Tropaeolin O Research Articles

Graphite counter electrode modified Tropaeolin‐O photo‐sensitized photogalvanic cells for solar power and storage

AbstractAn optimization, photo‐stability, and hysteresis property of the Graphite counter electrode‐modified Tropaeolin‐O (TPO) photo‐sensitized photogalvanic (PG) cells has been investigated. A complex H‐shaped cell design, a costly and delicate saturated calomel electrode (counter electrode), and a heavy sensitizer molecule (dye having high molecular weight, low diffusivity, and low photo‐stability) have been exploited for fabricating most of the PG cells so far. All these factors are not suitable for the fabrication of durable and cheap PG cells. Therefore, in the present study, the highly conductive/catalytically active robust graphite electrode with TPO dye photosensitizer (having a low molecular weight, higher diffusivity, and higher photo‐stability) has been exploited with diffusion‐friendly low cost and a simple transparent cylindrical glass tube. The cheap and robust graphite counter electrode has been exploited for optimization and long‐term study of the TPO photo‐sensitized PG cells. The observed electrical output is potential 676 mV, current 2000 µA, and power 340.0 μW. The power, current, and efficiency, have been found quite independent of the illumination window size. The potential and current have been observed to be quite stable over a long time during illumination, and the same has been supported by the hysteresis study.

Synthesis, characterization, and photocatalytic activity of ZnS and Mn-doped ZnS nanostructures

Semiconductor quantum dots such as zinc sulfide have interesting potential applications, due to their size-dependent optical properties. These nanostructures can be used for applications in agriculture, environmental chemistry, and fluorescence microscopy. The great rise in nanotechnology has sparked the scientific community’s interest in nanomaterials for the use of photodegradation in aquatic bodies. Quantum Dots (QDs) such as ZnS nanoparticles (NPs) can absorb electromagnetic radiation and generate subsequently reactive oxygen species (ROS) directly in aqueous phase. The presence of ROS in aquatic environments can be used to destroy organic contaminants by photocatalysis. Previous studies had evidenced that the presence of impurities (i.e. copper, manganese, nickel) in the crystalline structures of QDs can enhance their optical properties and consequently their catalytic capacity. Because of this, the present investigation was focused on generating water stable ZnS nanoparticles with catalytic properties. In this work, we have synthesized pure and doped ZnS nanoparticles using a reflux method. The morphology of these QDs was characterized by transmission electron microscopy (TEM). We also studied the photocatalytic properties of these nanostructures. A red shift was observed in the photoluminescence peak of pure ZnS nanoparticles when they were doped with heavy metals. Pure ZnS NPs and Mn-doped ZnS NPs showed luminescent peaks at 444 nm and 596 nm, respectively. Photodegradation studies were evaluated in the presence of organic dyes like Tropaeolin O (TO) and different concentrations of quantum dots (250 ppm and 500 ppm). The photodegradation of TO was dependent on the QDs concentration and exposure time. The destruction of organic dyes in the presence of photo-excited ZnS nanoparticles is envisioned as a fast and clean technology. The destruction of organic dyes in the presence of photo-excited ZnS nanoparticles is envisioned as a fast and clean technology.

Application of sulphanilamides disazo dyes with Tropaeolin O for simple, rapid and sensitive spectrophotometric assay of medicines

A rapid, simple and sensitive spectrophotometric method for the determination of some sulphanilamides is described. The method is based on the formation of blue coloured disazo dyes by the diazotization of sulphonamides viz. sulphanilamide (SA), sulphamerazine (SMR), sulphamethazine (SMZ), sulphadimethoxine (SDM), sulphamethoxazole (SMX), sulphadiazine (SDA), sulfathiazole (STZ), sulphaguanidine (SGN), sulphamonomethoxine (SMM), sulphamethoxypyridazine (SMP) in 0.5 M hydrochloric acid media at ice bath followed by the azocoupling reaction with acid monoazo dye Tropaeolin O (TrO) at pH = 10.5. Formed products are stable for 10 h at room temperature. Effective molar absorptivities at absorbance maxima 595 nm for disazo dyes were ∼10 4 M −1 cm −1. Stoichiometric ratios of the components of disazo dyes were determined by means of mole ratio and continuous variations methods. Linear ranges for sulphanilamides determination were 0.4–14.0 μg ml −1. The methods were successfully approved at suphanilamides determination in model solutions and commercial pharmaceutical preparations.

Masking is the Effective Alternative to the Separation during Osmium Determination by Means of Azo Dyes in Complex Samples

The selectivity of the spectrophotometric methods for determination of microgram quantities of osmium (IV) with acidic monoazo dyes Tropaeolin O (TpO) and Tropaeolin OOO-I (TpOOOI) in the presence of concomitant metals, particularly platinum group, heavy and rare earths (RE) has been studied. The tolerance ratios of interfering elements have been established. The selectivity of the interaction of TpOOOI with osmium (IV) relatively to platinum group elements (PGEs) is much better than TpO. It has been established that the influence of interfering ions can be easily eliminated by means of masking agents viz. EDTA, tartrate, citrate, pyrophosphate and fluoride, and thereby the selectivity of the methods of osmium determination with TpO and TpOOOI has been sufficiently improved. The methods have been approved during the analyses of various model solutions containing ruthenium, platinum, palladium, rhodium and iridium and the masking reagents. Also osmium content has been determined in the intermetallic alloy Nd20Os15Sі65. The standard deviations did not exceed typical values for spectrophotometric methods (RSDs < 5 %). Thus the elaborated methods with various masking agents may be used for direct determination of osmium in complex samples without any preliminary separation of osmium in the form of OsO4 as well as without the extraction of matrices elements.