title: A comparison of gas-liquid chromatography, NMR spectroscopy and Raman spectroscopy for determination of the substituent content of general non-ionic cellulose ethers.
abstract: This paper describes and compares three techniques that can be used to characterize the substituent content of hydroxypropylcellulose (HPC and L-HPC) and hydroxypropyl methylcellulose (HPMC): gas-liquid chromatography (GLC) with a BP1 column and FI detection, 13C-NMR spectroscopy of hydrolysed samples, and Raman spectroscopy. GLC and 13C-NMR spectroscopy both allow independent quantification of hydroxypropoxyl and methoxyl contents. 13C-NMR spectroscopy, though requiring lengthier sample preparation, has the advantage of also quantifying the degree of substitution at each substitutable glucopyranose hydroxyl. Raman spectroscopy may be useful for rapid approximate estimation of hydroxypropoxyl content.
authors.affiliation: Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Alvarez-Lorenzo
authors.forename: R A
authors.initials: RA
authors.lastname: Lorenzo-Ferreira
authors.forename: J L
authors.initials: JL
authors.lastname: Gómez-Amoza
authors.forename: R
authors.initials: R
authors.lastname: Martínez-Pacheco
authors.forename: C
authors.initials: C
authors.lastname: Souto
authors.forename: A
authors.initials: A
authors.lastname: Concheiro
mesh_terms: D002138:Calibration; D002482:Cellulose / Q000031:analogs & derivatives / Q000032:analysis*; D002849:Chromatography, Gas; D004987:Ethers / Q000032:analysis; D065347:Hypromellose Derivatives; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008747:Methylcellulose / Q000031:analogs & derivatives / Q000032:analysis; D015203:Reproducibility of Results; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D004987:Ethers; D007202:Indicators and Reagents; D065347:Hypromellose Derivatives; D002482:Cellulose; D008747:Methylcellulose; C008079:hydroxypropylcellulose