Project ID: D2016-76

Background

When water conditions are favorable for cyanobacteria growth, harmful algae blooms (HABs) can result, causing elevated levels of toxins called microcystins (MCs). There are over 300 microcystin variants. The EPA suggests that MC-LR variant concentration in drinking water should be less than 0.3 µg/L. Trace levels of MCs can be invisible to traditional detection techniques unless preconcentration of MCs is performed. Currently, enzyme-linked immunosorbent assay (ELISA) is used to detect MCs in water. This method relies on ADDA group identification and therefore is a measure of all microcystin variants. Liquid chromatography-mass spectrometry (LC-MS) is a more sensitive method for quantification than ELISA, but is challenged by sample preparation. In order to protect against HABs, there needs to be a method for preconcentrating water and patient samples in order to bring limits of detection within a meaningful range. 

Invention Description

Researchers at the University of Toledo have developed an accurate, reproducible and efficient technique for preconcentrating MCs. Extraction capabilities of solid-phase extraction allow for a quantitative trace analysis, even in complex matrices, such as lake water, blood, or urine. By preconcentrating samples, the more sensitive method for quantification of MCs, LC-MS, can be utilized. Using this technique lowers the detection limit well below EPA recommendations for safe drinking water, allowing for early warnings and better response times.

Applications

• Sample prep/preconcentration for quantifying via LC-MS analysis

• Water purification and detection of microcystins

• Diagnostic for MC exposure

• Sampling of MCs

• Robust and sensitive, even in complex matrices

• Can separate various MC congeners

Advantages

• Excellent MC recoveries

• Excellent Limits of Detection (LODs ~ 0.2 ng/L) and Limits of Quantification (LOQs ~ 0.6-1.0 ng/L) of MC congeners in water

• LOQs of MC congeners in urine ranging from ~0.15 μg/L to 0.5 μg/L, and in serum and plasma from ~0.5 μg/L to 1.0 μg/L.

IP Status:                             Issued US Patents 10,436,794 B1 and 10,809,259

Publication:                       Isailovic D, et al. Improved solid-phase extraction protocol and sensitive quantification of six microcystins in water using an HPLC-orbitrap mass spectrometry system Anal. Methods, 2017, 9, 2021-2030

                                                Isailovic D, et al. Development and applications of solid-phase extraction and liquid chromatography-mass spectrometry methods for quantification of microcystins in urine, plasma, and serum, https://www.sciencedirect.com/science/article/pii/S0021967318310264 J. Chromatogr. A, 2018, 1573, 66-67.