Expanding Microcystin Analyses to Include Other Toxic Cyanopeptides using Online Concentration LC-MS/MS

Freshwater harmful algal blooms (HABs) are increasing in frequency and intensity throughout the world. The advancement of untargeted analyses has expanded the known groups of cyanotoxins including a more diverse set of cyanopeptides. Cyanopeptides are secondary metabolites created by cyanobacteria that include cyclic peptides like MCs, nodularin, cyanopeptolins, and anabaenopeptins as well as straight chain peptides such as aeruginosamides, microginins, and oscillaginins. The cyanopeptides exhibit diverse modes of action. MCs, anabaenopeptins, and oscillamides are protein phosphatase inhibitors. Cyanopeptolins and microginins are known protease inhibitors. Furthermore, recent studies suggest that these cyanopeptides play an important role in changing the ecology of a source water habit, and hence changing source water quality.

A previously developed online concentration method that detected 12 MCs and nodularin was modified to include 10 cyanopeptides. This method was validated, and detection limits were determined. This new method is important in that it provide a robust, high throughput analysis of multiple classes of cyanotoxins, and minimizes analyst time, sample size, sample handling, and cost associated with analysis. Furthermore, this new method can detect multiple types of cyanotoxins in the low ppt range in 1 ml sample. This method has excellent linearity over a calibration range of 4 orders of magnitude (0.5 – 500 ng/L) and provides insight to the complexity of cyanopeptides present in source waters. The method run time is less than 15 minutes per sample because there is no need for bench solid phase extraction.

Presenter: Judy Westrick (Director, Lumigen Instrument Facility, Wayne State University)

Dr. Westrick is an accomplished environmental analytical chemist whose research focus is on cyanobacteria and their toxins. She has conducted cyanotoxin research in the following areas: 1) determining the occurrence and drinking water treatment removal and/or inactivation efficiency of cyanotoxins; 2) interpreting policy and identifying knowledge gaps between academia and industry; and 3) developing standard analytical methods for the priority cyanotoxins. She has organized and served on local, national, and international cyanotoxin panels. Her current research includes developing simple, robust liquid chromatography mass spectrometry methods to quantify cyanotoxins in water and tissue. Her background as an analytical chemist, a certified drinking water operator from 1995-2001, and a cyanotoxin expert, has enabled her to be a ‘linker’ between the academic, industry, and environmental health communities.