Detection of aflatoxins (G(1-2), B1-2), sterigmatocystin, citrinine and ochratoxin A in samples contaminated by microbes

A method is described for the simultaneous determination of common aflatoxi ns (G(1), G(2), B-1, B-2) and their precursor sterigmatocystin, and also ci trinine and ochratoxin A. The method was applied to a building material mat rix artificially contaminated with mycotoxin-producing fungi. The method in cludes extraction, sample pre-treatment and reversed-phase HPLC separation with tandem mass spectrometric identification and quantification using elec trospray ionisation on a quadrupole ion trap mass analyser (ESI-MS-MS). Aqu eous methanol was used in the initial extraction and solvent partitioning a nd solid phase extraction in the purification of samples. The HPLC separati on was run on-line with the ESI-MS-MS detection. The limit of quantificatio n of the procedure was 200 ng for all compounds. Recoveries of the sample p re-treatment varied from 28 to 99%. The average compound- and concentration -dependent accuracy and precision (RSD) were 21 and 113%. respectively. The method includes small sample volumes (similar to 1 g in 20 ml) and few, no n-labour intensive, sample treatment steps. It should allow for a high thro ughput of samples with good prospects of automation.