title: Pitfalls in microcystin extraction and recovery from human blood serum.
abstract: BACKGROUND
  Microcystins (MCs) contaminate water bodies due to cyanobacterial blooms all over the world, leading to frequent exposure of humans to MCs through consumption of meat, fish, seafood, blue-green algal products and water, accidental ingestion of contaminated water and scum during recreational activities and inhalation of cyanobacterial aerosols. For monitoring of human exposure, sensitive screening methods are needed. However, during the analytical process of various matrices, such as human serum, some problems appear to regularly occur during sample preparation and storage, leading to MC loss and thus to underestimation of the true MC concentration. The aim of the current study was therefore to assess the pitfalls of the MC-extraction method from human serum with more detail.
  
  
  METHODS
  Six MC congeners (MC-LR, -YR, -RR, -LA, -LW, -LF) and defined equimolar MC mixtures thereof were spiked into human serum, and quantified using the commercially available Adda-ELISA subsequent to standard extraction (methanol extraction with subsequent SPE). To detect the potential influence of sample storage and preparation/storage materials, different types of material such as glass, standard polypropylene and surface-treated polypropylene were compared.
  
  
  RESULTS
  Loss of MC during preparation and storage is largely dependent on (1) the handling of the stored material, (2) the 'surface' of the storage material and (3) the hydrophobicity of the MCs.
  
  
  CONCLUSIONS
  The pitfalls described for MC analysis with the ELISA are primarily associated with sample preparation and clean-up and thus also apply to other analytical techniques for MC detection beyond the ELISA used. It can be concluded that ELISA-based methods are suitable tools for the detection of MCs in human sera and other samples.
authors.affiliation: Human and Environmental Toxicology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany. Electronic address: alexandra.heussner@uni-konstanz.de.
authors.forename: Alexandra H
authors.initials: AH
authors.lastname: Heussner
authors.affiliation: Human and Environmental Toxicology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany. Electronic address: stefan.altaner@uni-konstanz.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Altaner
authors.affiliation: Abraxis LLC, 54 Steamwhistle Drive, Warminster, PA 18974, USA. Electronic address: lkamp@abraxiskits.com.
authors.forename: Lisa
authors.initials: L
authors.lastname: Kamp
authors.affiliation: Abraxis LLC, 54 Steamwhistle Drive, Warminster, PA 18974, USA. Electronic address: frubio@abraxiskits.com.
authors.forename: Fernando
authors.initials: F
authors.lastname: Rubio
authors.affiliation: Human and Environmental Toxicology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany. Electronic address: daniel.dietrich@uni-konstanz.de.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Dietrich
mesh_terms: D000818:Animals; D001774:Blood Chemical Analysis / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D057097:Harmful Algal Bloom; D006801:Humans; D052998:Microcystins / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D052616:Solid Phase Extraction / Q000379:methods; D014874:Water Pollutants, Chemical / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D052998:Microcystins; D014874:Water Pollutants, Chemical
keywords: Adsorption to lab ware; ELISA; Human serum; Hydrophobicity; Microcystin; Recovery