Regeneration and Reuse of Immunoaffinity Column for Highly Efficient Clean-Up and Economic Detection of Ochratoxin A in Malt and Ginger.

Xi Liu,Fang Wei,Lidong Zhou,Pinxuan Huang,Guangyao Ying,Xiaofei Liu,Weijun Kong,Jinghua Lu,Shuwei Zhang

doi:10.3390/toxins10110462

Abstract

Immunoaffinity columns (IACs) are most popularly used for mycotoxin clean-up in complex matrices prior to chromatographic analysis. But, their high cost has limited their wide application and the regeneration of IACs for multiple instances of reuse is important. This study aimed to investigate the feasibility of regeneration and reuse of IACs for purification of ochratoxin A (OTA) in spiked raw malt and dried ginger samples followed by high performance liquid chromatography-fluorescence detection. After each use, the IACs were filled with phosphate buffer saline (PBS) as the preservation solution and stored at 8 °C overnight for regeneration and reuse until the recovery rate was <70%. The results showed that matrix type, preparation procedure, and pH value of sample extraction exhibited major effects on the reuse of IACs for OTA clean-up. While, after modifying the sample preparation procedure using water as the diluent and the solution at a pH of 7 to 8, the IACs could be used eight and three times for the spiked raw malt and dried ginger samples with OTA after regeneration. Regarding the traditional procedure recommended in Chinese Pharmacopoeia (2015 edition), the IACs could be used for three and two times for the spiked raw malt and dried ginger samples with OTA, respectively. Therefore, the corresponding experimental cost could be reduced to one-eighth and one-third of the original cost. This is the first study on the regeneration and reuse of IACs for OTA clean-up in complex Chinese herbal medicines, providing a green and economical tool for a large number of samples analysis with low cost.

Highlights

Chinese herbal medicines (CHMs), cereals, and subsidiary agricultural products are susceptible to mycotoxins under the high temperature and humidity conditions during their growth, harvesting, processing, and storage processes [1,2,3]
The corresponding experimental cost could be reduced to one-eighth and one-third of the original cost. This is the first study on the regeneration and reuse of Immunoaffinity columns (IACs) for ochratoxin A (OTA) clean-up in complex Chinese herbal medicines, providing a green and economical tool for a large number of samples analysis with low cost
Key Contribution: This study firstly evaluated the performance of the multitime-regenerated IACs for High performance liquid chromatography (HPLC)-fluorescence detector (FLD) of OTA in CHMs

Summary

Introduction

Chinese herbal medicines (CHMs), cereals, and subsidiary agricultural products are susceptible to mycotoxins under the high temperature and humidity conditions during their growth, harvesting, processing, and storage processes [1,2,3]. The reported incidence of OTA in malt is up to 12.5%, which will affect the quality and safety, as well as lower the medical and edible values of this CHM/food. OTA could be detected in the peel, and in the innermost layer of ginger, no significant mildew was observed on the surface by naked eye. This is an extremely serious fact, posing a potential threat to the consumers of ginger and related products. Taking the high incidence and toxicity into consideration, WHO recommends that the highest permitted residue level of OTA in cereals is 5.0 μg/kg. In 2003, China stipulated that the OTA limit for cereals and beans should not exceed 5.0 μg/kg [13], while, no limits are listed for OTA in CHMs from on

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