Analysis of MCPA and TCP in water by liquid chromatography-ion trap-electrospray tandem mass spectrometry

Abstract

An HPLC-IT-MS technique with SPE preconcentration was used to determine 2-methyl-4-chlorophenoxy acetic acid (MCPA) and 2,4,6-thrichlorophenol (TCP) in water. The extraction procedure involved sieving 1 L water samples through a 0.5 g graphitised carbon black (GCB) extraction cartridge and elution of the analytes using methylene chloride/methanol (80:20 v/v) with 10 mmol L⁻¹ formic acid. Under optimised LC-MS/MS and SPE conditions, recoveries of 85–96% were achieved when three water samples were spiked with each acidic compound at concentrations between 50 and 200 ng L⁻¹. RSDs between 2% and 10% were obtained. Excellent linear relationships were observed within 0.02–1 μg L⁻¹ (solvent calibration) and 0.05–2.5 μg L⁻¹ (matrix-matching calibration) with linear correlation coefficients greater than 0.99. Detection limits between 3 and 14 ng L⁻¹ were obtained. The method was successfully used to determine MCPA and TCP in water and applied to real samples.

Keywords:

• LC-IT-MS
• matrix effect
• MCPA
• TCP
• SPE-GCB extraction
• water sample

Acknowledgement

The authors wish to thank the Special Fund for Agro-scientific Research in the Public Interest (No. 201203022) for their financial support.