Oxalate determination

Dilauroyl peroxide, determination, 701 Dimesityldioxirane, 26, 1133-4 3-(Dimethylamino)benzoic acid hydrogen peroxide determination, 635 oxalate determination, 633 DimethylaniUne, quinoneimine dyes, 630... 

Oxalo-niobates or niobo-oxalates correspond to the vanado-oxalates, and contain both oxalic acid and niobic add radicals in the complex anion. The only known series possesses the general formula 3R aO. Nb 205.6C203.a H20, where R stands for an alkali metal. The sodium, potassium and rubidium salts are prepared by fusing one molecular proportion of niobium pentoxide with three molecular proportions of the alkali carbonate in a platinum crucible. The aqueous extract of the melt jjs poured into hot oxalic add solution concentration and cooling, or addition of alcohol or acetone, then brings about precipitation of the complex salt. Comparison of the dectrical conductivity measurements of solutions of the alkali oxalo-niobates with those of the alkali hydrogen oxalates determined under the same conditions indicates that the oxalo-niobates are hydrolysed in aqueous solution, and that their anions contain a complex oxalo-niobic acid radical.6... 

Neodymium oxalate, determination of atomic weight of neodymium in, 2 60... 

Oxalates, determination of, in rare earth oxalates, 2 60 Oxalato salts, tri-, 1 35 Oxides, reduction of refractory metal, to metal powders with calcium, 6 47... 

In 1857, Schneider4 analysed cobalt oxalate, determining the carbon dioxide obtained by its combustion and the metal left after igniting the salt in air and subsequently in hydrogen. Four analyses gave the following result ... 

The determination of oxalate in urine is required for diagnosis of renal calculus and hyperoxaluria. For enzymatic oxalate determination, oxalate decarboxylase (EC 4.1.1.2) has been employed in enzyme thermistors (Danielsson etal., 1981), enzyme reactors (Lindberg, 1983), and potentiometric enzyme electrodes (Kobos and Ramsey, 1980). 

It is evident from the equation that potentiometric CO2 electrodes as well as amperometric O2 or H2O2 electrodes can be used as transducers. Both potentiometric and amperometric sensors have been covered by a layer of oxalate oxidase protected by a dialysis membrane (Bradley and Rechnitz, 1986 Rahni et al.f 1986a). The sensors had a pH optimum at pH 3.5-4. Diffusion control was reached at 1 U oxalate oxidase per electrode. Oxalate determination was not affected by ascorbic acid or amino acids. The hydrogen peroxide-detecting sensor (Rahni et al., 1986a) has been used to measure oxalate in urine diluted 1 40. 

MSC system for oxalate determination with chemiluminescence detection. HC holding coil R reagent RC reaction coil SV selection valve V solenoid valve. 

MSC has been widely used in the last years, e.g. MSC systems were proposed for the online SPE and determination of hydrochlorothiazide and losartan potassium in water samples [54], for oxalate determination with chemiluminescence detection in beer and urine [55], for thiazide diuretics determination exploiting SPE [56] and also coupled to spectrophotometric detectors for sulfonated azo dyes determination in environmental samples [57]. 

FIGURE 4.10 Schematic depiction of an multisyringe chromatography system applied to oxalate determination in beer and urine with chemiluminescence detection. HC holding coil KRC knotted reaction coil MC monolithic column—10 mm x 4.6 mm Qg coated with cetyltrimethyl ammonium bromide (CTAB) PMT photomultiplier Rl tris(2,2 -bipyridyl)dichlororuthenium(II) solution R2 cerium(IV) solution S syringe SFC spiral flow cell V three-way solenoid valve and W waste. 

Oxalacetate, determination of 60-65 Oxalate, determination of 60-65 Ozonisation products, determination of 216, 217... 

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