摘要：HPLC using a large-volume injection technique has been developed to determine trace levels of pesticides in water. To prevent disturbance of the base line from excess water injected, a reversed-phase guard cartridge is substituted for an injection loop as an enrichment column. This procedure is applied to Asulam, N'-methoxycarbonyl sulfanylamide, one of the herbicides used in golf links. One milliliter of sample made up in a solution of 0.5 mM in cetyltrimethylammonium chloride is passed through the cartridge, where Asulam is trapped quantitatively. Asulam is then back flushed from the cartridge onto an analytical column, where the separation is achieved. Asulam below ppb level can be readily detected. The precision of the measurements, evaluated by the analysis of spiked samples, is 3.3% at 1 ppb level.
