Preparation, Fractionation and Determination of Molecular Weight of COS using MALDI-TOF-mass Spectrometry Analysis

Abstract

Chitooligosaccharides (COS) derived from the hydrolysis of high molecular weight chitosan (HMWC) was prepared and fractionated in salting-out method with a wide range of NaCl, and characterized by Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) mass spectrometry analysis. It was confirmed that the COS before salting-out had a range from (GlcN)4 to (GlcN)15. A large decrease in COS molecules was confirmed according to the sequential salting-out, and finally, the COS according to the quaternary salting-out was mainly confirmed in (GlcN)5~7. Unfortunately, it was not possible to efficiently separate or purify molecules larger than (GlcN)7 in a single molecule according to salting-out, but if the concentration of NaCl can be more precisely controlled, it is thought that the separation of COS having a molecular size of (GlcN)7 or larger may be possible. Prior to separation and purification of single molecules, it is also necessary to improve methodological approaches that can efficiently produce degradation products sufficiently containing molecules of a certain size. Therefore, the results of this study emphasize once again the importance of the production method of COS of various sizes according to enzyme treatment, and at the same time suggest the need to establish a method for purifying COS of a specific molecular size for pharmaceutical applications.