Graphene-coated cotton fibers as a sorbent for the extraction of multiclass pesticide residues from water and their determination by gas chromatography with mass spectrometry.

A straightforward functionalization procedure is proposed for synthesizing a cotton-supported graphene as an extraction material, which is effectively employed for the extraction of multiclass pesticides from environmental waters prior to their determination by gas chromatography with mass spectrometry. Different experimental parameters that affect the extraction efficiency, including pH of the extraction, stirring rate, extraction time, ionic strength, presence of humic acid, sample volume, amount of sorbent, and elution conditions, were investigated and properly established. The advantages of the present extraction method are the simplicity of implementation, rapidity, and low consumption of sorbent per extraction. Moreover, the pesticides on the adsorbent are stable, under certain storage conditions, rendering the cotton-supported graphene suitable for environmental field studies. The applicability of the cotton-graphene-based procedure for routine analysis was demonstrated by the determination of pesticides in a lake water sample. The recoveries ranged from 83 to 107%, the limits of quantitation were in the range of 0.02-0.09 μg/L, and the calculated relative standard deviations varied from 3 to 8% (data obtained with the same batch of sorbent). Because of the acceptable analytical characteristics, the developed method shows great prospects in determining certain classes of pesticides in water.