Multiple mycotoxins analysis in animal feed with LC‐MS/MS: Comparison of extract dilution and immunoaffinity clean‐up

The aim of this study was a performance comparison of two clean‐up procedures (dilutions versus immunoaffinity columns) in the simultaneous determination of eight mycotoxins (aflatoxin B1, deoxynivalenol, fumonisin B1 & B2, ochratoxin A, toxin T‐2 & HT‐2 and zearalenone) in the animal feed. After extraction the analytes were separated on a Kinetex Biphenyl column with a gradient elution using methanol/0.01 M ammonium acetate as a mobile phase and analyzed with the LC‐MS/MS technique. Both of the procedures were validated by analysis of a series of spiked feed samples (n = 6) at three different concentration levels. Better signal to noise ratios were observed for immunoaffinity clean‐up. The recoveries of analyses were in the range 88–110% for the dilution procedure and 78–120% for the immunoaffinity clean‐up. The dilution procedure was more precise (coefficient of variation of the within‐laboratory reproducibility for it was 7.8–22.4% in comparison to 12–35.5% for the immunoaffinity clean‐up. The results show that both procedures fulfilled the requirements for mycotoxin analysis and can be used successfully in multi‐analyte determination. Although the dilution procedure shows better precision and trueness, the immunoaffinity clean‐up procedure can have advantages in more complex feed samples thanks to lower matrix effect and limits of detections.