Pesticide residues quantification in frozen fruit and vegetables in Chilean domestic market using QuEChERS extraction with ultra-high-performance liquid chromatography electrospray ionization Orbitrap mass spectrometry

Highlights

• Pesticides were detected in 96.6% of the 237 total frozen produce samples.

• 21 Samples exceeded local MRL and 1 sample exceeded CODEX standards.

• Iprodione, Spinosad A and D were the most detected molecules in frozen produce.

• Local frozen produce requires to be inspected and controlled by authorities to check pesticide standards compliance.

Abstract

Pesticide residues on foods are a global concern due to the impact on human health. Many countries have adopted regulations to establish Maximum Residue Levels (MRLs) to control use of pesticides. This study aimed to determine pesticide residues in frozen fruit and vegetables from Chilean retail stores using UHPLC-Orbitrap MS and QuEChERS™ multiresidue-extraction kit. 237 samples of frozen produce were sampled from different supermarkets and times during the year. Abamectin, Chlorpyrifos, Imidacloprid, Iprodione, λ-cyhalothrin, Spinosad A, and Spinosad D were quantified. Results showed that Iprodione, Spinosad A, and D were the most detected molecules. Pesticides were detected in 96.6% of samples and 21 samples exceeded MRL. Corn and faba beans showed the highest concentration of Iprodione with an average of 6.7 and 5.4 mg/Kg, respectively. Existence of nonconformity in samples highlights the importance to control pesticide residues of Chilean frozen produce, since it represents a latent health threat on consumers.

Introduction

In recent years the use of pesticides commercial in agriculture has led to a better efficiency and raise of production not only for export, but also for internal market. Abundance of agricultural commodities at a reasonably low cost and local consumer demand for a wide variety of products and availability of them along the whole year have promoted the development of frozen products that can be found nationwide in retail. However, current consumer awareness for food safety (Kaushik, Satya, & Naik, 2009) and agricultural commodities disadvantage of pesticide residual presence (Krol, Arsenault, Pylypiw, & Incorvia Mattina, 2000) contributed to establish strict maximum residue levels (MRL) to comply with the limitation of consumer’s total dietary intake of pesticides. Furthermore, in literature there is enough documentation that evidences that many of these compounds are known carcinogens and/or toxins, and therefore can cause significant health damage to humans (Alavanja et al., 2013, Koutros et al., 2010). Although, in Chile the government agency that has enforcement control of manufacturing, marketing, and application of pesticides and fertilizers is the Agriculture and Livestock Service (SAG), the institutions that set the national standards of MRL of pesticides that may occur in food are the Ministry of Health and the Secretariat of Public Health under the Exempt Resolution Norm 33 (Ministerio de Salud, 2010). According to the Exempt Resolution Norm 33 the MRLs range depending on the commodity and pesticide from 0.01 to 7 mg/kg.

Therefore, food safety inspection authorities require quick, sensitive and precise analytical methods to detect a wide diversity of pesticide residues and their levels on products such as frozen fruit and vegetables. Multiresidue methods incorporate a single extraction technique with analytical equipment that is able to determine diverse compounds (Krol et al., 2000). Determination of pesticide residues in food frequently involves quantification using gas chromatography (GC) combined with mass spectrometry (GC–MS) (Fillion et al., 2000, Gamon et al., 2001) since is very useful with volatile and semi-volatile compounds as well as with non-polar compounds because of an outstanding separation capacity and resolution (Wang, Wang, & Cai, 2013). However, other techniques have become broadly common recently such as liquid chromatography (LC) – tandem mass spectrometry (MS–MS) with triple quadrupole in selected reaction monitoring (SRM) mode for the quantitation of polar pesticides in food (Agüera et al., 2004, Cairns et al., 1993, Jansson et al., 2004, Klein and Alder, 2003, Štajnbaher and Zupančič-Kralj, 2003). Moreover, Ferrer et al. developed a multi-residue methodology using liquid chromatography–time-of-flight mass spectrometry (LC–TOF-MS) for routine pesticide residues determination in fruit and vegetables. LC-MS is widely applied for the simultaneous separation and analysis of complex food samples, including food contaminants and food components (Ferrer, Garcia-Reyes, Mezcua, Thurman, & Fernández-Alba, 2005). LC is used to separate not only the analytes but also some polar or non-polar interfering compounds in food samples (Wang et al., 2013). Moreover, LC together with full scan high-resolution mass spectrometry (LC–full scan HRMS) has demonstrated to be a successful method to detect the presence of a wide variety of analytes in food samples (García-Reyes et al., 2007, Kaufmann, 2012). Mol et al. evaluated the analytical capabilities of LC combined with single-stage HRMS using Orbitrap ion trap analyzer for selective detection during screening and to identify pesticides in 21 different vegetable and fruit commodities (Mol, Zomer, & de Koning, 2012). Authors achieved a screening detection limit of 0.01 or 0.05 mg/kg for 66% and 23% of the pesticides, respectively, therefore this method showed potential for testing maximum residue levels compliance of pesticides in commodities. Furthermore, ultra-high performance liquid chromatography (UHPLC) instrumentation has been developed and coupled to MS for food analysis, thus providing greater sensitivity, better peak capacity, higher speed, and increased resolution since the particle size of the stationary phase is significantly smaller (Bakırcı et al., 2014, Wang et al., 2009).

With all these considerations there is an assumption that there is potential of UHPLC coupled with Orbitrap MS technique for applicability in frozen fruit and vegetables pesticide routine analysis. Thus, the aim of this study has been to determine pesticide profile of frozen fruit and vegetables from Chilean retail stores using UHPLC- Orbitrap MS technique to evaluate compliance with MRL established in Chilean and international regulations.