Page:NIOSH Manual of Analytical Methods - 2506.pdf/2

 ACETONE CYANOHYDRIN: METHOD 2506, Issue 2, dated 15 August 1994 - Page 2 of 5

REAGENTS:

EQUIPMENT:

1.	Desiccant, bagged, for field use. 2.	Acetone cyanohydrin, 98% or better.* 3.	Ethyl acetate, chromatographic quality. 4.	Silicone oil (OV-17). 5.	Coated Chromosorb-T, 40/60 mesh, for GC stationary phase (APPENDIX). 6.	Calibration stock solution, ca. 1.8 mg/mL. Inject 2.0 µL acetone cyanohydrin into 1.0 mL ethyl acetate. Compute the actual concentration from analyte density. 7.	Nitrogen, purified. 8.	Hydrogen, purified. 9.	Air, filtered.
 * See SPECIAL PRECAUTIONS.

1.	Sampler: glass tube, 7 cm long, 6-mm OD, 4-mm ID; two sections (front = 100 mg; back= 50 mg) of pre-extracted 50/80 mesh Porapak QS held in place and separated by silanized glass wool plugs. Tubes are commercially available (SKC, Inc. #226-59-09, or equivalent). 2.	Personal sampling pump, 0.01 to 0.2 L/min, with flexible connecting tubing. 3.	Refrigerant, bagged (“Blue Ice,” or equivalent). 4.	Gas chromatograph, NPD, integrator, and column (page 2506-1 and APPENDIX). 5.	Vials, 2-mL, glass, PTFE-lined crimp caps. 6.	Ultrasonic bath, water. 7.	Syringe, 10-µL, readable to 0.1 µL. 8.	Pipet, 1-mL, with pipet bulb. 9.	Spatula.

SPECIAL PRECAUTIONS: Acetone cyanohydrin is extremely toxic; it is readily decomposed by water to form hydrogen cyanide and acetone. Perform all work with the analyte in a hood. Avoid dermal contact with acetone cyanohydrin. It is readily absorbed through the skin and will decompose in the body, with release of HCN, to induce cyanosis [3]. SAMPLING: 1.	Calibrate each personal sampling pump with a representative sampler in line. 2.	Break ends of the sampler immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. 3.	Sample at an accurately known flow rate between 0.1 and 0.2 L/min for a total sample size between 0.3 and 12 L. 4.	Cap the samplers with PTFE tape and plastic (not rubber) caps. Pack the samplers in a plastic bag containing bagged refrigerant. Ship in a refrigerated container at 0 °C. SAMPLE PREPARATION: 5.	Bring the samples to room temperature before uncapping. Remove the end caps from the sorbent tube. 6.	Remove the front glass wool plug. Place it in a vial along with the front (larger) sorbent section. Transfer the separating glass wool plug along with the back sorbent section to a separate vial. 7.	Add 1.0 mL ethyl acetate to each vial. Attach crimp cap to each vial. 8.	Agitate the samples in an ultrasonic waterbath for 60 min. CALIBRATION AND QUALITY CONTROL: 9.	Calibrate daily with at least six working standards over the range 0.1 to 50 µg acetone cyanohydrin per sample. a.	 Add aliquots of calibration stock solution or a serial dilution thereof to 1.0 mL ethyl acetate in 2-mL vials. Attach crimp cap to each vial. b.	 Analyze together with samples and blanks (steps 12 and 13). c.	 Prepare calibration graph (peak area vs. µg acetone cyanohydrin).

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition