Analysis of microcystins using high‐performance liquid chromatography and magnetic solid‐phase extraction with silica‐coated magnetite with cetylpyridinium chloride

Abstract

Microcystins (MCs), produced by freshwater cyanobacteria, can be serious water pollutants, so it is important to monitor their concentration in drinking water. We have developed a method for rapid and accurate determination of microcystin levels in environmental water, using magnetic solid-phase extraction and high-performance liquid chromatography with UV detection. The magnetic composite material, which was combined with cetylpyridinium chloride, was prepared by hydrothermal synthesis. The optimal extraction of microcystins in water sample was achieved by optimizing the amount of adsorbent, time of adsorption, ratio of eluting solvent, and volume of eluent. Under the optimal conditions, the limit of detection of MC-LR was 0.001 μg/L, and the limit of quantification was 0.0028 μg/L. The limit of detection of MC-RR was 0.001 μg/L, and the limit of quantification was 0.003 μg/L. These values are far lower than those established by the International Health Organization for the maximum concentration of microcystins in drinking water. The magnetic solid-phase extraction adsorbent used in this method has the advantages of simple preparation, low price, and easy solid-liquid separation, and it can be used for the rapid and sensitive monitoring of trace microcystins in environmental water samples.

A Mini-Review on Detection Methods of Microcystins

“…To improve upon the sensitivity and selectivity of HPLC, novels including magnetic solid-phase extraction (MSPE) coupled with HPLC/UV based on a magnetic bentonite sorbent fabricated by solvothermal synthesis method, MSPE based on mesoporous Fe3O4@mSiO2@Cu2 + nanoparticles (NPs) coupled with HPLC, and MSPE coupled with HPLC/UV where the magnetic composite material was combined with cetylpyridinium chloride prepared by hydrothermal synthesis [ 71 , 72 , 89 ] were developed and validated for trace detection and analysis of MCs.…”

“…To confirm and identify MC variants in an unknown sample, HPLC is preferred since it provides enough information on the MC variant(s) present. HPLC can also be used to generate both quantitative and qualitative data for MCs analysis [ 35 , 72 , 89 ]. In addition, it is capable of identifying and quantifying MC variants in a sample if suitable analytical standards are present.…”

“…HPLC is also constrained by the large number of diverse MC variants and the commercial availability of standard compounds without which identification of MC becomes impossible. Further, due to the slight difference that exists between MC variants, it sometimes becomes very difficult to use this technique for separation [ 33 , 89 , 90 , 91 ]. Interestingly, HPLC cannot differentiate between structural MC variants, and the retention time may not be an appropriate explicit detector for the toxins.…”

Magnetic solid‐phase extraction method for extraction of some pesticides in vegetable and fruit juices

“…One of the important characteristics of NPs is their large specific surface area that increases the adsorption capacity of these substances. Generally, for increasing durability of the sorbent and to prevent its oxidation, NPs surface is coated with inorganic materials (such as silica or alumina) [13] or organic compounds (such as chitosan or surfactants). Nowadays, among the NPs, MNPs attract increasing interest.…”

Simultaneous Pre-Concentration and HPLC-MS/MS Quantification of Phycotoxins and Cyanotoxins in Inland and Coastal Waters

“…Among the common techniques, solid phase extraction (SPE) and magnetic solid phase extraction (MSPE) are often used due to their attractive properties such as flexibility, high enrichment factor (EF), low consumption of reagents, and the possible choice among different sorbent materials. However, most of the existing literature data propose analytical methods for single class determination of toxins in water [15][16][17][18][19][20][21][22][23], whereas only few methods focus on simultaneous determination of the various classes of cyanotoxins and phycotoxins. Moreover, the use of a single SPE is not enough to provide quantitative recoveries for all the classes, so the multi-cartridge SPE approach was applied [24,25].…”