Plasma ochratoxin A levels in three Swedish populations surveyed using an ion-pair HPLC technique

A new HPLC method for the analysis of ochratoxin A in plasma samples is described. The analysis is performed at an alkaline pH using an ion-pair technique, fluorescence detection at an excitation wavelength 380 nm, and an emission wavelength 420 nm. The detection and quantification limits are 0.02 ng and 0.05 ng ochratoxin A/ml plasma, respectively. The method was used to determine the ochratoxin A content of human plasma samples, collected in three districts of Sweden. The Visby district had a significantly higher proportion of ochratoxin A positive samples and higher levels than the other two districts--Uppsala and Ostersund. The calculated daily intake of ochratoxin A in the Visby district (0.35 ng/kg body weight), exceeds the lower tolerable daily intake (TDI) value suggested by Kuiper-Goodman and Scott (1989). The calculated daily intake by the population on the mainland of Sweden (0.04 ng/kg body weight) is below the proposed TDIs.