Page:NIOSH Manual of Analytical Methods - 1404.pdf/2

 METHYLCYCLOHEXANOL: METHOD 1404, Issue 1, dated 15 August 1994 - Page 2 of 3 EQUIPMENT:

REAGENTS: 1. 2. 3. 4. 5. 6. 7.

m-Methylcyclohexanol *, ACS reagent grade. p-Methylcyclohexanol *, ACS reagent grade. Methylene chloride *, distilled in glass. Nitrogen, purified. Hydrogen, prepurified Air, filtered, compressed. Calibration stock solution, 14.8 mg/mL. Add 80 µL m-methylcyclohexanol and 80 µL p-methylcyclohexanol to 10 mL methylene chloride.

See Special Precautions

1. Sampler: glass tube, 7 cm long, 6-mm OD, 4-mm ID, flame-sealed ends with plastic caps, containing two sections 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 3-mm urethane foam plug follows the back section. Pressure drop across the tube at 1 L/min airflow must be less than 25 mm/Hg. Tubes are commercially available. 2. Personal sampling pump, 0.01 to 0.2 mL/min, with flexible polyethylene or PTFE tubing. 3. Gas chromatograph with a FID detector, recorder, integrator and column (page 1404-1). 4. Vials, 2-mL, PTFE-lined crimp caps. 5. Syringe, 10-µL and other sizes as needed,

SPECIAL PRECAUTIONS: Methylcyclohexanol can irritate the eyes and upper respiratory tract and can cause liver and kidney damage. Methylene chloride is an irritant, can be absorbed through the skin, and is a suspect carcinogen [3]. Prepare samples in a 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. Pack securely for shipment.

SAMPLE PREPARATION: 5. 6. 7.

Place the front and back sections of the sampler in separate vials. Discard the glass wool and foam plugs. Add 1.0 mL methylene chloride to each vial. Cap each vial. Allow to stand 30 min with occasional agitation.

CALIBRATION AND QUALITY CONTROL: 8.

9.

Calibrate daily with at least six working standards. a. Add known amounts of methylcyclohexanol to methylene chloride in 10-mL volumetric flasks and dilute to the mark. Use serial dilutions as needed to obtain concentrations in the range 0.02 to 10 mg/mL. b. Analyze with samples and blanks (steps 11 and 12). c. Prepare calibration graph (area vs. mg of methylcyclohexanol). Determine desorption efficiency (DE) at least once for each lot of sorbent used for sampling in the range of interest (step 8). Prepare three tubes at each of five levels plus three media blanks. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94