A novel stir bar sorptive-dispersive microextraction in combination with magnetically modified graphene for isolation of seven pesticides from water samples

摘要

A new sample preparation technique: stir bar sorptive-dispersive microextraction (SBSD mu E) with magnetically modified graphene (G-Fe3O4) as the sorbent was applied to isolation of multiclass seven pesticides (boscalid, chlorpyrifos, deltamethrin, dimethenamid-P, dimoxystrobin, metazachlor and tebuconazol) from spiked water samples. Selected experimental parameters were studied, and the optimized extraction conditions were as follows: 20 mg of the sorbent, sample pH 6, adsorption time - 12 min, addition of 1 g NaCl and 4.5 mL of acetone as the desorbing solvent. At the optimized conditions the developed extraction method was compared with magnetic solid phase extraction (MSPE). Extractions were performed in four replicates at three concentration levels of the pesticides. The average extraction yields of all the pesticides for the SBSD mu E and MSPE methods were 20-75% (RSD 1-12%) and 22-82% (RSD 2-13%), respectively. Compared with the MSPE method the proposed SBSD mu E approach is more quick and convenient in collecting of the sorbent, as well as more effective in mixing of larger volume samples.