Edward Bormashenko

Fiber optic evanescent wave spectroscopy (FEWS) for blood diagnosis: the use of polymer-coated AgClBr fibers and neural network analysis

Infrared spectral analysis of human blood serum was carried out using FTIR-FEWS (Fourier Transform Infrared Fiberoptic Evanescent Wave Spectroscopy). The fiberoptic sensor elements were short (10.5 cm) lengths of unclad AgClBr fibers of diameter 0.9 mm. In order to protect the fibers from interaction with the blood serum we developed a dip coating technique, which made it possible to control the coating thickness. Three polymer materials were tested: polysulfone, polystyrene and room temperature vulcanized silicone elastomer. It was found that layers of thickness 2 - 3 micrometer provide chemical protection, while making it possible to carry out FEWS measurements. The measured spectra were analyzed by neural network analysis, to predict the concentrations of urea, uric acid, cholesterol, total protein and cretonne. The predicted concentrations were compared with the results obtained using standard chemical analysis of the blood (SMAC) and good correlation was observed, with errors of only few percent.

Use of polymer-coated AgClBr fibers for fiber optic evanascent wave spectroscopy (FEWS) of biological fluids

Silver halide IR-transmitting fibers were coated with polymer films in order to protect them from deterioration caused by interaction with biological fluids. Such coated fibers can be used for human blood serum analysis carried out the fiberoptic evanescent wave spectroscopy (FEWS) using a Fourier transform infrared spectrometer. A dip-coating procedure was worked out for coating fibers with polystyrene or silicone-elastomer thin films. Deterioration tests of coated fibers in saline solution which imitates human blood serum salts were performed. These demonstrated that the polymer layers provide protection to the fibers, while making it possible to carry out FEWS measurements.

Luminescence and absorption spectra of Eu-complex-doped PVDF film : influence of controlled stretch

Poly(vinylidenefluoride) film (PVDF) doped with Eu(III)(NO3)3(o-Phenanthroline)2 complex (complex A) was manufactured using an extrusion technique. Emission spectrum of the film was compared to spectra of the dopant and polyethylene based film. Stretching the film resulted in a sharp growth of intensity and reshaping of the luminescence spectrum. The impact of the PVDF matrix on the photoluminescence spectra of complex A is attributed to the Stark effect. Reasons for the increase of luminescence intensity are discussed. Quantum chemical calculations revealed a marked longwave shift of the lowest triplet and singlet energy levels of complex A compared to free phenanthroline. The amplification and frequency shifting of the luminescent spectrum of europium-complex-doped PVDF may lead to promising applications.

Optical properties of the Eu(III)-La(III)-complex-doped polyolefine film and rod samples

The work is devoted to luminescent properties of trivalent lanthanide complexes dispersed in thermoplastic host matrices. Polyethylene-based film and polypropylene-based rod both doped with these complexes were manufactured using an extrusion technique. Two kinds of dopants were used: Eu(III)-thenoyltrifluoroacetone-1,10-phenanthroline complex (Eu(III)) and Eu(III)-La(III)-1,10-phenanthroline complex (Eu(III)-La(III)). Comparison was made between these samples regarding absorption, excitation, emission and a lifetime of luminescence. Dependence of emission intensity on the excitation energy was determined. Emission spectra of the films were studied at room and helium temperatures. Optical properties of Eu(III) samples are different from Eu(III)-La(III) samples. Significant difference in spectra of these two types of samples may be attributed to the La(III) action.