Nanosciences and Nanotechnology

Biography

Biography: Sari Ramo

Abstract

The Fusarium species causing Fusarium basal rot (FBR) in onion may also produce mycotoxins that are potentially harmful to humans and animals. The main mycotoxins produced by Fusarium oxysporum and Fusarium proliferatum are beauvericin (BEA), moniliformin (MON) and fumonisins B₁, B₂ and B₃ (FB₁, FB₂ and FB₃). A multiple reaction monitoring technique with ultra-high performance liquid chromatography tandem mass spectrometry (MRM UHPLC-MS/MS) for onion matrix was established to study these mycotoxins in the harvested onions. In the in-house validated protocol the onion samples were extracted with methanol:water (3:1) using magnetic stirring for 15 minutes. No cleanup of extracts was needed prior to analysis. The target mycotoxins were separated on an Acquity UPLC system BEH C18 column with gradient elution. Mycotoxins were identified and quantified using ¹³C-FB₁ as internal standard. FBs and BEA were determined directly from the filtered extracts by ES+ ionization with at least two MRMs whereas MON required sample concentration prior to analysis and ES- ionization with one usable MRM. Minor matrix effect was compensated using multipoint matrix-matched calibration curves with uninfected onion sample. For the mycotoxins studied, a good linearity was obtained (R²≥ 0.99) and the recoveries were in the range of 67-122%, with the highest standard deviation for MON, 22%. The limits of quantification were from 2.5 to 10 ng g^-1 in onion matrix. The method was successfully employed for the analysis of mycotoxins in harvested onions showing FBR symptoms and found to be infected with F. oxysporum and F. proliferatum.