Page:NIOSH Manual of Analytical Methods - 5602.pdf/4

 CHLORINATED AND ORGANONITROGEN HERBICIDES (AIR SAMPLING): METHOD 5602, Issue 1, dated 15 January 1998 - Page 4 of 14

different polarity. If primary analysis was performed using a nonpolar or weakly polar column (e.g., DB-1 or DB-5) confirmation should be accomplished by reanalysis on a polar columne.g., ( DB-17 or DB-1701). See Table 4 for approximate retention times for each column type. For positive identification of high-level analytes (1 to 10 µg/mL or greater), GC/MS may be used. Figure 4 shows a typical chromatogram using a DB-17 column. Figure 5 shows a typical chromatogram using a DB-5 column. Table 5 gives notes on the analytical characteristics of the chlorinated organonitrogen and acid herbicides. EVALUATION OF METHOD: The method was evaluated over the ranges listed in Table 3. These ranges represent 3 x LOQ to 30 x LOQ for each of the compounds. Table 3 also lists the measurement precision (r), overall sampling and measurement precision ( rT), bias, and accuracy for the compounds evaluated using this method. The analytical conditions used in the evaluation are in Table 4 with the DB-5ms column. The front filter of each sample tube was fortified with an aliquot of a solution containing the 8 herbicides. Air was then drawn through the tubes at 1 L/min for 8 h (480 Ltotal volume)at 30 °C. One set of samplers was tested at 15% relative humidity (RH) and the other set was tested at 80% RH. All samples were stored at 4C. Humidity did not affect the analyte recoveries from the samplers. A long-term storage study also was done. Samples were loaded at the 10 x LOQ level and 480 L of 80% RH air was pulled through the samples. Average recovery for individual pesticides on Day 1 was 110 to 120% with cyanazine having a high recovery of 150% and 2,4-D acid having a recovery of 91%. Day 30 storage samples had a range of recoveries from 70 to 82% based on Day 1, with 2,4-D acid and simazine having recoveries of 104% and 88%, respectively. Day 50 samples had average recoveries of 80% of Day 1, with 2,4-D acid having 101 % recovery, and cyanazine having a 69% recovery.

REFERENCES: [1] [2]

[3]

[4] [5]

NIOSH [1995]. Back-up data report for chlorinated organonitrogen and carboxylic acid herbicides. Prepared under NIOSH Contract 200-88-2618 (unpublished). NIOSH [1977]. 2,4-D: Method S279. In: Taylor DG, ed. NIOSH Manual of Analytical Methods (NMAM), 2nd ed., v. 5. Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 77-157C. NIOSH [1984]. 2,4-D and 2,4,5-T: Method 5001. In: Eller PM, ed. NIOSH Manual of Analytical Methods (NMAM), 3rd ed. Cincinnati, OH: National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 84-100 Hill RH Jr, Arnold JE [1979]. A personal air sampler for pesticides. Arch Environ Contam Toxicol 8:621-628. Black TH [1983]. The preparation and reactions of diazomethane. Aldrichimica Acta 16(1).

METHOD WRITTEN BY: Don C. Wickman, John M. Reynolds, and James B. Perkins, DataChem Laboratories, Salt Lake City, Utah

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition