C₁₈-Functionalized Magnetic Silica Nanoparticles for Solid Phase Extraction of Microcystin-LR in Reservoir Water Samples Followed by HPLC-DAD Determination

Abstract

In this study, C₁₈-functionalized magnetic silica nanoparticle (Fe₃O₄@SiO₂@C₁₈ MNPs) based magnetic solid phase extraction (MSPE) was successfully developed for the determination of microcystin-LR (MC-LR) in reservoir water samples followed by high performance liquid chromatography–diode array detection (HPLC–DAD). After the extraction, the adsorbent can be conveniently and rapidly separated from aqueous samples by an external magnet. The main factors influencing the extraction efficiency including the amount of the MNPs, the extraction time, the pH of sample solution, and desorption conditions were optimized to obtain high recoveries and extraction efficiency. High enrichment factor 500 was attained. Under the optimized experimental conditions, the calibration curve of MC-LR was linear in the range of 0.1–10.0 µg/L with correlation coefficients (r²) 0.9996. Limit of detection (LOD, S/N = 3) of the method was 0.056 µg/L. The developed method was successfully applied to the determination of MC-LR in reservoir water samples. The method recoveries were obtained ranging from 73.3–104% for three spiked concentrations, with the relative standard deviations (RSD) of 2.90–4.30%. The developed Fe₃O₄@SiO₂@C₁₈ MNPs-based MSPE coupled with HPLC–DAD demonstrated excellent sensitivity and repeatability, simplicity, rapidity, and ease of operation, as well as practical applicability.

Keywords:

• C₁₈-functionalized magnetic silica nanoparticles
• HPLC-DAD
• magnetic solid phase extraction
• microcystins
• preconcentration
• water samples