A Double Extraction Method for Determination of Diphenylamine in Fruits by GC/MS

Abstract

A double extraction method comprising ultrasound assisted QuEChERS treatment combined with hollow-fiber liquid phase micro extraction was developed for the determination of diphenylamine in various fruit samples using gas chromatography coupled to a single-quadrupole mass spectrometer. Briefly, a known portion of fruit sample underwent an ultrasound assisted QuEChERS treatment. The organic phase resulting from QuEChERS treatment of a fruit sample was diluted 5-fold with pure water followed by a hollow fiber liquid-phase micro extraction procedure for further cleaning and preconcentration. In the late procedure, the analyte was extracted from the diluted sample into a thin layer of (dodecane+10% tri-n-octylphosphine oxide) sustained in the pores of a porous hollow fiber. The analyte was back extracted into acetonitrile located inside the lumen of the hollow fiber. Selected ion monitoring mass spectrometry was used for quantitative determination. The calibration curve was linear over the concentration range of 20-200 µg kg-1. The relative recovery was in the range of 76-108% while, precision varied between 6.4-13.7%. Finally, the applicability of the joint method was tested through analysis of diphenylamine in various fruit samples.