Copper colorimetry

Yoshimura et al. [193] carried out microdeterminations of phosphate by gel-phase colorimetry with molybdenum blue. In this method phosphate reacted with molybdate in acidic conditions to produce 12-phosphomolybdate. The blue species of phosphomolybdate were reduced by ascorbic acid in the presence of antimonyl ions and adsorbed on to Sephadex G-25 gel beads. Attenuation at 836 and 416 nm (adsorption maximum and minimum wavelengths) was measured, and the difference was used to determine trace levels of phosphate. The effect of nitrate, sulfate, silicic acid, arsenate, aluminium, titanium, iron, manganese, copper, and humic acid on the determination were examined. 

Colorimetry. A variety of colorimetric techniques have been used to measure ions such as NH4, SO4-, and NO7 in ambient particles. For example, nitrate can be measured by reduction to nitrite using hydrazine in the presence of a copper catalyst, followed by its conversion to a colored azo dye, which can be measured by its absorbance at 524 nm (Mullin and Riley, 1955). Sulfate has been determined using an exchange reaction between sulfate and a barium-nitrosulfo-nazo(III) chelate in aqueous acetonitrile the chelate has an absorbance peak at 642 nm and hence the decrease in this peak can be followed as a measure of the amount of sulfate present that has exchanged with the chelate (Hoffer et al., 1979). Similarly, NH4 can be measured by the indophenol blue method (Weather-burn, 1967). 

Colorimetry. Copper (Duncombe 1963 Koops and Klomp 1977) or cobalt (Novak 1965) soaps of long-chain fatty acids (>C12) are soluble in chloroform and can be determined quantitatively by colorimetric determination of the extracted metal. Shipe et al. (1980B) have recently modified the original copper soap method to make it simpler, more rapid, and adaptable to automatic equipment. 

Chloroform-heptane-methanol Colorimetry of copper soaps Milk, cheese Koops and Klomp (1977),... 

Johri, K. N., Kaushik, N. K., Bakshi, K. Thin-layer chromatographic separation of copper (II), nickel(II), and cobalt(II) as thio-carbonato-complexes and determination by ring colorimetry. Chromatographia 5, 326 (1972)... 

Use Colorimetry (copper determination), complex-ing agent, oxidation inhibitor in ethyl ether. 

K. Yoshimura, H. Waki, S. Ohashi, Ion-exchanger colorimetry. 1. micro-determination of chromium, iron, copper and cobalt in water, Talanta 23 (1976) 449. 

Chromic acid (H2Cr207), disodium salt, dihydrate CRIS 6344 Dichromic xid (H2Cr207), disodium salt, dihydrate Sodium dichromate dihydrate. Used in colorimetry (copper determination), as a complexing agent, oxidation inhibitor in ethyl ether. Registered by EPA as a fungicide. Crystals d b 2.350 suspected carcinogen. British Chrome S Chemical Chemisphere Occidental Chem. Corp. OxyChem Rit-Chem. 

BIOLOGICAL PROPERTIES all water is corrosive to copper to some degree, which depends primarily on the pH of the water highly persistent in water, half-life >200 days can be detected in water by digestion followed by atomic absorption or by colorimetry or by Inductively Coupled Plasma Optical Emission Spectrometry dissolved form is detected by 0.45 j, filtration followed by the previous methods... 

Some of the most successful and widely used chelating reagents include dimethylglyoxime for the gravimetric determination of nickel 1,10-phe-nanthroline and its derivatives for the colorimetric determination of iron and copper dithizone for the separation and colorimetric determination of a number of metals but particularly lead, silver, zinc, cadmium, and mercury the dithiocarbamates such as diethylammonium diethyldithiocarbamate and ammonium pyrrolidinedithiocarbamate, used for colorimetry but more widely applied now as selective extractants and the most successful titrant, EDTA. 

Wilson s disease is often attributed to a hereditary deficiency of ceruloplasmin. Ceruloplasmin deficiency can be demonstrated by direct colorimetry of the blue protein, by determination of phenylenediamine oxidase activity, and by immunological techniques. The role of ceruloplasmin in copper metabolism is not known, but it is assumed to serve as an acceptor of the free copper in the plasma. The changes in cerulo-... 

The Dole method was adapted to colorimetry using either the copper salts (Itaya and Ui 1965) or color changes of phenol red (Mosinger 1965). Antonis proposed a semi-automated method (1965). 

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