Quantitative Analysis of Carbohydrates in Food Samples Using APCI-LC/MS with Post-column Reagent Addition and Ligand Exchange Chromatography

Introduction

Sensitive LC/MS methods for quantification of carbohydrates are in demand increasingly in foods, nutrition and biochemistry fields. The conventional analytical methods based on GC/MS or HPLC with ELSD, UV or fluorescence detection were used normally for few sugars or carbohydrates and derivatization of the compounds prior to analysis was needed mostly. It is desired to use LC/MS method without derivatization for quantitative determination of more carbohydrates. It is well known that ionization of carbohydrates by atmospheric pressure ionization (API) is difficult. Therefore, post-column addition of reagent such as chloroform is required. However, the high content of chloroform in the mobile phase may cause strong ion suppression and contamination to the interface and ion optics of LC/MS. Here, we report a new LC/MS method using a reduced content of chloroform by post-column addition in mobile phase and ligand exchange chromatography for analysis of twelve carbohydrates.

June 20, 2013 GMT