title: [HPLC analysis of microcystin-RR, YR and LR from Dianshan Lake].
abstract: OBJECTIVE
  To optimize the solid-phase extraction method of isolation, purification and determination of intracellular microcystin-RR, -YR and -LR (MC-RR,-YR,-LR), algal samples were collected from Dianshan Lake, which is a major water source of Shanghai.
  
  
  METHODS
  During extraction, Algal samples were treated with different solvent (5% acetic acid and 75% methanol), at different temperature (room temperature and 56 degrees C), centrifuge at 10000 x g, 30 min and 3500 rpm/min, 10 min, eluted with 80% methanol with or without trifluoroacetate acid(TFA). Further, gradient elution were employed to separate microcystins in high performance liquid chromatography (HPLC), the mobile phase consisted of aqueous acetonitrile and 0.05% TFA.
  
  
  RESULTS
  When dried algae cells were extracted by 5% acetic acid, 56 degrees C water bath combined with centrifuge at 3500 rpm/min was an effective and simple method for the extraction of microcystin-RR, elutant contains TFA can markedly increase the yield of microcystins extraction; the concentration of microcystin-RR in nature algal samples was higher than MC-LR and MC-YR.
  
  
  CONCLUSIONS
  The extraction efficacy of MC-YR and -LR is higher in 75% methanol aqueous and eluted with 80% methanol containing 0.05% TFA, while the extraction efficacy of MC-RR is higher in 5% acetic acid.
authors.affiliation: Key Laboratory of the Public Health and Safety, Ministry of Education, Department of Environmental Health, School of Public Health, Fudan University, Shanghai 200032, China.
authors.forename: Li-hong
authors.initials: LH
authors.lastname: Yin
authors.forename: Guo-zhou
authors.initials: GZ
authors.lastname: Zhang
authors.forename: Guo-guang
authors.initials: GG
authors.lastname: Cheng
authors.forename: Si-shun
authors.initials: SS
authors.lastname: Wei
mesh_terms: D002681:China; D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000378:metabolism; D005618:Fresh Water / Q000032:analysis; D008387:Marine Toxins; D052998:Microcystins / Q000032:analysis*; D014873:Water Pollutants / Q000032:analysis*
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D014873:Water Pollutants; C065685:microcystin YR; C063855:microcystin RR; C057862:cyanoginosin LR