A simple, rapid, inexpensive, and automated flow-through solid-phase spectroscopic sensing device is proposed for the sequential determination of 2 vitamins: thiamine and ascorbic acid. The vitamins are concentrated on ion-exchange gels, thiamine on Sephadex SP C-25, and ascorbic acid on Sephadex QAE A-25; both solid supports are packed in 2 different flow cells. The absorbance is monitored dir...

styrene is an important constituent of widely used organic solvents in industries for production of various synthetic materials. the use of solid-phase extraction (spe) has grown and is a fertile technique of sample preparation as it provides better results than those produced by liquidliquid extraction. in this study, spe has been optimized, regarding sample ph, sample concentration, sample fl...

In this research, the effect of two process control agent: methanol (liquid state) and stearicacid (solid state) on mechanical alloying process of Ti and Al with equal at%(Ti50Al50) wereinvestigated. Phase transformation at presence of two PCA was: at first, powder mixture wastransformed to a metastable solid solution of Al in Ti lattice (disordered hcp) and then transformed toamorphous phase w...

Platinum extraction from different secondary sources has been experimentally tested by many researchers. In this article, dissolution of platinum in aqua-regia solution from two types of spent catalysts (reforming and nitric acid production) was kinetically studied. A variety of kinetic models for heterogeneous solid-liquid reactions, including homogeneous diffusion model, shrinking core model,...

A simple extremely fast and efficient approach for the synthesis of substituted indazole ingood to excellent yield catalyzed by using silica sulfuric acid (SSA) in DMSO solvent at roomtemperature. This is solid state reaction have been attracting the synthetic organic chemist asthey provided enhance reaction rates, less environmental pollution, greater selectivity, cleanerproducts and manipulat...

Ammonium monovanadate (NH4VO3) has been devoted as an efficient, commercially available, eco-friendly and reusable catalyst for the synthesis of bis(indolyl)methanes (BIMs), oxindole derivatives and also Michael adducts of indoles at 50 °C under solvent-free conditions. The reusability of this solid acid catalyst in addition with its selectivity has also been examined.

The aim of this work is to chemically characterize olive tree prunings and use the material in hydrothermal and combustion processes. The influence of the hydrothermal treatment conditions, with and without acid catalyst, of the main fraction of olive tree prunings (stems with a diameter > 1 cm) (temperature 150 to 190oC, time 0 to 20 minutes after reaching the operation temperature, liquid/sol...

A main concern about cement materials for the construction of the repository is altering the groundwater to high alkalinity around the repository. Under such chemical condition, the behavior of the silicic acid is one of the key factors to estimate the initial condition of the repository system after the backfill. Since the solubility of silicic acid is extremely large in pH larger than 10, the...

an ion chromatography (ic) method for simultaneous determination of benzoic, salicylic and sorbic acids was developed. in this method the samples were purified by solid-phase extraction. the analytes were then eluted with methanol from c18 cartridge. the separation was performed on ion-exclusion column by an isocratic elution with 0.25 mmol /l sulfuric acid solution containing 20% (v/v) acetone...

abstract beneficial effects of humic substances on plant growth have been recognized by many researchers. a greenhouse experiment was conducted with humic acid (0, 20 and 50 mg/l) on lettuce cultivars ‘lollorossa’ and ‘javelina’ using completely randomized design at university of guilan. results showed that humic acid affected (p<5%) leaf number, height and nutrient uptake as well as ca, p and ...