Citation:

Maizels, M. AND W L. Budde. A LC/MS METHOD FOR THE DETERMINATION OF CYANOBACTERIA TOXINS IN WATER. Analytical Chemistry 76(5):1342-1351, (2004).

Impact/Purpose:

The purpose of this research project is to develop a strong qualitative and quantitative "gold standard" laboratory reference analytical method for the simultaneous selective and sensitive identification and measurement of those cyanobacteria toxins that are of the highest priority to EPA and state and local drinking water authorities. These toxins are on the drinking water candidate contaminant list (CCL), but the specific toxins that are the most likely to occur, and which are the potentially most hazardous, are not defined on the CCL. Six toxins were recommended for highest consideration by an EPA workshop in May, 2001. These are the alkaloids anatoxin-a and cylindospermopsin, and the four microcystins abbreviated RR, LR, YR , and LA (these characters are the standard single-character designations for four natural aminoacids). There are no published analytical methods that have been demonstrated to have the ability to detect and reliably measure the concentrations of these six compounds in a single drinking or source water sample. The purpose of this research is to not only develop and demonstrate this capability with real environmental samples, but also to do it in a single economical laboratory analytical method that requires about one hour from initial sample preparation to obtaining the results. It is expected that some other toxins will be found in the real environmental samples tested, and perhaps even new toxins may be discovered in this work. The techniques employed in this work, have the capability of tentatively identifying known and unknown toxins even when standards are not available.

Description:

The cyanobacteria toxins anatoxin-a, microcystin-LR, microcystin-RR, microcystin-YR, and nodularin were separated in less than 30 minutes on several 1 mm x 15 cm reverse phase liquid chromatography (LC) columns, and their electrospray mass spectra were measured with 50 ng or less injected amounts with a bench-top time-of-flight (TOF) mass spectrometer. New data from this work includes: (a) the impact of acetic acid concentrations in the methanol-water mobile phase on measured ion abundances; (b) the performance of the electrospray-TOF mass spectrometer as an LC detector; (c) the accuracy and precision of exact m/z measurements after LC separation with a routinely-used mass spectrometer resolving power of 5000; and, (d) recoveries of the five toxins from reagent water, river waters, and sewage treatment plant effluent samples extractged with C-18 silica particles enmeshed in thin Teflon (trademark) membrane filter disks. This technique has the otential of providing a relatively simple and reasonable-cost sample preparation and LC/MS method that provides the sensitivity, selectivity, reliability, and information content needed for drinking water occurrence and human exposure studies.

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