2P-35 PDF
Development of an Analytical Method for Microcystines using LC-Orbitrap MS
Microcystines are produced by toxic algae occurring at lakes or marshes, and many analogs for them exist. Conventional analytical methods for microcystines such as the 2-methyl-3-methoxy-4-phenyl butyric acid (MMPB) method and the enzyme-linked immunosorbent assay (ELISA) method all devote their attention to the common structure of microcystines. However, neither method can analyze individual microcystines selectively. Therefore, we developed an analytical method for individual microcystines with high precision using LC-Orbitrap MS.
In LC-Orbitrap MS measurements, microcystines were measured in the full MS mode and all ion fragment (AIF) mode. The extraction chromatograms of the presumed common structures from individual microcystines (m/z at 135.08044 for C9H11O+ and 103.05423 for C8H7+) were extracted from the chromatogram in the AIF mode. As a result of analyzing a certified reference material of water bloom, seven peaks were confirmed. Additionally, the concentration of total microcystines was calculated with an accuracy of 92%. Therefore, the developed method using LC-Orbitrap MS can be considered a suitable assay of microcystines.
Microcystines were extracted from algae-like material in water from a park in Ibaraki and analyzed. Six peaks were confirmed using LC-Orbitrap MS. Total concentration of six microcystines were equal to that obtained by the ELISA method.