Rapid determination of free active chlorine in water by diffuse reflectance spectroscopy after reaction with polyurethane foams

Дмитриенко, С. Г.; Sviridova, Olga A.; Pyatkova, L. N.; Zhukova, V.; Zolotov, Yu. A.

doi:10.1016/s0003-2670(99)00751-5

Cited by 44 publications

(14 citation statements)

References 13 publications

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“…For quantitative measurements, the literature describes many types of plots relating signal and concentration. [22][23][24][25][26][27][28][29][30] As an aid to the choice of an optimum concentration range for the reflectance measurements, the reflectance values for standards may be plotted as a logarithmic function of concentration. The curve is similar to a Ringbom plot for solution measurements.…”

Section: Munk Function F(t R ) Is Defined As F(t R ) = (1-t R )mentioning

confidence: 99%

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A simplified reflectometric method for the rapid determination of dipyrone in pharmaceutical formulations

Weinert¹,

Pezza²,

Pezza³

2007

J. Braz. Chem. Soc.

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Este artigo descreve um método simples, portátil e ambientalmente amigável para a rápida determinação de dipirona em medicamentos empregando a espectroscopia de reflectância difusa. O método proposto está baseado nas medidas de reflectância do composto alaranjado produzido na reação de spot-test entre dipirona e p-dimetilaminocinamaldeído (p-DAC), em meio ácido, usando papel de filtro como suporte sólido. Metodologias de planejamento de experimentos foram utilizadas para a otimização das condições experimentais. Todas as medidas de reflectância foram efetuadas em 510 nm e o intervalo linear foi de 1,42 × 10 -4 -2,85 × 10 -3 mol L -1 , com coeficiente de correlação de 0,999. Os limites de detecção (LOD) e de quantificação (LOQ) foram de 1,20 × 10 -5 mol L -1 e 4,00 × 10 -5 mol L -1 , respectivamente. A precisão intradia e interdia foi avaliada na análise de uma solução de dipirona 7,90 × 10 -4 mol L -1 (n = 10). Os coeficientes de variação foram 1,1 e 0,9%, respectivamente. O método proposto foi aplicado com êxito na determinação de dipirona em amostras comerciais de medicamentos. Não foram observadas interferências dos excipientes comuns em formulações farmacêuticas. Os resultados obtidos pelo método proposto estão em boa concordância com aqueles obtidos pelo procedimento da Farmacopéia Brasileira num nível de confiança de 95%. This paper describes a simple, portable and environmentally friendly method for the rapid determination of dipyrone in pharmaceuticals by using diffuse reflectance spectroscopy. The proposed method is based on the reflectance measurements of the orange compound produced from the spot test reaction between dipyrone and p-dimethylaminocinnamaldehyde (p-DAC), in acid medium, using a filter paper as solid support. Experimental design methodologies were used to optimize the measurement conditions. All reflectance measurements were carried out at 510 nm and the linear range was from 1.42 × 10 -4 -2.85 × 10 -3 mol L -1 , with a correlation coefficient of 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.20 × 10 -5 mol L -1 and 4.00 × 10 -5 mol L -1 , respectively. The intraday precision and interday precision were studied for 10 replicate analyses of 7.90 × 10 -4 mol L -1 dipyrone solution. The coefficients of variation were 1.1 and 0.9%, respectively. The proposed method was applied successfully to the determination of dipyrone in commercial brands of pharmaceuticals. No interferences were observed from the common excipients in formulations. The results obtained by the proposed method were favorably compared with those given by the Brazilian Pharmacopoeia procedure at 95% confidence level.

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Section: Munk Function F(t R ) Is Defined As F(t R ) = (1-t R )mentioning

confidence: 99%

“…3,[22][23][24][25][26][27][28][29] To the best of our knowledge, there are no reports on the use of the reflectance analytical methods for the determination of dipyrone in pharmaceuticals.…”

Section: Introductionmentioning

confidence: 99%

A simplified reflectometric method for the rapid determination of dipyrone in pharmaceutical formulations

Weinert¹,

Pezza²,

Pezza³

2007

J. Braz. Chem. Soc.

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“…41 The properties of redox media equilibrium of some quinonoid indicators were studied when they are immobilized by adsorption on XAD-2, synthetic copolymer, by reflectometry measurement. 42 The determination of Ni(II), Fe(III) and Cr(VI), 37 hydrogen chloride, 43 cations, 44 and free active chlorine, 45 in water, ammonium, phosphate and Cu(II), 46 Fe(III), 47 Cr(VI), 48 acetylsalicylic acid 49 and furosemide in pharmaceutical formulations 50 by reflectance spectroscopy were related. Moreover, a multiplexed colorimetric solid-phase extraction for determination of Ag(I), Ni(II), and sample pH by diffuse reflection spectroscopy was developed 51 and the interaction of aqueous iodine solutions with immobilized poly(vinylpyrrolidone) (PVP) by diffuse reflection spectroscopy was investigated.…”

Section: Introductionmentioning

confidence: 99%

Determination of methyldopa in pharmaceutical formulations by combined spot test-diffuse reflectance spectroscopy

Ribeiro¹,

Pezza²,

Pezza³

2006

J. Braz. Chem. Soc.

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Este trabalho descreve um método simples e rápido por "spot test" quantitativo, utilizando a espectroscopia de reflectância difusa para determinação de metildopa em formulações farmacêuticas. O método proposto baseia-se na reação de complexação entre metildopa e íons molibdato, formando um complexo amarelo na superfície do papel de filtro. As medidas de reflectância foram realizadas a 410 nm. A curva analítica obtida a partir do gráfico de densidade óptica do sinal de reflectância (A R ) vs. log da concentração de metildopa apresentou linearidade na faixa de 6,30 × 10 -3 a 1,89 × 10 -2 mol L -1 , com um coeficiente de correlação de 0,998. O limite de detecção foi de 2,74 × 10 -3 mol L -1 (R.S.D. = 1,02%). As substâncias comumente utilizadas como excipientes nas formulações farmacêuticas não interferem no método proposto. O método foi aplicado para a determinação de metildopa em formulações farmacêuticas comerciais. Os resultados obtidos por este método foram comparados favoravelmente com aqueles obtidos pelo método oficial, com 95% de nível de confiança. This paper describes a very simple and rapid quantitative reflectance spot test procedure for the determination of methyldopa in pharmaceutical formulations. This method is based on the complexation reaction of methyldopa with molybdate ions yielding a yellow stable complex on filter paper. Reflectance measurements were carried out at 410 nm. Under optimal conditions, the calibration graphs obtained for methyldopa by plotting the optical density of the reflectance signal (A R ) vs. the log of the concentration were linear from 6.30 × 10 -3 to 1.89 × 10 -2 mol L -1 , with a correlation coefficient of 0.998. The detection limit was 2.74 × 10 -3 mol L -1 (R.S.D. = 1.02%) for methyldopa. The common excipients used as additives in pharmaceuticals do not interfere in the proposed method. The method was applied to determine metyldopa in commercial pharmaceutical formulations. The results obtained by the proposed method compare favorably with those obtained by an official procedure at 95% confidence level. Keywords: methyldopa, diffuse reflectance, pharmaceuticals formulations IntroductionMethyldopa (α-methyl-3,4-dihydroxyphenylalanine, MTD) is a catechol derivative (catecholamine) widely used as antihypertensive agent. The MTD is a centrally acting alpha 2 -adrenoreceptor agonist, which reduces sympathetic tone and produces a fall in blood pressure. In recent years more and more strict regulations related to the quality control of pharmaceuticals led to increasing demands on the simplicity and rapidity of analytical assay. 34,35 Considering the simplicity of the spot test method, the use of small quantities of chemicals, the confidence and the rapidity of such kind of procedure, the quantitative spot-test analysis by diffuse reflectance spectroscopy could be interesting to develop analytical procedures for routine analysis of drugs in pharmaceuticals formulations. 675 Vol. 17, No. 4, 2006 For many years, the use of reflectance spectroscopy as an analytical techni...

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“…However, this method may suffer from attenuation caused by the matrix material and require special care in the measuring technique to attain a reliable reproducibility in the results. Recently, diffuse reflection spectroscopy (DRS) [15][16][17][18] has been reported for the determination of some inorganic and organic species after sorption into a proper solid matrix. The reflectance technique avoids lightattenuation problems, and allows for simple sample manipulation.…”

mentioning

confidence: 99%

“…Several other color systems 21 have been defined based on these tristimulus values, such as the (Y, x, y), (L*, a*, b*) and its derivatives (L*, C*, H˚), (L, a, b), and (L*, u*, v*). Recently, the determination of indium 22 after sorption into PAN or PAR immobilized on silica gel, and free active chlorine 18 after a reaction with PUF, using diffuse reflection spectroscopy, have been reported. The application of chromaticity characteristics for the determination of aluminum with Eriochrome Cyanine R immobilized into different solid supports has been described.…”

mentioning

confidence: 99%

Diffuse Reflectance Spectroscopic Determination of Phosphate with Applications of Chromaticity Coordinates and Color Temperature

Abbas¹

2003

ANAL. SCI.

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Rapid determination of free active chlorine in water by diffuse reflectance spectroscopy after reaction with polyurethane foams

Cited by 44 publications

References 13 publications

A simplified reflectometric method for the rapid determination of dipyrone in pharmaceutical formulations

A simplified reflectometric method for the rapid determination of dipyrone in pharmaceutical formulations

Determination of methyldopa in pharmaceutical formulations by combined spot test-diffuse reflectance spectroscopy

Diffuse Reflectance Spectroscopic Determination of Phosphate with Applications of Chromaticity Coordinates and Color Temperature

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