Partially selective semiconductor redox electrodes.

Redox electrodes made of passivated metals of the subgroups IV to VI of the periodic system with a surface coating of n-conducting metal oxides, generated by oxidizing agents or anodic oxidation, are well suited for measuring the concentration of oxidizing agents. Neither oxygen nor reducing agents affect the measurements. There is a correlation between the mean conductivity of the passive layer and its selectivity. The aged n-conducting passive layers permit reproducible potential settings, and the occurring changes in potential are greater than what is to be expected according to the Nernst equation. The potentiometric measuring of nitrosyl ions and chlorine is used as an example to demonstrate the selectivity of these electrodes.

[The adaptation of four protein determination methods to flow injection analysis (FIA)]. / Anpassung von vier Proteinbestimmungsmethoden an die Fliessinjektionsanalyse (FIA).

The adaptation of 4 manual methods to the flow-injection analysis is described for the determination of proteins (Biuret- and Exton-method, albumin and hemoglobin determination). The comparison of analytical results of FIA with the manual methods shows a very good agreement of values. Flow-injection-analysis appears not only as an excellent possibility to automate these 4 investigated methods but it also shows unlike the manual methods a considerable better precision and accuracy of the analytical results and a reduction of time and materials.

[Effect of infiltrating water vapors on mercury-zinc elements in implanted electric cardiac stimulators]. / O vliianii prosachivaniia vodianykh parov na rtutno-tsinkovye élementy implantiruemykh élektrokardiostimuliatorov.

A complex character of the water vapours effect on the energy source used in electrical pacemaker is investigated on the RMCC-1 type Hg-Zn element. The water vapours were shown to cause electrolyte effluence and hence the appearance of the leakage eddy currents amounted up to 22mA through the insulation of electrodes. The resulted charge loss reduce the clinical service term of the pacemaker electrodes. This can be avoided by the provision of equal water-vapours' partial pressure in the surrounding medium and in electrolyte, by means of special construction. At the doby temperature this requirement is achieved at the 27%-air relative humidity.

[Uptake of lead, cadmium and mercury by cultivated mushrooms]. / Zur Blei-, Cadmium- und Quecksilber-Aufnahme in Kulturchampignons.

It is reported of the uptake of lead, cadmium and mercury by cultivated mushrooms (Agaricus bisporus) from lead, cadmium and mercury-containing substrates. Cd and Hg were observed to accumulate significantly via the mycelium, whereas Pb accumulated scarely, even if the Pb contents in the substrate were high. High lead concentrations in wild mushrooms, therefore, are likely to be mainly due to emissions; whereas, with Cd and Hg, uptake from the soil must also be considered.