Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem Analytical Methods Analysis of pesticide residues in tuber crops using pressurised liquid extraction and gas chromatography-tandem mass spectrometry Zareen Khan, Narayan Kamble, Aarti Bhongale, Madhuri Girme, Vijay Bahadur Chauhan 1 , Kaushik Banerjee ⁎ National Referral Laboratory, ICAR-National Research Centre for Grape, P.O. Manjri Farm, Pune 412307, Maharashtra, India ARTICLE INFO Keywords: Multiresidue analysis of pesticides in tubers Pressurized liquid extraction GC–MS/MS Yam Taro Sweet potato Method validation ABSTRACT Tuber crops substantially contribute to the food security in the developing countries. Often, their cultivation involves unregulated applications of pesticides, leading to MRL non-compliances. Despite their rising currency in international trade, there exist scarcely any methods for pesticide residue analysis in these matrices. Therefore, we developed a multi-residue method for simultaneous analysis of a diverse range of pesticides in tuber crops, based on pressurized liquid extraction by ethyl acetate, followed by selective identification and quantification of the residues using GC–MS selected reaction monitoring. The method was evaluated for 150 pesticides. Results showed that their limits of quantification were 0.1–10 ng/g, with recoveries of 70–120%. When compared to the conventional analytical techniques, such as QuEChERS and buffered ethyl acetate extraction, this method pro- vided superior performance in terms of precision, and recovery of the spiked and incurred residues with similar productivity. The method holds promise for commercial and regulatory residue analysis. 1. Introduction In the developing countries, the principal tropical root crops, namely yam (Dioscorea alata), taro (Colocasia esculenta), and sweet potato (Ipomoea batatas L.) are largely known to contribute to the food security (FAO, 2010; Chandrasekara & Josheph Kumar, 2016; Scott, Rosegrant, & Ringler, 2000a; Shajeela, Mohan, Jesudas, & Soris, 2011; Campus & State, 2014). Despite their high annual global production and rising share in the global trade (Scott, Rosegrant, & Ringler, 2000b), good agricultural practices (GAP)-based recommendations for the safe use of pesticides are meagerly available for these crops. Often, their cultivation involves unregulated applications of pesticides, thereby leading to non-compliance issues related to trade, and potential health hazards to consumers (Campus & State, 2014; Olufade, Sosan, & Oyekunle, 2014; Cervera et al., 2010; Frenich, Fernández, Moreno, Vidal, & López-Gutiérrez, 2012; Gushit, Ekanem, Harami, & Chindo, 2013). According to a report provided by the United States – Food and Drug Administration, every year around 10% of the imported tuber crop samples fail to comply with the MRLs (U.S. FDA, 2013). In 2014, the European Union placed a temporary prohibition on the import of taro from India on account of food safety issues (EFSA, 2010). Despite these concerns, there exist scarcely any validated methods for the analysis of pesticide residues in these matrices. Given this gap of knowledge, we endeavored to develop an effective sample preparation method for multiresidue analysis of pesticides, particularly in yam, taro, and sweet potato. In the field of pesticide residue analysis, pressurized liquid extrac- tion (PLE) is a well-known technique that involves the extraction of residues from solid or semi-solid samples (Verma, 2010) at elevated temperatures and pressures, providing superior recoveries (Kettle, 2013; Beyer & Biziuk, 2008; Picó, 2017; Vazquez-Roig & Picó, 2015). Because of its importance, the PLE has been adopted by many re- searchers for the extraction of pesticides from various agricultural and food matrices (Chiesa et al., 2016; Kostik, 2014; Pang et al., 2006; Frenich, Salvador, Vidal, & López-López, 2005; Nemoto & Lehotay, 1998; Ridgway, Lalljie, & Smith, 2007). Higher recoveries of pesticides had been reported by the PLE in comparison to the supercritical fluid extraction (SFE) (Lehotay & Lee, 1997). Similarly, PLE was found to be superior over the soxhlet extraction (Suchan, Pulkrabová, Hajšlová, & Kocourek, 2004). Kostik, 2014 and Pang et al., 2006 used the solid phase extraction (SPE) as a clean-up approach after extraction of pesticides by the PLE. Fairly recent, a PLE method with “in-cell” clean-up has been reported for the detection of contaminants in honey in which the sample was cleaned by florisil for removing the co-ex- tractives (Chiesa et al., 2016). Despite various studies conducted so far, there is hardly any report http://dx.doi.org/10.1016/j.foodchem.2017.08.091 Received 15 May 2017; Received in revised form 27 August 2017; Accepted 28 August 2017 ⁎ Corresponding author. 1 ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram 695017, Kerala, India. E-mail address: kbgrape@yahoo.com (K. Banerjee). Food Chemistry 241 (2018) 250–257 Available online 31 August 2017 0308-8146/ © 2017 Elsevier Ltd. All rights reserved. MARK