COLLOIDAL SERS SPECTROSCOPY OF BIOLOGICAL FLUIDS

Vibrational spectroscopy is known to be a reliable technique for qualitative and quantitative chemical analysis of various biological fluids. Such analysis is rather efficient when molecular compound under study is present in the fluid with high concentration. There are many cases when determination of compounds at extremely low concentration is needed. Such cases include detection pharmaceuticals or their metabolites in blood, detection of cancer cells in biological fluids, etc. In such situations conventional vibrational spectroscopy techniques - infrared absorption and Raman scattering are not suitable due to too low sensitivity, therefore other more sensitive spectroscopic methods have to be used. This work presents some applications of colloidal SERS spectroscopy for the detection of medicine metabolites in blood and for detection of various cancer related chemical substances in intracellular and extracellular fluids. Various gold and silver nanoparticle colloidal solutions were used for the implementation of SERS spectroscopy and the best ones (giving the highest enhancement with the least interference to the spectra) were determined. We conclude that the SERS approach can be applied for screening of pharmaceuticals and drug usage. In case of aspirin consumption, the detection limit was found to be down to mild toxicity. Such approach also allows detection of cancerous tissue areas and, therefore, can be used during surgical operations for exact determination of tumour boundaries

CONFORMATIONAL ANALYSIS OF 1-ALKENE SECONDARY OZONIDES BY MEANS OF MATRIX ISOLATION FTIR SPECTROSCOPY

Author Institution: Dept. of General Physics and Spectroscopy, Faculty of Physics, Vilnius University, Sauletekio av. 9 bl. 3, LT-01222, Vilnius, LithuaniaAn ability of ozone to break double C=C bond in olefins is known for more than five decades. Understanding of those reactions is very important in atmospheric chemistry. During different steps of the reaction the primary ozonide (POZ), carbonyl oxide (COX) and the secondary ozonide (SOZ) are formed. Fate of the reaction depends on many parameters such as type of radical, conformation of alkene, temperature of the reaction and environmental effects. Despite of numerous studies of the reaction by different spectroscopic techniques the precise mechanism of the reaction is still unknown. It is experimentally observed that the SOZ is more stable than POZ. Stability of the SOZ depends on the size and configuration of the radical. Unfortunately, it is not much known about the spatial structures of the SOZ es. The aim of this study is to define the geometrical structures and stability of the different conformers of the 1-butene and 1-heptene secondary ozonides by combined analysis of the matrix isolation FTIR spectral data with the results of Density Functional Theory (DFT) calculations

ANALYSIS OF URINARY CALCULI USING INFRARED SPECTROSCOPIC IMAGING

Author Institution: Dept. of General Physics and Spectroscopy, Faculty of Physics, Vilnius University, Sauletekio av. 9 bl. 3, LT-01222, Vilnius, Lithuani; Dept. of Physiology, Biochemistry and Laboratory Medicine, Faculty of Medicine, Vilnius University, M. K. Ciurlionio str. 21, LT-03101, Vilnius, LithuaniaKidney stone disease is a cosmopolitan disease, occurring in both industrialized and developing countries and mainly affecting adults aged 2060 years. The formation of kidney stones is a process that includes many factors. Its primary and contributing pathogenic factors are genetic, nutritional and environmental, but also include personal habits. Information about the chemical structure of kidney stones is of great importance to the treatment of the kidney diseases. The usefulness of such information was first recognized in early 1950s. Analysis of urinary stones by various chemical methods, polarization microscopy, x-ray diffraction, porosity determination, solid phase NMR, and thermo analytical procedures have been widely used. Unfortunately, no one method is sufficient to provide all the clinically useful information about the structure and composition of the stones. Infrared spectroscopy can be considered a relatively new method of kidney stone analysis. It allows to identify any organic or inorganic molecules the constituents of kidney stones. So far this method had never been used to collect information about kidney stone component patterns in Lithuania. Since no epidemiological studies have been performed in this field, the medical treatment of kidney stone disease is empirical and often ineffective in hospitals around the country. The aim of this paper is to present some results of analysis of kidney stones extracted from local patients using FTIR spectroscopical microscopy

On the stability of the hydrogen chloride complexes with ethylene and acetylene. A high resolution gas phase and ab initio study

The temperature dependencies of the intensities of the HCl stretching bands of the hydrogen chloride complexes with acetylene and ethylene have been used to obtain estimates of the dissociation enthalpies of the two complexes. Quantum chemical calculations on the Hartree Fock and DFT/B3LYP levels of theory have been combined with experimental data to give estimates of the intensities of the HCl stretching vibration in the two complexes

Temperature-controlled kinetics of the growth and relaxation of alcohol clusters in an argon matrix

The clustering processes of monohydric alcohols (from methanol to hexanol) were investigated by FTIR spectroscopy using the isolation in an argon matrix technique. The transformation of the FTIR bands of the free O-H groups (3600-3800 cm(-1)) into diffuse bands (3000-3600 cm(-1)), which were assigned to the stretching vibrations of the H-bonded O-H groups in various clusters, was monitored in its initial stage during softening of the matrices by heating from 20 to 50 K. Band-shape analysis was carried out for the investigated systems. The magnitude of the inhomogeneous broadening due to the matrix effect was evaluated from the bandwidth of the monomer species. The H-bond dissociation times in matrices were evaluated from the cluster bandwidths. These data correlate with those measured directly in ultra-fast infrared experiments of alcohols in solution

High resolution far infrared spectroscopy of IBr using a synchrotron source

The high resolution far infrared absorption spectrum of IBr was recorded with a Fourier transform spectrometer. The fundamental 1-0 vibration-rotation band and the 2-1 and 3-2 hot bands were recorded at a resolution of 0.001 25 cm-1. The infrared continuum was provided by synchrotron radiation emission from the Max-I storage ring. For high resolution spectroscopy at 250cm-1 synchrotron radiation is about 5 times brighter than a conventional infrared glower. This increase in flux at the detector resulted in a corresponding increase in the signal-to-noise ratio and a much improved infrared spectrum.SCOPUS: ar.jinfo:eu-repo/semantics/publishe