scholarly journals A rapid spectrophotometric method for the determination of mercury in environmental, biological, soil and plant samples using diphenylthiocarbazone

2003 ◽  
Vol 17 (1) ◽  
pp. 45-52 ◽  
Author(s):  
M. Jamaluddin Ahmed ◽  
Md. Shah Alam
Keyword(s):  
Solvent Extraction ◽  
Human Blood ◽  
Spectrophotometric Method ◽  
Absorption Maximum ◽  
Stoichiometric Composition ◽  
Reagent Concentration ◽  
Environmental Waters ◽  
Plant Samples ◽  
Foreign Species

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−1and 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−1and 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.

scholarly journals A highly sensitive and selective spectrophotometric method for the determination of vanadium at nanotrace levels in some environmental, biological, soil, food, and pharmaceutical samples using salicylaldehyde-benzoylhydrazone

2020 ◽  
Vol 11 (4) ◽  
pp. 385-395
Author(s):  
Shaifa Abrarin ◽  
Mohammed Jamaluddin Ahmed
Keyword(s):  
Spectrophotometric Method ◽  
Biological Fluids ◽  
Stoichiometric Composition ◽  
Standard Reference Materials ◽  
Complexing Agents ◽  
Environmental Waters ◽  
Pharmaceutical Samples ◽  
Highly Sensitive ◽  
Interference Study

A very simple, non-extractive and new spectrophotometric method for the swift determination of trace amount of vanadium using salicylaldehyde-benzoylhydrazone (Sal-BH) has been developed. Sal-BH undergoes a reaction in a slightly acidic solution (0.0016-0.0032 M H2S04) with vanadium to give a light greenish-yellow chelate, which has an absorption maximum at 392 nm. The reaction is instantaneous and absorbance remains stable for over 24 hrs. The average molar absorption co-efficient and Sandell’s sensitivity were found to be 2.5039×105 L/mol.cm and 1.0 ng/cm2 V, respectively. Beer’s law was obeyed for 0.001-30 mg/L of V, providing a detection limit of 0.1 µg/L of V and RSD 0-2 %. The stoichiometric composition of the chelate is 1:1 (V:Sal-BH). Interference study shows that a large excess of over 60 cations, anions, and some common complexing agents (such as chloride, azide, tartrate, EDTA and SCN‑, etc.) satisfy the tolerance limit. The developed method was successfully used in the determination of vanadium in several standard reference materials as well as in some environmental waters, biological fluids, soil, food and pharmaceutical samples and solutions containing both vanadium (IV) and vanadium (V). The results of the proposed method for assessing biological, food and vegetable samples were comparable with ICP-OES and AAS were found to be in excellent agreement. The method has high precision and accuracy (s = ±0.01 for 0.5 mg/L).

scholarly journals A highly sensitive and rapid spectrophotometric method for the determination of molybdenum at nano-trace levels in some real, environmental, biological, food and soil samples using salicylaldehyde-benzoylhydrazone

2020 ◽  
Vol 11 (1) ◽  
pp. 37-49 ◽  
Author(s):  
Mohammed Jamaluddin Ahmed ◽  
Ayesha Afrin ◽  
Mohammad Ohi Uddin
Keyword(s):  
Spectrophotometric Method ◽  
Certified Reference Materials ◽  
Stoichiometric Composition ◽  
Bovine Liver ◽  
Soil Samples ◽  
Complexing Agents ◽  
Linear Calibration ◽  
Environmental Waters ◽  
Highly Sensitive

A very simple, sensitive and highly selective non-extractive new spectrophotometric method has been developed for the determination of molybdenum at nano-trace levels using salicylaldehyde-benzoylhydrazone (Sal-BH). The method is based on the reaction of non-absorbent Sal-BH in a slightly acidic solution (0.0025-0.0075 M H2S04) with molybdenum (VI) to give a light yellowish chelate, which has an absorption maximum at 440 nm. The reaction is instantaneous and absorbance remains stable for over 24 h. The average molar absorption coefficient and Sandell’s sensitivity were found to be 4.32×105 L/mol.cm and 5 ng/cm2 of molybdenum, respectively. Linear calibration graphs were obtained for 0.01-60.00 mg/L of molybdenum having detection limit of 1 µg/L and RSD 0.0-2.0 %. The stoichiometric composition of the chelate is 1:1 (Mo:Sal-BH). A large excess of over 60 cations, anions and some common complexing agents (such as chloride, azide, tartrate, EDTA, SCN- etc.) do not interfere in the determination. The method was successfully used in the determination of molybdenum in several Certified Reference Materials (Alloys, steels, water, hair and bovine liver) as well as in some environmental waters (Potable and polluted), biological samples (Human blood, urine, nails, hair, food and vegetables), soil samples, and solutions containing both molybdenum(VI) and molybdenum(V) as well as complex synthetic mixtures. The results of the proposed method for assessing biological, food and vegetables samples were found to be in excellent agreement with those obtained by ICP-OES and AAS. The method has high precision and accuracy (s = ±0.01 for 0.5 mg/L).

scholarly journals A simple spectrophotometric method for the determination of trace level lead in biological samples in the presence of aqueous micellar solutions

2006 ◽  
Vol 20 (5-6) ◽  
pp. 285-297 ◽  
Author(s):  
Humaira Khan ◽  
M. Jamaluddin Ahmed ◽  
M. Iqbal Bhanger
Keyword(s):  
Human Blood ◽  
Spectrophotometric Method ◽  
Biological Samples ◽  
Stoichiometric Composition ◽  
Complexing Agents ◽  
Micellar Solutions ◽  
Trace Level ◽  
Human Blood And Urine ◽  
Aqueous Micellar Solutions

A very simple, ultra-sensitive and fairly selective new spectrophotometric method has been developed for the rapid determination of lead(II) at ultra-trace level using 1,5-diphenylthiocarbazone (dithizone) in presence of aqueous micellar solutions. The proposed method enabled the determination of lead down to µg l−1in human blood and urine in aqueous media without resource of any “clean-up” step. The most remarkable point of this method is that the presence of micellar system avoids the previous steps of solvent extraction and reduces the cost, toxicity while enhancing the sensitivity, selectivity and the molar absorptivity. The complex formation of lead in blood with dithizone was completed within a minute at room temperature and the absorbance remains stable for 24 h. The average molar absorption coefficient and Sandell's sensitivity were found to be 3.99×105l mol−1 cm−1and 30 ng cm−2of Pb, respectively. Linear calibration graphs were obtained for 0.06–60 mg l−1of PbII; the stoichiometric composition of the chelate is 1:2 (Pb:dithizone). The interference from over 60 cations, anions and complexing agents has been studied at 1 mg l−1of PbII. The method was successfully used in the determination of lead in several biological samples (human blood and urine and bovine liver), solution containing both lead(II) and lead(IV) and complex synthetic mixtures. The results of biological analyses by the spectrophotometric method were in excellent agreement with those obtained by AAS. The results of lead concentration in biological samples were varied with age, sex and place which have been discussed.

Spectrophotometric Determination of Alendronate Sodium by using Sodium-1,2-Naphthoquinone-4-Sulphonate

2012 ◽  
Vol 4 (4) ◽  
pp. 1563-1568
Author(s):  
Sagar Suman Panda ◽  
Ravi Kumar B V V ◽  
D Patanaik
Keyword(s):  
Spectrophotometric Method ◽  
Absorption Maximum ◽  
Dosage Form ◽  
Dosage Forms ◽  
Alendronate Sodium ◽  
Colored Complex ◽  
Pharmaceutical Dosage Forms ◽  
Recovery Study ◽  
Assay Conditions

A simple, precise and accurate spectrophotometric method was developed for analysis of the osteoporesis drug alendronate sodium (ALS). The method is based on reaction of the drug with sodium-1,2-naphthoquinone-4-sulphonate (NQS) in presence of alkali to form a brown colored complex giving absorption maximum at 525 nm. The drug obeyed Beer’s law in the range of 5-70 µg/ml with a correlation coefficient of 0.999. The LOD and LOQ values are 1.7 µg/ml and 5.0 µg/ml, respectively. The average recoveries for recovery study were found to be in the range of 99.37%-100.46%. The R.S.D. values for intraday and inter-day precision were found to be 0.48 and 0.62, respectively. The optimized assay conditions were applied successfully for determination of ALS in pharmaceutical dosage forms. No interference was observed from the excipients present in the dosage form. The method is statistically validated as per the ICH requirements.  

scholarly journals A Highly Selective and Sensitive Spectrophotometric Method for the Determination of Lead at Ultra-trace Levels in Some Real, Environmental, Biological, Food and Soil Samples Using 5,7-Dibromo-8-Hydroxyquinoline

2019 ◽  
pp. 1-19
Author(s):  
M. Jamaluddin Ahmed ◽  
M. Tazul Islam ◽  
Sumaira Aziz
Keyword(s):  
Spectrophotometric Method ◽  
Stoichiometric Composition ◽  
Bovine Liver ◽  
Food Samples ◽  
Soil Samples ◽  
Standard Reference Materials ◽  
Complexing Agents ◽  
Linear Calibration ◽  
Ultra Trace

A very simple, ultra-sensitive and highly selective non-extractive spectrophotometric method for the determination of trace amounts of lead using 5,7-dibromo-8-hydroxyquinoline (DBHQ) has been developed. DBHQ reacts in a slightly acidic (0.0006-0.0025 M HCl) aqueous solution with lead (II) in 30% ethanolic media to produce highly absorbent a greenish-yellow chelate which has an absorption maximum at 390 nm. The reaction is instantaneous and the absorbance remains stable for over 24 h. The average molar absorption co-efficient and Sandal’s sensitivity were found to be 6.16 x 105 L mol-1cm-1 and 5 ng cm-2 of lead (II), respectively. Linear calibration graphs were obtained for 0.01- 60.0 mg L-1 of lead (II) having detection limit of 1.0 μg L-1 and RSD 0-2%. The stoichiometric composition of the chelate is 1:2 (Pb: DBHQ). A large excess of over 60 cations, anions and complexing agents (like, chloride, phosphate, azide, tartrate, oxalate, SCN- etc.) do not interfere in the determination. The developed method was successfully used in the determination of lead levels in several Standard Reference Materials (alloys, steels, natural water, bovine liver, human urine and hair) as well as in some environmental waters (potable and polluted), biological samples (human blood, urine and hair), soil samples, food samples (vegetables, rice, wheat) solutions containing both lead (II) and lead (IV) and complex synthetic mixtures. The results of biological and food analyses by the spectrophotometric method were found to be in excellent agreement with those obtained by AAS.

scholarly journals ULTRAVIOLET-SPECTROPHOTOMETRIC METHOD DEVELOPMENT AND VALIDATION FOR THE DETERMINATION OF NORFLOXACIN PRESENT IN TASTE MASKED DRUG RESIN COMPLEX

2018 ◽  
Vol 11 (4) ◽  
pp. 244
Author(s):  
Ayya Rajendra Prasad ◽  
Jayanthi Vijaya Ratna
Keyword(s):  
Spectrophotometric Method ◽  
Absorption Maximum ◽  
Method Development ◽  
Limit Of Detection ◽  
Statistical Parameters ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Validation Parameters ◽  
Development And Validation

 Objective: The objective of this study was developed and validated a novel, specific, precise, and simple ultraviolet (UV)-spectrophotometric method for the estimation of norfloxacin present in taste masked drug-resin complex.Methods: UV-spectrophotometric determination was performed with ELICO SL 1500 UV-visible spectrophotometer using 0.1 N HCl as a medium. The spectrum of the standard solution was run from 200 to 400 nm range for the determination of absorption maximum (λ max). λ max of norfloxacin was found at 278 nm. The absorbance of standard solutions of 1, 2, 3, 4, and 5 μg/ml of drug solution was measured at an absorption maximum at 278 nm against the blank. Then, a graph was plotted by taking concentration on X-axis and absorbance on Y-axis which gave a straight line. Validation parameters such as linearity and range, selectivity and specificity, limit of detection (LOD) and limit of quantification (LOQ), accuracy, precision, and robustness were evaluated as per the International Conference on Harmonization (ICH) guidelines.Results: Linearity for the UV-spectrophotometric method was noted over a concentration range of 1–5 μg/ml with a correlation coefficient of 0.9995. The LOD and LOQ for norfloxacin were found at 0.39 μg/ml and 1.19 μg/ml, respectively. Accuracy was in between 99.00% and 99.17%. % relative standard deviation for repeatability, intraday precision, and interday precision was found to be 0.600, in between 0.291 and 0.410, and in between 0.682 and 1.439, respectively. The proposed UV spectrophotometric method is found to be robust.Conclusion: The proposed UV-spectrophotometric method was validated according to the ICH guidelines, and results and statistical parameters demonstrated that the developed method is sensitive, precise, reliable, and simple for the estimation of norfloxacin present in taste masked drug-resin complex.

scholarly journals Development and validation of a simple spectrophotometric method for the determination of methyldopa in both bulk and marketed dosage formulations

2014 ◽  
Vol 50 (3) ◽  
pp. 573-582 ◽  
Author(s):  
Paulo Roberto da Silva Ribeiro ◽  
Reginária Morais Duarte
Keyword(s):  
Sodium Nitrite ◽  
Spectrophotometric Method ◽  
Confidence Level ◽  
Absorption Maximum ◽  
Pharmaceutical Preparations ◽  
Coefficient Of Determination ◽  
Colored Product ◽  
Development And Validation ◽  
Nitrosation Reaction

A simple, precise, sensitive, rapid, specific and economical spectrophotometric method was developed to determine methyldopa (MTD) content in bulk and pharmaceutical dosage formulations. The proposed method was based on the formation of a colored product from the nitrosation reaction of MTD with sodium nitrite in an acid medium. The resultant nitroso derivative species reacts further with sodium hydroxide and is converted it into a more stable compound. This yellow nitrosation product exhibited an absorption maximum at 430 nm. Beer's Law was obeyed in a concentration range of 6.37 to 82.81 μg mL-1 MTD with an excellent coefficient of determination (R2 = 0.9998). No interference was observed from common excipients in formulations. The results showed the method to be simple, accurate and readily applied for the determination of MTD in pure form and in pharmaceutical preparations. The analytical results obtained for these products using the proposed method are in agreement with those of the Brazilian Pharmacopoeia procedure at a 95% confidence level.

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