Magnetic activated carbon@ iron oxide@manganese oxide composite as an adsorbent for preconcentration of microcystin –LR in surface water, tap water, water and wastewater

A simple, rapid and effective method based on dispersive solid phase microextraction (DSPME) and UV–vis spectrophotometer was developed for the preconcentration and determination of microcystin-LR (MC-LR) in environmental matrices. The activated carbon@ iron oxide@manganese oxide composite was used as solid phase material. The composite was characterized by scanning electron microscope/energy dispersive x-ray spectroscopy (SEM/EDS), transmission electron microscope (TEM), X-ray powder diffraction (XRD), nitrogen adsorption/desorption and Fourier transform infrared (FTIR). The factors affecting the DSPME were optimized using multivariate strategy. Under optimized condition, the LOD, LOQ, repeatability (n = 10), reproducibility (n = 5) and preconcentration factor were 0.5 μg L⁻¹, 1.7 μg L⁻¹, 3.1, 4.5% and 50, respectively. The percentage recovery of MC-LR in spiked water samples was found to be 98.5%. The developed method DSPME/UV–vis method was simple, rapid, cost-effective and can be used for the detection of MC-LR in real samples without any expensive or sophisticated equipment.