Plasma protein contents determined by Fourier-transform infrared spectrometry.
BACKGROUND
Fourier-transform infrared (FT-IR) spectrometry has been used to measure small molecules in plasma. We wished to extend this use to measurement of plasma proteins.


METHODS
We analyzed plasma proteins, glucose, lactate, and urea in 49 blood samples from 35 healthy subjects and 14 patients. For determining the concentration of each biomolecule, the method used the following steps: (a) The biomolecule was sought for which the correlation between spectral range areas of plasma FT-IR spectra and concentrations determined by comparison method was greatest. (b) The IR absorption of the biomolecule at the most characteristic spectral range was calculated by analyzing pure samples of known concentrations. (c) The plasma concentration of the biomolecule was determined using the FT-IR absorption of the pure compound and the integration value obtained for the plasma FT-IR spectra. (d) The spectral contribution of the biomolecule was subtracted from the plasma FT-IR spectra, and the resulting spectra were saved for further analyses. (e) The same method was then applied to determining the concentrations of other biomolecules by sequentially comparing the resulting FT-IR spectra.


RESULTS
Results agreed with those obtained by clinical methods for the following biomolecules when analyzed in the following order: albumin, glucose, fibrinogen, IgG(2), lactate, IgG(1), alpha(1)-antitrypsin, alpha(2)-macroglobulin, transferrin, apolipoprotein (Apo)-A(1), urea, Apo-B, IgM, Apo-C(3), IgA, IgG(4), IgG(3), IgD, haptoglobin, and alpha(1)-acid glycoprotein.


CONCLUSIONS
FT-IR spectrometry is a useful tool for determining concentrations of several plasma biomolecules.
Petibois
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INSERM U443, Equipe de Chimie Bio-Organique, Faculté des Sciences du Sport et de l'Education Physique, and Département de Biochimie Médicale et Biologie Moléculaire, CHU Bordeaux, Université Victor Segalen Bordeaux 2, Bordeaux, France.
Cazorla
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Cassaigne
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Déléris
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D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D001798:Blood Proteins / Q000032:analysis*; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D015203:Reproducibility of Results; D017550:Spectroscopy, Fourier Transform Infrared; D014508:Urea / Q000032:analysis
D001786:Blood Glucose; D001798:Blood Proteins; D019344:Lactic Acid; D014508:Urea