Page:NIOSH Manual of Analytical Methods - 9200.pdf/2

 CHLORINATED AND ORGANONITROGEN HERBICIDES (HAND WASH): METHOD 9200 - Page 2 of 11

REAGENTS:

EQUIPMENT:

1. 2. 3. 4.

1. Bags, polyethylene, 12 in x 8", 4-mil wall thickness. (Scienceware®, or equivalent. NOTE: Test bags from each lot and supplier for interfering contaminants before use. 2. Gas chromatograph, electron-capture detector, integrator, and column (page 9200-1 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, 250-mL, PTFE-lined caps. 8. Vials, 2-mL, GC autosampler vials with PTFE-lined crimp caps. 9. Test tubes, glass, screw-top, with PTFE seals, 16 x 125 mm, 16-mL volume.

5. 6.

7.

8.

Analytes listed in Table 1. Isopropanol*, pesticide analytical grade. Silicic Acid, 100-mesh. Diazomethane* derivatizing reagent. (See APPENDIX) Diazald® (N-methyl-N-nitroso-p-toluenesulfonamide. 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 least 1 mg/mL, except simazine, which is soluble to 0.5 mg/mL. Calibration stock solution. Dilute the appropriate volume of herbicidestock solution to a known volume with isopropanol. NOTE: Spiking solutions may contain more than one analyte. Purified gases: helium, 5% methane in argon, or nitrogen.

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 alkylnitrosonitroguanidines. Avoid skin contact with Diazald® and herbicides. Avoid skin contact and open flame with solvents. Wear appropriate protective clothing and work with these compounds in a well ventilated hood. SAMPLING: 1. Pour 150 mL of isopropanol into the polyethylene bag. 2. Insert hand into bag. Wrap the top of the bag securely around the forearm, several inches above the wrist. NOTE: Allergies to alcohols are extremely rare. Before conducting thehandwash, check to see if the person has ever had a reaction to alcohols, or is taking medications that could react with the alcohol. Some skin conditions, such as cuts, abrasions, and eczema can be irritated by contact with alcohols. If the person’s hand seems “dried-out” after the handwash, hand lotion can be applied. 3. Shake hand in alcohol with constant back and forth motion for 30 seconds. Remove hand from bag and dry with paper towel. 4. Transfer solution to glass jar, cap securely. 5. Label and pack for shipment. 6. For field blank, add 150 mL isopropanol to a clean bag, shake for 30 seconds, then transfer the solvent to a glass jar for shipment. SAMPLE PREPARATION: 7. Pipette 10 mL of sample into a screw-top test tube with a PTFE-lined cap. 8. Add 0.5 mL of diazomethane derivatizing reagent. Mix and allow to stand for one hour. 9. Add approximately 10 mg of silicic acid to the solution. Mix and allow to stand an additional hour. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
 * See SPECIAL PRECAUTIONS