INVESTIGATION OF OPTICAL PROPERTIES OF WATER-SOLUBLE ELECTROLYTES BASED ON Α-AMINO ACIDS

Из литературы известно, что L - аминокислоты, кроме глицина, являются оптически активными веществами и обладают способностью вращать плоскость поляризации проходящего через него поляризованного луча света в левую сторону. В работе приводиться синтез и радикальная полимеризация водорастворимых полиэлектролитов на основе L - валина и L - лейцина. В работе описывается способ получения новых нанокомпозиционных материалов на основе синтезированных полимеров и модифицированного монтмориллонита. Исследованыоптически активных свойства и определены величина удельного вращения плоскости поляризации для алкилированной аминокислоты - N, N - диаллилвалина и N, N - диаллиллейцина. It is known from literature that L - amino acids, in addition to glycine, are optically active substances and have the ability to rotate the polarization plane of a polarized light beam passing through it to the left side. The paper presents the synthesis and radical polymerization of water-soluble polyelectrolytes based on L - valine and L - leucine. This paper describes a method for obtaining new nanocompositional materials based on synthesized polymers and modified montmorillonite. The optically active properties were investigated and the value of the specific rotation of the polarization plane for the alkylated amino acid - N, N - diallylvaline and N, N - diallylleucine was determined.

Underwater Use of a Hyperspectral Camera to Estimate Optically Active Substances in the Water Column of Freshwater Lakes

Freshwater lakes provide many important ecosystem functions and services to support biodiversity and human well-being. Proximal and remote sensing methods represent an efficient approach to derive water quality indicators such as optically active substances (OAS). Measurements of above-ground remote and in situ proximal sensors, however, are limited to observations of the uppermost water layer. We tested a hyperspectral imaging system, customized for underwater applications, with the aim to assess concentrations of chlorophyll a (CHLa) and colored dissolved organic matter (CDOM) in the water columns of four freshwater lakes with different trophic conditions in Central Germany. We established a measurement protocol that allowed consistent reflectance retrievals at multiple depths within the water column independent of ambient illumination conditions. Imaging information from the camera proved beneficial for an optimized extraction of spectral information since low signal areas in the sensor’s field of view, e.g., due to non-uniform illumination, and other interfering elements, could be removed from the measured reflectance signal for each layer. Predictive hyperspectral models, based on the 470 nm–850 nm reflectance signal, yielded estimates of both water quality parameters (R² = 0.94, RMSE = 8.9 µg L−1 for CHLa; R² = 0.75, RMSE = 0.22 m−1 for CDOM) that were more accurate than commonly applied waveband indices (R² = 0.83, RMSE = 13.2 µg L−1 for CHLa; R² = 0.66, RMSE = 0.25 m−1 for CDOM). Underwater hyperspectral imaging could thus facilitate future water monitoring efforts through the acquisition of consistent spectral reflectance measurements or derived water quality parameters along the water column, which has the potential to improve the link between above-surface proximal and remote sensing observations and in situ point-based water probe measurements for ground truthing or to resolve the vertical distribution of OAS.