a catalytic spectrophotometric method for determination of ultra-trace quantities of manganese(ii) id described. the method is based on the catalytic effect of manganese(ii) on the oxidation reaction of ferroin by potassium periodate in acidic media. the reaction is monitored spectrophotometrically at 510 nm by a slope method and mn(ii) is determinable in the range of 1-1000ngml-1. the limit of...

a novel optical sensor has been proposed for sensitive determination of bismuth ion basedon immobilization of 4-(4-nitrophenylazo)-1-naphthol on a triacetylcellulose membrane.chemical binding of bismuth ions in solution with a 4-(4-nitrophenylazo)-1-naphtholimmobilized on the triacetylcelluse surface could be monitored spectrophotometrically. theoptode shows excellent response over wide concent...

OBJECTIVE The aim of this in-vitro study was to evaluate the efficacy of bleaching products, determine the applicability and validation of the measurement methods. MATERIALS AND METHODS Freshly extracted 110 human incisor teeth were stained with whole blood and hemolysate solution prior to the application of 10 different home-bleaching products. Spectrophotometric measurements of the tooth sh...

the multivariate calibration method, partial least square regression (pls) was applied for thesimultaneous spectrophotometric determination of lidocaine (lid) and hydrocortisone acetate(hca) in their mixtures. the parameters of chemometric technique were optimized and theproposed method was validated with synthetic samples and applied to analyze these drugs inpharmaceutical products with good a...

abstracta novel floatation-spectrophotometric extraction method was developed for the recovery of tin (ii) from aqueous samples prior to determination by uv spectrophotometric detection. the method is based on the formation of a complex between tin (ii) and kalmagyte in ph=8. the complex is floated in the interface of n-hexane and aqueous phases. after removing the aqueous phase, the floated pa...

a simple, rapid and sensitive spectrophotometric method has been proposed for the determinationof vanadium (iv). the method is based on the catalytic effect of v (iv) on the oxidation of alkali blue bypotassium bromate at ph 4. the rate of decrease in the absorbance of alkali blue (at 572 nm) wasproportional to the concentration of v (iv) in the range of 100-6000 ng ml-1. the detection limit wa...

cloud point extraction and spectrophotometric determination of trace quantities of cadmium in some vegetables have been developed. the research area for vegetables analysis was near to the zarin shahr where the soil received heavy metals from the esfahan steel company. cloud point extraction used dithizone as complexing agent and non ionic surfactant triton-x114 as micellar phase. several impor...

a simple, sensitive and rapid method for determination of trace amounts of nitrite ion in real samples is reported. the reaction is initiated by adding known volumes of a nitrite ion solution of identified concentration to acidic solutions of thionine which causes decolorizaiton of reagent with time. the absorbance changes is then monitored spectrophotometrically at lmax = 602nm at 25 °c. calib...

Autonomous sensors are required for a comprehensive documentation of the changes in the marine carbon system and thus to differentiate between its natural variability and anthropogenic impacts. Spectrophotometric determination of pH – a key variable of the seawater carbon system – is particularly suited to achieve precise and drift-free measurements. However, available spectrophotometric instru...

Zero, first and second order derivative spectrophotometric methods were developed for the determination of insulin. The standard solutions and pharmaceutical sample were prepared in 0.01 M HCl. Absorbences of insulin were measured at 276 nm for the zero order by measuring height of peak from zero, at 264, 277 and 284 nm for the first order and at 277, 280, 283 and 289 nm for second order deriva...