Application of UHPLC-MS/MS in determination of the phytoplankton pigment and size fraction

In order to explore the feasibility of applying ultra-high performance liquid chromatography tandem triple quadrupole mass spectrometry (UHPLC-MS/MS) on pigment analysis and size fraction monitoring, seawater samples collected from 3 different water layers at 47 sites in the Yellow Sea were analyzed, it in terms of pigment concentrations acquired by ultra-high performance liquid chromatography (UHPLC) and UHPLC-MS/MS respectively and results got from the two ways were compared. No observious differences were observed from the result comparisons between the two methods for most cases although UHPLC-MS/MS were more sensitive, and the two methods were both suitable for pigment detection in the Yellow Sea. Based on the pigment results provided by UHPLC-MS/MS, the spatial distribution of chlorophyll a (Chl a) and size fraction were studied. The concentration of Chl a was much higher in the northeast of Yangtze River mouth and coastal waters of Shandong Peninsula, where micro phytoplankton was the dominant size fraction. The concentration of Chl a was much lower in the central Yellow Sea, and the contribution of nano-and pico-phytoplankton increased significantly in this region. Compared with previous studies, the absolute concentrations of Chl a and contribution of size fractions in our study showed some differences, which may be caused by the differences of investigation time, sites or analytical methods. Thus, more comparison study is still needed to further probe the reason behind these differences