Stability of fumonisins (FB₁and FB₂) in solution

Abstract

The stability of fumonisins B1 and B2 (FB1 and FB2) during 6 week storage was studied in acetonitrile:water (1:1) and methanol at four storage temperatures (-18, 4, 25 and 40 degrees C). Samples were analysed by HPLC with fluorescence detection after derivatization with o-phthaldialdehyde. Decomposition of fumonisins was evident in a methanol solution after 6 week storage at 4, 25 and 40 degrees C (signals for both toxins decreased by 5, 35 and 60%, respectively), whereas no losses were observed in samples stored at -18 degrees C. Both fumonisins were quite stable in acetonitrile:water solution at any of the four storage temperatures. The stability of fumonisins in acetonitrile:water (1:1) was confirmed over a period of 6 months at three temperatures (-18, 4 and 25 degrees C) in two solutions at different mass concentrations. No significant difference (t0.95-test) was observed between solutions stored in the dark at different temperatures and for different times (3 and 6 months). The overall coefficient of variation (n = 24, four measurements at each storage time and temperature) in each solution was < 3% for both toxins. Acetonitrile:water (1:1), unlike methanol, is a suitable solvent for fumonisin reference solutions.

Fumonisins in corn cultivars in the state of São Paulo

“…Fumonisins B 1 and B 2 standard solutions: Individual stock solutions of FB 1 and FB 2 (Sigma Chemical Company, St. Louis, MO) were prepared dissolving 1 mg in acetonitrile/water (1+1) according to Visconti et al (23). Working solutions were then prepared with concentrations of 50 µg/ml of FB 1 and FB 2 , respectively.…”

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

“…According to Andrade et al, stock standard solutions of AFLs, ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), 3-acetyl-and 15-acetyl deoxynivalenol (3-AcDON and 15-AcDON) and citreoviridin (CTV) were considered valid after a storage period if their UV-spectrophotometric check resulted in a maximum of 3% difference with the previous check of freshly prepared solutions [10]. Some other authors also reported 2%-3% variation as suitable [11,12], while the majority did not address this point. In the present study, the repeatability of intra-day absorbance values was evaluated.…”

“…Traditionally, FBs are monitored by HPLC after their pre-column derivatization with o-phthalic aldehyde [48,49]. This method was used by Visconti et al to monitor methanol and acetonitrile-water (50:50, v/v) FB1 (100 µg/mL) and FB2 (50 µg/mL) standard solutions during storage in fire sealed glass ampoules for six months [12]. Methanol solutions proved to be stable under freezing for six weeks storage, at 4 • C their degradation started in three weeks, about 25% loss was detected within this period at ambient temperature.…”

Determination of fumonisins B1 and B2 in Chinese rice wine by HPLC using AQC precolumn derivatisation

“…This result differs from that of Velázquez et al , who found the best solvent to be methanol. Although methanol was tested as an extraction solvent, FB 1 and FB 2 were not stable enough in methanol , . Therefore water/acetonitrile (1:1 v/v) was used as the optimal solvent for dissolving FB 1 and FB 2 standards and samples.…”