Simultaneous determination of fumonisin B(1) and hydrolyzed fumonisin B(1) in corn products by liquid chromatography/electrospray ionization mass spectrometry

A method for the simultaneous determination of fumonisin B(1) (FB(1)) and its major hydrolysis product (HFB(1)), which is known to be formed during alkaline treatment of fumonisin-containing corn meal, was devised to analyze the levels of these mycotoxins in corn products available on the German market. Liquid chromatography/electrospray mass spectrometry in combination with selected ion monitoring (SIM) was used for unambiguous detection of FB(1) and HFB(1) after extraction of samples with acetonitrile/methanol/water (25:25:50) and solid-phase C18 cleanup. Quantitation was carried out using labeled fumonisin FB(1)-D(6) as an internal standard. The detection limits achieved with this method were 8 ng/g for HFB(1) (signal-noise ratio = 5:1) and 5 ng/g for FB(1) (s/n = 5:1) using the protonated molecule signals m/z 406 and 722 in the SIM mode. A screening of several corn-containing foodstuffs, among them extrusion products and alkali-processed corn food such as tortilla chips, showed HFB(1) and FB(1) contamination with levels of 8-80 and 5-450 ng/g, respectively.