This work combines laboratory quantitative analysis of colored solutions and common devices for digital imaging (digital or web cameras or mobile phones, i.e., smartphones). ColorX software, specially designed for this study, was used for data collection and analysis in order to calculate concentrations of colored solutions from measured RGB values. Three different custom methods for determination of concentration have been developed: (i) RGB value measurement by pixel, (ii) RGB value measurement by pixel and Gaussian blur, and (iii) calculation of average RGB value of the selected image area. The performance of the developed software, ColorX, is demonstrated using different colored solutions, KMnO 4 (purple), CoSO 4 (red), NiSO 4 (green), and CuSO 4 (blue) solutions, as well as the Lowry protein assay (blue) in terms of its determination of the concentrations of unknown samples. The most suitable and effective method for studying the mentioned solutions was the calculation of an average RGB value for a selected image area. ColorX software is primarily designed for accessibility and simplicity, with the aim of promoting and encouraging students to explore and discover potential applications for digital imaging technology in basic analytical chemistry concepts.

Characterization of nanocrystalline triple perovskites synthesized by a novel modified sol–gel route instead of bulk materials synthesized by a solid-state route.

Complex perovskites have attracted extensive attention due to their fascinating physical properties and novel features owing to the coexistence of the ferro-/ferri-magnetic ground state and semiconducting behavior in the single material. Herein, the triple perovskite Sr 3 Co 2 WO 9 (SCWO) has been successfully synthesized for the first time in the nanocrystalline form with an average crystallite size of 23 nm using a high yield (81%) aqueous citrate sol−gel method. At room temperature, the crystal structure of Sr 3 Co 2 WO 9 is cubic, space group Fm3̅ m, with lattice parameter a = 7.9073(6) Å. The formation of SCWO triple perovskite was studied in situ by X-ray diffraction and subsequently analyzed by the Rietveld analysis. The detected hysteresis loops with nonzero remanent magnetization and rather large coercive field reveal ferrimagnetic ordering with a Curie temperature of 144 K. The measured effective magnetic moment of 3 μ B is close to the expected value for the rarely observed intermediate spin S = 1. It is found that the compound exhibits semiconducting properties with the optical band gaps equal to 3.52 eV (indirect) and 3.76 eV (direct), respectively, further confirmed by the determination of the AC conductivity, which in the measured temperature range (25−500 °C at 1 kHz) lies within the interval from 10 −5 −10 −4 Ω −1 cm −1 . The Maxwell−Wagner model is employed to describe the frequency dependent dielectric constant. The frequency-dependent AC conductivity follows the universal Jonscher power law. Since it possesses both magnetic and semiconductor properties, this material could be a promising candidate to use in devices where its semiconducting properties would be spin-controlled.

Carbon quantum dots (CQDs) have recently emerged as innovative theranostic nanomaterials, enabling fast and effective diagnosis and treatment. In this study, a facile hydrothermal approach for N-doped biomass-derived CQDs preparation from Citrus clementina peel and amino acids glycine (Gly) and arginine (Arg) has been presented. The gradual increase in the N-dopant (amino acids) nitrogen content increased the quantum yield of synthesized CQDs. The prepared CQDs exhibited good biocompatibility, stability in aqueous, and high ionic strength media, similar optical properties, while differences were observed regarding the structural and chemical diversity, and biological and antioxidant activity. The antiproliferative effect of CQD@Gly against pancreatic cancer cell lines (CFPAC-1) was observed. At the same time, CQD@Arg has demonstrated the highest quantum yield and antioxidant activity by DPPH scavenging radical method of 81.39 ± 0.39% and has been further used for the ion sensing and cellular imaging of cancer cells. The obtained results have demonstrated selective response toward Fe3+ detection, with linear response ranging from 7.0 µmol dm−3 to 50.0 µmol dm−3 with R2 = 0.9931 and limit of detection (LOD) of 4.57 ± 0.27 µmol dm−3. This research could be a good example of sustainable biomass waste utilization with potential for biomedical analysis and ion sensing applications.