The rate of substitution of aqua ligands by three nucleophiles, thiourea (TU), N,N-dimethylthiourea (DMTU) and N,N,N,N-tetramethylthiourea (TMTU), for the complexes [cis-{PtOH2(NH3)2}2-μ-pyrazine](ClO4)2 (pzn), [cis-{PtOH2(NH3)2}2-μ-2,3-dimethylpyrazine](ClO4)2 (2,3pzn), [cis-{PtOH2(NH3)2}2-μ-2,5-pyrazine](ClO4)2 (2,5pzn) and [cis-{PtOH2(NH3)2}2-μ-2,6-dimethylpyrazine](ClO4)2 (2,6pzn) was inves...

Solid-phase spectrophotometry has been improved for the determination of the total and dissolved phosphate in water. The target phosphate-P at sub-µg dm(-3) to µg dm(-3) levels in a 20-cm(3) water sample was concentrated as the molybdenum blue species to 0.06 or 0.12 cm(3) using a Sephadex G-25 within 30 min, and gel beads were introduced to a 1.5-mm or 3-mm diameter flow cell having a 10-mm li...

This study investigated the influence of ZnO nanostructures on dye adsorption to increase the photovoltaic conversion efficiency of solar cells. ZnO nanostructures were grown in both tree-like and nanorod (NR) arrays on an AZO/FTO film structure by using a hydrothermal method. The results were observed in detail using X-ray diffraction, field-emission scanning electron microscopy (FE-SEM), UV-v...

Recent advances in digestion methods used in the analysis of precious metal samples by spectrometric techniques are reviewed. The applicability of a fire assay, a wet acid treatment, chlorination and alkaline oxidizing fusion to a quantitative recovery of metals from various materials is discussed. Data on the precious metal contents obtained by using particular digestion methods as well as UV-...

The total flavonoids of Houttuynia cordata are determined by UV-Vis spectrophotometry. The extraction condition of flavonoids from Houttuynia cordata includes: the extraction temperature is 70 ̊C, solid-liquid ratio is 1:20, solvent is 80% ethanol, extraction time is 65 min. We studied the antioxidation of flavonoids in Houttuynia cordata, and results showed that flavonoids had strong reducing c...

The complex network of chemical reactions of the compound 6-hydroxyflavylium perchlorate was studied by different techniques including UV-vis absorption spectrophotometry, stopped-flow, electrochemistry, and photochemistry. The network is characterized by the formation of a very reactive zwitterionic base as well as by p-quinoidal chalcones. The trans-chalcone is metastable in very acidic solut...

The primary azo compound 1-(3-formyl-4-hydroxyphenylazo)-4-nitrobenzene reacts with some aliphatic and aromatic diamines and yields the corresponding azo-azomethine compounds. These compounds were characterized by elemental analysis, IR, UV/Vis, and NMR spectroscopy. The primary azo compound exists entirely in the azo form in solution as well as in the solid phase. The tautomeric structure of a...

Background: MSG has become one of the most widely used food flavorings in world, FDA (Food and Drug Administration) reported an average per capita intake United States 550 mg / day 1973. The use as a additive been regulated by its use. WHO. This rule stipulates that daily consumption person should not exceed safe threshold 120 kg day. is proven to be risk factor for obesity. increase body weigh...