HPLC-MS/MS Analysis And Application On Photosynthetic Pigments Of Marine Environment

As primary producers of marine ecosystem, phytoplankton play a key role in influencing high-level structures of food web, the transfer of material and energy, and also the processing of biochemical cycle. Therefore, it is needed for the study on the structural function and dynamics of ecosystem to understand composition and abundance of phytoplankton. Pigments are commonly used as quantitative biomarkers for the composition and biomass of marine phytoplankton. Thus, microscopic examination has been replaced by pigment analysis on identification and quantitation of phytoplankton. Moreover, the application of pigments has been a powerful tool on studying phytoplankton structures with chromatographic technologies developed.For decades, HPLC analysis to algal pigments has presented a challenge to pigment identification due to the diversity of large molecules spanning a wide range of polarities, including many that have closely similar chemical structures. High performance liquid chromatography-mass spectrometry (HPLC-MS/MS) can provide more sensitive and selective quantification of target compounds than HPLC when used the multiple-reaction monitoring mode, which can improve the analysis stability by eliminating the interference of other complex matrices.Analysis on pigments by HPLC-MS/MS is known little in China. In this study, based on the traditional HPLC method, we developed HPLC-MS/MS for analyzing20chemotaxonomically useful pigments. Concentrations of pigment standards on7levels were detected. The results showed that peak areas of majority pigments have good linear relation with the concentrations (R>0.9507). These methods are accurate, stable and with good reproducibility (RSD%<5%), which can be used as the identification and quantitation of20pigments. These methods were applied for estimating phytoplankton communities in three offshore marine aquaculture zones of Dalian (Dalijia, Jinshitan, and Dachangshan Island) in the North Yellow Sea, China.12pigments were detected by HPLC-MS/MS in all of sampling sites. From the pigment species detected, it can be concluded that diatom, dinoflagellate, chrysophyte and cyanobacteria existed. CHEMTAX results showed that the main phytoplankton species were diatom and dinoflagellate, while chrysophyte were moderate and cyanobacteria were minor. The average of total biomass of three zones were2.703,1.506and 1.182μg/L (Dalijia>Jinshitan>Dachangshan Island), respectively. According to the hydrology state simultaneously determined, it can be known that the obvious reproduction capacity of dinoflagellate in the Dachangshan Island may also attribute to the lower nutrient levels, which is in agreement with relative report.The development of HPLC-MS/MS methods of pigments in this study became a new and useful tool on study of phytoplankton structures. Meanwhile, the application of these methods on phytoplankton structures of the North Yellow Sea can offer fundamental data for marine investigation.