Quantitative Characterization of Pulmonary Fat Emboli by Attenuated Total Reflectance–Fourier Transform Infrared (ATR-FTIR) Spectroscopy and Partial Least-Squares (PLS) Regression: A Preliminary Study

This rapid method for determining the degree of degradation of frying rapeseed oils uses Fourier-transform infrared (FTIR) spectroscopy combined with partial least-squares (PLS) regression. One hundred and fifty-six frying oil samples that degraded to different degrees by frying potatoes were scanned by an FTIR spectrometer using attenuated total reflectance (ATR). PLS regression with full cross validation was used for the prediction of acid value (AV) and total polar compounds (TPC) based on raw, first, and second derivative FTIR spectra (4000–650 cm−1). The precise calibration model based on the second derivative FTIR spectra shows that the coefficients of determination for calibration(R2)and standard errors of cross validation (SECV) were 0.99 and 0.16 mg KOH/g and 0.98 and 1.17% for AV and TPC, respectively. The accuracy of the calibration model, tested using the validation set, yielded standard errors of prediction (SEP) of 0.16 mg KOH/g and 1.10% for AV and TPC, respectively. Therefore, the degradation of frying oils can be accurately measured using FTIR spectroscopy combined with PLS regression.

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Rapid determination of fecal fat by Fourier transform infrared analysis (FTIR) with partial least-squares regression and an attenuated total reflectance accessory

Clinical Chemistry ◽

10.1093/clinchem/42.12.2015 ◽

1996 ◽

Vol 42 (12) ◽

pp. 2015-2020 ◽

Cited By ~ 21

Author(s):

P Franck ◽

J L Sallerin ◽

H Schroeder ◽

M A Gelot ◽

P Nabet

Keyword(s):

Fourier Transform ◽

Least Squares ◽

Partial Least Squares ◽

Rapid Determination ◽

Fourier Transform Infrared ◽

Attenuated Total Reflectance ◽

Infrared Spectrometry ◽

Infrared Analysis ◽

Least Squares Regression ◽

Total Reflectance

Abstract Fecal lipid content is usually determined by titrimetric or gravimetric methods, but these methods are time consuming and involve dangerous solvents. We have developed a new method of measuring fecal lipids by Fourier transform infrared spectrometry (FTIR) with an attenuated total reflectance accessory that is fast and requires no solvents. The spectra of stools from 4000 to 750 cm-1 were analyzed, and the lipid concentrations were measured by using a calibration curve prepared by partial least-squares analysis of data from 34 stools. The linearity of the method was tested by mixing low-lipid stools with lipid-overloaded stools to give a range of 0.5-15% lipid. The prediction residual values were -0.49-0.78% for calibrators, and -2.55-2.34% for unknown samples. There was good agreement between the fecal lipids measured by gravimetric (x) and FTIR(y) methods: y = 0.87x + 5.5. The standard error of prediction was 1.07%.

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Characterization of polysaccharides from Eremurus hissaricus roots by FTIR spectroscopy

Proceedings of universities Applied chemistry and biotechnology ◽

10.21285/2227-2925-2021-11-2-281-289 ◽

2021 ◽

Vol 11 (2) ◽

pp. 281-289

Author(s):

A. I. Ashurov ◽

A. S. Dzhonmurodov ◽

S. R. Usmanova ◽

Sh. E. Kholov ◽

Z. M. Muhidinov

Keyword(s):

Fourier Transform ◽

Ftir Spectroscopy ◽

Absorption Maximum ◽

Attenuated Total Reflectance ◽

Pyranose Ring ◽

Total Reflectance ◽

Software Applications ◽

Soluble Polysaccharide ◽

Stretching Vibrations

The structure of water'soluble gluco' and galactomannans (GlcMan and GalMan) isolated from the roots of several Eremurus'related plant species has been studied previously. This article characterizes polysaccharides and other extraction products from the root tubers of Eremurus hissaricus by Fourier' transform infrared (FTIR) spectroscopy using an attenuated total reflectance (ATR) accessory. Polysaccharide samples were purified from protein substances with the Sevage method and discoloured through a polyamide column. In the FTIR spectra, the main peaks attributed to asymmetric and symmetric stretching vibrations of CH2 of the pyranose ring (for GluMan - 2886, 1373, 1244 cm-1; for GalGluMan - 2923, 1370, 1238 cm-1) were enhanced by purification after removing bound protein impurities. The KnownitAll and IR-Pal 2 software applications were used to examine the spectra of a sample of purified GalGluMan in the studied polysaccharides. The results show that the intensity of the absorption maximum decreased at 1732 cm-1. At the same time, at 1552.92 cm-1, a new band appeared that refers to the valence vibrations of carboxyl (CO) or nitroso (NO) groups in the purified polysaccharide. This band appeared as a result of the Maillard reaction between the protein and the reducing end of the polysaccharide unit. The intensity of the bands in the 1238-1244 cm-1 region also decreased in the purified samples, which may be due to the elimination of a small fraction of protein. The use of FTIR spectroscopy allows the process of purifying watersoluble GluMan and acid-soluble polysaccharide of GalGluMan from acrylamide impurities to be characterized timely and accurately. Additionally, this method allows a comparative estimation of functional groups in polysaccharides of the root tubers of E. hissaricus.

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