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S G Weber

Publications and source records attributed to S G Weber.

47 records · Page 3Linked to original sources
PubMed1989

Ultrafiltration of human serum to determine the size of species that poison voltammetric electrodes.

Solutions containing the electroactive species tris(2,2'-bipyridine)-ruthenium dication and ferrocene carboxylate as well as bovine serum albumin (BSA), gamma globulin (IgG) or human serum were ultrafiltered. Cyclic voltammetry at a glassy carbon electrode showed that the deleterious effects of BSA and IgG were eliminated by passing the solution through a 30 kdalton filter. This was insufficient filtration of serum, however. Ultrafiltration with 3 or 5 kdalton filters was required for good voltammetry. This indicates that the removal of the preponderant proteins is necessary, but not sufficient, to protect electrochemical surfaces.

Biosensing Techniques↗
PubMed1987

Selectivity in micellar chromatography using a zwitterionic surfactant.

This work discusses the effects of neutral zwitterionic micelles composed of N-dodecyl-N,N-dimethylammonium-3-propane-1-sulfonate (C12DAPS) on the retention of several substituted benzene compounds. The correlation of molecular properties and retention demonstrates that negative charge, hydrophobicity, and polarizability are important in governing a solute's distribution in the micelles. The selectivity of the micelles differs from that of the native reversed-phase stationary phase, especially for nitrophenol isomers and halobenzenes.

Benzene Derivatives↗
PubMed1984

Non-aqueous liquid chromatography of some metalloporphyrins on a reversed-phase column.

The effect of the hetaerons tetraphenylarsonium chloride (Ph4AsCl) and tetraphenylarsonium perchlorate (Ph4AsClO4) on the retention of neutral and cationic metalloporphyrins on a reversed-phase column with an acetonitrile-tetrahydrofuran (85:15, v/v) mobile phase was investigated. The adsorption properties of the two hetaerons on the stationary phase were dramatically different. While Ph4AsCl adsorbed, reaching saturation at a concentration of 4 mM, Ph4AsClO4 did not adsorb. The retention of neutral metalloporphyrins was unaffected, while cationic metalloporphyrins demonstrated decreasing retention with an increase in the concentration of either hetaeron. The possible equilibria involved are discussed.

Arsenicals↗
PubMed1983

Photoelectroanalytical chemistry: possible interferences in serum and the selective detection of tris(2,2'-bipyridine)ruthenium(II) in the presence of interferents.

Photoelectroanalytical chemistry, the application of photoelectrochemistry to analysis, as reported here, is based on the amperometric detection of tris(2,2'-bipyridine)ruthenium(III) after its production from the corresponding Ru(II) complex in an excited state and quenching by electron transfer. The Ru(II) complex is detectable in concentrations less than 10(-10) mol/L injected into a flow stream in 100 microL. The selectivity of the detection is based upon several competitive reactions and their rates. The complex can be detected accurately in the presence of at least 10(4) molar excess of the potent interferents uric acid and oxalic acid. We anticipate that this complex will be used in assays that involve the use of labels.

2,2'-Dipyridyl↗