[Detection of 11 Organophosphate Pesticides and Atrazine in Water by Dispersive Liquid-Liquid Microextraction Combined with Gas Chromatography Mass Spectrometry].

Objective: To develop a method for detecting 11 organophosphate pesticides and atrazine in water samples by dispersive liquidliquid microextraction combined with gas chromatographymass spectrometry (DLLMEGC/MS) .

Methods: DLLME and GCMS parameters were optimized for efficient extraction of chemicals. The proposed method was used for detecting organophosphate pesticides in tap water and river water samples,with 200 μL of dimethylbenzene as extractant and 800 μL of methanol as dispersant. They were mixed,emulsified and dispersed into 10 mL of water samples. The extractant (1 μL) from centrifugation was injected into the GC/MS system for analyses. GC separation was performed on HP5 column (30 m×0.25 mm,0.25 μm) by temperature programming. Mass spectrometric analysis was done with EI and selected ion monitoring (SIM) mode was used for quantitative analysis.

Results: Good linear ranges for detecting the 11 pesticides and atrazine appeared from 2.0 ng/mL to 50 ng/mL,with a limit of 0.121.38 ng/mL. The relative standard derivations ranged from 5.57% to 9.85%. The average recoveries ranged from 75.5% to 107%.

Conclusion: The method is sensitive and rapid,with simultaneous extraction and concentration procedures. The lowdensity organic solvent after extraction is easy to isolate. The method fits for analyses of organophosphate pesticides and atrazine in water samples.