Improved chemical analysis of cellulose ethers using dialkylamine derivatization and mass spectrometry.
Oligosaccharides of hydroxypropylmethyl cellulose, hydroxypropyl cellulose, and methyl cellulose were investigated by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The cellulose ether oligosaccharides were produced either by enzymatic depolymerization utilizing the purified family 5 endoglucanase from Bacillus agaradhaerens or by partial acidic depolymerization. To lower the limit of detection in MALDI-MS three dilakylamines, dimethyl-, diethyl-, and dipropylamine were studied as reagents for reductive amination of the oligosaccharides. All three amines contributed to a significant increase in sensitivity in MALDI-MS, especially for oligosaccharides with a degree of polymerization (DP) < 3. These reagents were also attractive due to their high volatility, which facilitated the purification of the reaction mixtures. It was established that low-mass discrimination in MALDI-MS in the DP range 1-7 was substantially reduced with dialkylamine derivatization. Hence, dialkylamine derivatization of cellulose ether oligosaccharides obtained by endoglucanase depolymerization increased the number of detected analyte components. Dimethylamine was concluded to be the preferred reagent of those evaluated.
Momcilovic
Dane
D
Department of Technical Analytical Chemistry, Lund University, Post Office Box 124, S-221 00 Lund, Sweden.
Schagerlöf
Herje
H
Wittgren
Bengt
B
Wahlund
Karl-Gustav
KG
Brinkmalm
Gunnar
G
D000588:Amines / Q000737:chemistry*; D001407:Bacillus / Q000378:metabolism; D001672:Biocompatible Materials / Q000737:chemistry; D002241:Carbohydrates / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry* / Q000302:isolation & purification*; D002845:Chromatography; D004987:Ethers; D013058:Mass Spectrometry; D009844:Oligosaccharides / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000588:Amines; D001672:Biocompatible Materials; D002241:Carbohydrates; D004987:Ethers; D009844:Oligosaccharides; D011108:Polymers; D002482:Cellulose