Simple methods are described for the analysis of sulphate, sulphite and dithionate mixtures by potentiometric titration with lead perchlorate (and use of a lead ion-selective electrode). The error and precision are both about 2-5% for the sulphate concentration range 3 x 10(-3) -6 x 10(-4)M. The sulphur content in fuels derived from refuse was determined by potentiometric titration after bomb-c...

Dithiodibenzoic (DTB) acid and mercaptobenzoic (MB) acid were studied to characterize their abilities as modifier agents for lead(II) sensors. For both sensors, the best results were obtained with modified carbon paste electrodes with 24.1% of ligand. The pH influence on the potentiometric response was studied. The selectivity coefficients for both modified electrodes were tabulated. A potentio...

The protonation constants of new group of peptidomimetic cyclophanes with valine or phenylalanine moieties incorporated into the macrocyclic skeleton as well as their linear analogues were determined by potentiometric measurements in solutions of methanol-water mixtures at 25°C and constant ionic strength. The influence of cavity size, location of protonation sites, and attached substituents of...

Sodium was determined by flame photometry and by direct potentiometry in 56 serum or plasma samples from 24 patients with multiple myeloma or macroglobulinemia. We observed differences between the two techniques as large as 17 mmol/L (12%). The flame-photometric values decreased relative to the direct-potentiometric values as protein increased or water content decreased. Moreover, the two sodiu...

A rapid and simple sequential potentiometric method is described for the determination of nitrate and chloride ions in vegetables, by using home-made ion selective electrodes. The extraction of both ions from the vegetable samples was effected by magnetic stirring of the samples during 30 min in water at room temperature. Direct Potentiometry was used as analytical technique for measurement. Th...

A plasticized Cr3+ ion sensor by incorporating 2,3,8,9-tetraphenyl-1,4,7,10-tetraazacyclododeca-1,3,7,9-tetraene (TTCT) ionophore exhibits a good potentiometric response for Cr3+ over a wide concentration range (1.0 x 10(-6)-1.0 x 10(-1) M) with a slope of 19.5 mV per decade. The sensor response is stable for at least three months. Good selectivity for Cr3+ in comparison with alkali, alkaline e...

The interactions of Zn(ll) ions with the blocked hexapeptide models -TESHHK-, -TASHHK- and -TEAHHK- of the -ESHH- motif of the C-terminal of historic H2A were studied by using potentiometric and IH-NMR techniques. The first step of these studies was to compare the pKa values of the two His residues inside each hexapeptide calculated by potentiometric or H-NMR titrations. Hereafter, the potentio...

A rapid and reproducible method for chloride estimation in urine is described. The colour produced is stable and obeys Beer's law over a wide range of concentrations using a simple colorimeter and filter. The method gives good agreement with both the potentiometric titration method of Sanderson (1952) and the mercurimetric titration method of Schales and Schales (1941). The precision of the col...

In this study, a potentiometric sensor composed of palm shell activated carbon modified with trioctylmethylammonium thiosalicylate (TOMATS) was used for the potentiometric determination of mercury ions in water samples. The proposed potentiometric sensor has good operating characteristics towards Hg (II), including a relatively high selectivity; a Nernstian response to Hg (II) ions in a concent...

Potentiometric sensor based on commercial pencil graphite electrodes coated with polyaniline (PAni) composite with Eosin Y (EY) termed as PGE/PAni-EY have been developed for potentiometric determination of silver ion. The electrode exhibited linear response with Nernstian slope of 57.6±0.8 mV per decade within the range of 1.0×10 to 1.0×10 M with limit of detection 6.5×10 M silver ion. Fast and...