Saturated brine dissolution and liquid-liquid extraction combined with UPLC-MS/MS for the detection of typical Alternaria toxins in pear paste

BACKGROUND

Alternaria can infest pears to produce metabolites, which can contaminate pears and their processed products. Pear paste, one of the most important pear-based products, is popular among Chinese consumers especially for its cough relieving and phlegm removal properties. Although people are concerned about the risk of Alternaria toxins in many agro-foods and their products, little is known about the toxins in pear paste.

RESULTS

A method was developed for the determination of tenuazonic acid, alternariol, alternariol menomethyl ether, altenuene and tentoxin in pear paste by ultra-performance liquid chromatography tandem mass spectrometry with saturated sodium sulphate dissolution and acidified acetonitrile extraction. The mean recoveries of the five toxins were 75.3-113.8% with relative standard deviations of 2.8-12.2% at spiked levels of 1.0-100 μg kg-1 . Alternaria toxins were detected in 53 out of 76 samples, with a detection rate of 71.4%. Tenuazonic acid (67.1%), alternariol (35.5%), tentoxin (23.7%) and alternariol monomethyl ether (7.9%) were detected in all samples at concentrations of < limit of quantification (LOQ)-105.0 μg kg-1 , < LOQ-32.1 μg kg-1 , < LOQ-74.2 μg kg-1 and < LOQ-15.1 μg kg-1 , respectively. Altenuene was never found in pear paste samples. Tenuazonic acid, alternariol, tentoxin and alternariol menomethyl ether should be focused on due to their toxicity and detection rates.

CONCLUSION

To the best of our knowledge, this is the first report on the detection method and residue levels of Alternaria toxins in pear paste. The proposed method and research data can provide technical support for the Chinese government to continuously monitor and control Alternaria toxins in pear paste, especially tenuazonic acid. It can also provide a useful reference for related researchers. © 2023 Society of Chemical Industry.

[Application of isotope dilution-liquid chromatography-tandem mass spectrometry in the preparation and certification of reference material of tenuazonic acid and tentoxin in wheat flour]

A method for the preparation and certification of the reference material of tenuazonic acid (TeA) and tentoxin (TEN) in wheat flour was developed. This method provided methodological references to develop of standard material for analyzing alternaria toxins in grains. The wheat flour reference materials were based on wheat grains which were naturally contaminated with alternaria toxins. The certified values for TeA and TEN were determined by isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) and cooperated certification of multiple laboratories. The wheat flour reference materials were stored at room temperature, protected from light and characterized by low uncertainty. The wheat flour reference materials are currently the only wheat flour reference materials that naturally contaminate TeA and TEN, and it can be used in the evaluating related analytical methods involved in food safety risk monitoring, product quality testing and quality control measurements.