Spectral and luminescent properties of an indotricarbocyanine dye are studied in solutions and after deposition on quartz or silicon substrates. It is found that the dye molecules self-assemble in aqueous EtOH solutions to form H * -aggregates. The absorption band of the H * -aggregates shows a hypsochromic shift of 192 nm (5291 cm -1 ) relative to the absorption maximum of dye monomers (706 nm) and has a full width at half maximum of 21 nm (797 cm -1 ). The morphology of the H * -aggregates of the indotricarbocyanine dye is studied for the fi rst time. It is found that the aggregates are rod-like species ~10 nm high, 100 nm wide, and several micrometers long. H-aggregates with a fl uorescence maximum at 560 nm and Stokes shift of 325 cm -1 in addition to non-fl uorescent H * -aggregates form in aqueous EtOH solutions and are nanoparticles with a height of 1-3 nm and lateral dimensions of ~100 nm.
The interaction of indotricarbocyanine dyes with human blood serum proteins was studied. The spectral and fluorescent properties of dyes in butanol, Dulbecco’s sodium and potassium phosphate buffer (0.14 mol/L) with pH 7.4, and human blood serum solutions were determined. It was shown that the spectral properties of dyes in butanol differ significantly from the spectral properties in solutions of Dulbecco’s sodium and potassium phosphate buffer and human blood serum, and that butanol effectively extracts the molecules of the studied dyes that do not form covalently bound complexes with blood serum components. By analysing the extraction products, the proportion of covalent complexes of dyes with protein molecules was determined. It has been established that indotricarbocyanine dyes with a chlorine-substituted orthophenylene bridge in the conjugation chain are partially passes into butanol, the degree of extraction depends on the ratio of dye and protein concentrations. Thus, at a concentration of 10 mmol/L in 5 % human serum, the degree of extraction of these dyes is ~50 – 60 % respectively, the proportion of dye molecules in strong covalently bound complexes with blood serum components is ~ 40 –50 %. On the contrary, the dye with a free polymethine chain is extracted almost completely (91.4 % extraction rate). The indotricarbocyanine dyes are promising for use as a photosensitisers for photodynamic therapy.
A laser atomic emission multichannel spectrometer (LAEMS) with an achromatic optical confi guration is developed for research and educational purposes. The new spectrometer fi ts all the requirements for equipment for laser atomic emission spectroscopy, and has a number of advantages owing to the features of the design and technical characteristics of its components. The excitation source for the spectrometer includes two Nd:YAG lasers pumped by semiconductor laser diode arrays with a controllable energy (from 0 to 100 mJ) and interval between between pulses (from 1 to 100 μs), and an average pulse duration of ≈15 ns. The LAEMS provides for studies in both a single pulse and a double pulse laser ablation regime and excitation of emission spectra. Double pulse laser ablation on the LAEMS provides a substantial (up to a factor of 10) increase in the analytic signal with a negligible (1.5-2 times) increase in surface damage.
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