Stability of Mycotoxins in Individual Stock and Multi-Analyte Standard Solutions

• Main Authors: Mariya Kiseleva, Zakhar Chalyy, Irina Sedova, Ilya Aksenov
• Format: Article
• Language: English
• Published: MDPI AG 2020-01-01
• Series: Toxins
• Subjects: mycotoxins; stability; multi-mycotoxin detection; standard solution; uv-spectroscopy; hplc-ms/ms
• Online Access: https://www.mdpi.com/2072-6651/12/2/94

Standard solutions of mycotoxins prepared in RP HPLC solvents from neat standards are usually used for analytical method development. Multi-mycotoxin HPLC-MS/MS methods necessitate stability estimation for the wide spectrum of fungal metabolites. The stability of individual diluted stock standard solutions of mycotoxins in RP-HPLC solvents and multi-analyte HPLC-MS/MS calibrants was evaluated under standard storage and analysis conditions. Individual stock standard solutions of aflatoxins, sterigmatocystin, A- and B-trichothecenes, zearalenone and its analogues, ochratoxin A, fumonisins, <i>Alternaria</i> toxins, enniatins and beauvericin, moniliformin, citrinin, mycophenolic, cyclopiazonic acids and citreoviridin were prepared in RP-HPLC solvents and stored at &#8722;18 &#176;C for 14 months. UV-spectroscopy was utilized to monitor the stability of analytes, excluding fumonisins. The gradual degradation of &#945;-, &#946;-zearalenol and &#945;-, &#946;-zearalanol in acetonitrile was detected. Aflatoxins and sterigmatocystin, zearalenone, <i>Alternaria</i> toxins, enniatins and beauvericin, citrinin, mycophenolic, cyclopiazonic acids and citreoviridin can be referred to as stable. The concentration of the majority of trichothecenes should be monitored. Diluted multi-mycotoxin standard in water/methanol (50/50 <i>v/v</i>) solutions acidified with 0.1% formic acid proved to be stable in silanized glass at 23 &#176;C exposed to light for at least 75 h (CV &#8804; 10%). An unexpected manifestation of MS/MS signal suppression/enhancement was discovered in the course of multi-mycotoxin standard solution stability evaluation.