Potential of two-dimensional correlation spectroscopy in analyses of NIR spectra of biological fluids. I. Two-dimensional correlation analysis of protein and fat concentration-dependent spectral variations of milk

Abstract

T wo-dimensional (2D) corre l ation spectro s c o py has recently received keen interest because it is a totally n ew and powerful spectral analytical method [1][2][3][4]. The 2D correlation spectroscopy enables us to obtain spectral information not readily accessible from one-dimensional spectra by spreading spectral peaks over the second dimension [1][2][3][4][5][6][7]. Band assignments and studies of inter-and intramolecular interactions become easier by selective correlations between various bands in synchronous and asynchronous 2D correlation spectra. Probing the specific order of the spectral intensity va ri ations is also possible by inspecting the asynchronous 2D spectra. Two-dimensional (2D) correlation analysis hasbeen applied to analyze protein and fat concentration-dependent near-infrared (NIR) spectral variations of milk. Synchronous and asynchronous 2D correlation spectra of milk enhance spectral resolution and provide information about concentration-dependent intensity changes not readily accessible from one-dimensional spectra. The asynchronous 2D correlation map shows marked differences between the protein and fat concentration-dependent spectral changes.

Generalized two-dimensional correlation near-infrared spectroscopy and principal component analysis of the structures of methanol and ethanol

“…Summing up the above analysis results and referring to corresponding literature [8][9][10][11][12][13][14], we present the assignments of NIR bands in Table 2. CH str and CC str .…”

Better Quality Food and Beverages: The Role of near Infrared Spectroscopy

“…milk quality analysis, has witnessed greater research activity. 26,27,[29][30][31][32]35 Wang et al 35…”

“…Fluid fat and protein reflectance 800-1100 nm Huang et al 27 fat and protein transflectance 1100-2500 nm Wang et al 35 fat and protein transmittance 1100-2500 nm purnomoadi et al 29 fat, protein and lactose transmittance 800-1100 nm Šašić & ozaki 30 unhomogenised milk composition transmittance 700-2400 nm tsenkova et al 31 unhomogenised milk composition transmittance 1100-2400 nm tsenkova et al 32 Somatic cell count transmittance 400-1100 nm pravdova et al 28 Somatic cell count transflectance 1100-2500 nm tsenkova et al 33 Somatic cell count transmittance 700-1100 nm tsenkova et al 34 reported that two-dimensional (2d) correlation spectroscopy in the nIr region could be used for the analysis of fat and protein in milk; this procedure revealed the existence of a number of hidden bands and also helped explain why certain wavelengths were selected in chemometric calibration models. 2d correlation spectroscopy enables spectral information not readily accessible from one-dimensional spectra to be obtained by spreading spectral peaks over a second dimension.…”

“…probing the specific order of the spectral intensity variations is also possible by inspecting the asynchronous 2d spectra. 35 tsenkova et al 31 analysed the influence of factors such as wavelength region, sample thickness and spectral data treatment on the accuracy of fat, total protein and lactose content determination in unhomogenised milk. the goal of this research was the development of a tool for on-line milk analysis during the milking process and these authors reported that both spectral region and sample thickness were significant factors in the accurate determination of milk fat and total protein, although not lactose.…”

Generalised 2D-correlation NMR analysis of a wine fermentation

“…Studies in which concentration is the 'perturbation' variable include a 2D NIR analysis of fat and protein in milk [25], a 2D IR study of polymer blends and copolymers [26][27][28] and a 2D IR study of antioxidants in aircraft engine oil [29]. Surprisingly, there have been relatively few reports of 2D correlation spectroscopy being applied in process monitoring analysis or application of the generalised 2D method to NMR analysis.…”