Biotin-Streptavidin-enhanced Enzyme-Linked Immunosorbent Assay for the Determination of Parathion-Methyl in Vegetables

Abstract

The development of rapid, simple, and sensitive analytical methods for food contaminants is a topic of considerable interest. Polyclonal antibody against parathion-methyl (PM) was raised and used to develop a biotin-streptavidin indirect competitive enzyme-linked immunosorbent assay (BS-icELISA) with improved sensitivity for the determination of PM in vegetable. At the optimum conditions, the IC₅₀ and limit of detection of BS-icELISA for PM were found to be 1.2 µg/L and 0.2 µg/L, respectively, which is 6-fold more sensitive than the traditional icELISA. This method was applied to determine PM residue in three vegetable samples with a simple and effective extraction procedure, good recoveries (in the range of 88.2–108.7% and with coefficients of variation below 15%) and accuracy (correlation coefficient of 0.9576 with GC-MS) were obtained. Our results indicated that the biotin-streptavidin system is useful in improving the sensitivity of ELISA and could be used for routine monitoring of pesticide at trace level.

Keywords:

• Biotin-streptavidin enzyme-linked immunosorbent assay
• Parathion-methyl
• Sensitivity
• Vegetable

Notes

^a Natural antibody for icELISA and biotinylated antibody for BS-icELISA.

^b IgG-HRP for icELISA and SA-HRP for BS-icELISA.

^a Percentage of CR was calculated according to the following equation: CR(%) = [IC₅₀ (PM, mmol/L)/IC₅₀ (analogs, mmol/L)] × 100.

^a The concentration spiked was lower than the limit of detection and undetectable.