ВЫСОКОЧУВСТВИТЕЛЬНЫЕ ЛАЗЕРНЫЕ ФЛУОРОМЕТРЫ ДЛЯ БЛИЖНЕГО ИНФРАКРАСНОГО И ВИДИМОГО ДИАПАЗОНОВ

Laser spectrometers for registration of luminescent signals with nanosecond temporal resolution are presented. The versatile spectrometer is capable to operate with up to tenth of nanometer resolution in wide spectral range. The specialized spectrometer for singlet oxygen luminescence measuring in vitro and in vivo possesses unique sensitivity in the near infrared region. Experimental results confirming high technical capacities of the setups are presented.Представлены лазерные флуорометры, способные регистрировать сигналы люминесценции с наносекундным временным разрешением. Универсальный флуорометр позволяет работать в широком спектральном диапазоне с разрешением вплоть до десятых долей нанометра. Специализированный флуорометр для измерения свечения синглетного кислорода in vitro и in vivo обладает уникальной чувствительностью в ближней инфракрасной области. Приведены экспериментальные результаты, подтверждающие высокие технические возможности установок

HIGHLY SENSITIVE LASER SPECTROMETERS FOR NEAR INFRARED AND VISIBLE RANGES

Laser spectrometers for registration of luminescent signals with nanosecond temporal resolution are presented. The versatile spectrometer is capable to operate with up to tenth of nanometer resolution in wide spectral range. The specialized spectrometer for singlet oxygen luminescence measuring in vitro and in vivo possesses unique sensitivity in the near infrared region. Experimental results confirming high technical capacities of the setups are presented

Concentration increase of the singlet-oxygen generation quantum yield by an indotricarbocyanine dye

Regularities in the generation of singlet oxygen sensitized by the indotricarbocyanine dye HITC with I– and ClO4– anions in highly and slightly polar solvents were studied as functions of dye concentration (Cd). The yield of singlet-oxygen formation (γΔ) by HITC (I–) increased in slightly polar solvents as its concentration increased. It was shown that HITC with Cd < 10–7 M in CHCl3 and <5·10–6M in o-dichlorobenzene with any anion was found primarily in the form of free ions. It was established that the concentration increase of singlet-oxygen generation by HITC (I–) was due to the heavy-atom effect of the anion as a result of their existence as contact ion pairs and an increase of the fraction of such pairs in a solution with an increased photosensitizer concentration. The quantum yield of singlet-oxygen formation for HITC with ClO4– counterion was stable in various solvents as Cd was varied over a wide rang

Improvement of LOD in Fluorescence Detection with Spectrally Nonuniform Background by Optimization of Emission Filtering

The limit-of-detection (LOD) in analytical instruments with fluorescence detection can be improved by reducing noise of optical background. Efficiently reducing optical background noise in systems with spectrally nonuniform background requires complex optimization of an emission filter–the main element of spectral filtration. Here, we introduce a filter-optimization method, which utilizes an expression for the signal-to-noise ratio (SNR) as a function of (i) all noise components (dark, shot, and flicker), (ii) emission spectrum of the analyte, (iii) emission spectrum of the optical background, and (iv) transmittance spectrum of the emission filter. In essence, the noise components and the emission spectra are determined experimentally and substituted into the expression. This leaves a single variable–the transmittance spectrum of the filter–which is optimized numerically by maximizing SNR. Maximizing SNR provides an accurate way of filter optimization, while a previously used approach based on maximizing a signal-to-background ratio (SBR) is the approximation that can lead to much poorer LOD specifically in detection of fluorescently labeled biomolecules. The proposed filter-optimization method will be an indispensable tool for developing new and improving existing fluorescence-detection systems aiming at ultimately low LOD

Concentration increase of the singlet-oxygen generation quantum yield by an indotricarbocyanine dye

Regularities in the generation of singlet oxygen sensitized by the indotricarbocyanine dye HITC with I– and ClO4– anions in highly and slightly polar solvents were studied as functions of dye concentration (Cd). The yield of singlet-oxygen formation (γΔ) by HITC (I–) increased in slightly polar solvents as its concentration increased. It was shown that HITC with Cd < 10–7 M in CHCl3 and <5·10–6M in o-dichlorobenzene with any anion was found primarily in the form of free ions. It was established that the concentration increase of singlet-oxygen generation by HITC (I–) was due to the heavy-atom effect of the anion as a result of their existence as contact ion pairs and an increase of the fraction of such pairs in a solution with an increased photosensitizer concentration. The quantum yield of singlet-oxygen formation for HITC with ClO4– counterion was stable in various solvents as Cd was varied over a wide rang