Determination of atrazine and its deethylated degradation product in water and sediment by using gas chromatography/ion trap mass spectrometry

A gas chromatography/ion trap mass spectrometry method was used for the trace analysis of atrazine and its deethylated degradation product deethylatrazine in environmental water and sediment samples. The isotope dilution technique was applied for the quantitative analysis of atrazine at parts-per-trillion levels. Water samples were pre-concentrated by solid-phase extraction using a C₁₈ cartridge while the sediment samples were extracted by sonication with methanol. The concentrated extracts were analysed by a GC/ion trap MS operated in the MS/MS method. The extraction recoveries for the analytes were better than 83% when 1 L of water or 10 g of sediment was analysed. The method detection limits were 0.75 ng/L and 0.13 ng/g for atrazine and deethylatrazine detected in water and sediment, respectively. The precisions of the method represented by the relative standard deviation were in the range of 3.2-16.1%. The method was successfully applied to analyse surface water and sediment samples collected from Beijing Guanting reservoir. Trace levels of atrazine at 35.9-217.3 ng/L and 2.4-8.4 ng/g were detected in the water and sediment samples, respectively. The levels of deethylatrazine were five to 20 times lower that those of atrazine.