Page:NIOSH Manual of Analytical Methods - 5601.pdf/2

 ORGANONITROGEN PESTICIDES: METHOD 5601, Issue 1, dated 15 January 1998 - Page 2 of 21 REAGENTS:

EQUIPMENT:

1. Carbamate, urea, and sulfenimide analytes listed in Table 1; internal standards acetanilide and acetophenone, analytical grade.* 2. Acetonitrile, UV grade.* 3. Methanol, HPLC grade.* 4. Deionized water, ASTM Type II. 5. 1-Propanol, UV grade.* 6. n-Butyl isocyanate.* 7. Triethylamine (TEA), HPLC grade.* Keep refrigerated (0 to 4 °C) and store under nitrogen for longer shelf life [1,8]. 8. Ortho-phosphoric acid, >85% by weight, ACS grade or better.* 9. Extraction solution. Prepare separate triethylamine phosphate (TEA-PO4 ) preservative and internal standard solutions. a. TEA-PO4 preservative, 0.1 M. Dissolve 1.4 mL of TEA in 90 mL of deionized water. Add phosphoric acid to lower pH to 7.0 (± 0.1) as indicated by a calibrated pH meter. Bring volume to 100 mL. Keep tightly capped and refrigerated. NOTE: Do not use chloroacetic acid as a preservative [9]. Formetanate, at least, is unstable with chloroacetic acid. b. Internal standard stock solution, 5mg/mL. Add 100 mg of each internal standard of choice for each 20 mL of solution required. Dissolve in acetonitrile. Store capped at –12 ± 1 °C. c. Final extraction solution. Add 1 mL of the TEA-PO4 solution and 12 mL of the internal standard stock solution to a 500-mL volumetric flask. Dilute to volume with acetonitrile. Concentration of TEA = 0.2 mM, water = 0.2%, and internal standards = 120 µg/mL. Stableup to 30 days at 0 to 4 °C. 10. Individual analyte stock solutions, 5 mg/mL. Add each analyte to acetonitrile in separate volumetric flasks. Use methylene chloride for benomyl and carbendazim. Use 50/50 v/v methanol/acetonitrilefor formetanate. Store at –12 ± 1 °C. (Solutions are stable up to 30 days.) 11. Calibration stock solution. Combine stock solutions of analytes of interest in a volumetric flask to produce the highest concentration standard (suggest 120 to 480 µg/mL). NOTE: Do not combine benomyl and carbendazim in the same standard

1. Sampler: OSHA Versatile Sampler (OVS-2 tube), 13-mm OD inlet, 6-mm OD outlet. Front section contains 270 mg 20/60 mesh XAD-2 sorbent held in place by an 11-mm diameter quartz fiber filter and Teflon® ring, separated from the back section of 140 mg XAD-2 sorbent by a short plug of polyurethane foam. The back section is held in place with a plug of polyurethane foam (See Figure 2). The tube is available commercially (SKC #226-58). OVS-2 tubes with glass fiber filters have equivalent desorption efficiencies and are available from SKC (#226-30-16) and Supelco (#ORBO-49P). 2. Personal sampling pump: 0.1 to 1 L/min with flexible and inert connecting tubing. 3. High Performance Liquid Chromatograph capable of mixing two mobile phases in a linear gradient. Must be capable of pumping up to 4000 psi, to accommodate 300 mm long columns. 4. Autosampler, low dead-volume, capable of 5-µL injections. Preservative (TEA-PO4) in the desorbing solution may be eliminated if a refrigerated autosampler tray is available.** 5. Analytical columns. a. Primary column: Base-deactivated octadecylsilyl (C1 8 ) column, e.g., NOVA-PAK® C18, 3.9-mm ID X 300 mm, 5-µm particle size or equivalent. b. Secondary column: Cyanopropyl silica column, e.g., Supelco LC-CN® 4.6 X 250-mm, 5-µm particle size or equivalent. 6. Guard column, low dead-volume, containing analytical column packing material.** 7. Ultraviolet detector, low dead-volume, with 1-cm path length cell capable of monitoring two wavelengths (200- and 225-nm) simultaneously. 8. Vials: 4-mL with PTFE-lined caps; 2-mL HPLC autosampler vials with PTFE- or polyethylene-lined snap caps. 9. Syringes: 0.01-, 0.05-, 0.1-, 1.0- and 2.5-mL; Luer lock, 1- or 2.5-mL for sample filtering. 10. Volumetric flasks: 2-, 5-, 10-, 25-, 50-, 100-, 500-, and 1000-mL. 11. PTFE syringe filter: 0.45-µm. (Gelman Acrodisc® CR PTFE 0.45-µm filter, Product equivalent.) 12. Forceps. 13. Small vial/tube tumbler capable of 5 to 10 RPM 14. pH meter. 15. Graduated cylinders, 10-mL, 25-mL.
 * 1) 4472, Gelman Sciences, Ann Arbor, MI or

NIOSH Manual of Analytical Methods, Fourth Edition