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United States Department of Agriculture

Agricultural Research Service

Research Project: Environmental and Ecological Approaches to Eliminate Fungal Contamination and Mycotoxin Production in Plant Products

Location: Foodborne Toxin Detection and Prevention

Title: High sensitive and throughput screening of Aflatoxin using MALDI-TOF-TOF-PSD-MS/MS

Authors
item Hua, Sui Sheng
item Woo, Nathan
item Sultan, Omar
item Fagerquist, Clifton

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2012
Publication Date: June 5, 2012
Citation: Hua, S.T., Woo, N., Sultan, O., Fagerquist, C.K. 2012. High sensitive and throughput screening of Aflatoxin using MALDI-TOF-TOF-PSD-MS/MS. Meeting Abstract. [abstract].

Technical Abstract: We have achieved sensitive and efficient detection of aflatoxin B1(AFB1) through matrix-assisted laser desorption/ionization time-of-flight-time-of-flight mass spectrometry (MALDI-TOF-TOF) and post-source decay (PSD) tandem mass spectrometry (MS/MS) using an acetic acid – a-cyano-4-hydroxycinnamic acid (CHCA) matrix. AFB1 was detected with a limit of detection range as low as 0.0015 – 0.015 ng/µL. The MS/MS spectra showed several consistent peaks that we were able to rationalize and use to produce an energetically favorable fragmentation pattern. The MALDI-TOF-TOF technique is fast, requires minimal sample preparation, and is capable of detecting aflatoxin at concentrations lower than many conventional methods, including HPLC. Additional confirmation of an analyte’s identity can be achieved by studying its MS/MS spectrum and looking for signature peaks. The speed, usability, and simplicity of MALDI-TOF/TOF-MS/MS make it exceptionally useful for high-throughput, high-sensitivity, and high-specificity screening for aflatoxins. We tested an aflatoxin B1 standard at varying concentrations in order to establish a standard curve and determine the limit of detection (LOD). We countered large variations in signals between runs, indicating that MALDI is not ideal for quantitation and should be reserved for confirmatatory analyses for detection very low amount of AFB1 in samples. Twelve Aspergillus flavus isolates were screened for AFB1 using this technique. AFB1 was positive in seven and negative in five of these strains. These results were further confirmed by HPLC analysis on an Agilent model 1260 ChemStation.

Last Modified: 4/23/2014