Analytical method validation and comparison of two extraction techniques for screening of azoxystrobin from widely used crops using LC–MS/MS

Abstract

A simple analytical method was developed and validated in chilli, tomato, grape and mango fruits using liquid chromatography tandem mass spectrometry. The method comprised of extraction with ethyl acetate and cyclohexane mixture followed by d-SPE cleanup employing modified quick, easy, cheap, effective, rugged and safe extraction method and quantified in LC–MS/MS using gradient elution. The method was validated in concentration ranging from 0.01 to 0.1 µg g−1. The recovery of azoxystrobin in different crops was ranging from 84.36 to 95.64 % at three different concentration levels of analytes with relative standard deviation (HorRat < 20 %) of 4–14 %. The global uncertainty was calculated at limit of quantification level i.e. 0.01 µg g−1. In order to evaluate in safety use in India, a field study was conducted with the following extraction method. The calculated half life periods of azoxystrobin were ranging from 3.10–3.46, 3.64–3.46, 1.65–1.96 and 1.32–1.36 days respectively for experimental substrates. The PHI values of azoxystrobin in chilli, tomato, grape and mango fruits were determined as 4.76, 3.90, 4.06 and 10.74 days respectively.