Detection of Saxitoxin from Source and Drinking Water using Solid Phase Extraction and Hydrophilic Interaction Liquid Chromatography - Mass Spectrometry

Academic Research Topics in Environmental Measurement and Monitoring
Oral Presentation

Prepared by , R. Lahr

Contact Information: gawankar@msu.edu; 517-974-6666


ABSTRACT

Saxitoxin is a potent neurotoxin which can cause paralytic shellfish poisoning (i.e., binding to sodium channels on cell membranes and inhibiting the supply of sodium ions into cells). These are produced by marine dinoflagellates and freshwater cyanobacteria, typically in tropical regions. However, climate change is predicted to increase the occurrence of saxitoxins in temperate regions. This is concerning as saxitoxins, the most potent of all cyanotoxins, are not regulated for monitoring and removal by drinking water treatment plants. The detection of saxitoxin is challenging as compared to other cyanotoxins due to its low molecular mass and highly polar nature. In addition, the existing drinking water treatment processes that are implemented during algal blooms work for microcystins but are not effective for the removal of saxitoxins.
Our research objective was to develop a sensitive and reliable method for the detection of saxitoxin from freshwater and from treated drinking water samples. An Acquity BEH Amide Column was used for liquid chromatography, and a Quadrupole/Time-of-Flight (Q-TOF) instrument was used for detection by mass spectrometry. The detection limit obtained by injecting a standard that was not concentrated by solid-phase extraction (SPE) was 0.125 uM. Strata™-X-CW 33 µm Polymeric Weak Cation Exchange cartridges manufactured by Phenomenex were used to examine the recovery of the toxin. The typical protocol provided for SPE using weak cation exchange cartridges was not successful for the extraction of saxitoxin. Therefore, we used different elution solutions to compare the recovery percentages. We will be optimizing the concentration of saxitoxins from environmental samples using a weak cation exchange SPE method.