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Lin C.,Jilin University | Liu Z.-S.,Jilin University | Wang D.-X.,Jilin University | Ren H.-L.,Jilin University | And 6 more authors.
Analytical Methods | Year: 2014

In this study, a highly sensitive and reliable analytical micro-plate chemiluminescence enzyme immunoassay (CLEIA) based on a monoclonal antibody (McAb) against okadaic acid (OA) was developed and validated for the detection of okadaic acid from a shellfish matrix. A competitive immunocomplex was formed through the binding of an immobilised antigen, OA, in analyzed samples and the McAb against OA. The conjugate OA-BSA was immobilised physically on a polystyrene micro-plate well as a solid phase antigen. Subsequently, free toxins in the analyzed samples competed with the solid phase antigen to bind the McAb against OA. The assay conditions, including the composition and pH of the coating solution, the dilution ratios and amounts of the McAb and the HRP-labelled goat anti-mouse IgG antibody, the time of the antibody-coating, incubation and chemiluminescence reactions and other relevant variables were studied and optimised. The optimised system allowed OA determination in a linear working range from 0.0098-10 μg kg-1 (R = 0.99), and the calibration curve obtained for OA revealed a detection limit of 0.0098 μg kg-1. Importantly, the CLEIA was approximately 10 times more sensitive than an ELISA using the same antibody. In addition, the intra- and inter-assay RSDs were both less than 10.0%. Moreover, this method was successfully applied to the evaluation of OA in seashells, with recoveries of 97.2%, 111.2% and 104.7%, respectively, for low-, medium- and high-concentration samples. Good recoveries were obtained from spiked food samples, and the results correlated well with those obtained using conventional indirect competition ELISA, indicating the potential utilisation of the CLEIA as a preliminary screening tool for analyzing OA contamination in shellfish. © the Partner Organisations 2014.

Lin C.,Jilin University | Liu Z.-S.,Jilin University | Tan C.-Y.,Dalian Zhongxin Testing Technology LLC | Guo Y.-P.,Dalian Zhongxin Testing Technology LLC | And 7 more authors.
Environmental Science and Pollution Research | Year: 2014

With the increasing number of outbreaks of food-borne diseases caused by okadaic acid (OA) and its analogue dinophysistoxin-1 (DTX-1), two key diarrhetic shellfish poison (DSP) toxins, OA and DTX-1, have become a serious threat to public health and have attracted significant public attention in China. The aim of our study was to monitor OA and DTX-1 contamination in commercially available seafood and to provide references for tracking these toxins and preventing disease outbreaks. From 2010 to 2012, 40 species were collected from six coastal cities of four inland seas in China. An enzyme-linked immunosorbent assay (ELISA) and a lateral flow immunochromatographic (LFIC) test strip were used to analyse the samples, and the results were further confirmed using a commercially available ELISA kit. The monitoring results indicated that 23 of 40 species were positive for contamination. In addition, 14 of the positive species were determined to be inedible because the content of OA and DTX-1 was above the regulatory limit. Simultaneously, we verified that the digestive glands of shellfish tended to accumulate toxin, in contrast to the flesh. The highest concentrations of OA and DTX-1 were recorded in Scapharca broughtonii, which was collected from Qing Dao, in relation to the other analysed species. Moreover, the Arca family as well as Mytilus galloprovincialis were severely contaminated by OA and its analogue. The above results indicate that some of the commercially available seafood from the coastal cities in China may be inedible due to serious marine toxin contamination. The results of this study might play an important role in protecting consumer health and safety screening of marine products. © 2014 Springer-Verlag Berlin Heidelberg.

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