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...

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...

Focus of this paper is the description of common used methods for hexavalent chromium measurement. This work is focused especially on commonly available spectrophotometric method based on the reaction with 1,5-diphenylcarbazide, because not every laboratory is equipped with modern devices for this pollutant measurement,. Special attention was focused on the variability possibilities of the basi...

A cost-effective b[combining low line]a[combining low line]ttery-powered s[combining low line]pectrophotometric s[combining low line]ystem (BASS) was developed for quantitative point-of-care (POC) analysis on a microfluidic chip. By using methylene blue as a model analyte, we first compared the performance of the BASS with a commercial spectrophotometric system, and further applied the BASS for...

the present work reports a kinetic spectrophotometric method for the determination of traceamounts of sulphite that is based on inhibitory effect of sulphite on the oxidation of methyleneblue (mb) in acidic media. the reaction is followed spectrophotometrically by monitoring thedecrease in absorbance of mb at 664 nm with a fixed time of 0.5-4.5 minutes. it was found thatsulphite exert a strong ...

a simple, economical, precise and fast visible spectrophotometric method has been developed for the determination of azathioprine in tablet dosage form. developed method is based on the formation of extractable colored complex of drug with colouring agent indigo carmine and methyl orange. a wavelength maximum was found to be 683.7 nm and 566 nm. the concentration range of 15-50 μg ml-1 with of ...

A derivative UV spectrophotometric and a reversed phase high-performance liquid chromatographic method for the determination of ciprofibrate in tablets was developed. The first-order derivative UV spectrophotometric method was found to be accurate with 100.57±0.97 recovery and precise with a coefficient of variation of 1.44. These results were compared to those obtained by reference methods, ze...

A spectrophotometric recycling assay for the quantitation of L-phenylalanine (and phenylpyruvate) has previously been reported (Cooper et al., Anal. Biochem. 183, 210-214, 1989). The procedure involves the coupling of bacterial phenylalanine dehydrogenase with rat kidney cytosolic glutamine transaminase K. The latter enzyme possesses high affinity for phenylpyruvate. Recycling results in a > or...

The most common spectrophotometric reagents employed for the determination of titanium (IV) are hydrogen peroxide[1] and tiron[2]. However, N-benzoylN-phenylhydroxylamine[3,4] and N-phenyllaurohydroxamic acid[5] are introduced for extractive spectrophotometric determination of titanium (IV). Aroylhydraones such as pyridoxal salicyloylhydrazone[6], diphenylglyoxal bis (benzoylhydrazone)[7] and d...