Determination of Five Pesticide Residues in Water by Gas Chromatography-Electron Capture Detection

Objective To determine atrazine, lindane, chlorothalonil, chlorpyrifos, and deltamethrin simultaneously in water samples by gas chromatography- electron capture detection.

Methods Pretreated by liquid-liquid extraction and dehydrated with anhydrous sodium sulfate, water samples were, directly injected into the gas chromatograph for determination. The tests were done to optimize the sorts and amount of solvent, and the amount of sodium chloride used in this method which were the factors affecting the recovery rates. The spiked recovery rates at three concentration levels (low, medium, and high) were determined by adding the external standard samples. Each concentration level was determined for six times.

Results The standard curves obtained by this method showed good linear correlation within the determined range of concentration, and the coefficients were all over 0.999 6. The detection limits were at the range from 0.01 μg/L to 0.30 μg/L, the average recovery rates were 90.5%-110.0%, with the relative standard deviation ranged from 0.4% to 3.2%.

Conclusion This method was suitable for determination of five pesticide residues simultaneousiy in water samples, which was simple to operate without being concentrated, less interference, rapid analysis, good sensitivity and linearity, high precision and accuracy.