Vidal, JLM; Gonzalez, FJE; Glass, CR; Galera, MM; Cano, MLC
A proposed gas chromatographic method for determining lindane (58899), alpha-endosulfan (959988), beta-endosulfan (33213659), and endosulfan-sulfate (1031078) in greenhouse air was developed. Air samples were collected on SKC model PCEX3KB personal samplers packed with polyurethane foam (PUF). The analytes were desorbed from the PUF sorbent by Soxhlet extraction using 100 milliliters (ml) of an 85:15 hexane/light petroleum mixture or 100ml acetone. The extracts were cleaned up in a filter tube packed with anhydrous sodium-sulfate, after which they were evaporated to 4ml by heating at 40 degrees-C and then to 0.4ml under a nitrogen stream. The sample was diluted to 4ml with hexane, 0.4 microgram dieldrin was added as an internal standard, then injected into a gas chromatograph fitted with an electron capture detector. The detection limits for lindane, alpha-endosulfan, beta-endosulfan, and endosulfan-sulfate were 1.9, 2.5, 3.1, and 3.6 nanograms (ng) per ml, respectively. The corresponding limits of quantitation were 6.3, 8.3, 10.2, and 12.0ng/ml. Studies conducted using standard atmospheres spiked with known concentrations of the analytes indicated that air sample volumes of 30 to 480 liters at flow rates of 1 to 2 liters per minute could be sampled and detectable amounts of the compounds could be trapped on the PUF sorbent. The method was applied to examining the rate of decrease of 4.4mg/m3 alpha-endosulfan, 4.2mg/m3 beta-endosulfan, and 3.3mg/m3 lindane when applied in an experimental greenhouse. Sequential air sampling indicated that after 24 hours, 7.5% of the initial concentrations of alpha-endosulfan and beta-endosulfan and 8.7% of the initial lindane concentration were still present in the greenhouse air. Experiments investigating the adsorbent properties of Chromosorb 102, Porapak-R, Supelpak-2, Amberlite XAD-2, and Amberlite XAD-4 as well as PUF were described.