Occurrence of pesticide residues and transformation products in different types of dietary supplements

Abstract

The purpose of this study was to evaluate the presence of pesticide residues and transformation products in dietary supplement products. Thirty-two samples were analysed to determine 177 pesticides by gas chromatography–tandem mass spectrometry (GC-MS/MS) and 333 pesticides by liquid chromatography–high-resolution mass spectrometry (LC-HRMS). Pesticides were extracted from different kinds of dietary supplements by the use of a modified QuEChERS extraction method. Six samples contained pesticide residues at concentration up to 92.7 µg kg⁻¹, but only butralin exceeded the maximum residue limits set for raw material. In addition to target compounds, LC-HRMS enables the simultaneous detection of non-target pesticides. In this case, transformation products of pesticides were detected in the analysed samples using HRMS analyser (Exactive-Orbitrap). These compounds were not included in the original method, and they were monitored as post-target compounds, knowing their molecular formula and exact mass. Mass accuracy was always < 2 ppm, corresponding to a maximum mass error. The positive findings endorse the idea that a deeper and continuous investigation of pesticide residues and transformation products in dietary supplement products is necessary in order to guaranty consumer’s safety.

Graphical Abstract

Keywords:

• Exactive-Orbitrap
• GC-QqQ-MS/MS
• dietary supplements
• pesticides
• transformation products

Additional information

Funding

The authors gratefully acknowledge the Spanish Ministry of Economy and Competitiveness (MINECO) and FEDER (Project ref. CTQ2012-34304). This work was also supported by the Scientific Grant Agency of the Slovak Republic VEGA (Project No. 1/503/14) and by the Slovak Research and Development Agency (Contract No. APVV-0797-11). AP is grateful for National Scholarship Programme of the Slovak Republic. RRG is also grateful for personal funding through the “University Research Plan” (Almería University) and Cajamar.