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Spectrophotometric determination of nitrite based on its catalytic effect on the reaction of nuclear fast red and potassium bromate
HASSAN ZAVVAR MOUSAVI,HAMID SHIRKHANLOO
Journal of the Serbian Chemical Society , 2009,
Abstract: A highly selective and sensitive catalytic spectrophotometric method was developed for the determination of nitrite in water samples. The method is based on its catalytic effect on the nuclear fast red–potassium bromate redox reaction in acidic medium. The reaction was followed spectrophotometrically by measuring the change in the absorbance at 518 nm of nuclear fast red 5 min after initiation of the reaction. In this study, the experimental parameters were optimized and the effects of other cations and anions on the determination of nitrite were examined. The calibration graph was linear in the range 2.0–45 μg mL-1 of nitrite. The relative standard deviations for the determination of 15 and 30 μg mL-1 of nitrite were 3.1 and 1.75 %, respectively (n = 8). The detection limit calculated from three times the standard deviation of the blank 3Sb was 0.7 μg mL-1. The method was successfully applied to the determination of nitrite in spiked tap, natural and wastewater samples.
CATALYTIC KINETIC SPECTROPHOTOMETRIC DETERMINATION OF TRACE TITANIUM BASED ON TITANIUM(IV)-(DBS-ARSENAZO)-POTASSIUM BROMATE SYSTEM
Qing-Zhou Zhai
Bulletin of the Chemical Society of Ethiopia , 2007,
Abstract: Based on the property that in 0.12 M sulfuric acid medium titanium(IV) catalyzes the discoloring reaction of DBS-arsenazo oxidized by potassium bromate, a new catalytic kinetic spectrophotometric method for the determination of trace titanium (IV) was developed. The linear range of the determination of titanium is 0-2.4 μg/25 mL. The detection limit of the method is 0.47 ng/mL. The effects of fifty coexisting substances were studied and most of common substances do not interfere with the determination of titanium. The method has good selectivity. The present method was used in the determination of trace amount of titanium in cabbage and potato samples with satisfactory results. The relative standard deviations of ten replicate determinations of the method are 1.4-1.5 % and the recoveries of standard addition are 97.6-98.0 %, respectively. KEY WORDS: Titanium(IV), Catalytic kinetic spectrophotometry, DBS-Arsenazo, Potassium bromate, Cabbage, Potato Bull. Chem. Soc. Ethiop. 2007, 21(3), 451-456.
Catalytic kinetic spectrophotometric determination of trace titanium based on titanium(IV)-(DBS-arsenazo)-potassium bromate system  [cached]
Qing-Zhou Zhai
Bulletin of the Chemical Society of Ethiopia , 2007,
Abstract: Based on the property that in 0.12 M sulfuric acid medium titanium(IV) catalyzes the discoloring reaction of DBS-arsenazo oxidized by potassium bromate, a new catalytic kinetic spectrophotometric method for the determination of trace titanium (IV) was developed. The linear range of the determination of titanium is 0-2.4 μg/25 mL. The detection limit of the method is 0.47 ng/mL. The effects of fifty coexisting substances were studied and most of common substances do not interfere with the determination of titanium. The method has good selectivity. The present method was used in the determination of trace amount of titanium in cabbage and potato samples with satisfactory results. The relative standard deviations of ten replicate determinations of the method are 1.4-1.5 % and the recoveries of standard addition are 97.6-98.0 %, respectively.
Spectrophotometeric determination of bromate in bread by the oxidation of dyes
EO Ojeka, MC Obidiaku, C Enukorah
Journal of Applied Sciences and Environmental Management , 2006,
Abstract: A spectrophotometric method for the determination of bromate based on the oxidation of congo red and crystal violet dyes in a hydrochloric acid medium is described. The bromate level in bread samples determined range from 3.70 μg g-1 to 12.10 μg g-1; with limits of quantification of 0.45 – 0.78 μg g-1. Results show the presence of detectable residue levels of potassium bromate in all the bread samples analysed and the results compare favourably with established AOAC method. Journal of Applied Sciences and Environmental Management Vol. 10 (3) 2006: 43-46
Kinetic Spectrophotometric Method for Trace Amounts Determination of Bromide in Pharmaceutical Samples Using Janus Green-Bromate System
Masoud Reza Shishehbore,Roohollah Jokar
International Journal of Industrial Chemistry , 2011,
Abstract: A new simple and rapid kinetic spectrophotometric method has been developed to trace amounts determination of bromide. This method is based on the catalytic effect of bromide on the reaction between Janus Green and bromate in sulfuric acid media. The reaction was followed spectrophotometrically by measuring the absorbance at 618 nm. The fixed-time method was used for the first 210 s. The influence of reagents concentration, temperature and time on the sensitivity was studied. Under optimum experimental conditions, bromide can be determined in the range of 10.0-1800.0 μg/L. The relative standard deviations (n = 10) were 0.22 and 0.19% for 100.0 and 1000.0 g/L of bromide, respectively. The detection limit of the proposed method was 4.1 μg/L. The influence of potential interfering of some ions and biological species on the selectivity was studied. The proposed method was successfully applied for the determination of bromide in pharmaceutical samples. The new developed method was found to have fairly good selectivity, sensitivity, simplicity and rapidity.
Catalytic Spectrophotometric Method for Determination of Formaldehyde Based on its Catalytic Effect on the ReactionBetween Bromate and Safranin  [PDF]
Mohsen Keyvanfard
Journal of Chemistry , 2010, DOI: 10.1155/2010/948018
Abstract:
Sensitive and rapid titrimetric and spectrophotometric methods for the determination of stavudine in pharmaceuticals using bromate-bromide and three dyes
Basavaiah, Kanakapura;Ramakrishna, Veeraiah;Somashekar, Chikkaswamy;Kumar, Urdigere R. Anil;
Anais da Academia Brasileira de Ciências , 2008, DOI: 10.1590/S0001-37652008000200003
Abstract: four sensitive and rapid methods for the determination of stavudine (stv) in bulk drug and in dosage forms were developed and optimized. in titrimetry, aqueous solution of stv was treated with a known excess of bromate-bromide in hcl medium followed by estimation of unreacted bromine by iodometric back titration. spectrophotometric methods involve the addition of a measured excess of bromate-bromide in hcl medium and subsequent estimation of the residual bromine by reacting with a fixed amount of methyl orange, indigocarmine or thymol blue followed by measurement of absorbance at 520 nm (method a), 610 nm (method b) or 550 nm (method c). in all the methods, the amount of bromate reacted corresponds to the amount of stv. calculations in titrimetry were based on a 1:0.666 (stv:kbro3) stoichiometry and the method was found to be applicable over 3.5-10 mg range. a linear increase in absorbance with concentration of stv was observed in the spectrophotometric methods, and the beer's law was obeyed over the concentration ranges 0.125-1.75, 1-10 and 1-9.0 μg ml-1 stv for method a, method b and method c, respectively. the methods when applied to the determination of stv in tablets and capsules were found to give satisfactory results.
Titrimetric and spectrophotometric determination of doxycycline hyclate using bromate-bromide, methyl orange and indigo carmine  [PDF]
Pavagada Jagannathamurthy Ramesh,Kanakapura Basavaiah,Mysore Ranganath Divya,Nagaraju Rajendraprasad
Chemical Industry and Chemical Engineering Quarterly , 2010,
Abstract: One titrimetric and two indirect spectrophotometric methods are described for the determination of doxycycline hyclate (DCH) in bulk drug and in its formulations. The methods use bromate-bromide, methyl orange and indigo carmine as reagents. In titrimetry (method A), DCH is treated with a known excess of bromate- -bromide mixture in acid medium and the residual bromine is back titrated iodometrically after the reaction between DCH and in situ bromine is ensured to be complete. In spectrophotometric methods, the excess of bromine is estimated by treating with a fixed amount of either methyl orange (method B) or indigo carmine (method C) and measuring the change in absorbance either at 520 or 610 nm. Titrimetric method is applicable over 1-8 mg range and the calculations are based on a 1:2 (DCH:bromate) stoichiometric ratio. In spectrophotometry, the calibration graphs were found to be linear over 0.25-1.25 and 1.0-5.0 μg mL-1 for method B and C, respectively, with corresponding molar absorptivity values of 2.62×105 and 6.97×104 L mol-1 cm-1. The accuracy and precision of the assays were determined by computing the intra-day and inter-day variations at three different levels of DCH.
A new system for the spectrophotometric determination of trace amounts of nitrite in environmental samples
Cherian, Tom;Narayana, Badiadka;
Journal of the Brazilian Chemical Society , 2006, DOI: 10.1590/S0103-50532006000300022
Abstract: a selective and rapid spectrophotometric method for the determination of nitrite is presented. it is based on the reaction of nitrite with p-nitroaniline in acid medium to form diazonium ion, which is coupled with ethoxyethylenemaleic ester or ethylcyanoacetate in basic medium to form azo dyes, showing absorption maxima at 439 and 465 nm respectively. the method obeys beer's law in the concentration range of 0.5-16 μg ml-1 of nitrite with ethoxyethylenemaleic ester and 0.2-18 μg ml-1 of nitrite with ethylcyanoacetate. the molar absorptivity and sandell's sensitivity of p-nitroaniline-ethoxyethylenemaleic ester and p-nitroaniline-ethylcyanoacetate azo dyes are 5.04 x 104 l mol-1cm-1, 0.98 x 10-2 μg cm-2 and 1.21 x 104 l mol-1 cm-1, 0.98 x 10-2 μg cm-2 respectively. the optimum reaction conditions and other analytical parameters were evaluated. the method was successfully applied to the determination of nitrite in various water samples and soil samples.
A new system for the spectrophotometric determination of trace amounts of nitrite in environmental samples  [cached]
Cherian Tom,Narayana Badiadka
Journal of the Brazilian Chemical Society , 2006,
Abstract: A selective and rapid spectrophotometric method for the determination of nitrite is presented. It is based on the reaction of nitrite with p-nitroaniline in acid medium to form diazonium ion, which is coupled with ethoxyethylenemaleic ester or ethylcyanoacetate in basic medium to form azo dyes, showing absorption maxima at 439 and 465 nm respectively. The method obeys Beer's law in the concentration range of 0.5-16 μg mL-1 of nitrite with ethoxyethylenemaleic ester and 0.2-18 μg mL-1 of nitrite with ethylcyanoacetate. The molar absorptivity and Sandell's sensitivity of p-nitroaniline-ethoxyethylenemaleic ester and p-nitroaniline-ethylcyanoacetate azo dyes are 5.04 X 10(4) L mol-1cm-1, 0.98 X 10-2 μg cm-2 and 1.21 X 10(4) L mol-1 cm-1, 0.98 X 10-2 μg cm-2 respectively. The optimum reaction conditions and other analytical parameters were evaluated. The method was successfully applied to the determination of nitrite in various water samples and soil samples.
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