Validation Study of LC-MS/MS for Paralytic Shellfish Toxins and Tetrodotoxin in Scallops

Recently, an instrumental analysis using LC-MS/MS has been developed and validated for paralytic shellfish toxins (PSTs) and tetrodotoxin (TTX) in bivalve molluscs in Japanese domestic and overseas. The method for 11 PSTs and TTX in scallops was validated in accordance with a previous report and CODEX-STAN. The samples were prepared by adding the standard mixture of PSTs and TTX to scallop (Patinopecten yessoensis) homogenates, extracted with 1% acetic acid and then cleaned up using an ENVI-Carb (250 mg/3 mL) cartridge. A single analyst extracted and analyzed in two samples per day on five successive days. As result of the validation, 11 PSTs were found falling within all the guideline criteria (the trueness, repeatability, within laboratory reproducibility, LOD, LOQ) in the tests using matrix-matched calibration or solvent calibration.However, the trueness of TTX was low value in the test using solvent standard. It would be due to the matrix effects at the LC-MS/MS analysis. The slope of the calibration curve at the matrix-matched standards of mussel was about the same as the slope at the solvent standards. Therefore, it is necessary to choose the most appropriate matrix depending on shellfish.