Barrier film protected, and mixed solvent optimized micro-scale membrane extraction of methyl carbamate pesticides.

Hollow fiber based microextraction has emerged as an effective alternative to conventional preconcentration techniques. The loss of the extractant solvent through the membrane has been an important issue, and dip-coating with a barrier film is a method for stabilizing the acceptor. Typically, only one solvent is used to serve as the extractant, which limits the range of compounds that can be analyzed simultaneously. Mixing solvents in varying proportions can increase the range of compounds enriched. This paper reports the optimization of the microextraction system by implementing a barrier film to reduce solvent loss, in conjunction with the use of mixed solvents to enrich a broader spectrum of analytes. A group of five carbamate pesticides were studied here. The detection limits were at ppb levels and the enrichment was as high as 1600 times depending upon the solvent. R2 and %RSD ranged from 0.9501 to 0.9991 and 1.90 and 9.53, respectively.