title: Temperature-independent near-infrared analysis of lysozyme aqueous solutions.
abstract: Digital Fourier filtering is used to produce a temperature-insensitive univariate calibration model for measuring lysozyme in aqueous solutions. Absorbance spectra over the 5000-4000 cm-1 spectral range are collected for lysozyme standards maintained at 14 degrees C. These spectra are used to compute the calibration model while a set of spectra collected at temperatures ranging from 4 to 24 degrees C are used to validate the accuracy of this model. The root-mean-square error of prediction (RMSEP) is 0.279 mg/mL over a tested lysozyme concentration range of 0.036-51.6 mg/mL. The detection limit is 0.68 mg/mL. In addition, multivariate calibration models based on partial least-squares regression (PLS) are evaluated and compared to the results from the univariate model. PLS outperforms the univariate model by providing a RMSEP of 0.090 mg/mL. Analysis of variance showed that both calibration methods effectively eliminate the adverse affects created by variations in solution temperature.
authors.affiliation: Department of Chemistry and Optical Science and Technology Center, University of Iowa, Iowa City 52242, USA.
authors.forename: S Y
authors.initials: SY
authors.lastname: Hu
authors.forename: M A
authors.initials: MA
authors.lastname: Arnold
authors.forename: J M
authors.initials: JM
authors.lastname: Wiencek
mesh_terms: D000818:Animals; D002645:Chickens; D004527:Egg Proteins / Q000032:analysis*; D005260:Female; D005583:Fourier Analysis; D009113:Muramidase / Q000032:analysis*; D012996:Solutions; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D004527:Egg Proteins; D012996:Solutions; D014867:Water; D009113:Muramidase