the present article reports on the application of modified organo nanoclay as a green, easily prepared and stable solid sorbent for the preconcentration of trace cobalt ion in aqueous solution. the organo nanoclay was modified by adsorption of 5-(4-dimethyl amino-benzylidene) rhodanin reagent onto it. the sorption of co2+ ions was quantitative in the ph range of 7.0 to 8.5, whereas quantitative...

manganese and cobalt concentrations in hair and nail were determined by flame atomic absorption spectrophotometer (aas).the mean manganese in hair and nail were 0.54 â± 0.35mg/g and 0.68 â± 0.30mg/g while the mean cobalt in hair and nail were 0.30 â± 0.24mg/g and 0.460.37mg/g respectively. a progressive increase in cobalt concentrations in hair and nails with age indicated no significant differ...

Alpha-benzilmonoxime in sodium dodecylsulfate micellar media has been used for the spectrophotometric determination of cobalt at pH 9.0. The linear range of calibration is 0.05-1.50 microg cm(-3) of cobalt at 380 nm with molar absorptivity of 3.72 x 10(4) dm3 mol(-1) cm(-1), which is about 1.5-times greater than that of the alpha-benzilmonoxime extraction based method. The relative standard dev...

A sensitive and selective procedure is presented for the voltammetric determination of cobalt. The procedure involves an adsorptive accumulation of cobalt Pyrogallol Red (PGR) complex on a stationary mercury drop electrode, followed by cathodic stripping voltammetry measurement of the reduction current of the adsorbed complex at –1.17 V (vs. Ag/AgCl). The optimum conditions for the determinatio...

A method for the preconcentration and determination of cobalt in human urine samples was developed. The online preconcentration and determination were attained using inductively coupled plasma atomic emission spectromety (ICP-AES) coupled to a flow injection (FI) method. Cobalt was retained on an Amberlite XAD-7 resin as cobalt-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complex at pH 9.5. Co...

Speciation studies of cobalt species, cobalt (II) and cobalt (III) have been carried out using spectrophotometric determination with the chromophoric reagent bis (5-bromosalicylaldehyde) orthophenilinediamine (BBSOPD). The methodology is direct and non extractive and is carried out in 40% ethanolic medium containing acetate buffer. The colour development is almost instantaneous and remained con...

Alpha-benzilmonoxime has been used for the extraction and determination of cobalt at microgram amount. The reagent reacts with cobalt(II) in the pH range of 8.8 - 9.3 to form a yellow-color chelate, which is extracted in chloroform, toluene, and some other non-polar solvents. The chelate is stable in chloroform for about one day. Under the optimum conditions of the a-benzilmonoxime concentratio...

A flowthrough spectrophotometric sensor for the determination of cobalt at the nanogram per millilitre level using pyridoxal 4-phenylthiosemicarbazone as reagent and integrated preconcentration and detection in the flow cell is proposed. The method is highly selective for cobalt(II); it features detection and determination limits of 0.02 and 0.06 mug ml(-1) respectively, and a linear range of a...

1-(2-Pyridylazo)-2-naphthol (PAN) has been used for the simultaneous and individual determination of palladium and cobalt at trace levels. PAN complexes of palladium and cobalt at neutral pH form green-color neutral complexes, which are soluble in aqueous SDS micellar media. Under optimum conditions, calibration graphs for individual determinations by zero and first-derivative spectrophotometry...

A new method for the determination of cobalt was developed by dispersive liquid-liquid microextraction preconcentration and flame atomic absorption spectrometry. In the proposed approach, 1,5-bis(di-2-pyridyl) methylene thiocarbohydrazide (DPTH) was used as a chelating agent, and chloroform and ethanol were selected as extraction and dispersive solvents. Some factors influencing the extraction ...