Development of an ultrasensitive immunoassay for rapid measurement of okadaic acid and its isomers.

ABSTRACT

This report highlights the characteristics of an okadaic acid immunoassay with limits of detection in the subfemtomole range. Two different immunoassay formats were investigated and their characteristics compared in relation to linear ranges, limits of detection, and cross-reactivity with other seafood toxins present in water and/or mussel samples. The developed ELISA system can be manipulated to quantitatively measure total diarrhetic shellfish poisoning (DSP) content or for okadaic acid and dinophysistoxin-1 individual concentrations by variation of the format of the immunoassay. Real mussel samples were validated in percentage recovery test. Calibration curves were established, and aliquots of real samples were tested. Very good recoveries were attained, highlighting the validity of the ELISA system to accurately determine the DSP concentration in mussel samples.