Lake Fear?

By July 10, 2017


Cyanotoxins can ruin your day in the water — but, with HRMS, not your day in the laboratory

As the summer season heats up, many of us head to lakes and rivers for swimming and various water activities. But before you take the plunge, take a look at the color of the water. If you see a greenish-blue color, there could be a harmful algae bloom.

Blue-green algae, or cyanobacteria, are primitive organisms, some of which can produce toxins. This type of algae occurs naturally in lakes and rivers, but excessive growth of blue-green algae is a recognized problem in water bodies around the world. The most widespread of the cyanotoxins are the peptide toxins in the class called microcystins. There are at least 80 known microcystins, including microcystin-LR, which is generally considered one of the most toxic.

Consumption of large amounts of these toxins by animals or humans can result in muscle cramps, twitching, paralysis, and cardiac or respiratory failure. Recent data shows that harmful algae blooms have been implicated in human and animal illnesses and deaths in at least 43 states in the U.S.

More than a dozen countries have developed regulations or guidelines for microcystins in drinking water and recreational waters. Most of the drinking water guidelines are based on the World Health Organization (WHO)’s provisional value for drinking waters of 1.0 μg/L microcystin-LR.

And you can’t tell if it’s safe just by looking: Determining whether the cyanobacteria present in a water body are producing toxins requires laboratory testing. However, detection of microcystins is a challenging problem for water testing laboratories. Many laboratories have turned to liquid chromatography–triple quadrupole mass spectrometry (LC-MS/MS) for the concurrent detection and quantification of a range of mycotoxins and marine biotoxins.

Untargeted QTof HRMS finds what QqQ MS missed

Waters has been closely working with the Ministry of Environment and Climate Change (MOECC) in Toronto, Canada to develop both targeted and untargeted methods to identify and analyze microcystins produced from algae blooms. The ministry recently published an excellent paper using the Xevo G2-XS QTof high-resolution mass spectrometer (HRMS) as an alternative to the common tandem quad MS approach. By combining on-line solid phase extraction with LC-QTof MS, the MOECC lab achieved quantitative results for 12 known microcystin variants – and characterized two unknowns – in three hours compared to traditional methods that require several days of sample preparation due to matrix complexity and required low detection limits.

A related collaborative application note produced by Waters and MOECC scientists details a comprehensive methodology from LC-MS analysis to data interpretation using UNIFI Software workflows designed for environmental analysis. Detection and quantification using QTof HRMS demonstrated excellent sensitivity despite a small injection volume. We confirmed three microcystins were present above legislative limits in the lake water samples tested, and, building a library of historical data in UNIFI software, were able to identify another positive result that would not have been found using a tandem quadrupole MS instrument.

Hopefully we all enjoy a fun summer out on the water. But remember – if the lake water has a strange bluish greenish hue, check with your local water authority. If it looks and smells bad, don’t take a chance.

As water officials say, “When in doubt, stay out.”

 

Additional reading:

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Categories: Environmental