Rapid and Accurate Analysis of Microcystins Using UPLC/MS/MS

Oral Presentation

Prepared by Y. Li, J. Whitaker
Eurofins Eaton Analytical, Inc., 110 South Hill Street, South Bend, IN, 46617, United States


Contact Information: YongtaoLi@eurofinsUS.com; 574-472-5562


ABSTRACT

Enzyme-linked immunosorbent assay (ELISA) is a relatively low cost analytical technique that has been commonly used as a screening tool for analyses of algal toxins. Liquid chromatography/tandem mass spectrometry (LC/MS/MS) is superior to ELISA in selectivity and is often needed to provide confirmatory toxin results for responding to cyanobacterial blooms. The 2014 Toledo case has proven that rapid and accurate results are very important for regulatory and local decision makers with responsibilities for recreational and drinking water closures to protect public health.

This presentation will describe an alternate method of using ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) with the simple direct aqueous injection (DAI) of water samples for rapid and accurate analysis of microcystins. The presented method used a selected internal standard to reduce analytical errors and matrix interferences. It was able to clearly resolve and detect each of the selected microcystins in a few minutes. Because of the rapidness, standard addition calibration could also be used to provide the ultimate accuracy of results for challenging matrices. The presentation highlights will include: 1) optimized experimental conditions of DAI-UPLC/MS/MS to achieve accurate results in a few minutes; 2) accuracy, precision, and sensitivity of the optimized method; 3) evaluation of suitable preservatives to reduce degradation of selected microcystins; and 4) comparison of the internal standard method with the standard addition method for real world samples. It is our expectation that this presentation will provide a fast and reliable tool for monitoring cyanobacterial blooms and for timely response to emergency of microcystin contamination events.