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Determination of fumonisins in rodent feed using HPLC with electrospray mass spectrometric detection

Churchwell, M.I., Cooper, W.M., Howard, P.C., Doerge, D.R.
Journal of agricultural and food chemistry 1997 v.45 no.7 pp. 2573-2578
feeds, fumonisins, chemical analysis
A method based on liquid chromatography with electrospray ionization mass spectrometry was validated for analysis of low-level contamination of rodent feed by fumonisins B1 (10-200 ppb) and also applied to the analysis of fumonisin B2 and B3. The quantitation limit for a fumonisin B1 standard was 1.1 ppb using the protonated molecule signal (m/z 722), and similar sensitivity was observed for protonated molecules for fumonisins B2 and B3 in feed. To increase specificity of the mass spectrometric analysis, two fragment ions for fumonisin B1 (m/z 352 and 334) were also acquired by using rapid sampling cone-skimmer potential switching in concert with acquisition of the respective ion. This permitted the use of ion intensity ratios for structural confirmation of fumonisin B1 at levels >10 ppb. Intra-assay precision for fumonisin B1 determination in feed (6-16% relative standard deviation) was comparable to inter-assay precision (7.7- 16.0%) and appeared to be affected most by the variability in recovery of analytes from the immunoaffinity cleanup column. A survey of fumonisin contamination in rodent feed from 12 U.S. biomedical research institutions showed median contamination of 237 ppb and a range from 46 to 923 ppb of total fumonisin B congeners.