Determination of Microcystin-LR in Environmental Water by Magnetic Solid Phase Extraction-High Performance Liquid Chromatography

A rapid analytical method was established for the determination of trace amounts of microcystin (MC-LR) in environmental water samples by using magnetic solid phase extraction (MSPE) coupled with HPLC/UV based on a magnetic bentonite sorbent fabricated by solvothermal synthesis method. Several factors influencing the extraction efficiency of MC-LR, such as sorbent amount, pH condition, sample volume, adsorption and desorption time, and desorption solvent, were investigated and optimized. Under the optimal extraction conditions, the limits of detection and quantification for the method were 0.75 and 1.5 ng L−1, respectively, which was far below the guideline recommended by the World Health Organisation. The method showed a good linearity (R2 = 0.9993) in the concentration ranges of 0.25–250 μg L−1 for MC-LR. The MSPE sorbent was simple in preparation, low cost and magnetizable, and the developed MSPE-HPLC method was suitable for the rapid and sensitive determination of MC-LR in nature water samples.