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A method for the detection of microcystins (microcystin LR, RR, and YR) in cyanobacteria by supercritical fluid extraction (SFE) and liquid chromatography‐mass spectrometry (LC/MS) has been developed. Supercritical fluids for the analytical extraction of nonvolatile, higher molecular weight compound, and microcystins from cyanobacteria were investigated. The microcystins included in this study are sparsely soluble in neat supercritical fluid CO2. However, the microcystins was successfully extracted with a ternary mixture (90% CO2, 9.5% methanol, 0.5% water) at 40°C and 250 atm. The polar carbon dioxide‐aqueous methanol fluid system gave high extraction efficiency for the extraction of the polar microcystins from cyanobacteria. The microcystins were determined by liquid chromatography‐tandem mass spectrometry (LC/MS/MS).

Microcystins are a family of cyclic polypeptides produced by different species of cyanobacteria (blue green algae), which can form blooms in lakes and water reservoirs. However, it is difficult to detect microcystins directly in the water since the concentration of the toxins in water is usually too low. It is necessary to develop a simple and quick method to detect microcystins. In this paper, different detection characteristics of fluorescence immunochromatography and gold colloidal immunochromatography for analysis of cyanobacterial toxins were studied. These two immunochromatography assays are easy to perform, rapid, sensitive, and their quantitative range is within detectable microcystin concentrations in water samples. The fluorescence immunochromatographic system has the unique advantages of low detection limit, and satisfactory accurate results are obtained. The gold colloidal immunochromatographic system has the strong advantage of direct detection of microcystins at the test site withou...

An efficient method for the simultaneous separation and purification of microcystins (LR), (RR), and (YR) from the cyanobacterium is described. The method involves supercritical fluid extraction for the fast extraction and column chromatography for the purification of the microcystins LR, RR, and YR. A new method for the simultaneous extraction of microcystins LR, RR, and YR was developed by using supercritical CO2. Three kinds of microcystins were successfully extracted with a ternary mixture (90% CO2, 9.4% acetic acid, 0.6% water). The separation and purification procedure results in a purity of up to 95% for microcystins RR and YR without the need for a preparative high performance liquid chromatography (HPLC). Only for the purification of microcystin LR, we used a further preparative HPLC purification step. The advantage of the method developed here is that the sample handling steps were minimized, thus reducing possible losses of microcystins and saving extraction and purification time.

A rapid and efficient method for extraction and isolation of microcystin-LR from the cyanobacterium is described. The method involves supercritical fluid extraction (SFE) for the fast extraction and silica gel flash chromatography for the purification of the microcystin-LR. The microcystin-LR can be successfully extracted with aqueous methanol modified supercritical carbon dioxide fluid. The procedure results in a purity of up to 95% microcystin-LR with the following preparative HPLC purification steps. The advantage of the method developed here is that the sample handling steps are minimized, thus reducing possible losses of microcystin-LR and saving extraction and purification time.