A New Method For Rapid Determination Of Typical Microcystins

For the past few years, with the industrial and agricultural development, water eutrophication is becoming more and more serious in China. The aggravated eutrophication of surface water sources and climate changes have result in cyanobacterial blooms in many drinking and irrigating water resources. Microcystins is the most common and harmful forms of cyanobacterial blooms in aquatic environments. These toxins can be accumulated in different organisms and crops and can easily reach human consumers. Previous studies have shown that the consumption of aquatic products, drinking water and crops are important exposure routes of microcystins to humans. Microcystins have the function of liver toxicity and tumor promotion.They not only have a toxic effect on aquatic organisms, but also harmful to human health through drinking water and food chain.Microcystins have been continually studied mainly due to their toxicity to human and enhanced occurrence frequency. The monitoring of the quality of water bodies to assess the presence of microcystins is of the utmost importance and often difficult because cyanobacterial blooms may generate many different kinds of microcystins. For successful treatment of microcystins and to minimize the risk to human health, sensitive and reliable methods able to detect the different types of microcystins are urgently required. Several methods for microcystins determination, such as biological-based screening methods and analytical techniques, have been developed. However, these methods may be improved by developing more rapid and efficient approaches.There are two main approaches to detect the presence of microcystins: bio-chemical assays and instrument analytical methods. Biochemical assays can detect the total amount of microcystins in samples. However, they are incapable of distinguishing microcystin analogues and may be strongly affected by matrix effects. Instrumental analytical methods are effective and powerful technologies to detect microcystins in complex matrices. However, methods based only on high performance liquid chromatography alone fail to provide structural information.Moreover, many of the classical analytical methods usually need complex sample pretreatment in order to remove the reagents used and derivatization for HPLC analysis. In recent years,although the mass spectrometry technology obtained fast development, a lot of efforts and exploration need to do, before the detecting technology applicated in the practical work. We decided to perform this study to establish a rapid method for the detection of microcystins.In this study we propose two kinds of rapid and real time microcystins determination method, which detect MC-LR and MC-RR at the same time. Rapid microcystins determination method was established, using paper spray ionization with time-of-flight mass spectrometry system, to detect two typical microcystins(MC-LR,MC-RR). The limit of detection is 1?g/L and the limit of quantitation is 3?g/L. Recovery for target microcystins were 77-103.6%. This method exhibits the potential to perform rapid, real time and high-throughput assays for the detection and quantitation of microcystins. Rapid detection was performed to record the release process of microcystins. Although the routine detection frequency is every 3 min, one whole testing period for our method is only 1 min, and the testing frequency can be increased according to requirements. The identification time of microcystins was reduced from several hours to few minutes. The ability to rapidly collect quantitative and qualitative information may bridge the gap in current methodologies which are either slow and accurate or fast and nonspecific.Environmental water samples were collected, the determination method was evaluated by complex matrix. In the analysis performed on the five sampling sites, the predominant toxin detected was MC-RR, with a range of concentration of 0-9.1?g/L. MC-LR was detected in ranges from 0-5.8?g/L.Rapid determination method, which identify microcystins and cyanobacterial at the same time, was established on the basis of matrix assisted laser desorption ionization and time-of-flight mass spectrometry. We get mass spectra of 23 kinds of cyanobacteria, and these pictures were used to identify algae. The characteristic peak of every algae strains was stable and can be reproduced. Algal strains produced from different waters in china have similar mass spectra. Foreign algal strains got different mass spectra compare to local algal strains.