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Showing papers in "Analytical Chemistry in 1959"











Journal ArticleDOI
TL;DR: This chapter discusses variable gradient device for chromatography, which provides a means of sharpening the peaks without introducing the artifacts that can result when stepwise changes in eluting agents are made.
Abstract: Publisher Summary This chapter discusses variable gradient device for chromatography. Since the introduction of gradient elution to chromatography several years ago, there have been many applications of the general technique in the fractionation of mixtures of substances having a wide range of elution requirements. In such cases, the use of a gradient greatly facilitates the operational aspects of chromatography, as it automatically encompasses these requirements. Moreover, in the case of substances that have a tendency to be eluted in broad, tailing bands when a single solvent is used, gradient elution provides a means of sharpening the peaks without introducing the artifacts that can result when stepwise changes in eluting agents are made. Several methods for the production of gradients have appeared in the literature. With the exception of those that can utilize differential pumping rates, all require a change in apparatus for each change in the shape of the gradient.

198 citations



Journal ArticleDOI
TL;DR: In this article, a basic technique of kinetic colorimetry was developed for determining oxidants in mixtures, and an appropriate reagent to produce a slowly developed color was added.
Abstract: A basic technique of kinetic colorimetry was developed for determining oxidants in mixtures. An appropriate reagent to produce a slowly developed color was added. Components were resolved graphically using a plot of logarithm of undeveloped color (maximum absorbance minus that at given time) vs. reaction time. Iodometric microdeterminations were thus made of liquid dilutions of various oxidants. This technique was applied to study the stoichiometry of iodide reagents with low concentrations of ozone in air. Reactions appeared to involve both hypoiodite and perphosphate. The most satisfactory reagent was 1% potassium iodide in neutral phosphate buffer. Comparisons were made with an independent method found to be specific for ozone in gaseous mixtures, based on converting ozone to nitrogen dioxide by reaction with excess nitric oxide. These methods should be valuable for differentiating natural smog oxidant into its components; the kinetic colorimetry technique should have broad analytical applications in making specific determinations, even if the available reactions are nonspecific.






Journal ArticleDOI
TL;DR: In this paper, a carbon radioassay with cupric oxide was performed in sealed Vycor tubes at 850 deg C. The carbon determination was as precise as it is in other types of oxidaiion used for carbon radio assay and the carbon dioxide is very pure as judged by its counting characteristics.
Abstract: Conventional wet or dry combustions are associated with the formation of nitrogen oxides which even in minute amounts cause undesirable effects in proportional counters. Simultaneous microdeterminations of total carbon and carbon-l4 may be performed by oxidation with cupric oxide in sealed Vycor tubes at 850 deg C. Masganese dioxide is added io provide free oxygen and cupric chloride displaces carbonyic whenever basic metals are present. The carbon determination is as precise as it is in other types of oxidaiion used for carbon radioassay and the carbon dioxide is very pure as judged by its counting characteristics. (auth)


Journal ArticleDOI
TL;DR: In this article, the potential of the polarized electrodc with respect to the reference electrode to equal that of the linearly inereasing control potential independently or circuit and of cell resistances is exploited in the versatile controlledpotential and derivative polarograph.
Abstract: Controlled-potential polarography has been exploited in the versatile controlled-potential and derivative polarograph. An amplifier continuously forces the potential of the polarized electrodc with respect to the reference electrode to equal that of the linearly inereasing control potential independently or circuit and of cell resistances. Controlled-potential pularography is espeeially suitable for high resistance media or for high current polarography in aqueous media where polarograms on ordinary instruments suffer distortion. because of iR drop in the electrolyte. The polarograph can be used for the analysis of irreversible and reversible species at very low conccntrations. It is possible to record the instantaneous currents, the successive peak currents, the successive average currents, easr the time derivative of the polarographic wave as a function of the potential of the polarized electrode with respect to the solution. Regular and derivative polarograms are presented that illustrate the advantage of controlled-postential over conventional polarography. (auth)





Journal ArticleDOI
TL;DR: In this paper, a rapid chromatographic separation is based on the greater affinity of a cation exchange resin for a trivalent than for a bivalent metal ion, and a solution of ethylenediammonium chloride serves as the eluting agent.
Abstract: A rapid chromatographic separation is based on the greater affinity of a cation exchange resin for a trivalent than for a bivalent metal ion A solution of ethylenediammonium chloride serves as the eluting agent Conditions are worked out for separation of zinc and lanthanum, and the effect of variables is studied This type of separation should be applicable to a wide variety of analytical problems (auth)