Elsevier

Food Chemistry

Volume 309, 30 March 2020, 125503
Food Chemistry

Multi-residue analysis of 126 pesticides in chicken muscle by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

https://doi.org/10.1016/j.foodchem.2019.125503Get rights and content

Highlights

  • A multi-residue analysis method for 126 pesticides in chicken muscle was developed.

  • A modified QuEChERS method was used for sample preparation and purification.

  • A new adsorbent (EMR-Lipid) selectively removed lipids from the sample matrix.

  • UHPLC–QToF–MS was used for sensitive and reliable pesticide identification.

  • The method was successfully validated and showed negligible matrix effects.

Abstract

Ensuring food safety requires effective methods for the simultaneous analysis of pesticide residues in animal-origin foods. A sensitive and reliable method for the multi-residue analysis of 126 pesticides in chicken muscle was developed using a modified QuEChERS technique and ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. A new enhanced matrix removal-lipid material was used as the QuEChERS dispersive purification adsorbent. Method validation revealed satisfactory linearities with correlation coefficients higher than 0.994 for all pesticides. All limits of quantification were below 10 µg/kg, except in the cases of oxadiazon, clomazone, and lactofen. The matrix effects were nearly negligible, ranging from 73.09% to 125.22%. The recoveries at three spiked levels (50, 100, and 200 μg/kg) were 71.38–120.43% and the intra-day and inter-day precisions were lower than 10%, indicating the good accuracy and precision of the established method.

Introduction

The global demand for chicken muscle, an important protein source, has been increasing. However, recent studies have indicated that animal-origin foods including chicken muscle may be contaminated in a variety of ways by not only high-profile veterinary drugs but also pesticides. For example, insecticides and acaricides used to spray breeding houses to control ectoparasites may come into direct contact with chickens, leading to pesticide residues in the muscle (LeDoux, 2011). Herbicides, insecticides, and rodenticides used in the cultivation and storage of forage crops may also be transferred to animal-origin foods and eventually be concentrated in the human body through the food chain, posing a threat to human health (MacLachlan, 2008). Reports in some countries have indicated that the current status of pesticide residues in chicken muscle is not optimistic (MacLachlan, 2008). As a result, the analysis of pesticide residues in chicken muscle should be given due attention.

Reported methods concerning the analysis of pesticides in chicken muscle have mainly focused on the detection of one or several pesticides (Garrido Frenich et al., 2006, Lou et al., 2018, Park et al., 2006, Rahman et al., 2016, Rahman et al., 2017, Wu et al., 2011, Zhang et al., 2016). However, the establishment of multi-residue analytical methods has been enormously challenging because of the significant differences among the chemical and physical properties of different pesticides, as well as matrix effects caused by the huge amounts of lipids and proteins in chicken muscle samples. QuEChERS (quick, easy, cheap, effective, rugged, and safe), a relatively new sample preparation method, was introduced in 2003 to quantify pesticide residues in fruits and vegetables (Anastassiades, Lehotay, Štajnbaher, & Schenck, 2003). This method includes a salting-out solvent extraction step and a dispersive solid-phase extraction (dSPE) clean-up step to remove water and unwanted matrix components from the sample matrix. Compared with other sample preparation methods, QuEChERS is faster, less expensive, more rugged, and exhibits compatibility with a wide range of pesticide residues in different products (de Oliveira et al., 2019, Li et al., 2019, Nardelli et al., 2018, Wu et al., 2011, Zhang et al., 2019).

Reported analysis methods have used targeted approaches based on gas chromatography (GC) or liquid chromatography coupled with triple quadrupole mass spectrometry operating in selected reaction monitoring (SRM) or multiple reaction monitoring (MRM) mode (Garrido Frenich et al., 2006, Rahman et al., 2016, Rahman et al., 2017, Zhang et al., 2017, Zhang et al., 2016). However, targeted analysis is limited to a predefined list of pesticides of most concern, and other pesticides excluded from the list cannot be analyzed. Moreover, the number of pesticides that can be analyzed in SRM or MRM mode is limited by the number of appropriate data points within the chromatographic peak time. High-resolution mass spectrometry (HRMS) provides the possibility of simultaneously screening unlimited pesticides at high resolution (Mezcua, Malato, García-Reyes, Molina-Díaz, & Fernández-Alba, 2009). When used for screening purposes, HRMS also allows for retrospective analysis by reprocessing the acquired data for possible non-targeted or unknown compounds without reinjection of the sample (Gómez-Pérez, Romero-González, Vidal, & Frenich, 2015). Moreover, the use of HRMS decreases the possibility of false positive identification, especially when dealing with complex matrices (Saito-Shida, Hamasaka, Nemoto, & Akiyama, 2018).

Thus, multi-residue analysis of pesticides in chicken muscle can be realized by combining a QuEChERS sample preparation method with an HRMS-based analysis method. In the present study, a QuEChERS method was employed to extract pesticides from chicken muscle. The salting-out solvent extraction and dSPE clean-up processes were optimized to reduce matrix effects and efficiently extract pesticides from chicken muscle, which was considered to contain many lipids and proteins. Subsequently, ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC–QToF–MS), which has high selectivity and sensitivity, was used for pesticide analysis.

Section snippets

Chemicals and reagents

Pesticide standards (Table 1) with purities ranging from 96.2% to 99.9% were purchased from First Standard of Alta Scientific Co., Ltd. (Tianjin, China). Acetonitrile (HPLC grade), acetone (HPLC grade), and methanol (MS grade) were purchased from Fisher Scientific (Waltham, MA). Ultrapure water was prepared using a Milli-Q Academic system (Millipore, Burlington, MA). Formic acid (≥99.0%), acetic acid (≥99.0%), and ammonium formate (≥99.0%) were purchased from Sigma-Aldrich (St. Louis, MO).

UHPLC–QToF–MS analysis

To establish a general method for the multi-residue analysis of pesticides in chicken muscle, 126 typical compounds in 6 pesticide classes were chosen to obtain a diversity of physicochemical properties. The chromatographic parameters were evaluated to obtain appropriate separation of the compounds. Considering the diversity of the analyte physicochemical properties, water and methanol were used as the mobile phase. The addition of salts to the mobile phase can increase the analyte sensitivity

Conclusion

In the present study, a high-throughput multi-residue method for the simultaneous analysis of 126 pesticides in chicken muscle was successfully established using a QuEChERS sample preparation process and UHPLC–QToF–MS. The method provided satisfactory sensitivity, with all the LOQs being below the MRLs of the corresponding pesticides. The matrix effects were negligible and the method accuracy and precision were good, indicating that the developed method is reliable and suitable for the analysis

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported by the National Key R&D Program of China (No. 2018YFC1602402 and 2017YFF0211304), the Major Project of Beijing Municipal Science and Technology Commission of China (D171100002017004), the Technical Innovation Project funded by the Chinese Academy of Agricultural Sciences, and the National Risk Assessment Project of Agro-food Safety and Quality funded by the Ministry of Agriculture and Rural Affairs of China (No. GJFP201800704).

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