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Chromotropic Acid (chromotropic + acid)
Selected AbstractsNovel, Sensitive Voltammetric Methods for Titanium Determination Using Chromotropic Acid and Azo-Compounds as Complexing AgentsELECTROANALYSIS, Issue 12 2003Marcin Gawrys Abstract Voltammetric behavior of titanium(IV) complexes with chromotropic acid, its azo-derivatives: 2-(4-sulfophenylazo)-1,8-dihydroxy-3,6-naphthalenedisulfonic acid (SPANDS), chromotrope 2B, sulfonazo III and other azo-compounds: calmagite, tropeoline O and kalces was investigated at a hanging mercury drop electrode. These complexes strongly adsorb onto the electrode, thus can be determined by an adsorptive stripping voltammetry (optimal pH about 6). At pH about 3 reduction current enhancement for Ti-kalces complex was observed in the presence of chlorate ions. It is a rare example of a catalytic process with azo-compound as a complexing agent. Signal for Fe-calmagite complex reduction was also observed. Influence of foreign ions and the optimal conditions for titanium determination are described in detail. Additionally, a connection between obtained results and a structure of titanium complexes is discussed. [source] Application of the MTD-PLS method to heterocyclic dye,cellulose interactionsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 11 2007Ludovic Kurunczi Abstract The minimal topologic difference method in a projection in latent structures variant procedure was applied to a series of heterocyclic monoazo dyes of the type: RC6H4N = NY (R = benzothiazole, benzimidazole, N-containing aromatic pentacycles; Y = , acid, H acid, chromotropic acid, R acid). A statistically excellent model was obtained: RX2 = 0.625, RY2 = 0.940, Q2 = 0.822. The analysis of this model reveals the nature of dye,fiber interactions, which determine the dye affinity. Hydrophobic character in the R group and H-bond donor groups in a specific Y substitution position augment the dye affinity for cellulose. An increase of the polar nature of atoms in R depletes the affinity. Also some lateral substituents belonging to the Y coupling components suffer steric hindrance, and their presence is detrimental for the affinity. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [source] Chromotropic acid-functionalized polyurethane foam: A new sorbent for on-line preconcentration and determination of cobalt and nickel in lettuce samplesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2006Valfredo Azevedo Lemos Abstract A chromotropic acid-functionalized polyurethane foam has been developed for use in an on-line preconcentration system for cobalt and nickel determination. The packing material was prepared by covalent coupling of chromotropic acid with the polyurethane foam through an azo group. Co and Ni ions were sorbed in the minicolumn, from which they could be eluted directly to the nebulizer-burner system of a flame atomic absorption spectrometer. Elution of cobalt and nickel from the minicolumn can be accomplished with 0.50 and 0.75 M HCl solutions, respectively. The enrichment factors obtained were 22 (Co) and 27 (Ni), for 60 s preconcentration time, and 57 (Co) and 59 (Ni), if a preconcentration time of 180 s was used. Under the optimum conditions, the proposed procedure allowed the determination of metals with detection limits of 0.43 (cobalt) and 0.52 ,g/L (nickel), respectively, on using preconcentration periods of 180 s. The accuracy of the developed procedure was evaluated by analysis of the certified reference materials NIST 1515 Apple Leaves and NIST 1570a Spinach Leaves. The method was applied to the analysis of lettuce samples. The contents of cobalt in the samples analyzed varied from 0.75 to 0.98 ,g/g. Nickel was not detected in the lettuce samples. [source] | ||||||||||