Simple method for the study of heterogeneous nucleation in calcium oxalate urolithiasis.

A simple method, based on optic microscopy and a counting chamber, has been devised for the study of heterogeneous nucleation in calcium oxalate urolithiasis. Calcium phosphate, uric acid, silica and macromolecular mucoprotein are proposed as possible nucleants. The importance of heterogeneous nucleation as a fundamental step in the formation of calcium oxalate calculi is demonstrated.

A simple thermometric technique for reaction-rate determination of inorganic species, based on the iodide-catalysed cerium(IV)-arsenic(III) reaction.

A very simple reaction-rate thermometric technique is used for determination of iodide (5-20 ng ml ), based on its catalytic action on the cerium(IV)-arsenic(III) reaction, and for determination of mercury(II) (1.5-10 ng ml ) and silver(I) (2-10 ng ml ), based on their inhibitory effect on this reaction. The reaction is followed by measuring the rate of temperature increase.

Spectrofluorimetric determination of desoxycholic acid in the presence of cholic and chenodesoxycholic acids by use of Ce(IV) and concentrated sulphuric acid.

A method for the quantitative estimation of desoxycholic acid (200-700 micrograms/ml) in the presence of cholic and chenodesoxycholic acids is described. The method is based on the transformation of desoxycholic acid in fluorescent products (lambda ex = 350 nm, lambda em = 458 nm) by the action of concentrated sulphuric acid, this being enhanced by the presence of Ce(IV). The sample is mixed with a solution of Ce(IV) and concentrated sulphuric acid under standard conditions.

Fluorimetric reaction-rate methods of inorganic analysis: a review.

A review is given of the utilization in analytical chemistry of the rate of fluorescence reactions of inorganic species. These methods are of recent development and suggest the possibility of further analytical procedures. Two main types of methods, enzymatic and non-enzymatic, are distinguished, and their applications to inorganic analysis are discussed.

Iron(III) as activator for catalytic fluorimetric microdetermination of V(V).

The activation of the vanadium(V)-catalysed aerial oxidation of sodium 4,8-diamino-1,5 -dihydroxyanthraquinone-2,6-disulphonate by iron(III) is discussed. The oxidation product is intensely fluorescent and allows fluorescence-monitoring of the slow reaction, which is preceded by an induction period. On the basis of this investigation, an accurate method for determination of vanadium(V) at the 1-10 ng/ml level has been developed.

Kinetic fluorimetric determination of traces of vanadium(V) by means of a catalysed autoxidation process.

A kinetic method for determination of traces of vanadium(V) (0.04-0.5 ppm) is described.