Page:NIOSH Manual of Analytical Methods - 9201.pdf/2

 CHLORINATED AND ORGANONITROGEN HERBICIDES (PATCH): METHOD 9201, Issue 1, dated 15 January 1998 - Page 2 of 11

REAGENTS:

EQUIPMENT:

1. Analytes* listed in Table 1. 2. Isopropanol, pesticide analytical grade. 3. Silicic Acid, 100-mesh. Aldrich Chemical Co. or equivalent. 4. Diazomethane* derivatizing reagent. (See APPENDIX) 5. D i a z a l d ® ( N - m e t h y l - N - n i t r o s o p-toluenesulfonamide*), Aldrich Chemical Co. or equivalent. 6. Herbicide stock solutions. Prepare individual standard stock solutions of each herbicide of interest in isopropanol. NOTE: All herbicides in Table 1 were found to be soluble to at least1 mg/mL, except simazine, which is soluble to 0.5 mg/mL. 7. Calibration stock solution. Dilute the appropriate volume of herbicide stocksolution to a known volume with isopropanol. NOTE: Spiking solutions may contain more than one analyte. 8. Purified gases: Helium, 5% methanein Argon, or nitrogen.

1. Polyurethane foam (PUF) patch. 10 x 10 x 0.6-cm, contained ina aluminized card holder, 10 x 10 cm, which has a 7.6-cm-diameter circle in one side. (SKC Inc., Eighty Four, PA 15330 or equivalent.) NOTE: Before use, clean the PUF patch by soxhlet extraction for 20 hours in acetone/methanol, 88/12, v/v, followed by three hexane rinses. 2. Gas chromatograph, electron capture detector, integrator, and column (see Page 9201-1 and Table 2). 3. Syringes, 2-, 5-mL, and 10-, 50-, and 100-µL for making standard solutions and GC injections 4. Syringes, luer lock, 1-, 2.5-, or 5-mL for sample filtering. 5. PTFE syringe filters, 0.45-µm pore size. (Gelman Acrodisc® CR or equivalent). 6. Volumetric flasks, 2-, 5-, 10-, 25-, 50-, and 100-mL for working standard preparation and solutions.. 7. Jars, glass, 120-mL, PTFE-lined cap. 8. Vials, glass, 2-mL, GC autosampler, with PTFE-lined caps. 9. Test tubes, glass screw-top, with PTFE seals, 16 x 125 mm, 16-mL volume. 10. Forceps. 11. Platform shaker.


 * See SPECIAL PRECAUTIONS.

SPECIAL PRECAUTIONS: Diazomethane has been cited as a carcinogen. It is extremely toxic and highly irritating. Diazomethane may explode under some conditions. Do not heat above 90 °C. Avoid ® rough surfaces: fire-polish glass tubing, or use Teflon . Do not expose solutions to strong light. Keep dilute ® solutions at 0 °C. Prepare in a hood [2]. Diazald is far more convenient to use on a large scale than the alkyl-nitrosonitroguanidines.Avoid skin contact withDiazald® and herbicides. Avoid skin contact and open flame with solvents. Use in a hood. SAMPLING: 1. Dermal Patch a. Insert a cleaned PUF patch into patch holder. Secure to desired location on clothing or skin. b. At the conclusion of the sampling period, remove PUF patch from holder with solvent-washed (acetone or isopropanol) forceps and place in a 120-mL jar; cap securely. c. Label and pack for shipment. SAMPLE PREPARATION: 2. Add 20 mL of isopropanol toPUF in jar. Add an additional 20 mL diazomethane derivatizing reagent to jar. Cap securely, and using platform shaker rotate 5 to 10 RPM for a minimum of 1.5 hours. 3. Transfer a 10-mL sample aliquot into a screw-top test tube with a PTFE-lined cap. Add approximately 10 mg of silicic acid to the solution. Allow to stand an additional hour. 4. Filter an aliquot through a 0.45-µm PTFE filter into a 2-mL GC vial. Label. NOTE: It is important to filter the samples because the silicic acid fines can build-up in the chromatographic system and cause deterioration of analytical column performance.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition