A chemical catalytic method for determination of silver in human saliva.
Abstract A catalytic method for the determination of silver in saliva is suggested. Silver was determined by a very simple technique in concentrations in saliva higher than 1 μg/100 ml with a coefficient of variation of 5.7 per cent. The method was used to investigate the correlation between some pathogalvanic phenomena connected with the presence of amalgam restorations in the oral cavity and the concentration of silver in saliva. The application of the method showed no correlation between the number of restorations and the silver concentration in saliva. The joint effects of restorations, their corrosion potential and the concentration of silver in saliva were correlated with the occurrence of unpleasant sensations in the mouth.
Simple and sensitive catalytic method for determination of copper in blood serum
SummaryA new catalytic method is proposed for determination of copper in blood serum, based on the oxidation of sulphanilic acid with H2O2, catalysed by copper(II). Because of its high sensitivity the method requires a serum sample of only 0.10 ml. Using the fixed-time method reduces the procedure to that of an ordinary photometric determination. The method shows reasonable precision and accuracy and is suitable for routine serial analyses in clinical practice.ZusammenfassungEine neue katalytische Methode wurde für die Bestimmung des Kupfers in Blutserum vorgeschlagen. Sie beruht auf der durch Cu(II) katalysierten Oxydation der Sulfanilsäure mit H2O2. Infolge ihrer großen Sensitivität genügt für diese Methode eine Serumprobe von nur 0,10 ml. Infolge Ablesung nach Ablauf einer bestimmten Zeit verlangt das Verfahren nicht mehr Zeit als eine gewöhnliche photometrische Methode. Es zeigt gute Genauigkeit und eignet sich für Serienanalysen in der klinischen Praxis.
The silver catalysed oxidation of manganous ion by persulphate
Abstract The oxidation of bivalent manganese by persulphate is very slow, but becomes fast in the presence of the silver ions. The product of oxidation is trivalent manganese which immediately disproportionates into manganese dioxide and divalent manganese. The kinetics were followed by running the reaction mixture into excess of oxalic acid and estimating the unused oxalic acid with permanganate. The reaction was found to be first order with respect to the persulphate ion and zero order with respect to the manganous ion. The salt effect is negative and exponential. The energy and entropy of activation have been calculated. The entropy is negative. In the presence of sulphuric acid the reaction mixture turns slightly red and the reaction rate appears to be much slowed down in sulphuric acid of strength 3·6 M and above. A mechanism has been suggested consistent with the observed facts.