scholarly journals Micro-level Estimation of Mercaptoacetic Acid Using its Inhibitory Effect to Mercury Catalyzed Ligand Exchange Reaction of Hexacyanoruthenate(II)

2020 ◽  
Vol 10 (6) ◽  
pp. 7152-7161
Keyword(s):  
Kinetic Method ◽  
Inhibitory Effect ◽  
Bioactive Molecules ◽  
Mercaptoacetic Acid ◽  
Ligand Exchange Reaction ◽  
Donor Ligand ◽  
Cyanide Ligand ◽  
Quality Check ◽  
Micro Level ◽  
Kinetic Spectrophotometric

The sulfur-containing bioactive molecules (soft base) tends to bind strongly with Hg(II) (soft acid), thereby inhibiting the mercury (II) catalyzed exchange rate of cyanide ligand from [Ru(CN)6]4- by pyrazine. This inhibitory effect of Mercaptoacetic acid (MAA) encourages us to establish a new kinetic method for its micro-level estimation. Optimized reaction condition viz. 6.25×10-5 M [Ru(CN)64-], pH = 4.0, 7.5×10-4 M [Pyrazine], 0.05 M KCl, 8.5 ×10-5 M [Hg+2] and 45 (±0.1) oC temperature were utilized for the kinetic spectrophotometric investigation at 370nm (λmax of [Ru(CN)5 Pz]3- complex). The modified mechanistic scheme for inhibition caused by sulfur donor ligand, MAA has been proposed. The proposed analytical method provides the detection of MAA up to 2.0 × 10-6 M, indicates that the methodology can be effectively and economically employed to analyze the biological samples having MAA. This method can also be convincingly adopted for the quality check of MAA containing industrial products.

scholarly journals The development of a new inhibition kinetic spectrophotometric method for the determination of phenylhydrazine

2005 ◽  
Vol 70 (7) ◽  
pp. 987-993 ◽  
Author(s):  
Violeta Mitic ◽  
Snezana Nikolic ◽  
Vesna Stankov-Jovanovic
Keyword(s):  
Detection Limit ◽  
Rate Equation ◽  
Reaction Rate ◽  
Method Development ◽  
Kinetic Method ◽  
Inhibitory Effect ◽  
Reagent Concentration ◽  
Inhibition Kinetic ◽  
Kinetic Spectrophotometric

Anew sensitive kinetic method has been developed for the determination of trace amounts of phenylhydrazine in the range of 1.08x10-7 to 1.08x10-6 g/cm3. The detection limit of this method is 0.008 ?g/cm3, based on the 3Sb criterion. Themethod is based on the inhibitory effect of phenylhydrazine on the oxidation of Victoria Blue 4-R by KBrO3. The reaction was monitored spectrophotometrically at 596.3 nm. The method development includes the optimization of the reagent concentration and temperature. The kinetic parameters of the reaction are reported and a rate equation is suggested. The effects of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. The new developed method was found to have fairly good selectivity, sensitivity, simplicity and rapidity.

scholarly journals Thionine-Bromate as a New Reaction System for Kinetic Spectrophotometric Determination of Hydrazine in Cooling Tower Water Samples

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Masoud Reza Shishehbore ◽  
Ali Sheibani ◽  
Masoumeh Eslami
Keyword(s):  
Water Samples ◽  
Kinetic Method ◽  
Reaction System ◽  
Fixed Time ◽  
Inhibitory Effect ◽  
Optimum Conditions ◽  
Acid Media ◽  
Relative Standard ◽  
Kinetic Spectrophotometric

A simple, selective, and inexpensive kinetic method was developed for the determination of hydrazine based on its inhibitory effect on the thionine-bromate system in sulfuric acid media. The reaction was monitored spectrophotometrically at 601 nm by a fixed time method. The effect of different parameters such as concentration of reactants, ionic strength, temperature, and time on the rate of reaction was investigated, and the optimum conditions were obtained. Under optimum conditions, the calibration curve was linear in the concentration range from 0.8–23.0 μg mL−1of hydrazine, and the detection limit of the method was 0.22 μg mL−1. The relative standard deviation for five replicate determinations of 1.0 μg mL−1of hydrazine was 0.74%. The potential of interfering effect of foreign species on the hydrazine determination was studied. The proposed method was successfully applied for the determination of hydrazine in different water samples.

scholarly journals Micro-level Estimation of Methionine Using Inhibitory Kinetic Spectrophotometric Method

2020 ◽  
Vol 11 (3) ◽  
pp. 10654-10663
Keyword(s):  
Quantitative Estimation ◽  
Bioactive Molecules ◽  
Stable Complex ◽  
Kinetic Measurements ◽  
Kinetic Determination ◽  
Mechanism Of Inhibition ◽  
Optimum Reaction ◽  
Amino Acid Methionine ◽  
Micro Level ◽  
Kinetic Spectrophotometric

A large number of bioactive molecules and drugs contain sulfur as an important constituent. Organo-sulfur compounds form a stable complex with Hg2+, thereby inhibiting its catalytic activity. The Hg2+ catalyzed the exchange rate of cyanide with nitroso-R-salt [N-R-salt] from [Ru(CN)6]4- will be reduced by the addition of sulfur-containing amino acid, methionine (MET). This inhibitory property of MET can be employed for its micro-level kinetic determination. Optimum reaction condition viz. I=0.05 M (KNO3), pH = 7.0 ± 0.02, [Ru(CN)64] = 5.25 × 10-5 M, [N-R-salt] = 6.5 × 10-4 M, [Hg+2] = 5.5 × 10-5 M, and Temperature = 45.0 ± 0.1 o C were utilized to investigate the kinetic measurements at 525 nm (λmax of [Ru(CN)5 N-R-salt]3- complex). To explain the mechanism of inhibition caused by methionine on Hg2+ catalyzed exchange of cyanide with N-R-salt from [Ru(CN)6]4-, a modified mechanistic scheme has been proposed. MET can be quantitatively determined up to 2.5 × 10-6 M level by the proposed analytical method. The methodology can be economically and effectively employed for the quantitative estimation of MET in distinct samples.

scholarly journals Development of a kinetic spectrophotometric method for insecticide diflubenzuron determination in water and baby food samples

2018 ◽  
Vol 72 (5) ◽  
pp. 305-314 ◽  
Author(s):  
Emilija Pecev-Marinkovic ◽  
Zora Grahovac ◽  
Aleksandra Pavlovic ◽  
Snezana Tosic ◽  
Ivana Rasic-Misic ◽  
...  
Keyword(s):  
Spectrophotometric Method ◽  
Solid Phase ◽  
Kinetic Method ◽  
Inhibitory Effect ◽  
Food Samples ◽  
Hplc Method ◽  
Baby Food ◽  
Relative Standard ◽  
Concentration Interval ◽  
Kinetic Spectrophotometric

A kinetic spectrophotometric method for determining residues of insecticide diflubenzuron 1(4-chlorphenyl)-3-(2,6-diflubenzoyl)urea (DFB) has been developed and validated. Kinetic method was based on the inhibitory effect of DFB on the oxidation reaction of sulfanilic acid (SA) by hydrogen peroxide in the presence of Co2+ ions in a phosphate buffer, which was monitored at 370 nm. DFB can be measured in the concentration interval 0.102 ? 3.40 ?g mL-1 and 3.40 ? 23.80 ?g mL-1. The detection and quantification limits of the method were calculated according to the 3? criteria and found to be 0.077 ?g mL-1 and 0.254 ?g Ml-1, respectively. The relative standard deviations for five replicate determinations of 0.102, 1.70 and 3.40 ?g mL-1 DFB were 2.08, 1.22 and 1.21 %, respectively, for the first concentration interval, and the recovery percentage values were from 94.12 to 97.35 %. HPLC method was used as a parallel method to verify results of the kinetic method. The kinetic method was successfully applied to determine diflubenzuron concentrations in spiked water and baby food samples after solid phase extraction of the samples. The F and t values at 95% confidence level are lower than the theoretical ones, confirming agreement of the developed and the HPLC method.

scholarly journals Kinetic spectrophotometric determination of Bi(III) based on its catalytic effect on the oxidation of phenylfluorone by hydrogen peroxide

2009 ◽  
Vol 74 (8-9) ◽  
pp. 977-984
Author(s):  
Sofija Rancic ◽  
Snezana Nikolic-Mandic
Keyword(s):  
Hydrogen Peroxide ◽  
Spectrophotometric Determination ◽  
Reaction Rate ◽  
Catalytic Effect ◽  
Limit Of Detection ◽  
Kinetic Method ◽  
Limit Of Quantification ◽  
Kinetic Spectrophotometric ◽  
Good Agreement

A new reaction was suggested and a new kinetic method was elaborated for determination of Bi(III) in solution, based on its catalytic effect on the oxidation of phenyl-fluorone (PF) by hydrogen peroxide in ammonia buffer. By application of spectrophotometric technique, a limit of quantification (LQ) of 128 ng cm-3 was reached, and the limit of detection (LD) of 37 ng cm-3 was obtained, where LQ was defined as the ratio signal: noise = 10:1 and LD was defined as signal 3:1 against the blank. The RSD value was found to be in the range 2.8-4.8 % for the investigated concentration range of Bi(III). The influence of some ions upon the reaction rate was tested. The method was confirmed by determining Bi(III) in a stomach ulcer drug ('Bicit HP', Hemofarm A.D.). The obtained results were compared to those obtained by AAS and good agreement of results was obtained.

scholarly journals Kinetic Spectrophotometric Determination of Gemifloxacin Mesylate and Moxifloxacin Hydrochloride in Pharmaceutical Preparations Using 4-Chloro-7-nitrobenzo-2-oxa-1,3-diazole

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Mohammed G. Abdel Wahed ◽  
Ragaa El Sheikh ◽  
Ayman A. Gouda ◽  
Sayed Abou Taleb
Keyword(s):  
Limit Of Detection ◽  
Kinetic Method ◽  
Pharmaceutical Preparations ◽  
Fixed Time ◽  
Spectrophotometric Methods ◽  
Relative Standard ◽  
Significant Difference ◽  
Kinetic Spectrophotometric ◽  
Comparison Of The Results

Simple, sensitive, and accurate kinetic spectrophotometric method was proposed for the determination of gemifloxacin mesylate (GMF) and moxifloxacin hydrochloride (MOX) in pure forms and pharmaceutical preparations (tablets). The method is based on coupling the studied drugs with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in the presence of alkaline borate buffer. Spectrophotometric measurement was achieved by recording the absorbance at 466 and 464 nm for GMF and MOX, respectively, after a fixed time of 20 and 15 min on a water bath adjusted at 70 ± 5°C for both drugs. The different experimental parameters affecting the development and stability of the color were carefully studied and optimized. The absorbance-concentration plots were linear over the ranges 0.5–8.0 and 2.0–12 μg mL−1for GMF and MOX, respectively. The limit of detection of the kinetic method was about 0.12 (2.47 × 10−7 M) and 0.36 (8.22 × 10−7 M) μg mL−1for GMF and MOX, respectively. The proposed methods have been applied and validated successfully with percentage relative standard deviation (RSD% ≤ 0.52) as precision and percentage relative error (RE% ≤ 1.33) as accuracy. The robustness of the proposed method was examined with recovery values that were 97.5–100.5 ± 1.3–1.9%. Statistical comparison of the results with the reference spectrophotometric methods shows excellent agreement and indicates no significant difference in accuracy or precision.

Reference Flow Injection Analysis of Trace Amounts of Tannin with Inhibited Kinetic Spectrophotometric Detection

2013 ◽  
Vol 838-841 ◽  
pp. 2455-2460
Author(s):  
Lan Yu
Keyword(s):  
Flow Injection ◽  
Inhibitory Effect ◽  
Enhanced Sensitivity ◽  
Response Range ◽  
Reference Flow ◽  
Highly Sensitive ◽  
Relative Standard ◽  
Kinetic Spectrophotometric ◽  
Sulphuric Acid Medium

A simple and highly sensitive reference flow injection inhibited kinetic spectrophotometric method is proposed for the determination of trace tannin in tea and wine samples. The method was based on the enhanced sensitivity of cetylpyridinium bromide on the redox reaction between Eosine Y and KBrO3, and on inhibitory effect of tannin on the same reaction in the sulphuric acid medium. The resulting red complex product was stable in sulphuric acidic medium and has a maximum absorption at 540 nm. The linear response range and detection limit are 0.010-0.45 mg L-1and 4.82μg L-1respectively. The sampling frequency was 20 samples per hour. The relative standard deviation for 11 determinations of 0.10mg L-1tannin acid was 1.78% and values of recovery in the rang of 96.7%-107.3%.The proposed method has been successfully used to determine tannin in tea and wine samples. The results obtained were compared with those provided by the FolinDenis method.

scholarly journals Kinetic Spectrophotometric Method for the Determination of Ranitidine and Nizatidine in Pharmaceuticals

2002 ◽  
Vol 85 (6) ◽  
pp. 1316-1323 ◽  
Author(s):  
Mohamed I Walash ◽  
Fathalla Belal ◽  
Fawzia Ibrahim ◽  
Mohamed Hefnawy ◽  
Manal Eid
Keyword(s):  
Spectrophotometric Method ◽  
Reaction Pathway ◽  
Kinetic Method ◽  
Fixed Time ◽  
Borate Buffer ◽  
The Other ◽  
Average Recovery ◽  
Kinetic Spectrophotometric ◽  
Good Agreement

Abstract An accurate and simple kinetic method is described for the determination of ranitidine and nizatidine in pure form and in pharmaceuticals. The method is based on the reaction of the compounds with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole in pH 7.4 borate buffer at 60°C for a fixed time of 25 min for both compounds. The absorbance of the reaction product is measured at 495 nm for ranitidine and nizatidine. Calibration graphs were linear over the concentration range of 2–20 μg/mL, with limits of detection of 0.13 (3.7 × 10−7M) and 0.25 μg/mL (7.5 × 10−7M) for ranitidine and nizatidine, respectively. The proposed method was applied successfully to the determination of ranitidine in tablets and ampoules with average recoveries of 100.26 ± 0.69 and 100.29 ± 0.59%, respectively, and to the determination of nizatidine in capsules with an average recovery of 104.26 ± 0.44%. The results obtained are in good agreement with those obtained by the other methods used for comparison. A proposal of the reaction pathway is also presented.

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