Fast determination of alkylphenol ethoxylates in leafy vegetables using a modified quick, easy, cheap, effective, rugged, and safe method and ultra-high performance supercritical fluid chromatography–tandem mass spectrometry

Abstract

In the present study, a quick and sensitive method was developed for simultaneous determination of nonylphenol ethoxylates (NPxEOs) and octylphenol ethoxylates (OPxEOs) (x=2–20) in three leafy vegetables, including cabbage, lettuce, and spinach using a modified “QuEChERS” method and ultra-high performance supercritical fluid chromatography–tandem mass spectrometry (UHPSFC-MS/MS) with scheduled multiple reaction monitoring (MRM). Under optimized conditions, the 38 target analytes were analyzed within a short period of time (5 min). The linearities of the matrix-matched standard calibrations were satisfactory with coefficients of determination (R2)>0.99 and the limits of detection (LOD) and quantification (LOQ) were in between 0.02–0.27 and 0.18–1.75μgkg−1, respectively. The recovery of all target analytes spiked at three (low, medium, and high) fortification levels in various leafy vegetables were ranged from 72.8–122.6% with relative standard deviation (RSD) ≤18.3%. The method was successfully applied to market samples and the target analytes were found in all monitored samples, with total concentrations of 0–8.67μgkg−1 and 15.75–95.75μgkg−1 for OPxEOs and NPxEOs (x=2–20), respectively. In conclusion, the newly developed UHPSFC-ESI–MS/MS method is rapid and versatile and could be extrapolated for qualitative and quantitative analysis of APxEOs in other leafy vegetables.