Liquid Chromatography MS/MS Responses on Lentinan for Structure Characterization of Mushroom Polysaccharide β-D-Glucan

Abstract

Lentinan, a complex polysaccharides β-D-glucan found in Shiitake Mushroom has been known to have medicinal effect such as anticancer and immune-modulatory properties. Analysis on lentinan through application of high-end biotechnology instrument such as mass spectrometry is still limited. In this study, Liquid Chromatography Mass Spectrometry-Quadropole Time of Flight (LC/MS Q-TOF) has been used to optimize the MS/MS response in elucidating the lentinan characteristics. Analysis was done by using lentinan standard at different concentrations through different combinations of four types of columns and four types of buffers. Four levels of MS/MS collision energies or known as Collision Induced Dissociation (CID) were applied. Data presented shown that the optimum MS/MS CID that generated all six product ion of lentinan at the most combinations of column and buffer was at 20.0 V. Combination of Altima Hydrophilic Interaction Liquid Chromatography (HILIC) column without any buffer in mobile phase (AH; NB) and Hypercarb column with the present of 0.1% acetic acid in mobile phase (TH; 0.1% AA) respectively were found to be the best combinations among other combinations as these combinations were able to generate product ions of lentinan at lentinan concentration as low as 0.156 mg/mL. This suggested that these column and buffer combinations have given good sensitivity to enhance peak efficiency of lentinan at low concentration which was required to meet MS/MS abundance threshold. As the conclusion, suitable combinations of column and buffer are crucial in order to enhance peak efficiency of lentinan at optimum ionization intensity to allow optimum MS/MS responses for elucidation of their structure characteristics. Determination of appropriate collision energy also plays an important role to generate MS/MS spectra of all product ions for the lentinan.