Aim: An immunomagnetic capture protocol for use with LC-MS was developed for the quantitation of saxitoxin (STX) in human urine.
Materials & methods: This method uses monoclonal antibodies coupled to magnetic beads. STX was certified reference material grade from National Research Council, Canada. Analysis was carried out using LC-MS.
Results: With an extraction efficiency of 80%, accuracy and precision of 93.0-100.2% and 5.3-12.6%, respectively, and a dynamic range of 1.00-100 ng/ml, the method is well suited to quantify STX exposures based on previously reported cases.
Conclusion: Compared with our previously published protocols, this method has improved selectivity, a fivefold increase in sensitivity and uses only a third of the sample volume. This method can diagnose future toxin exposures and may complement the shellfish monitoring programs worldwide.
Keywords: MS; antibody; immunocapture; liquid chromatography; magnetic beads; marine toxins; saxitoxin.