Resolution enhancement of overlapping peaks in molecular spectra by derivative spectrometry method based on continuous wavelet transform

In this paper we consider a numerical differentiation algorithm based on the continuous wavelet transform for improving resolution of composite spectra. This approach provides the best contrast in differential curves as compared to the conventional derivative spectrometry. A main merit is that the wavelet-based technique gives stable estimations of derivative without using the regularization and on the other hand, it does not make peak shift. A comparative study of conventional derivative spectrometry based on the statistical regularization method and wavelet-based derivative spectrometry is made. Examples of the application of these for improving resolution of synthetic composite bands and real-world composite ones coming from molecular spectroscopy are given

Spatial structure of absorbing vapor in a transversely heated graphite atomizer with a probe

The dynamics of the spatial structure of absorbing layers of silver atoms and molecules and condensed particles of sodium chloride and potassium sulfate in a transversely heated graphite atomizer during atomization of these substances from a platform and evaporation of their condensate from a tungsten probe is investigated by shadow spectral visualization. The fractional probe atomization significantly decreases the spatial inhomogeneities of absorbing layers, the level of nonselective absorption, and the suppression of atomic absorption. As a result, the photometric error decreases. The use of a probe made it possible to increase the maximum amounts of sodium chloride and potassium sulfate allowable for interference-free atomic absorption analysis in a silver sample from 100 to 4000 μg and from 20 to 750 μg, respectively. These values exceed by a factor of 5-8 the acceptable levels in the generally accepted procedure of atomization from a platform with the Pd-Mg modifier. © Nauka/Interperiodica 2006

Continuous wavelet transform for improving resolution of overlapped bands

In this paper we consider a numerical differentiation algorithm based on the continuous wavelet transform for improving resolution of composite spectra. This approach provides the best contrast in differential curves compared to the conventional derivative spectrometry. A main merit is that the wavelet-based technique gives stable estimations of derivative without using the regularization, on the other hand, it does not make peak shifts. A comparative study of conventional derivative spectrometry based on the statistical regularization method and wavelet-based derivative spectrometry is made. Examples of the application of these for improving resolution of synthetic composite bands and real-world composite ones coming from molecular spectroscopy are given

Dynamics of fractional condensation of a substance on a probe for spectral analysis

The fractional separation of trace metals on a cold tungsten probe from salt matrix vapor, which interferes with the spectral analysis, is studied. The spatial structure of the vapor flows of sodium chloride, potassium sulfate, and indium atoms is visualized at characteristic wavelengths as they interact with the probe. The vapor flow rate and the probe orientation were varied. It is found that the smoke of the matrix does not prevent the deposition of the metal on the probe because of spatial separation of these fractions and that the detrimental effect of thermal gas expansion and other factors is eliminated. The sensitivity of the atomic absorption analysis of indium impurities in these salts is increased by an order of magnitude. © 2008 Pleiades Publishing, Ltd