Quantification of ochratoxin A in Chinese liquors by a new solid-phase extraction clean-up combined with HPLC-FLD method

Abstract

Ochratoxin A (OTA), one mycotoxin produced by certain filamentous species of Aspergillus and Penicillium, is not known whether existing in Chinese liquors. However, specific method to detect OTA as well as OTA occurrence in Chinese liquors has not been reported so far. For this purpose, based on reversed phase/strong anion-exchange mixed-mode column (ProElut™ PXA), a novel solid-phase extraction (SPE) clean-up method followed by high-performance liquid chromatographic (HPLC) quantification was developed to detect OTA in Chinese liquors. Meanwhile, the matrix effects were evaluated by using the post-extraction spiked method with the signal suppression/enhancement (SSE) as the evaluation index. Under the optimized conditions, no matrix effects were found due to the SSE values below 20%, and the external standard method can be used to determine OTA in Chinese liquors. The recovery rate of spiked samples ranged from 81.6 to 100.8%. Intra-day and inter-day relative standard deviation were below 7.3% and 12.8%, respectively. The limits of detection and quantification were 0.006 and 0.02 μg/L, respectively. This approach was then applied to analyze the 76 samples from different geographical regions in China, including 40 strong aroma-, 30 light aroma- and 6 soy sauce aroma-type raw liquors. The results showed that OTA was detected in 9 samples with a maximum concentration of 0.17 μg/L. Considering that ∼12% of the samples were OTA positive, it is necessary to recommend a routine monitoring of this commodity.