scholarly journals A multicommuted flow analysis method for the photometric determination of amoxicillin in pharmaceutical formulations using a diazo coupling reaction

2011 ◽  
Vol 22 (2) ◽  
pp. 279-285 ◽  
Author(s):  
Sueny K. B Freitas ◽  
Valdinete Lins da Silva ◽  
Alberto N Araújo ◽  
Maria Conceição B. S. M Montenegro ◽  
Boaventura F Reis ◽  
...  
1991 ◽  
Vol 40 (8) ◽  
pp. 377-381
Author(s):  
Yuji SUZUKI ◽  
Yoshikatsu SAKAGISHI

1961 ◽  
Vol 7 (6) ◽  
pp. 603-625 ◽  
Author(s):  
Derek Watson

Abstract A critical evaluation of existing colorimetric and spectrophotometric methods for the determination of bilirubin in blood plasma is presented. The stoichiometric equivalences of the reagents used in the diazo coupling reaction are re-evaluated. The elimination of turbidity is discussed, as well as methods using diazo-coupling promoters. Recommendations are made concerning the preservation of specimens to prevent oxidation and procedures that give maximal specificity for the type of bilirubin pigment being assayed.


2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Safwan M. Fraihat

AbstractGreen, sensitive and selective spectrophotometric methods were developed for the determination of nitrite in water samples. The methods (A, B and C) are based on the reduction of 5-nitroimidazoles; metronidazole (MTL), secnidazole (SCL) and tinidazole (TNL), respectively, followed by diazotization using nitrite in acidic medium, then coupling with pyrogallol (PG). The amount of nitrite was determined by measuring the absorbance of the colored product at 385 nm. The new methods were linear in the ranges of 2.5–30 μgml


2007 ◽  
Vol 4 (4) ◽  
pp. 496-501 ◽  
Author(s):  
M. Vamsi Krishna ◽  
D. Gowri Sankar

Simple, rapid and sensitive spectrophotometric procedures were developed for the analysis of Alfuzosin hydrochloride (AFZ) in pure form as well as in pharmaceutical formulations. The methods are based on the reaction of AFZ with nitrite in acid medium to form diazonium ion, which is coupled with ethoxyethylenemaleic ester (Method A) or ethylcyanoacetate (Method B) or acetyl acetone (method C) in basic medium to form azo dyes, showing absorption maxima at 440, 465 and 490 nm respectively. Beer’s law is obeyed in the concentration of 4-20 μg/mL of AFZ for methods A, B and 3-15 μg/mL of AFZ for method C. The molar absorptivity and sandell’s sensitivity of AFZ- ethoxyethylenemaleic ester, AFZ- ethylcyanoacetate and AFZ-acetyl acetone are1.90 × 104, 0.022; 1.93 × 104, 0.021 and 2.67 × 104L mole-1cm-1, 0.015 μg cm-2respectively. The optimum reaction conditions and other analytical parameters were evaluated. The methods were successfully applied to the determination of AFZ in pharmaceutical formulations.


2016 ◽  
Vol 230 (2) ◽  
Author(s):  
Caihong Chen ◽  
Zhening Yang ◽  
Fengxian Qiu ◽  
Tianlin Cao ◽  
Guorong Cao ◽  
...  

AbstractAn azo chromophore molecular S(-)-1,2-bis(4-azophenyl-4-nitro)-ethylenediamine (OABANEDA) was synthesized with 4-nitroaniline and S(-)-1,2-diphenyl ethylenediamine by diazo-coupling reaction. The azo polyurethane-urea (OAAPUU) was obtained from OABANEDA, polyether diol (NJ-210) and isophorone diisocyanate (IPDI). The structure of OAAPUU was characterized by the Fourier transform infrared and UV-visible spectroscopy. The physical and mechanical properties of OAAPUU were investigated. The refractive index (


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