Quantitative determination of mycotoxins in urine by LC-MS/MS

Abstract

Naturally occurring mycotoxins are responsible for a wide array of adverse health effects. The measurement of urinary mycotoxin levels is a useful means of assessing an individual's exposure, but the development of sensitive and accurate analytical methods for detecting mycotoxins and their metabolites in urine samples is challenging. Urinary mycotoxins are present in low pg ml⁻¹ concentrations, and the chromatographic identification of their metabolites can be obscured by other endogenous metabolites. We developed an analytical method focused on the selection of two appropriate multiple-reaction monitoring transition for unambiguous identification and quantification of carcinogenic aflatoxin M₁ (AFM₁), ochratoxin A (OTA) and fumonisin B₁, B₂ (FB₁, FB₂) in urine samples from a small volunteer group in a pilot study. AFM₁, OTA, FB₁ and FB₂ were concentrated selectively, interfering substances were removed using an immunoaffinity column (IAC), and mycotoxins were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in combination with a stable-isotope standard-dilution assay (SIDA). The method was sensitive enough to measure mycotoxins and their metabolites at pg ml⁻¹ levels in urine. The combination of LC-MS/MS and SIDA was critical to distinguishing pseudo-OTα interference from genuine OTα. Twelve urine samples contained OTA ranging from 0.013 to 0.093 ng ml⁻¹ (mean = 0.031 ng ml⁻¹). AFM₁ were detected in one sample at a 0.002 ng ml⁻¹ level, while FB₁ and FB₂ were undetectable in all 12 samples. None of the samples in this pilot study contained a detectable level of OTα, despite the presence of OTA, and this may suggest the need for further epidemiological investigation of OTA exposure in the Korean population.

Multimycotoxin analysis in urines to assess infant exposure: A case study in Cameroon

“…Similar findings were also reported for the Korean population (Ahna et al, 2010). However, as suggested by Munoz et al (2009Munoz et al ( , 2012 interindividual variability in the detoxification of OTA in human urine may account for the observed variations in urinary OT alpha and the possibility cannot be excluded that a low rate of OTA detoxification is a characteristic of some populations.…”

A direct assessment of mycotoxin biomarkers in human urine samples by liquid chromatography tandem mass spectrometry

“…Only a few analytical methods for multi-determination of mycotoxin biomarkers in human urine have been reported so far [34][35][36]. Most often, only a limited number of analytes are targeted due to the unavailability of commercial standards, which otherwise can be synthesized at the laboratory scale.…”

Development and application of salting-out assisted liquid/liquid extraction for multi-mycotoxin biomarkers analysis in pig urine with high performance liquid chromatography/tandem mass spectrometry

“…The use of immuno-affinity columns can solve these problems, however, these columns are sometimes very expensive. Furthermore, it is not generic material and not applicable for muti-analyte detection [30][31][32].…”