Analytical Letters

Guilbault, G. G.

doi: 10.1080/00032716708051091pmid: N/A

Zambonin, Pier Giorgio; Jordan, Joseph

doi: 10.1080/00032716708051092pmid: N/A

Abstract The first successful electroanalytical investigation of the superoxide ion O2, is reported in molten alkali nitrate solvents at 265°C. At Levich's rotated platinum disk electrode, the reactions O2 − + e = O2 − and O2 − = O2 + e yielded Nernst controlled voltammograms with well-defined limiting currents.

Cruser, Stephen A.; Bard, Allen J.

doi: 10.1080/00032716708051093pmid: N/A

Abstract Analytical applications of electrochemiluminescence are described. The peak intensity of luminescence, generated by application of an alternating current to solutions of 9,10-diphenylanthracene, varies linearly with concentration over the range 0.2 – 10 mM.

Flaschka, H.; Mann, J.

doi: 10.1080/00032716708051094pmid: N/A

Abstract Observations are made on the end point of the photometric EDTA titration of nickel in the presence of large amounts of cobalt using murexide as indicator. Difficulties with the end point are believed due to an ionic strength effect and may be remedied by dilution of the sample to be titrated.

Rechnitz, G. A.; Lin, Z. F.

doi: 10.1080/00032716708051095pmid: N/A

Abstract A cupric ion-selective electrode of the liquid-liquid membrane type is shown to respond selectively to Cu++ activity over the range of pCu++ = 2–5 in aqueous solutions of pH 3.5–6.5. Cupric ion activity measurements in the presence of complexing ligands have yielded a reliable estimate of formation constants for a number of soluble copper complexes.

Rechnitz, G. A.; Lin, Z. F.; Zamochnick, S. B.

doi: 10.1080/00032716708051096pmid: N/A

Abstract A preliminary evaluation of SO4 −2 and PO4 −3 sensitive electrodes of the precipitate-impregnated silicone rubber membrane type shows these electrodes to be useful for direct potentiometry and potentiometric titration under limited circumstances.

Chen, Raymond F.

doi: 10.1080/00032716708051097pmid: N/A

Abstract Fluorescence quantum yields (Q) for tyrosine, tryptophan, and phenylalanine in water at 23° determined by the comparative method using a quinine standard were found to be 0.14, 0.13, and 0.024, respectively. Similar values were obtained with phenol as the standard. The numbers are much lower than those literature values which have been widely used to calculate protein fluorescence quantum yields. Possible reasons for the discrepancies are discussed. The quantum yields of isomeric tyrosines and fluorophenylalanines are also reported.

Bratzel, M. P.; Winefordner, J. D.

doi: 10.1080/00032716708051098pmid: N/A

Abstract The influence of flame type and composition on atomic fluorescence flame spectrometric limits of detection of sixteen metals introduced into several different turbulent flames is considered. Limits of detection for sixteen metals using optimum flame types with Beckman and Zeiss total-consumption nebulizer-burners are tabulated and compared with previous values given in the literature.

Wänninen, Erkki; Lindholm, Allan

doi: 10.1080/00032716708051099pmid: N/A

Abstract In the determination of copper by atomic absorption spectrophotometry different salts were found to affect the absorbance to a greater or lesser degree with increasing salt concentration. In this connection, the effect of some organic solvents on the absorbance was also investigated. The decrease in absorbance in the presence of a salt and the increase in absorbance when an organic solvent was present, were found to depend on changes in specific gravity, surface tension and viscosity of the solution. The course of the absorbance curves can be interpreted with the aid of curves showing surface tension and viscosity as functions of specific gravity of the solution.

Summers, Ruby M.; Mefferd, Roy B.

doi: 10.1080/00032716708051100pmid: N/A

Abstract A procedure is described for the preparation of very thin, uniform cellulose thin-layer plates. The cellulose is sprayed onto the plates in a fine mist from a standard chromatograph sprayer.