Multipoint recognition of domoic acid from seawater by dummy template molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography

- Different compounds were investigated as dummy templates to synthesize DA-MIPs.
- CA as dummy template achieved the most adsorption amount.
- The obtained polymer was proved to have high binding capacity and good selectivity.
- The MISPE was successfully applied to the efficient extraction of DA in seawater.
- Hydrophilicity of CA was proved to be the most important factor for high adsorption.

Due to the high cost of domoic acid (DA), different carboxylic acid compounds including indole-3-acetic acid (IAA), pyrrole-2-formic acid (PFA), pyridine-2,3-dicarboxylic anhydride (PDA), trimesitinic acid (TA) and citric acid (CA) were investigated as dummy templates for the molecularly imprinted solid-phase extraction (MISPE) for selective isolation and pre-concentration of an amnesic shellfish poison (ASP), DA. The highest binding amount of the polymers towards DA was obtained when CA was used as dummy template owing to its high hydrophilicity. In addition, the “four-point” recognition site constructed by three COOH groups and a OH group in CA was also speculated to be the reason for the high binding amount of CA-MIPs and the rebinding of DA can be depend on the three COOH groups and a NH group with conformational change in the recognition process. Finally, the CA-MISPE column was chosen for DA isolation and pre-concentration and effective result was obtained with recoveries higher than 90% and relative standard deviation (RSD) less than 5% (n = 3). This new polymer can be effectively applied to the monitoring and predicting the existence of trace DA.