Color reaction

About: Color reaction is a research topic. Over the lifetime, 1194 publications have been published within this topic receiving 19579 citations.

Analytical Utility of the Unique Colour Reaction Between Uranyl Ions and Alizarin Fluorine Blue

Abstract: The uranyl-alizarin fluorine blue chelate complex shows an absorption peak at 560 nm, 30 nm higher than that of any other single metal complex of the reagent. The complex shows, at pH 4.5, a conditional stability constant of 2.3 × 106 litres mole−1 and molar absorptivity of 4100 litres mole−1 cm−1. Study of the feasibility of using this reaction for the photometric determination of Uo2 +2 in both one and two liquid phase systems reveals serious interference from other metal ions.

New colorimetric method for the determination of chloral hydrate in semi-bright nickel baths using barbituric acid

Abstract: A new method for the determination of chloral hydrate in semi-bright nickel baths by visible spectroscopy is proposed. The method is based on the colour reaction between chloral hydrate and barbituric acid at 60 °C. It is a slow reaction and samples are taken each minute whilst the reaction is carrying on. These samples are cooled down in order to stop the reaction before measuring the absorbance at 454 nm. In this way a plot of absorbance against time can be obtained. This plot presents two parts, a linear plot for 7 minutes and a plateau between 8 and 12 minutes. These behaviours allow us to use two kinds of analyses: classical and kinetic methods.

Study on Solid Phase Extraction Spectrophotometric Determination of Copper(II) with 2-(2-Quinolinylazo)-1,5-Dihydroxidebenzene

Abstract: Based on the color reaction of 2-(2-quinolinylazo)-1,5-dihydroxidebenzene (QADHB) with copper (Ⅱ) and the solid phase extraction of its colored complex with Waters Porapak ○R Sep-Park-C 18 cartridge, a new method for the determination of trace copper (Ⅱ) is studied. In the medium of CTMAB and presence of pH=4.0 buffer solution, QADHB can reacts with copper (Ⅱ) to form a stable 2∶1 complex. The colored complex can be extracted by C 18 cartridge, eluted by ethanol, and then determined by spectrophotometry at 560 nm. Beer's law is obeyed in range of 0~1.0 μg/mL. This method can be applied to the determination microamount of copper in water with satisfactory results.

Color reaction of estrone with the antimony trichloride reagent.

Abstract: The color reaction of estrone with the antimony trichloride reagent was investigated in order to clarify the reaction mechanism. Two reaction products, 3'-methyl-7-acetoxy-1, 2-cyclopenteno-3, 4-dihydrophenanthrene (I) and estrone acetate (II), were isolated from the colored reaction mixture. It was found that acetyl chloride is indispensable for the color reaction, and that the respective steroids are colored by the formation of the cation-radicals. It was assumed that the cation-radical of the substance I should be responsible for the coloration. The reaction mechanism for the formation of the substance I was inferred, and the relationship between the absorption maxima observed in the absorption spectra and the cation-radicals was discussed.

Determination of total serotonin derivatives in safflower seed meal by spectrophotometry

Abstract: A spectrophotometric method for determination of total serotonin derivatives was described.The method included a series of solvent extraction with diethyl ether anhydrous,methanol and ethyl acetate for the removal of oil and for the enrichment of serotonin.The final determination of serotonin was based on a color reaction between serotonin and Ehrlich's reagent.A regression equation y=0.0085+0.2213 x was obtained.The method was applied to four samples,with average recovery of 99.6%.Experimental results indicate that the method has good selectivity,reproducibility,and simplicity,and it is suitable for routine analysis.