Simultaneous determination of aflatoxins, ochratoxin A andFusariumtoxins in maize by liquid chromatography/tandem mass spectrometry after multitoxin immunoaffinity cleanup

Abstract

A liquid chromatography/tandem mass spectrometry method was developed for the simultaneous determination of aflatoxins (B(1), B(2), G(1), G(2)), ochratoxin A, fumonisins (B(1), B(2)), deoxynivalenol, zearalenone, T-2 and HT-2 toxins in maize. A double extraction approach, using a phosphate-buffered solution followed by methanol, was applied to achieve effective co-extraction of the 11 mycotoxins under investigation having quite different polarities and chemical structures. A new multitoxin immunoaffinity column containing antibodies for all these mycotoxins was used to clean up the extract. Detection and quantification of the 11 mycotoxins were performed by reversed-phase liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry (LC/ESI-MS/MS) using, as chromatographic mobile phase, a linear gradient of methanol/water containing 0.5% acetic acid and 1 mM ammonium acetate. Method performances were quite satisfactory for all tested mycotoxins at contamination levels close to or below the relevant EU maximum permitted or recommended levels. Limits of detection in maize ranged from 0.3 to 4.2 microg/kg. Recoveries higher than 79% were obtained for all tested mycotoxins with relative standard deviations less than 13%.

Advanced LC–MS-based methods to study the co-occurrence and metabolization of multiple mycotoxins in cereals and cereal-based food

“…IAC cleanup should provide a purified sample completely free of the matrix, which allows the use of a solvent calibration curve for quantification. However, as discussed later [41,42], ion suppression/enhancement (caused by the IAC sorbent) has been observed. In the past, IACs were mainly designed for one or two toxins.…”

“…Huge differences in the extent of matrix effects are not only seen for different matrices; high deviations between individual samples of one matrix type are also observed [58,59]. Matrix effects were present also after highly extensive immunoaffinity cleanup [41,42].…”

“…Although, the application of IACs is a preferred and selective tool for sample cleanup, the sample extraction and handling procedure recommended by the manufacturer is very laborious and time-consuming, and produces large volumes of solvent waste. Special attention has to be paid to the extraction solvent, elution rate, and column capacity to achieve optimal recoveries of targeted analytes [41,42]. In addition, column capacity may be hindered as a result of antibody cross-reactivity (affinity for other structurally related toxins).…”

“…This, on the other hand, is a big advantage in the determination of conjugated mycotoxins (discussed later). An LC-MS/MS method for simultaneous determination of AFs, OTA, and Fusarium mycotoxins in maize using multifunctional IACs (AOZFDT2 TM ) was developed and validated in-house [41]. Despite the laborious cleanup and long chromatographic gradient (59 min), matrix effects were observed (i.e., significant suppression for AFB 1 and AFG 1 and a slight suppression for OTA).…”

A Rapid Method with UPLC for the Determination of Fusaric Acid in Fusarium Strains and Commercial Food and Feed Products

“…The column temperature was maintained at 25°C with the detection wavelength set at 220 nm [27]. The mobile phase ''A'' was water/TFA (1000:1, v/v) and the phase ''B'' was acetonitrile containing TFA (1000:1, v/v).…”