Nature of hafnium-chloranilic acid metallochrome by matrix rank, contour mapping, and iterative analysis of absorption spectra

Abstract

Formation of colored adducts between chloranilic acid and low concentrations of small, highly charged metal ions in strong perchloric acid solutions is of special analytical interest. Irreproducibility due to hydrolysis

Solvent effects on thiamin-enzyme model interactions. I. Interactions with tryptophan

“…Within experimental error, a single point was observed (0.575, 0.575,0.570,0.570, 0.578 for /Jisonm/^-tonm and 0.302, 0.320, 0.325, 0.306, and 0.308 the corresponding values for the A 360nm/^4 340nm ratio). This suggests the existence of a single 1:1 complex or (the unlikely possibility) of two complexes, providing the ratios of their extinction coefficients at the three wavelengths are nearly identical (Coleman et al, 1970; Wallace, 1960; Ainsworth, 1961; Wallace and Katz, 1964;Katakis, 1965;Varga and Weatch, 1967). (b) Secondly, Job's plot (Job, 1928) was constructed keeping the sum of TRP and THC concentrations constant at 0.05 M and varying the mole fraction TRP from 0 to 1.…”

Predicting gas-chromatographic resolution for pairs of normal alkane homologs

“…The following method is based upon principal-component analysis which, under certain restrictions, can effect a deconvolution of two chromatographic peaks. In chemistry, principal-component analysis has been used, especially in spectrometry, for determining the number of absorbing species (1-5) and their absorption curves (6, 7), and for determination of equilibrium constants (8,9).…”

“…In chemistry, principal-component analysis has been used, especially in spectrometry, for determining the number of absorbing species (1-5) and their absorption curves (6,7), and for determination of equilibrium constants (8,9).…”

“…instruments (2, 3), the total analysis time should no longer be limited by calculation of the experimental data but by the separation time itself. The problem of separation time in gas chromatography has been considered from the standpoints of minimum time for a prescribed resulution (4)(5)(6) and for normalized-time analysis (7)(8)(9) in which resolution is maximized for a prescribed analysis time. Hawkes (IO) has used computer (2) A. W. Westerberg, ANAL.…”

Equilibrium composition, additive properties and stoichiometry

“…This correction is increasingly in excess, the more the composition point involved lies away from AB and toward C, and it is thus maximally overcorrecting the part of the curve in which the maximum is sought, tending to flatten the peak. In spite of its being an overcorrection, this procedure is likely to continue popular, because it is so readily made, either calculationally after measuring series of samples of the reactants separately (4), or instrumentally by using partitioned optical cells such as Hellma No. 238 in which the unmixed reactants serve as reference sample in a doublebeam spectrophotometer and thus are deducted automatically from the total absorbance of the mixed sample in the working position.…”