Sensitive determination of 2,4,6-trichloroanisole in water samples by ultrasound assisted emulsification microextraction prior to gas chromatography–tandem mass spectrometry analysis

Abstract

A novel application of an ultrasound assisted emulsification microextraction (USAEME) technique is proposed for the extraction and preconcentration of 2,4,6-trichloroanisole (2,4,6-TCA) from water samples prior to its determination by gas chromatography–tandem mass spectrometry (GC–MS/MS). USAEME employs a non-polar high-density solvent (extractant solvent), which forms an oil-in-water emulsion (O/W) in the aqueous sample bulk assisted by ultrasonic radiation. Several factors including, solvent type and volume, extraction time, extraction temperature, shaking mode and matrix modifiers were studied and optimized over the relative recovery of the target analyte. An aliquot of 5 mL water sample was conditioned by adding 150 L 6.15 mol L−1 sodium chloride and 300 L 0.05 mol L−1 phosphate buffer (pH 6), and finally extracted with 40 L chloroform by using USAEME technique. Under the optimal experimental conditions 2,4,6-TCA was quantitatively extracted achieving an enrichment factor (EF) of 555. The detection limit (LOD), calculated as three times the signal-to-noise ratio (S/N), was 0.2 ng L−1 and the RSD was 6.3% (n = 5) when 1 ng L−1 2,4,6-TCA standard mixture was analyzed. The coefficients of estimation of the calibration curves obtained following the proposed methodology was ≥0.997 and the linear working range was 1–5000 ng L−1. Finally, the proposed technique was successfully applied for extraction and determination of the 2,4,6-TCA in water samples. Recovery studies lead values ≥94%, which showed a successfully robustness of the analytical methodology for determination of nanogram per liter of 2,4,6-TCA in water samples.