Determination of Imidacloprid and Benzimidazole Residues in Fruits and Vegetables by Liquid Chromatography–Mass Spectrometry after Ethyl Acetate Multiresidue Extraction

Abstract

A simple and sensitive method based on liquid chromatography–atmospheric pressure ionization–mass spectrometry is described for the determination of 4 benzimidazole pesticides (carbendazim, thiabendazole, benomyl, and thiophanate-methyl) and imidacloprid in vegetables and fruits. Food samples were typically extracted with ethyl acetate to draw the analytes into the organic phase. No cleanup step was necessary before injection into the liquid chromatographic (LC) system with electrospray mass spectrometric detection. The analytes were separated on a reversed-phase C8LC column. Limits of detection for the compounds were in the μg/L range. Results are reported for validation studies with fortified pear and tomato samples and for residues of the target compounds found in the pesticide residue monitoring program during 1998.

Analysis of the dissipation kinetics of thiophanate‐methyl and its metabolite carbendazim in apple leaves using a modified QuEChERS–UPLC–MS/MS method

“…To the best of our knowledge, little attention has been paid to fungicide dissipation in apple leaves, a non‐edible part which has no direct relation to human health. Various methods have been developed for the determination of TM and MBC in biological samples, including spectrophotographic assays (İlktaç, Aksuner, & Henden, ; Jiao et al, ), capillary electrophoresis (Picó, Rodrı́Guez, & Mañes, ), Raman imaging (Li, Sun, Pu, & Jayas, ), mass spectrometry (Yang et al, ), thin‐layer chromatography coupled with image analysis (Skowron, Zakrzewski, & Ciesielski, ), high‐performance liquid chromatography (Akkbik & Hazer, ; Sandahl, Mathiasson, & Jönsson, ; Singh, Foster, & Khan, ; Veneziano et al, ; Yu, Sun, Wang, He, & Feng, ; Zhang et al, ) and liquid chromatography–mass spectrometry (Chen et al, ; Chen et al, ; Chen, Cao, & Liu, ; Dong, Yang, Pang, & Hu, ; Dreassi et al, ; Economou, Botitsi, Antoniou, & Tsipi, ; Fernández‐Alba, Tejedor, Agüera, Contreras, & Garrido, ; Ferreira et al, ; Ferreira et al, ; Golge & Kabak, ; Morales, Ruiz, Oliva, & Barba, ; Qin et al, ; Wang & Leung, ; Wu, Chen, Li, & Fan, ; Zhang, Mei, Wang, Zhang, & Zhu, ). Among these methods, the Quick Easy Cheap Effective Rugged Safe (QuEChERS) method followed by UPLC–MS/MS detection has attracted more attention because of its satisfactory sensitivity, good selectivity and short analysis time (Bruzzoniti et al, ; Lehotay, ; Wilkowska & Biziuk, ).…”

Control of pesticide residues by liquid chromatography‐mass spectrometry to ensure food safety

“…Acetone (Yoshii et al, 2000; Obana et al, 2003; Sannino, 2004; Sannino, Bolzoni, & Bandini, 2004; Zamora et al, 2004), acetonitrile (Hogenboom et al, 2000; Okihashi et al, 2000; Zrostlikova et al, 2003; Hetherton et al, 2004; Lehotay et al, 2005; Lehotay, Mastovska, & Lightfield, 2005; Lehotay, Mastovska, & Yun, 2005; Thurman et al, 2005), methanol (Castro, Moyano, & Galceran, 2001; Granby & Vahl, 2001; Sage et al, 2001; Klein & Alder, 2003; Alder et al, 2004; Granby, Andersen, & Christensen, 2004; Sancho et al, 2005; Thurman, Ferrer, & Fernández‐Alba, 2005), diethyl ether (Yoshioka, Akiyama, & Teranishi, 2004), and ethyl acetate are the most used organic solvents in the extraction of pesticides from food (Zrostlikova et al, 2002; Agüera et al, 2004; Blasco, Font, & Picó, 2004b; Ortelli, Edder, & Corvi, 2004; Sannino, Bolzoni, & Bandini, 2004; Soler, Mañes, & Picó, 2005a). Ethyl acetate with anhydrous sodium sulfate and/or pH adjustment is the most applied method for the highest number of pesticides and different matrices (Fernández‐Alba et al, 2000; Fernández et al, 2001; Fernández, Picó, & Mañes, 2001a,b, 2002; Sage et al, 2001; Blasco et al, 2002a; Taylor et al, 2002; Zrostlikova et al, 2002; Ito et al, 2003; Mickova et al, 2003; Agüera et al, 2004; Blasco, Font, & Picó, 2004b; Garrido Frenich et al, 2004; Jansson et al, 2004; Soler, Mañes, & Picó, 2004, 2005a,b; Ferrer et al, 2005b; Ferrer, Thurman, & Fernández‐Alba, 2005). Acetonitrile is a good candidate as an extraction solvent for low fatty matrices because it gives high recoveries of a wide polarity range of pesticides, and yet it does not significantly dissolve highly non‐polar fats or highly polar proteins, salt, and sugars common in foods (Lehotay, Mastovska, & Lightfield, 2005).…”

“…As a general rule, the greater is the fragmentation achieved, the lower the sensitivity. Most applications of LC‐MS found in the literature for food‐sample analysis monitor only the protonated or deprotonated molecules of the pesticide, which is not enough according to the current legislation to confirm unequivocally the presence of the analyte (Fernández‐Alba et al, 2000; Yoshii et al, 2000; Fernández et al, 2001; Pous et al, 2001; Wu et al, 2002; Blasco et al, 2002a,b, 2003b, 2004; Obana et al, 2003; Juan‐García et al, 2004; Yoshioka, Akiyama, & Teranishi, 2004; Blasco, Font, & Picó, 2002, 2004a; Soler, Mañes, & Picó, 2005a; Blasco, Picó, & Font, 2002; Fernández, Picó, & Mañes, 2000, 2001a,b; Valenzuela, Picó, & Font, 2001, 2000; Takino, Yamaguchi, & Nakahara, 2004). At least three characteristic ions (three IPs) are required for correct LC/MS confirmation.…”

“…There has been a strong tendency for LC/MS methods to be developed for a relatively small‐multi‐residue set of analytes so that both LC and MS conditions can be fully optimized for maximum sensitivity, depending on the physicochemical properties of analytes. Several methods has been reported for a few fungicides (Fernández‐Alba et al, 2000; Fernández et al, 2001; Ito et al, 2003; Blasco et al, 2003b; Juan‐García et al, 2004; Zamora et al, 2004; Yoshioka, Akiyama, & Teranishi, 2004; Blasco, Picó, & Font, 2002), carbamates (Wu et al, 2002; Blasco et al, 2002b, 2003b; Biogialli et al, 2004; Bogialli et al, 2004; Sánchez‐Brunete, Albero, & Tadeo, 2004; Fernández, Picó, & Mañes, 2000; Takino, Yamaguchi, & Nakahara, 2004), dithiocarbamates (Blasco, Font, & Picó, 2004a), triazines (Okihashi et al, 2000), macrocyclic lactones (Yoshii et al, 2000), neonicotinoids (Obana et al, 2003), organophosphorus (Mol & van Dam, 2003; Blasco et al, 2004), phenylureas (Wu et al, 2002), and benzoylureas (Valenzuela, Picó, & Font, 2000). Others have been reported for multi‐class pesticides, in a number between 10 and 30.…”

Comparison of four mass analyzers for determining carbosulfan and its metabolites in citrus by liquid chromatography/mass spectrometry

“…Liquid chromatography/mass spectrometry (LC/MS) has been widely accepted as the main tool in the identification, structural characterization and quantitative analysis of pesticides and their TPs, owing to its superior sensitivity, specificity and efficiency 2, 6, 9–12. Many studies dealing with routine pesticide determination in food are based on LC/MS using a single quadrupole4, 13–17 because it was the first robust LC/MS equipment able to analyze a very large number of samples. The guidelines on quality control procedures for pesticide residue analysis and the 2002/657/EEC Commission Decision, concerning the performance of analytical methods for the determination of organic residues and contaminants in live animal and animal products,18, 19 affirm that ‘methods based only on chromatographic analysis without the use of molecular spectrometric detection are not suitable for use as confirmatory methods’, and the latter explicitly requires a combination of mass spectrometry with either an on‐line and/or off‐line chromatographic separation.…”