shutterstock_221007223Green water for drinking? Not something you see every day, and definitely not something you would ever consider for yourself or for your loved ones. However, in 2014, a serendipitous slug of toxins and the loss of drinking water for a half-million residents in Ohio led scientists and government officials to initiate a thorough investigation of Lake Erie. Flooded by tides of phosphorus washed from fertilized farms, cattle feedlots and leaky septic systems, the most intensely developed area of the Great Lakes was increasingly being choked each summer by thick mats of algae, much of it poisonous. However, the problem was not limited to Great Lakes only. Poisonous algae were found in polluted inland lakes from Minnesota to Nebraska to California, and even in the glacial-era kettle ponds of Cape Cod in Massachusetts.

Blue-green algae, or cyanobacteria, often known as red tides, are harmful algal blooms that have severe impacts on human health, aquatic ecosystems, and the economy. To address this issue and prevent any major threats, the United States Environmental Protection Agency (EPA) developed methods that focus on technologies that enable confident quantitation of such contaminants. The EPA method 544 for unregulated contaminant monitoring rule 4 (UCMR 4) program collects data for contaminants that are suspected to be present in drinking water lacking health-based standard regulation under the Safe Drinking Water Act (SDWA).shutterstock_208404

Challenges in Quantitation

From increasing sample analysis throughput to addressing sensitivity and reproducibility goals, liquid chromatography coupled with triple-stage mass spectrometry (LC-MS/MS) has become the technique of choice for such and several other types of quantitative analysis. In this particular example, the analytical scientists were not only challenged with identifying contaminants fast, they also had to quantify the contaminants to determine the level of toxicity, and establish a robust method that would identify and quantify the level of toxins with high efficiency and confidence, regularly. While triple quadrupole MS (QQQ) has been serving the analytical scientific community for years, the requirements and hence, expectations, continue to rise, which often challenges the capabilities of the traditional LC-MS/MS platforms. A robust, reliable, reproducible, sensitive quantitation assay to quantify hundreds of molecules across varied matrices that can be developed and implemented by users of all expertise, all while addressing critical regulatory challenges is a common expectation in today’s world of targeted quantitation. And it is definitely not something that can be addressed by a simple LC-MS/MS platform. A start-to-finish comprehensive workflow solution comprising LC and QQQ with best-in-class capabilities are essential. In this regard, the quantitative performance of the latest generation of QQQ instruments enhances quantitation for these groups of compounds. A workflow solution was developed comprising Vanquish Flex HPLC system and Thermo ScientificTM TSQ QuantisTM triple quadrupole MS platform and using EPA Method 544: Determination of Microcystins in Drinking Water by Solid Phase Extraction (SPE) and Liquid Chromatography Electrospray Ionization and Tandem Mass Spectrometry (LC-ESI-MS/MS).

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Addressing Requirements

The EPA has strict requirements for the analysis of any sample, referred to as the Initial Demonstration of Capability (IDC). These requirements include the demonstration of low background noise, precision by analyzing four to seven extracted laboratory fortified reagent water blanks (LFB) at mid-level, the demonstration of accuracy, and finally, the demonstration of capability necessary to meet the minimum reporting limit (MRL). The percent relative standard deviation (%RSD) of the results for replicate analyses must be ≤ 30%. The average percent recovery for each analyte must be within ± 30% of the true value. Aided by the outstanding Vanquish Flex HPLC that offers superior resolution and speed, and TSQ Quantis — which offers supreme confidence in quantitation for every molecule, in every matrix, for every user day after day — a sensitive, robust, and reproducible workflow solution was developed that can consistently quantify microcystins in nodularin in drinking water following EPA method requirements.

Being on Top

Learn more about such quantitation assays and many more by downloading the application note “Quantitation of cyanotoxins in drinking water according to EPA 544 guidelines.

For more information on addressing environmental and food safety analysis with a robust and reliable workflow comprising of ultra high performance liquid chromatography (UHPLC) systems and HPLCs with QQQs, see our dedicated web page.