LAUSR

BACKGROUND Aflatoxin M1 (AFM1) is a carcinogenic hydroxylated metabolite commonly found in milk. It is relatively stable towards decontamination procedures posing a major health risk, and requires an international regulatory mandate of detection at trace levels. OBJECTIVE To develop a high throughput, reliable and compliant method for the identification of AFM1 in milk samples using AP-MALDI selected reaction monitoring (SRM) quantitation. METHOD Milk sample was diluted in water and cleaned with immunoaffinity chromatography (IAC), followed by analysis using AP-MALDI hyphenated with a triple quadrupole mass spectrometer for SRM. RESULTS A fast and reliable AP-MALDI SRM quantitative method was developed for the determination of AFM1 with analysis time of one minute per sample. The diagnostic product ions of AFM1 at 273.1 u and 229.2 u were monitored during the SRM. The calibration curves yielded excellent linearity (R2=0.99) with good recoveries for quality control samples (97-106%). The ion ratios of the qualifier to quantifier displayed excellent %RSD (1-7.8%) for n = 3. CONCLUSIONS The developed method provided rapid quantification for AFM1. The fast AP-MALDI SRM method can allow analysis of AFM1 in a large number of milk samples. Given the time required for analysis, cost effectiveness and superior analytical performance, this method can be adopted in commercial food testing laboratories. HIGHLIGHTS Aflatoxins (AF) are a major health risk. Speedy analysis of large sample sizes from food is a risk mitigation strategy but yet remains an unmet need. Quantitative, chromatography-free and internal standard-free AP-MALDI SRM based analysis of AF is a high throughput and cost-efficient alternative. Satisfactory performance was achieved for quantitative AP-MALDI SRM analysis of AFM1 in milk subsequent to a simple sample clean-up step.