Liquid Chromatography Post-Column Oxidation (PCOX) Method for the Determination of Paralytic Shellfish Toxins in Mussels, Clams, Oysters, and Scallops: Collaborative Study

Abstract

Sixteen laboratories participated in a collaborative study to evaluate method performance parameters of a liquid chromatographic method of analysis for paralytic shellfsh toxins (PST) in blue mussels (Mytilus edulis), soft shell clams (Mya arenaria), sea scallops (Placopectin magellanicus), and American oysters (Crassostrea virginicus). The specifc analogs tested included saxitoxin, neosaxitoxin, gonyautoxins-1 to -5, decarbamoyl-gonyautoxins-2 and -3, decarbamoyl-saxitoxin, and N-sulfocarbamoylgonyautoxin-2 and -3. This instrumental technique has been developed as a replacement for the current AOAC biological method (AOAC Offcial MethodSM 959.08) and an alternative to the pre-column oxidation LC method (AOAC Offcial MethodSM 2005.06). The method is based on reversed-phase liquid chromatography with post-column oxidation and fluorescence detection (excitation 330 nm and emission 390 nm). The shellfsh samples used in the study were prepared from the edible tissues of clams, mussels, oysters, and scallops to contain concentrations of PST representative of low, medium, and high toxicities and with varying profles of individual toxins. These concentrations are approximately equivalent to ½ maximum level (ML), ML, or 2×ML established by regulatory authorities (0.40, 0.80, and 1.60 mg STX·diHCl eq/kg, respectively). Recovery for the individual toxins ranged from 104 to 127%, and recovery of total toxin averaged 116%. Horwitz Ratio (HorRat) values for individual toxins in the materials included in the study were generally within the desired range of 0.3 to 2.0. For the estimation of total toxicity in the test materials, the reproducibility relative standard deviation ranged from 4.6 to 20%. A bridging study comparing the results from the study participants using the post-column oxidation (PCOX) method with the results obtained in the study director’s laboratory on the same test materials using the accepted reference method, the mouse bioassay (MBA; AOAC Offcial MethodSM 959.08), showed that the average ratio of results obtained from the two methods was 1.0. A good match of values was also achieved with a new certifed reference material. The results from this study demonstrated that the PCOX method is a suitable method of analysis for PST in shellfsh tissue and provides both an estimate of total toxicity, equivalent to that determined using the MBA AOAC Offcial MethodSM 959.08, and a detailed profle of the individual toxin present in the sample.

Receptor binding assay for the detection of paralytic shellfish poisoning toxins: comparison to the mouse bioassay and applicability under regulatory use

“…Currently laboratory testing is underway at CDPH to validate the RBA for use with oyster tissue. An alternative technique for the detection of PSP toxins is a HPLC method (Lawrence et al 2005;van de Riet et al 2009), which has also been accepted by the ISSC and U.S. Food and Drug Administration (USFDA) as an Approved Method for unlimited use within the NSSP.…”

The hunt for red tides: Deep learning algorithm forecasts shellfish toxicity at site scales in coastal Maine

“…1;~3000 samples). Bigelow Analytical Services toxin testing follows a chemical analytical technique that uses high-performance liquid chromatography (HPLC; Rourke et al 2008, Van De Riet et al 2009) for monitoring PST levels (Anon 2011). Through each season, M. edulis and other shellfish species were collected weekly by DMR from each location and delivered to BAS for analysis.…”

Saxitoxin Poisoning in Green Turtles (Chelonia mydas) Linked to Scavenging on Mass Mortality of Caribbean Sharpnose Puffer Fish (Canthigaster rostrata-Tetraodontidae)

“…Samples analyzed at LANASEVE were extracted using 0.1 M HCl as described above and were deproteinated using trichloroacetic acid (30% v/v) as described in Rourke et al (10). At both labs, samples were analyzed using high performance liquid chromatography with fluorescence detection (HPLC-FL) and post-column oxidation (10,11). Saxitoxin congeners were identified and quantified by comparison to certified reference solutions of saxitoxin (STX), neosaxitoxin (neoSTX), gonyautoxin-1/4 (GTX-1/4), GTX-2/3, 21-N-sulfocarbamoyl saxitoxin (GTX-5/B1), decarbamoyl saxitoxin (dcSTX), dcGTX-2/3, and C1/2 purchased from National Research Council Canada.…”