A. Fernández-Gutiérrez

Some observations on the use of 1,4-dihydroxyanthraquinone as a fluorometric reagent for traces of lithium

Abstract A new fluorometric method for the determination of lithium based on the formation of a fluorescent species with 1,4-dihydroxyanthraquinone (Quinizarine), in acetone-water (90-10%) medium and 10−3M in NaOH is described. The fluorescent species has two excitation maxima at 560 and 596 nm and one emission maxima at 620 nm. It is stable at least 7 hr and the calibration graph is linear over the range 50–700 ppb Li. The method has a relative error over the average of measurements of 1.62%.

L, 8-Dihydroxyanthraquin0Ne-Li(I) Reaction. Spectrofluorometric Determination Of Li(I) In An Ethanolic And Acetonic Media

Abstract A spectrofluorometric study of the reaction 1, 8-Didydroxv anthraquinone-Li(I) was made in ethanol and acetone media. A new method for the spectrofluorometric determination of Li(I) is proposed, with a range between 100 and 700 ppb of Li(I) in ethanolic medium and between 50 and 450 ppb in acetone medium. The methods show errors of 2.00 and 2.90 % respectively.

1,8-dihydroxyanthraquinone-Mg(II) complex: II. Spectrophotometric study. Determination of Mg(II)

Abstract The 1,8-dihydroxyanthraquinone (1,8-DHAn) shows a colored and fluorescent reaction with the ion Mg(II) in a hydroalcoholic and ammonical medium. In the present work we have studied spectrophotometrically the 1,8-DHAn-Mg(II) complex in a hydroethanolic and ammonical, 8 × 10−4M medium. We found that the complex shows a maximum absorbance at 510 nm, and obeys a 1:1 stoichiometry with log K of 4.08. We propose a new method for the spectrophotometric determination of Mg(II) which is valid for concentrations between 0.25 and 2.00 ppm, and yields an error of 1.32%.

Spectrofluorimetric Determination of IO− 3

Abstract The IO− 3 anion gives a redox reaction, in hydrochloric acid medium, with 1,2,4-trihydroxyanthraquinone-3-carboxylic acid (Pseudopurpurin), which shows adequate analytical fluorescent characteristics. The oxidation product produces a fluorescent emission at 625 nm (wavelength of excitation =515 nm). After studying many variables, as a conclusion, we propose a new spectrofluorimetric method for the determination of IO− 3 between 0.2 and 2.0 ppm with a 0.90 % relative error. The interference levels, stoichiometry and nature of reaction are studies.

Spectrophotometric Study of 1,2,7-Trihydroxyanthraquinone-Mg(II) Complex. Determination of Mg(II)

Abstract The spectrophotometric study of violet complex Anthrapurpurin-Mg(II) in a basic medium and a hydroalcoholic solution was made (δmax - 530 nm., ∊ = 3.5 × 103 1 mol−1 cm−1, stoichiometry 1:1, apparent constant of stability log K = 9. 26). A new method for the spectrophotometric determination of Mg(II) is proposed for concentrations between one and six ppm. Relative errors between replicate samples were 0.90 %.

1,8-Dihydroxyanthraquinone-Mg(II) complex: III. Spectrophotometric determination of Mg(II) by extraction in isoamyl alcohol

Abstract In this paper a direct spectrophotometric method is proposed to determine Mg(II). This new method is based on the extraction in isoamyl alcohol of the complex formed between Mg(II) and 1,8-dihydroxyanthraquinone. The method permits the determination between 1.25 and 12.5 γ (in aqueous phase). The error and the molar absorptivity are values of 2.22% and 10,114 liters mol −1 cm −1 , respectively. Also studied were the values of the constant of exchange and the interference levels caused by foreign ions.

Spectrophotometric determination of BrO3− using the 1,2,4-trihydroxyanthraquinone-3-carboxylic acid as reagent

Abstract The reaction between the 1,2,4-trihydroxyanthraquinone-3-carboxylic acid and BrO3− in hydrochloric acid medium has been studied spectrophotometrically. The red color of the oxidation product serves as basis for a new method for determination of traces of BrO3−, measuring the absorbance at 520 nm. The influence of foreign ions on the determination, the stoichiometry of the reaction, and the nature of the oxidation product, have been reported.

Fluorometric Determination of Traces Of Mg(II) Using 1, 5-Dihydroxyanthracuinone as Reagent

Abstract The florescent characteristics of the complex formed by 1, 5-dihydroxyanthraquinone with Mg(II) in aqueous ethanol (λex 490 nm,λem=600 nm; pHap=9.1-9.6; 10% H2O; reagent concentration=4×10−5M) are described. The stoichiometry and the stability constant (1:1 and log K=4.90) are determined. A new fluorometric method for the determination of 10-100 ppb Mg(II) is proposed.

Spectrophotometric study of 1,2,5,8-tetrahydroxyanthraquinone-In(III) complex: Determination of In (III)

Abstract The 1,2,5,8-tetrahydroxyanthraquinone (quinalizarin) forms a colored complex with the ion In(III) in dimethylformamide-water solution. The 3:1 (R:In(III)) complex shows a λ max of 565 nm and a molar absorptivity of 4.59 × 10 4 liters mol −1 cm −1 . A new method for the spectrophotometric determination of In(III) between 0.2 and 2.2 ppm with a relative error of 1.57% is proposed.

Spectrophotometric study of pseudopurpurin-Pd(II) dimer complex. Spectrophotometric determination of traces of Pd(II)

Abstract We have studied spectrophotometrically the Pseudopurpurin-Pd(II) complex in an ethanolic-water medium ¦Ethanolamine ¦ optimum = 4 × 10 −1 M ; λ = 670 nm; 20% H 2 O; stable for at least 4 hr; ¦Reagent¦ optimum = 5 × 10 −5 M ; stoichiometry 2:2; log K = 17.7. A new method for the spectrophotometric determination of Pd traces is proposed for concentrations between 0.30 and 2.40 ppm. The relative error and the interferences of the method have been investigated.