Spectrophotometric Determination of Ruthenium(III) Using 1-Nitroso-2-Naphthol-3,6-Disulfonic Acid (Disodium Salt)

AbstractPhotometric determination of aqueous Co(II), Cu(II), Ni(II) and Fe(III) was performed using indicator films prepared by immobilization of 1-nitroso-2-naphthol-3,6-disulfonic acid disodium salt (NRS) into hardened photographic film. Immobilization was based on electrostatic interaction of reagent and metal complexes with the gelatin. The isoelectric point pH of hardened gelatin (4.46±0.04) was evaluated by viscometry. Co(II), Fe(III), Ni(II) form 1:3 complexes with NRS in gelatin at pH 2 and Cu(II) forms 1:2 complexes. Their log β′ values were: Co-6.7, Fe-8.6, Cu-8.0, and Ni-6.4. The absorption maxima were: 370nm for NRS, and 430nm, 470nm, 495nm and 720nm for complexes of Co(II), Ni(II), Cu(II) and Fe(III). An algorithm for their simultaneous determination using the indicator films was developed. The detection limits were: clim(Co2+) = 0.45×10−5 M, clim(Fe3+) = 0.50×10−5 M, clim(Cu2+) = 0.67×10−5 M, clim(Ni2+) = 0.75×10−5 M,; and their sum clim(ΣMn+) = 0.82×10−5 M.

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A Simple and Sensitive Inhibitory Kinetic Method for the Carbocisteine Determination

Journal of the Mexican Chemical Society ◽

10.29356/jmcs.v66i1.1654 ◽

2021 ◽

Vol 66 (1) ◽

Author(s):

Abhishek Srivastava ◽

Vivek Sharma ◽

Vinay Kumar Singh ◽

Krishna Srivastava

Keyword(s):

Good Accuracy ◽

Quantitative Estimation ◽

Kinetic Method ◽

Fixed Time ◽

Disodium Salt ◽

Disulfonic Acid ◽

Stable Complex ◽

Reaction Conditions ◽

Kinetic Determination

Abstract. A fast, reproducible, and sensitive method is proposed for the kinetic determination of carbocisteine (CCys). The method depends on the inhibitory property of carbocisteine, which reduces the Hg2+ catalyzed substitution rate of cyanide from [Ru(CN)6]4- with N-R-salt (1-Nitroso-2-naphthol-3,6-disulfonic acid disodium salt) via forming a stable complex with Hg2+. Spectrophotometric measurements were carried out by recording the absorbance at 525 nm (λmax of [Ru(CN)5 Nitroso-R-Salt]3- complex) at a fixed time of 10 and 15 min under the optimized reaction conditions with [N-R-salt] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M and [Ru(CN)64-] = 4.25 × 10-5 M. With the proposed method, CCys can be determined quantitatively down to 3.0 × 10-6 M. This methodology can be effectively used for the rapid quantitative estimation of CCys in the pharmaceutical samples with good accuracy and reproducibility. The addition of common excipients in pharmaceuticals even up to 1000 times with [CCys] does not interfere significantly in the estimation of CCys. Resumen. Se propone un método rápido, reproducibley sensible para la determinación cinética de la carbocisteina (CCys). El método depende de la propiedad inhibitoria de la carbocisteina que reduce la tasa de sustitución catalizada por Hg2+ del cianuro de [Ru(CN)6]4- con la sal N-R (sal disódica del ácido 1-Nitroso-2-naftol-3,6-disulfónico) mediante la formación de un complejo estable con Hg2+. Las mediciones espectrofotométricas se llevaron a cabo registrando la absorbancia a 525 nm (λmax del complejo [Ru(CN)5 Sal-Nitroso-R]3-) en un tiempo fijo de 10 y 15 min en las condiciones de reacción optimizadas con [sal-NR] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M y [Ru(CN)64-] = 4.25 × 10-5 M. Con el método propuesto, CCys se puede determinar cuantitativamente hasta 3,0 × 10-6 M. Esta metodología se puede utilizar eficazmente para la estimación cuantitativa rápida de CCys en las muestras farmacéuticas con buena precisión y reproducibilidad. La adición de excipientes comunes en productos farmacéuticos incluso hasta 1000 veces con [CCys] no interfiere significativamente en la estimación de CCys.

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Spectrophotometric determination of thorium in food using 2-(2,5-disulfonic-4-methoxyphenylazo)-7-(2-hydroxyl-5-carboxylphenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid

Journal of Analytical Chemistry ◽

10.1134/s1061934807100085 ◽

2007 ◽

Vol 62 (10) ◽

pp. 946-950 ◽

Cited By ~ 5

Author(s):

S. Meng ◽

M. Tian ◽

Y. Liu ◽

Y. Guo ◽

Y. Fan

Keyword(s):

Spectrophotometric Determination ◽

Disulfonic Acid

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Determination of Seven Manufacturing Impurities in FD&C Red No. 40 by Ultra-High-Performance Liquid Chromatography

Journal of AOAC International ◽

10.5740/jaoacint.19-0179 ◽

2020 ◽

Vol 103 (1) ◽

pp. 235-243

Author(s):

Bhakti Petigara Harp ◽

Marianita Perez-Gonzalez ◽

Hector M Cordero-Nieves ◽

Rachel S Pandian ◽

Bryan K Bowes

Keyword(s):

Sulfonic Acid ◽

High Performance ◽

Hplc Method ◽

Disodium Salt ◽

Disulfonic Acid ◽

Linear Calibration ◽

Acid Sodium Salt ◽

Color Additive ◽

Survey Analyses

Abstract Background: The U.S. Food and Drug Administration batch-certifies color additives to ensure that each lot meets published specifications for coloring food, drugs, and cosmetics. Objective: An ultra-high-performance LC (UHPLC) method was developed to determine seven manufacturing impurities in the monoazo color additive FD&C Red No. 40 (R40). The analytes consist of two intermediates, an impurity originating from one intermediate, a reaction by-product, and three subsidiary colors. The intermediates are 4-amino-5-methoxy-2-methylbenzenesulfonic acid [cresidine-p-sulfonic acid (CSA)] and 6-hydroxy-2-naphthalene sulfonic acid sodium salt (SS). The impurity originating from the intermediate SS is 6,6′-oxybis[2-naphthalenesulfonic acid] disodium salt. The reaction by-product is 4,4′-(diazoamino)bis[5-methoxy-2-methylbenzenesulfonic acid disodium salt. The subsidiary colors are sodium salts of CSA coupled with 2-naphthol-3,6-disulfonic acid, 2-naphthol-6,8-disulfonic acid, or 2-naphthol. Methods: Samples of R40 were dissolved in an ammonium acetate buffer modified to pH 9.2, filtered, and analyzed by UHPLC. Quantitation of the analytes was performed by calibration in the presence of the color additive matrix. Results: UHPLC validation studies showed linear calibration curves (R2 = 0.9999), good recovery (95–121%) and precision (RSDs = 1.0–6.3%), and LOQs ranging from 0.002 to 0.030%. Survey analyses of 31 samples from 11 manufacturers yielded results by the new UHPLC method and a previously used HPLC method that are consistent within experimental error. Conclusions: The new UHPLC method provides faster analysis time, improved separation, and similar sensitivity compared to the HPLC method. Highlights: An UHPLC method was developed and validated to determine seven manufacturing impurities in R40 submitted to the FDA for batch certification.

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