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Copper and Mercury in Food, Biological and Pharmaceutical Samples: Spectrophotometric Estimation as Cu(DDTC)2  [PDF]
Mohammad Nasir Uddin, Nur Mostaq Shah, Mohammad Amzad Hossain, Md. Muzahidul Islam
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.513093
Abstract: An alternative spectrophotometric method was optimized and validated for the estimation of mercury using diethyldithiocarbamate (DDTC), a common reagent, widely used for the preconcentration and isolation of metal ions in complex matrices followed by their estimation by varied techniques. Diethyldithiocarbamate forms yellow Cu(DDTC)2 with copper and white Hg(DDTC)2 with mercury (having d10 system) which are extracted in CCl4. The UV-visible spectrum of Cu(DDTC)2 is very stable at pH 5.0 and has a maximum absorption (λmax) at 435 nm. Hg(DDTC)2 is more stable than Cu(DDTC)2. Estimation of mercury is based on a quantitative displacement of Cu(II) of Cu(DDTC)2 with the addition of mercury followed by the measurement of reduced absorbance. Primarily, method was optimized and validated for the estimation of copper. Therefore, simultaneous determination of Cu(II) and Hg(II) in mixture is proposed fractionating the extract. The molar specific coefficient (ε) for the mercury was 1.4 × 104 mol﹣1·L·cm﹣1 and for copper was 3.16 × 105 mol﹣1·L·cm﹣1 at 435 nm. The detection limits of Cu2+ and Hg2+ were 0.023 μg·mL﹣1 and 0.029 μg·mL﹣1, respectively. The calibration curve shows good linearity of 0.02 - 12.0 and 0.02 - 15.0 μg·mL﹣1 for the Cu2+ and Hg2+ determination, respectively. Proposed technique was applied to food, biological and pharmaceutical samples for the determination of Cu(II) and Hg(II).
Spectrophotometric determination of gatifloxacin in pharmaceutical formulations and biological samples  [cached]
Sivasubramanian Lakshmi,Muthukumaran A
Indian Journal of Pharmaceutical Sciences , 2006,
Abstract: Three new simple and sensitive spectrophotometric methods in ultraviolet region have been developed for the determination of gatifloxacin in bulk drug, pharmaceutical preparations and biological samples. Gatifloxacin exhibited maximum absorbance at 289 nm (method A) with apparent molar absorptivity of 1.23x10 4 l/molxcm when dissolved in sodium hydroxide; and maximum absorbance at 292 nm (method B) with apparent molar absorptivity of 1.71x10 4 l/molxcm when dissolved in hydrochloric acid. Third developed method (method C) was based on the formation of yellow coloured chromogen with ferric chloride and potassium dichromate, which showed maximum absorbance at 352 nm with apparent molar absorptivity of 1.23 x 10 4 l/molxcm. Beer′s law was obeyed in the concentration range of 5-30 μg/ml. Results of analysis of all methods were validated statistically and by recovery studies.
A rapid spectrophotometric method for the determination of mercury in environmental, biological, soil and plant samples using diphenylthiocarbazone  [PDF]
M. Jamaluddin Ahmed,Md. Shah Alam
Spectroscopy: An International Journal , 2003, DOI: 10.1155/2003/250927
Abstract: A simple, sensitive and highly selective direct spectrophotometric method for the determination of trace levels of mercury(II) in various samples is described. Diphenylthiocarbazone (dithizone) reacts in slightly acidic 50% aqueous 1,4-dioxane media (0.18–1.80 M sulphuric acid) with mercury(II) to give an orange chelate which has an absorption maximum at 488 nm. The average molar absorption co-efficient and Sandell's sensitivity were found to be 2.5×104l?mol−1?cm−1 and 0.015 μg of Hg(II) cm−2, respectively. The reaction is immediate and absorbance remains stable for over 24 h. Beer's law is obeyed for concentration range of mercury(II) between 0.1 μg?ml−1 and 25 μg?ml−1; the stoichiometric composition of the chelate is 1?:2 (mercury?:?dithizone). The various analytical parameters, such as effect of time, acidity, reagent concentration and foreign species, were studied. The method was applied successfully to a number of environmental waters (portable and polluted), biological samples (human blood, urine and fish), soils, plant samples (potato, cabbage, lettuce, carrot and tomato), solutions containing both mercury(I) and mercury(II) and complex synthetic mixtures. The method is very simple and requires no solvent extraction or pre-concentration steps.
Development of an Extractive Spectrophotometric Method for the Determination of Copper(II) in Leafy Vegetable and Pharmaceutical Samples Using 2–acetylpyridine 4–phenyl –3-thiosemicarbazone (APPT)
RD Nagarjuna, RK Vasudeva
Momona Ethiopian Journal of Science , 2012,
Abstract: A highly sensitive extractive spectrophotometric method has been developed for the determination of copper(II) using 2-acetylpyridine-4-phenyl-3-thiosemicarbazone as an analytical reagent. The APPT forms reddish brown complex of copper(II) at a pH range of 3.0-5.5, and the complex was extracted into n-butanol. The Cu(II)-APPT complex shows maximum absorbance at 440 nm, with molar absorptivity and Sandell’s sensitivity being 2.16 x 104 L mol-1cm-1 and 2.94 x 10-3μg cm-2, respectively. The system obeys Beer’s law in the range of 0.2-5.0 mg/L. The regression coefficient of the Beer’s law straight line is 0.338, and the correlation coefficient is 0.96. The detection limit of the method is 0.0065 μg mL-1. Most of the common metal ions generally found associated with copper do not interfere. The repeatability of the method was checked by finding the relative standard deviation. The developed method has been successfully employed for the determination of copper (II) in leafy vegetable and pharmaceutical samples. The method is evaluated by analyzing samples from the Bureau of Analyzed Samples (BCS 233, 266, 216/1, 207, and 179) and by inter-comparison of experimental values using AAS.
A Sensitive Spectrophotometric Method for the Determination of Pregabalin in Bulk, Pharmaceutical Formulations and in Human Urine Samples  [cached]
Rajinder Singh Gujral,Sk Manirul Haque,Prem Shanker
International Journal of Biomedical Science , 2009,
Abstract: A simple and sensitive spectrophotometric method was developed and validated for the determination of pregabalin in bulk, pharmaceutical formulations and in human urine samples. The method was based on the reaction of drug with the mixture of potassium iodate and potassium iodide. The method was linear in the range of 0.5-3.5 μg/ml. There is no official method for the determination of pregabalin. The absorbance was measured at 353 nm. The method was validated with respect to accuracy, precision, specificity, ruggedness, robustness, limit of detection and limit of quantitation. This method was used successfully for the quality assessment of five pregabalin drug products and in human urine samples with good precision and accuracy.
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.
DIRECT ORTHOGONAL SIGNAL CORRECTION-PARTIAL LEAST SQUARES FOR SIMULTANEOUS SPECTROPHOTOMETRIC DETERMINATION OF SULFAMETHOXAZOLE AND TRIMETHOPRIM IN PHARMACEUTICAL FORMULATION AND SYNTHETIC SAMPLES
GOODARZI,MOHAMMAD; SHAHBAZIKHAH,PARVIZ; REZA SOHRABI,MAHMOUD; FATHABADI,MOZHGAN; HASSAN NOURI,SAREZOO;
Journal of the Chilean Chemical Society , 2009, DOI: 10.4067/S0717-97072009000300022
Abstract: this work describes a very simple, novel and selective spectrophotmetric method for simultaneous determination of sulfamethoxazole and trimethoprim in pharmaceutical preparation and synthetics samples using direct orthogonal signal correction-partial least squares (dosc-pls). the all factors affecting on the sensitivity were optimized and the linear dynamic range for determining of these drugs was found. the pls modeling was used for the multivariate calibration of the spectrophotometric data and dosc was used for preprocessing of data matrices and the prediction results of model. the experimental calibration matrix was designed by measuring the absorbance over the range 200-400 nm for 32 samples of 2.0-15.0 and 0.4-6.0 μg ml-1 of sulfamethoxazole and trimethoprim, respectively. the root mean square error of prediction for sulfamethoxazole and trimethoprim using dosc-pls and pls were 0.02212, 0.02363 and 0.17014, 0.01660, μg ml-1 respectively. application of the method to synthetic samples of standard solutions and in pharmaceutical formulation was performed and satisfactory results were obtained.
DIRECT ORTHOGONAL SIGNAL CORRECTION-PARTIAL LEAST SQUARES FOR SIMULTANEOUS SPECTROPHOTOMETRIC DETERMINATION OF SULFAMETHOXAZOLE AND TRIMETHOPRIM IN PHARMACEUTICAL FORMULATION AND SYNTHETIC SAMPLES  [cached]
MOHAMMAD GOODARZI,PARVIZ SHAHBAZIKHAH,MAHMOUD REZA SOHRABI,MOZHGAN FATHABADI
Journal of the Chilean Chemical Society , 2009,
Abstract: This work describes a very simple, novel and selective spectrophotmetric method for simultaneous determination of sulfamethoxazole and trimethoprim in pharmaceutical preparation and synthetics samples using direct orthogonal signal correction-partial least squares (DOSC-PLS). The all factors affecting on the sensitivity were optimized and the linear dynamic range for determining of these drugs was found. The PLS modeling was used for the multivariate calibration of the spectrophotometric data and DOSC was used for preprocessing of data matrices and the prediction results of model. The experimental calibration matrix was designed by measuring the absorbance over the range 200-400 nm for 32 samples of 2.0-15.0 and 0.4-6.0 μg mL-1 of sulfamethoxazole and trimethoprim, respectively. The root mean square error of prediction for sulfamethoxazole and trimethoprim using DOSC-PLS and PLS were 0.02212, 0.02363 and 0.17014, 0.01660, μg mL-1 respectively. Application of the method to synthetic samples of standard solutions and in pharmaceutical formulation was performed and satisfactory results were obtained.
Two Spectrophotometric Assays for Dopamine Derivatives in Pharmaceutical Products and in Biological Samples of Schizophrenic Patients Using Copper Tetramine Complex and Tri-iodide Reagent
F. A. Nour El-Dien,M. A. Zayed,Gehad. G. Mohamed,Reham G. El-Nahas
Journal of Biomedicine and Biotechnology , 2005, DOI: 10.1155/jbb.2005.1
Abstract: Two simple, rapid, and sensitive spectrophotometric methods are proposed for the determination of levodopa (LD). The first method is based on coupling of 4-aminoantipyrine (4-AAP) with one of the dopamine derivatives (LD, CD) to give a new ligand that reacts with copper tetramine complex to give intensely colored chelates. The colored products are quantified spectrophotometrically at 525 and 520 nm for LD and CD, respectively. The optimization of the experimental conditions is described. The method has been used for the determination of 19.7–69.0 and 18.1–54.3μg mL−1 of LD and CD, respectively. The accuracy of the method is achieved by the values of recovery (100±0.2%) and the precision is supported by the low standard deviation (SD =0.17–0.59) and relative standard deviation (CV =0.4%–1.54%) values. The second method is based on the formation of ion-pair iodinated inner sphere or outer sphere colored complexes between the LD and triiodide ions at pH 5 and room temperature (23±3°C). This method has been used for the determination of LD within the concentration range 39.44–78.88μg mL−1 with SD =0.22–0.24 and recovery percent =100±0.3%. The sensitivity of the two methods is indicated by Sandell's sensitivity of 0.014–0.019 g cm−2. The results of the two methods are compared with those of the official method. The interference of common drug additives, degradation products, and excipients was also studied. The proposed methods were applied successfully to the determination of the LD-CD synthetic mixture and Levocare drug. The determination of LD in urine of some schizophrenic patients was applied with good precision and accuracy. The reliability of the methods was established by parallel determinations against the official British pharmacopoeia method.
Two Spectrophotometric Assays for Dopamine Derivatives in Pharmaceutical Products and in Biological Samples of Schizophrenic Patients Using Copper Tetramine Complex and Tri-iodide Reagent  [cached]
Nour El-Dien F. A.,Zayed M. A.,Mohamed Gehad. G.,El-Nahas Reham G.
Journal of Biomedicine and Biotechnology , 2005,
Abstract: Two simple, rapid, and sensitive spectrophotometric methods are proposed for the determination of levodopa (LD). The first method is based on coupling of 4-aminoantipyrine (4-AAP) with one of the dopamine derivatives (LD, CD) to give a new ligand that reacts with copper tetramine complex to give intensely colored chelates. The colored products are quantified spectrophotometrically at 525 and 520 nm for LD and CD, respectively. The optimization of the experimental conditions is described. The method has been used for the determination of 19.7 –69.0 and 18.1 –54.3 μ g mL 1 of LD and CD, respectively. The accuracy of the method is achieved by the values of recovery (100 ± 0.2 %) and the precision is supported by the low standard deviation (SD = 0.17 –0.59 ) and relative standard deviation (CV = 0.4 %–1.54 %) values. The second method is based on the formation of ion-pair iodinated inner sphere or outer sphere colored complexes between the LD and triiodide ions at pH 5 and room temperature (23 ± 3 ° C). This method has been used for the determination of LD within the concentration range 39.44 –78.88 μ g mL 1 with SD = 0.22 –0.24 and recovery percent = 100 ± 0.3 %. The sensitivity of the two methods is indicated by Sandell's sensitivity of 0.014 –0.019 g cm 2 . The results of the two methods are compared with those of the official method. The interference of common drug additives, degradation products, and excipients was also studied. The proposed methods were applied successfully to the determination of the LD-CD synthetic mixture and Levocare drug. The determination of LD in urine of some schizophrenic patients was applied with good precision and accuracy. The reliability of the methods was established by parallel determinations against the official British pharmacopoeia method.
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