Assessment of strobilurin fungicides’ content in soya-based drinks by liquid micro-extraction and liquid chromatography with tandem mass spectrometry

Abstract

Seven strobilurin fungicides were pre-concentrated from soya-based drinks using dispersive liquid–liquid micro-extraction (DLLME) with a prior protein precipitation step in acid medium. The enriched phase was analysed by liquid chromatography (LC) with dual detection, using diode array detection (DAD) and electrospray-ion trap tandem mass spectrometry (ESI-IT-MS/MS). After selecting 1-undecanol and methanol as the extractant and disperser solvents, respectively, for DLLME, the Taguchi experimental method, an orthogonal array design, was applied to select the optimal solvent volumes and salt concentration in the aqueous phase. The matrix effect was evaluated and quantification was carried out using external aqueous calibration for DAD and matrix-matched calibration method for MS/MS. Detection limits in the 4–130 and 0.8–4.5 ng g⁻¹ ranges were obtained for DAD and MS/MS, respectively. The DLLME-LC-DAD-MS method was applied to the analysis of 10 different samples, none of which was found to contain residues of the studied fungicides.

Keywords:

• strobilurin fungicides
• soya drinks
• dispersive liquid–liquid micro-extraction (DLLME)
• liquid chromatography (LC)
• ion trap-tandem mass spectrometry (IT-MS/MS)

ORCID

Natalia Campillo http://orcid.org/0000-0001-6616-951X

Pilar Viñas http://orcid.org/0000-0001-5219-3711

Manuel Hernández-Córdoba http://orcid.org/0000-0003-1795-3476

Additional information

Funding

The authors acknowledge the financial support of the Comunidad Autónoma de la Región de Murcia [CARM, Fundación Séneca, project number 19462/PI/14], the Spanish MINECO [project number CTQ2012-34772] and the European Commission (FEDER/ERDF).