Fingerprinting of hydroxy propyl methyl cellulose by comprehensive two-dimensional liquid chromatography-mass spectrometry of monomers resulting from acid hydrolysis

• Published in: Journal of Chromatography A 2024-05, Vol.1722, p.464874, Article 464874
• Main Authors: Bos, Tijmen S., Pirok, Bob W.J., Karlson, Leif, Schantz, Staffan, Dahlseid, Tina A., Stoll, Dwight R., Somsen, Govert W.
• Format: Article
• Language: English
• Subjects: Comprehensive two-dimensional liquid chromatography; Fingerprinting; Hydroxypropyl methyl cellulose; Monomer composition
• ISSN: 0021-9673
• DOI: 10.1016/j.chroma.2024.464874

•Analysis of the monomer composition HPMC by LC × LC-MS.•Separation of the monomers based on the number and position of the substituents.•Identification of constitutional isomers through LC × LC-MS/MS.•Comparison of the two industrial samples with the same average substitution. Hydroxypropyl methyl cellulose (HPMC) is a type of cellulose derivative with properties that render it useful in e.g. food, cosmetics, and pharmaceutical industry. The substitution degree and composition of the β-glucose subunits of HPMC affect its physical and functional properties, but HPMC characterization is challenging due to its high structural heterogeneity, including many isomers. In this study, comprehensive two-dimensional liquid chromatography-mass spectrometry was used to examine substituted glucose monomers originating from complete acid hydrolysis of HPMC. Resolution between the different monomers was achieved using a C18 and cyano column in the first and second LC dimension, respectively. The data analysis process was structured to obtain fingerprints of the monomers of interest. The results revealed that isomers of the respective monomers could be selectively separated based on the position of substituents. The examination of two industrial HPMC products revealed differences in overall monomer composition. While both products contained monomers with a similar degree of substitution, they exhibited distinct regioselectivity.