Ochratoxin A in Chinese dried jujube: method development and survey.

A method was developed for the determination of the mycotoxin ochratoxin A in dried jujube (Zizyphus jujuba Miller) using alkaline methanolic extraction, immunoaffinity column clean-up (IAC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination. The limit of detection (LOD) was 0.01 μg kg–1 and limit of quantification (LOQ) was 0.03 μg kg–1. The average recoveries were 82%, 98% and 115% at 5, 0.5 and 0.1 μg kg–1 spiked levels with relative standard deviations (RSD) of 2.9%, 5.2% and 9.2% accordingly. The method showed good linearity for both solvent standard calibration and matrix-matched standard calibration with correlation coefficients of 0.9998 and 0.9997 respectively. The intra-day precision RSD was 3.3% and the inter-day precision RSD was 4.0%. In addition, there was almost no matrix interference in LC-MS/MS detection after the IAC clean-up process. The proposed analytical set-up was successfully used to test 20 samples that were collected from local markets and stores. The res...