The conditions of color reaction of Aluminium(Ⅲ) with a new organic reagent 2,3,7 trihydroxy 9 [2,4 dihydroxy)phenylazo]phenylfluorone (ARPF) in the presence of cetyltrimethyammonium bromide(CTMAB) were studied....The conditions of color reaction of Aluminium(Ⅲ) with a new organic reagent 2,3,7 trihydroxy 9 [2,4 dihydroxy)phenylazo]phenylfluorone (ARPF) in the presence of cetyltrimethyammonium bromide(CTMAB) were studied. It was found that Aluminium(Ⅲ) reacts with ARPF and CTMAB in pH 6.5 HAc NaAc buffer solution to form a 1∶2 red complex with maximum absorption at 562 nm .The molar absorptivity is 1.10×10 5 L·mol -1 ·cm -1 . Beer's law is obeyed in the range of 0 5.5 μg Al(Ⅲ) per 25 mL. The method has been applied to determination of Aluminium in the limestone with satisfactory results.展开更多
Synthesis of a new high sensitive water soluble chromogenic reagent mes o tetra (2 chloro 4 sulfophenyl)prophyrin and the conditions for the reaction of this reagent with cadmiun(Ⅱ) were studied. The apparent...Synthesis of a new high sensitive water soluble chromogenic reagent mes o tetra (2 chloro 4 sulfophenyl)prophyrin and the conditions for the reaction of this reagent with cadmiun(Ⅱ) were studied. The apparent molar absorption coefficient at 434 nm is 5.20×10 5 L·mol -1 ·cm -1 . The method has been applied to the determination of 5.0×10 -9 (content by weight) Cadmium(Ⅱ) in honey.展开更多
Nickel(II) reacts with 2-acetylpyridine-4-methyl-3-thiosemicarbazone (APMT) and forms a yellow colored complex, which was extracted into n-hexanol from sodium acetate and acetic acid buffer at pH 6.0. The absorbance v...Nickel(II) reacts with 2-acetylpyridine-4-methyl-3-thiosemicarbazone (APMT) and forms a yellow colored complex, which was extracted into n-hexanol from sodium acetate and acetic acid buffer at pH 6.0. The absorbance value of the Ni(II)-APMT complex was measured at different intervals of time at 375 nm to ascertain the time stability of the complex. The extraction of the complex into the solvent was instantaneous and stable for more than 72 hrs. The system obeyed Beer’s law in the concentration range of 0.235 - 2.43 μg·ml–1 of nickel(II), with an excellent linearity and a correlation coefficient of 0.999. The molar absorptivity and Sandell’s sensitivity of the extracted species were found to be 2.16 × 104 L mol–1 ·cm–1 and 0.003 μg·cm–2 at 375 nm, respectively. Hence a detailed study of the extraction of nickel(II) with APMT has been undertaken with a view to developing a rapid and sensitive extractive spectrophotometric method for the determination of nickel(II) when present alone or in the presence of diverse ions which are usually associated with nickel(II) in environmental matrices like soil and industrial effluents. Various standard alloy samples (CM 247 LC, IN 718, BCS 233, 266, 253 and 251) have been tested for the determination of nickel for the purpose of validation of the present method. The results of the proposed method are comparable with those from atomic absorption spectrometry and were found to be in good agreement.展开更多
Spectrophotometric study was carried out, for the first time, to investigate the reaction between the vasodilator pentoxifylline hydrochloride (POX) and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. The reaction occu...Spectrophotometric study was carried out, for the first time, to investigate the reaction between the vasodilator pentoxifylline hydrochloride (POX) and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. The reaction occurs in alkaline medium to activate the nucleophilic substitution reaction producing an orange-colored product measured spectrophometrically at λ<sub>max</sub> 472 nm. The variables affecting the reaction were carefully studied and the conditions were optimized. The kinetics of the reaction was investigated and its activation energy was found to be 0.262 cal/mol. Owing to its low activation energy, the reaction proceeded easily and was successfully used for simple and rapid assay of POX. The stoichiometry of the reaction was determined (1:1), and the reaction mechanism was suggested. To develop a high-throughput methodology used in quality control laboratory, a comparative study of the reaction using the conventional spectrophotometric versus microwell assay was applied. Under the optimum reaction conditions, the initial rate and fixed time methods were utilized for constructing the calibration graphs for determination of POX concentrations. The linear range was 10 - 120 μg/ml with good correlation coefficients (0.9987 - 0.9998). The LOD was 2.5 and 3.4 μg/ml for initial rate and fixed time methods, respectively. The intra- and inter-day accuracy and precision of the developed methods were satisfactory, where RSD was ≤3.94%. The present methods have been successfully applied to the determination of POX in its pharmaceutical tablets, and the percentage recovery values were 97.9% - 101.9%. Therefore, we strongly recommend the proposed methods for determination of POX in quality control laboratories.展开更多
文摘The conditions of color reaction of Aluminium(Ⅲ) with a new organic reagent 2,3,7 trihydroxy 9 [2,4 dihydroxy)phenylazo]phenylfluorone (ARPF) in the presence of cetyltrimethyammonium bromide(CTMAB) were studied. It was found that Aluminium(Ⅲ) reacts with ARPF and CTMAB in pH 6.5 HAc NaAc buffer solution to form a 1∶2 red complex with maximum absorption at 562 nm .The molar absorptivity is 1.10×10 5 L·mol -1 ·cm -1 . Beer's law is obeyed in the range of 0 5.5 μg Al(Ⅲ) per 25 mL. The method has been applied to determination of Aluminium in the limestone with satisfactory results.
文摘Synthesis of a new high sensitive water soluble chromogenic reagent mes o tetra (2 chloro 4 sulfophenyl)prophyrin and the conditions for the reaction of this reagent with cadmiun(Ⅱ) were studied. The apparent molar absorption coefficient at 434 nm is 5.20×10 5 L·mol -1 ·cm -1 . The method has been applied to the determination of 5.0×10 -9 (content by weight) Cadmium(Ⅱ) in honey.
文摘Nickel(II) reacts with 2-acetylpyridine-4-methyl-3-thiosemicarbazone (APMT) and forms a yellow colored complex, which was extracted into n-hexanol from sodium acetate and acetic acid buffer at pH 6.0. The absorbance value of the Ni(II)-APMT complex was measured at different intervals of time at 375 nm to ascertain the time stability of the complex. The extraction of the complex into the solvent was instantaneous and stable for more than 72 hrs. The system obeyed Beer’s law in the concentration range of 0.235 - 2.43 μg·ml–1 of nickel(II), with an excellent linearity and a correlation coefficient of 0.999. The molar absorptivity and Sandell’s sensitivity of the extracted species were found to be 2.16 × 104 L mol–1 ·cm–1 and 0.003 μg·cm–2 at 375 nm, respectively. Hence a detailed study of the extraction of nickel(II) with APMT has been undertaken with a view to developing a rapid and sensitive extractive spectrophotometric method for the determination of nickel(II) when present alone or in the presence of diverse ions which are usually associated with nickel(II) in environmental matrices like soil and industrial effluents. Various standard alloy samples (CM 247 LC, IN 718, BCS 233, 266, 253 and 251) have been tested for the determination of nickel for the purpose of validation of the present method. The results of the proposed method are comparable with those from atomic absorption spectrometry and were found to be in good agreement.
文摘Spectrophotometric study was carried out, for the first time, to investigate the reaction between the vasodilator pentoxifylline hydrochloride (POX) and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. The reaction occurs in alkaline medium to activate the nucleophilic substitution reaction producing an orange-colored product measured spectrophometrically at λ<sub>max</sub> 472 nm. The variables affecting the reaction were carefully studied and the conditions were optimized. The kinetics of the reaction was investigated and its activation energy was found to be 0.262 cal/mol. Owing to its low activation energy, the reaction proceeded easily and was successfully used for simple and rapid assay of POX. The stoichiometry of the reaction was determined (1:1), and the reaction mechanism was suggested. To develop a high-throughput methodology used in quality control laboratory, a comparative study of the reaction using the conventional spectrophotometric versus microwell assay was applied. Under the optimum reaction conditions, the initial rate and fixed time methods were utilized for constructing the calibration graphs for determination of POX concentrations. The linear range was 10 - 120 μg/ml with good correlation coefficients (0.9987 - 0.9998). The LOD was 2.5 and 3.4 μg/ml for initial rate and fixed time methods, respectively. The intra- and inter-day accuracy and precision of the developed methods were satisfactory, where RSD was ≤3.94%. The present methods have been successfully applied to the determination of POX in its pharmaceutical tablets, and the percentage recovery values were 97.9% - 101.9%. Therefore, we strongly recommend the proposed methods for determination of POX in quality control laboratories.
