Suitability of postcolumn oxidation liquid chromatography method AOAC 2011.02 for monitoring paralytic shellfish toxins in alaskan shellfish-initial pilot study versus mouse bioassay and in-house validation

Abstract

An in-house study was conducted to confirm the suitability of the postcolumn oxidation (PCOX) LC method, AOAC 2011.02, for regulatory monitoring of paralytic shellfish toxins (PSTs) in Alaskan shellfish. The following parameters were evaluated: calibration linearity, linear range, retention time stability, accuracy, repeatability, LOQ, and comparability with AOAC 959.08, the mouse bioassay (MBA) for PSTs. Mean recoveries for oyster homogenate spiked at 66 μg saxitoxin (STX) diHCl eq./100 g and 5 μg STX diHCl eq./100 g were 95 (n = 8) and 104%, respectively. Repeatability (n = 8) was 1.6 and 7% RSD, respectively. LOQ was estimated at 5 μg STX diHCl eq./100 g with S/N = 6 for STX. Comparability with the MBA was evaluated by duplicate analysis of regulatory samples using the original homogenate for both methods. Forty-one samples with MBA results varying between 40 and 500 μg STX diHCl eq./100 g were compared to corresponding PCOX values. The correlation coefficient (r 2) = 0.96, with a slope of 2.1. The slope indicates an average 2X higher total toxicity result for PCOX versus MBA, a result that is consistent with prior literature showing low recoveries using the MBA. © 2014 Publishing Technology.