Study And Application Of Highly Sensitive Analysis Of Trace Domoic Acid Shellfish Toxin

Domoic acid(DA)is a strong neurotoxic shellfish toxin which possesses highly toxicity.The study and establishment of efficient analytic technology with ultra-high sensitivity for domoic acid in environmental samples or aquatic foods is of great significance for food safety and environmental safety analysis.In this paper,based on high performance liquid chromatography(HPLC)with fluorescence detection(FLD),a facile HPLC-FLD analytic method and a sensitive two-dimensional HPLC-FLD method have been presented and used to separate trace domoic acid.The main contents are shown as follows:In chapter one,literature review.The main analytical methods of domoic acid have been summarized,and the two-dimensional liquid chromatography method and its hyphenated technology have ben reviewed.Bansed on this,the topic and research scheme of this thesis were summed up.In chapter two,a facile HPLC-FLD method for the sensitive analysis of trace domoic acid(DA)was fabicated.The chromatographic separation behavior and matrix effect of DA fluorescent labeling products in different matrices were investigated,and various factors including the conditions of fluorescence labeling reaction of DA,separation behavior and sample matrix interference were also optimized.The efficient analysis of trace DA in different shellfish samples and seawater was realized,the detection limits of trace DA in different shellfish samples and seawater were of 0.5ng/mL.The recoveries of DA were in the range of 76.7%-97.7%and 89.3-95.6%respectively in shellfish and seawater samples.In chapter three,a new technique of on-line two-dimensional HPLC-FLD for trace analysis of domoic acid was presented.The two-dimensional chromatographic separation behavior of domoic acid has been systematically studied.Effects of various parameters such as the sampling volume in first-dimensional chromatograph or the second-dimensional chromatograph,and the composition of mobile phases in two-dimensional chromatogram,have been investigated.In this work,the first dimension was finished with polar silica gel embedded with Cl8 stationary phase for DA fluorescent derivatives,and the second dimension was analyzed by ODS reversed-phase column.By using the heart-cutting technology,the two-dimensional liquid chromatography with on-line enrichment and continuous separation model was optimized for the trace analysis of DA in shellfish and seawater samples.Under the optimal conditions,a baseline separation and ultra-high sensitivity detection of DA in shellfish and seawater were achieved.The detection limit of DA in the shellfish was 1 ng/g,and that in seawater was 25 pg/mL.The recoveries were in the range of 71.0%-90.6%and 88.1%-97.1%respectively.In chapter four,the enrichment Dynamic curve of DA in Clams was establi shed,and the transfer behavior of trace DA from seawater to shells was evaluat ed.Based on the two-dimensional HPLC-FLD method mentioned above,the chan ges of DA in shellfish(clam)in different seawater medium and different feedi ng cycles were investigated systematically,and the dynamic curves of DA in se awater with shellfish(clam)were established.The effect of DA concentration in seawater on the enrichment of DA in shellfish(clam)was also analyzed.After 18 days,the enrichment effect of DA in seawater wan gained with a level nea rly 10 times of the original DA concentration.This method might be used to es timate the concentration of DA toxin in shellfish through the analysis of trace DA toxin in seawater.lt could provide a potential new way for the assessment and early warning of DA residues in shellfish.