No abstract

No abstract

No abstract

Hydroxide ion chemical ionization mass spectra of two classes of trichothecenes are described. The spectra provide molecular weight information as well as fragment ions indicative of structure. The discussion of fragmentation is aided by the use of high resolution mass measurements, mass analyzed ion kinetic energy spectra and chloride attachment spectra. Certain novel fragmentation processes under hydroxide ion conditions are noted. The chloride attachment spectra are also useful for verification of molecular weight.

Asimple, rapid, and solvent-efficient method for determining aflatoxins in corn and peanut butter is described. Aflatoxins B1, B2, G1, and G2 were extracted from SO g sample with 200 mL methanol-water (85 + 15). A portion of the extract was diluted with 10% NaCl solution to a final concentration of 50% methanol, and then defatted with hexane. The aflatoxins were partitioned into chloroform. The chloroform solution was evaporated, and the residue was placed on a 0.5 g disposable silica gel column. The column was washed with 3 mL each of hexane, ethyl ether, and methylene chloride. Aflatoxins were eluted with 6 mL chloroform-acetone (9 + 1). The solvent was removed by evaporation on a steam bath, and the aflatoxins were determined using thin layer chromatography (TLC) with silica gel plates and a chloroform-acetone (9 + 1) developing solvent. Overall average recovery of aflatoxin B] from corn was 82%, and the limit of determination was 2 ng/g. For mass spectrometric (MS) confirmation, aflatoxin B1, in the extract from 3 g sample (20 ng/g) was purified by TLC and applied by direct oncolumn injection at 40°C into a 6 m fused silica capillary gas chromatographic column. The column was connected directly to the ion source. After injection, the temperature was rapidly raised to 250¯C, and the purified extract was analyzed by negative ion chemical ionization MS.