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Hg-Ni OTTLE at this pH, showing that the glyoxylic acid wave is obscured by hydrogen evolution at this electrode. As a result of the extended negative range, glyoxylic acid could be analyzed by thin-layer coulometry and by thin-layer differential pulse voltammetry in the Hg-Au OTTLE (26, 27).Reduction of Metals. The utility of the Hg-Au minigrid for the reduction of metal ions to the elemental form is limited by the tendency of the gold which is dissolved in the mercury film to form intermetallic compounds with other metals (Cd, Mn, Sn, Zn) deposited in the mercury (28). For example, lead, which does not form an intermetallic compound with gold, gave a well-behaved, reversible cyclic voltammogram at the Hg-Au minigrid. By contrast, cadmium gave a good reduction wave, but the oxidation wave for Cd°was absent due to the formation of a Cd-Au intermetallic compound.

SUMMARYWindow factor analysis (WFA) is a self-modeling method for extracting the concentration profiles of individual components from evolutionary processes such as flow injection, chromatography, titrations and reaction kinetics. The method takes advantage of the fact that each component lies in a specific region along the evolutionary axis, called the 'window'. Theoretical equations are derived. The method is used to extract the concentration profiles and spectra of seven bismuth species from data obtained by Gemperline and Hamilton, who injected bismuth perchlorate into a flowing stream of hydrochloric acid.

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SUMMARYFisher variance ratio tests are developed for determining (1) the number of statisticaliy significant abstract factors responsible for a data matrix and (2) the significance of target vectors projected into the abstract factor space. F-tests, developed from the viewpoint of vector distributions, are applied to various data sets taken from the chemical literature.