Simple and rapid method for the determination of ethylenebisdithiocarbamate fungicides in fruits and vegetables using liquid chromatography with tandem mass spectrometry

Abstract

A simple and rapid method for determining ethylenebisdithiocarbamates (EBDCs; mancozeb, maneb, and zineb) in fruits and vegetables is described. EBDCs are transformed into dimethylethylenebisdithiocarbamate (EBDC-dimethyl) by methylation after their decomposition with ethylenediaminetetraacetic acid (EDTA). These processes were performed simultaneously in this method. Dimethyl sulfate was used as the methylation reagent, and acetonitrile extracts obtained from partitioning with anhydrous magnesium sulfate and sodium chloride were subjected to dispersive solid-phase extraction with the primary secondary amine sorbent. Liquid chromatography with tandem mass spectrometry in the positive heated-electrospray ionization mode was used for the determination of EBDC-dimethyl produced from EBDCs. The method was validated at levels of 10, 50, and 100 ng g(-1) maneb as a representative EBDC. The recoveries of the present method were between 71 and 101%. The limits of detection and quantification were 0.24 and 0.8 ng g(-1) maneb, respectively.

Current mass spectrometry strategies for the analysis of pesticides and their metabolites in food and water matrices

“…The sample treatment step is somehow a bottleneck for the development of large scale screening procedures in pesticide residues analysis. Troublesome compounds (i.e., chlormequat, paraquat, dithiocarbamates, glyphosate) not recovered with the generic sample treatment procedures should be analyzed with single-residue methods (Andersen, Bille, & Granby, 2007;Crognorac, Schmauder, & Schwack, 2008;Hanke, Singer, & Hollender, 2008;Hayama & Takada, 2008;Esparza, Moyano, & Galceran, 2009). Based on the cited literature, simpler sample treatment procedures are usually required for LC-MS analysis (Table 1) while more exhaustive sample pre-treatment procedures involving additional clean-up steps have been applied in GC-MS analysis (Table 2).…”

“…Approximately 60% of the methodologies reviewed in the present article covering the last 3 years are based on LC-QqQ-MS. Even though the majority of methodologies proposed in the field of pesticide residue-analysis focus on the development of multi-residue multi-class methods using LC-QqQ-MS, several deal with single-residue and/or single-class applications especially in cases where the definition of the residue in the MRL (Commission Regulations (EC), 396/2005, 149/2008, 839/2008 encompass metabolites and transformation products of the parent compound (Goto et al, 2006b;Soler et al, 2006a;Barceló & Petrovic, 2007;Hengel & Miller, 2007;Perreau et al, 2007;Poulsen et al, 2007;Sannino, 2007;Caboni et al, 2008;Crnogorac, Schmauder, & Schwack, 2008;Hayama & Takada, 2008;Hanke, Singer, & Hollender, 2008;Koesukwiwat, Sanguankaew, & Leepipatpiboon, 2008;Sarais et al, 2008;Xinyi et al, 2008;Esparza, Moyano, & Galceran, 2009;Tokman et al, 2009). Nowadays, parent compounds and their transformation products can be analyzed with LC-QqQ-MS in the same chromatographic run; this is especially helpful for official and/or routine laboratories.…”

A rapid and sensitive analysis of dithiocarbamate fungicides using modified QuEChERS method and liquid chromatography–tandem mass spectrometry

“…In this case, the addition of a conventional EDTA solution [12][13][14][15][16][17][21][22][23][24][25] was not appropriate, as the LC-MS/MS peak corresponding to EDTA overlapped with the peak originating from PBMe. We therefore investigated the effect of the NaHCO 3 concentration on the sample prior to methylation, using propineb, mancozeb, and thiuram as representative compounds for PB, EB, and DD, respectively, as previously mentioned.…”

“…Thus, we attempted to prevent degradation by adding DTT as a stabilizer, as it has been reported that reducing agents are effective stabilizers. 26) In this case, we could not select cysteine, [12][13][14][15][16][17][22][23][24][25] as the retention times for the methylated form of cysteine and DDMe were comparable under the same MS/MS conditions due to their similar molecular weights. Thus, we also investigated the effect of the DTT concentration on the samples and found that degradation was prevented in a number of cases, resulting in enhanced methylation rates.…”

“…Therefore, a method based on the use of highly sensitive GC-mass spectrometry (GC-MS) was developed. 15,16) However, the issues relating to tedious sample preparation remained for these methods, which led Hayama et al 17) to develop a simplified methylation technique by applying the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) approach. The QuEChERS method is a simple and easy method for the multiresidue analysis of pesticides in fruits and vegetables; it employs acetonitrile extraction/partitioning and dispersive solid-phase extraction.…”