A simple, rapid and novel method based on salting-out assisted liquid–liquid extraction for ochratoxin A determination in beer samples prior to ultra-high-performance liquid chromatography coupled to tandem mass spectrometry

ABSTRACT

A novel, simple, easy and cheap sample treatment strategy based on salting-out assisted liquid-liquid extraction for ochratoxin A (OTA) ultra-trace analysis in beer samples using ultra-high-performance liquid chromatography-tandem mass spectrometry determination was developed. The factors involved in the efficiency of pre-treatment were studied employing factorial design in the screening phase and the optimal conditions of the significant variables on the analytical response were evaluated using a central composite face-centred design. Consequently, the amount of salt ((NH₄)₂SO₄), together with the volumes of sample, hydrophilic (acetone) and nonpolar (toluene) solvents, and times of vortexing and centrifugation were optimised. Under optimised conditions, the limits of detection and quantification were 0.02 µg l⁻¹ and 0.08 µg l⁻¹ respectively. OTA extraction recovery by SALLE was approximately 90% (0.2 µg l⁻¹). Furthermore, the methodology was in agreement with EU Directive requirements and was successfully applied for analysis of beer samples.

GRAPHICAL ABSTRACT

KEYWORDS:

• Ochratoxin A
• beer
• salting-out assisted liquid-liquid extraction
• ultra-high-performance liquid chromatography

Acknowledgments

The authors wish to acknowledge the financial support received by Universidad Nacional de San Luis [Project PROICO 2–1816]. Consejo Nacional de Investigaciones Científicas y Técnicas [Projects: PUE 2016 N° 0113 and PIP: 2015 N° 0111]. Agencia Nacional de Promoción Científica y Tecnológica [Projects: PICT 2014–0347 and PICT 2016–1776]. Instituto de Química de San Luis (INQUISAL. UNSL-CONICET) and Instituto Nacional de Vitivinicultura (INV). Also, the first author desires to thank the PhD scholarship supplied by CONICET.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary data

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Additional information

Funding

This work was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas;Fondo para la Investigación Científica y Tecnológica;Universidad Nacional de San Luis.