Mass spectral investigations on trichothecene mycotoxins. II. Detection and quantitation of macrocyclic trichothecenes by gas chromatography/negative ion chemical ionization mass spectrometry.

A general, sensitive gas chromatographic/negative ion chemical ionization mass spectrometric (GC/NICIMS) method of analysis was developed for the detection and quantitation of several polar, thermally labile, toxic macrocyclic trichothecenes. The procedure involves the conversion of the molecules to their corresponding alcohols (verrucarols) by alkaline hydrolysis, followed by derivatization of the hydrolysate with heptafluorobutyrylimidazole and analysis by GC/MS technique under negative ion chemical ionization conditions. Nanogram (250 ng) quantities of several macrocyclic trichothecenes with different verrucarol and ester moieties were analyzed successfully with good precision by this procedure. The method was applicable for the accurate determination of at least low ppb levels of these macrocyclic trichothecenes in environmental samples, such as fungal products, fermentation broths, and plant samples. This is the first reported, well developed, sensitive, and applicable method for the detection and quantitation of these compounds in naturally occurring samples.