Optimization Of The Method For Measuring Microcystin And Case Analysis

Eutrophication is a global environmental problem. With the increasingly serious degree of eutrophication of water bodies occur cyanobacterial blooms are common, water caused by the blue-green algae blooms caused by biological poisoning is a major concern of cyanobacterial toxins pollution. So the water is very important to monitor cyanobacteria toxins, especially for drinking water sources. Microcystins are a class of toxins produced by cyanobacteria Microcystis door under Microcystis metabolism, mainly the liver, kidneys causing functional impairment.The study found capable of producing microcystin in cyanobacteria have suspicious Microcystis, a few Anabaena and Oscillatoria, especially Microcystis aeruginosa is the most common.This article selecting the laboratory cultured FACHB-905 type Microcystis aeruginosa, against fresh algal cells in vivo was measured microcystin. In view of low concentration MCs of water, Design the experimental device and used the single factor response surface method to optimize and improve the MCs determination of water in the pretreatment process. Aha Reservoir in Guizhou Province as an example, for a period of 5 months(165) cycle of MCs monitoring, based on the combination of ecology and environmental science data and statistical analysis of Aha Reservoir microcystin periodic distribution of the correlation between change characteristics and environmental factors was obtained, clear of microcystin in Guizhou Plateau reservoir in Aha Reservoir space distribution characteristics and influencing factors, provide data support for reservoir management. The study results showed that:(1) In the study of the RP-HPLC method for the determination of the intracellular toxin of FACHB-905 type. Design of L9(34) by single factor experiment and orthogonal test, the results showed that methanol concentration 60 %, ultrasonic power 200 W, extraction time 50 min, solid-liquid ratio 1:15 g/m L, extraction temperature 50±5 ℃are the optimization extraction conditions. Through methodology study, the mobile phase group has become: acetonitrile- 0.02 % TFA solution gradient elution separation effect was better, at this time both the separation degree was 9.21. Optimum absorption wavelength was 238 nm. The precision was good(MC-RR,RSD %= 0.79 %;MC-LR,RSD %= 1.08 %;n= 6). The test solution for 48 h at room temperature stable(Area MC-LR: RSD %= 1.92 %). Preparation for test repeatability(CMC-LR: RSD %= 3.3 %). Linear relationship between content and peak area was good in the range of 0.019~0.154 μg/m L(YMC-RR= 38094 X+421.21, R2= 0.9997, YMC-LR= 23223 X+2921.1, R2MC-LR= 0.9999). Adopt infinite dilution method, determine the MC-RR and MC-LR absolute detection limit of 9.5 ng(ppt) and quantitation limit was 0.019 μg(100 ppm).Validation experiments showed that the average value of MC-LR content was 0.5190 μg/m L(RSD %= 0.80 %), the MC-RR was no detected. RP-HPLC method for the determination of FACHB-905 type of intracellular MCs, the method was simple and accurate.(2) In view of the determination of MCs in water, Used SPE-C18 solid phase extraction column, Self designing sample pretreatment device, The response surface One-Factor method was used to optimize the experiment, and the analysis of variance(P<0.01) was carried out that used pure water(25 m L) leaching to remove more polar impurities and discard, 30 % methanol(25 m L) used to remove impurity and discard, successively. The end used 80% acid methanol(0.02 %TFA, 25 m L) elution and 40 ℃spin dry methanol to obtain the test solution(1 m L). Selective medium solution and field water samples for analysis. The result showed that average concentration of MC-LR in medium solution was 0.7048 μg/L(RSD %=0.73 %) and average concentration of MC-RR and MC-RR in field water samples were 0.4177 μg/L and 0.5547 μg/L.(3) Based on the determination method of RP-HPLC and SPE pretreatment method. The MCs in water had been periodic tracking monitoring in Aha Reservoir. The results showed that microcystin content and cyanobacteria abundance of temporal and spatial variation present lag, microcystin content peak appeared later than cyanobacteria abundance. After principal component analysis and correlation analysis, the results showed that nitrogen and phosphorus concentration had a strong influence on the distribution of MC-LR(P<0.05). Simultaneously, effects of nitrogen more evident than phosphorus. Water temperature was also the main effects factors of MC-LR distribution(P<0.05). Microcystins exposure in the natural state, reduce to a very low level after 90±5 d. But cyanobacteria bacillus larvae sink into the sediment still created a higher outbreak bloom risk and it’s a terrible problem in drinking water.