A method is described for measuring the concentrations of both glucose and glutamine in binary mixtures from near infrared
(NIR) absorption spectra. Spectra are collected over the range from 5000–4000/cm (2.0–2.5μm) with a 1-mm optical path length.
Glucose absorbance features at 4710, 4400, and 4300/cm and glutamine features at 4700, 4580, and 4390/cm provide the analytical
information required for the measurement. Multivariate calibration models are generated by using partial least squares (PLS)
regression alone and PLS regression combined with a preprocessing digital Fourier filtering step. The ideal number of PLS
factors and spectral range are identified separately for each analyte. In addition, the optimum Fourier filter parameters
are established for both compounds. The best overall analytical performance is obtained by combining Fourier filtering and
PLS regression. Glucose measurements are established over the concentration range from 1.66–59.91 mM, with a standard error of prediction (SEP) of 0.32 mM and a mean percent error of 1.84%. Glutamine can be measured over the
concentration range from 1.10–30.65 mM with a SEP of 0.75 mM and a mean percent error of 6.67%. These results demonstrate
the analytical utility of NIR spectroscopy for monitoring glucose and glutamine levels in mammalian and insect cell cultures. 相似文献
A possible approximation of the enthalpy of formation of C,H,N,O-containing compounds by trigonometric Fourier series has been shown.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1389–1390, August, 1994. 相似文献
Summary The coupling of carbon dioxide supercritical fluid chromatography with Fourier transform infrared spectrometry (SFC-FTIR)
is a powerful tool for the separation and on-line identification of non-volatile compounds. The IR transparency of carbon
dioxide in the Fermi resonance bands region versus its density has been studied. Functional groups with stretching vibrations
outside the transparent window of carbon dioxide are examined. SFC-FTIR separations allow Gram-Schmidt reconstruction chromatograms
or IR window chemigrams with high quality spectra to be obtained. This SFC-FTIR lightpipe (flow cell, beam condensing optics,
narrow band detector) has allowed detection limits of 250ng for benzonitrile and 70ng for methyl benzoate to be reached. The
feasibility of very rapid SFC-FTIR separations is shown along with the subsequent peak spectra. 相似文献
IR spectroscopy was coupled with the matrix isolation technique to study the molecular complex formed between C3O2 and HCl and its photodissociation. The vibrational frequencies of the complex were compared with those of HCl and C3O2 monomers. For C3O2, a bent structure was characterized in the solid environment.
The vibrational frequencies were calculated in the 4000–400 cm−1 range using an ab initio method at the MP2/6-31G** level for the most stable complex; these frequencies describe the hydrogen interaction with the central carbon atom of C3O2 (T complex). The measured shifts between the vibrational mode frequencies of the complex and monomers were in good agreement with the calculated values.
Broad-band UV irradiation ( > 230 nm) of the T complex leads preferentially to ketene chloride and carbon monoxide. Ketene chloride formation can be explained by the reaction between HCl and the carbene C2O, which results from photo-dissociation at the C=CO bond of C3O2. 相似文献
We prove the Cramér theorem forK-invariant Gaussian measures on irreducible symmetric spacesX=G/K withG semisimple noncompact. To do this we use a kind of Abel transform ofK-invariant measures onX.This research is supported by KBN Grant. 相似文献
Let μ be a measure in a Banach spaceE, f be an even function onR. We consider the potentialg(a)=fEf(‖x?a‖)dμ(x). The question is as follows: For whichf does the potentialg determine μ uniquely? In this article we give answers in the cases whereE=l∞n and wheref(t)=|t|p andE is a finite dimensional Banach space with symmetric analytic norm. Calculating the Fourier transform of the functionf(‖x‖∞) we give a new proof of the J. Misiewicz's result that the functionf(‖x‖∞) is positive definite only iff is a constant function. 相似文献
Theorem 3 gives a condition when two -weights can be ``pasted' together to yield another -weight. It is subsequently used in Example 6 to give an example that shows that a necessary condition by Gohberg, Krupnik, and Spitkovsky is not sufficient.
The decomposition of N2O in a 13.56-MHz parallel-plate system was studied usingin situ Fourier transform infrared (FTIR) spectroscopy. Areas of two infrared absorption bands of N2O recorded at 8 cm–1 resolution were used to estimate relative gas-phase dissociation as a function of rf power and flow rate at 500 mT. Flow rate was found to strongly affect band areas over the range of powers investigated (10–90 W). The effect of rf power on band areas diminished above 40 W, probably due to poor plasma confinement. Distortion of the band shapes by the plasma permitted rotational temperatures to be estimated. Rotational temperature increased essentially linearly with power at constant flow rate, reaching 450 K at 80 W, but was independent of flow rate at constant power. Rotational temperatures were also found to depend on the temperature of the electrodes, which were heated by plasma exposure. No infrared-active product species were observed even under batch conditions where all N2O was irreversibly dissociated. This lack of detectable products and a 50% pressure rise observed in a batch study suggest that N2 and O2 are the primary stable discharge products. 相似文献