acceptable. 2. Personal sampling pump, 0.01 to 0.2 L/min, with flexible connecting tubing. 3. Ultrasonic bath. 4. Gas chromatograph, sulfur-specific FPD, integrator and column (page 2510-1). 5. Vials, glass, 2- and 5-mL, crimp seals or caps, PTFE-lined silicone rubber septa. 6. Pipets, 1-, 2- and 5-mL, with pipet bulb. 7. Syringes, 10- and 100-µL.

SPECIAL PRECAUTIONS: Acetone is highly flammable (flash point = -18 °C). Thiols are malodorous [2]. Prepare samples and standards in well-ventilated hood.

SAMPLING: 1. 2. 3. 4.

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 total sample size of 1 to 15 L. Cap the samplers with plastic (not rubber) caps and 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 and foam plugs. Add 2.0 mL acetone to each vial. Attach crimp cap to each vial. Place vials in an ultrasonic bath for 45 min.

CALIBRATION AND QUALITY CONTROL: 8.

Calibrate daily with at least six working standards over the range 1 to 60 µg 1-octanethiol per sample. a. Add known amounts of calibration stock solution to acetone in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with samples and blanks (steps 11 and 12). NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94