Development of a QuEChERS-Based UHPLC-MS/MS Method for Simultaneous Determination of Six Alternaria Toxins in Grapes

Abstract

A simple and reliable analytical method for the simultaneous determination of alternariol (AOH), altenuene (ALT), tentoxin (TEN), altenusin (ALS), tenuazonic acid (TeA), and alternariol monomethyl ether (AME) in grapes was developed by ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS). A modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure with the extraction by acetonitrile and purification by sodium chloride (0.5 g) and anhydrous magnesium sulfate (0.5 g) was established to recover the six Alternaria toxins. After validation by determining the linearity (R2 > 0.99), recovery (77.8–101.6%), sensitivity (limit of detection in the range of 0.03–0.21 μg kg−1, and limit of quantification in the range of 0.09–0.48 μg kg−1), and precision (relative standard deviation (RSD) ≤ 12.9%), the analytical method was successfully applied to reveal the contamination state of Alternaria toxins in grapes. Among 56 grape samples, 40 (incidence of 71.4%) were contaminated with Alternaria toxins. TEN was the most frequently found mycotoxin (37.5%), with a concentration range of 0.10–1.64 μg kg−1, followed by TeA (28.6%) and AOH (26.8%). ALT (10.7%), AME (3.6%), and ALS (5.4%) were also detected in some samples. To the best of our knowledge, this is the first report about the Alternaria toxins contamination in grapes in China.

Levels of Alternaria Toxins in Selected Food Commodities Including Green Coffee

“…Applicability of the QuEChERS (Quick, Easy, Cheap, Efficient, Rugged and Safe) approach for the analysis of Alternaria toxins was considered in parallel since already validated elsewhere [8,9,25]. This approach is faster, user friendly, cost efficient, and already used in many laboratories dealing with chemical contaminants analysis, e.g., mycotoxins, veterinary drugs, pesticides [26][27][28][29].…”

“…In this context, various methodologies and studies on Alternaria toxins in foods and drinks have been published over the last years, e.g., in tomato-based products, fruit and vegetable-based products, wine [5,8], grapes [9], tea and herbal infusions [10], dried figs, olives, sunflower seeds and cereals [11], wolfberry [12], drinking water [13]. A study from the Technical University of Munich [14] has showed that infant cereals and baby food purees purchased from German supermarkets were frequently contaminated with Alternaria toxins.…”

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“…A. alternata produce all or part of the toxins listed in host cells, but with varying concentrations, one of them is higher than other concentrations. Thus, these toxins sequenced by different concentrations within the host (Guo et al, 2019, Noser et al, 2011, Patriarca et al, 2007, Scott et al, 2012. Moreover, a single isolate of A. alternata can infect two different hosts by producing two different HSTs (Masunaka et al, 2005).…”

“…Chromatographic techniques are the leading techniques in the diagnosis of fungal toxins in general and Alternaria toxins in particular like UPLC (Noser et al, 2011), HPLC-DAD (Anderson and Thrane, 1995) and the MS/MS (Noser et al, 2011, Scott et al, 2012, Guo et al, 2019. Some of these toxins concentrations have been also detected using PCR in hepatocytes with a concentration of 50 mM (Hessel-Pras et al, 2019).…”

Application of LC–MS/MS in the Mycotoxins Studies

“…After extraction and purification, the method is applied to the determination of MON in maize and wheat samples.The potential of LC-MS/MS for multi-mycotoxin determination in different food matrices is shown in different contributions of this Special Issue. For instance, Guo et al propose a modified QuEChERS (Quick, Easy, Cheap, Efficient, Rugged, and Safe) procedure for the determination of 6 Alternaria toxins in 56 grape samples [6]. A total of 40 samples (incidence of 71.4%) were contaminated with Alternaria toxins, tentoxin being the most frequently found mycotoxin (37.5%).…”