scholarly journals Development of a new highly sensitive and selective spectrophotometric method for the determination of selenium at nano-trace levels in various complex matrices using salicylaldehyde-orthoaminophenol

2021 ◽  
Vol 12 (4) ◽  
pp. 469-481
Author(s):  
Muhammad Jamaluddin Ahmed ◽  
Muhammad Jihan Uddin ◽  
Muhammad Emdadul Hoque
Keyword(s):  
Spectrophotometric Method ◽  
Certified Reference Materials ◽  
Biological Fluids ◽  
Stoichiometric Composition ◽  
Bovine Liver ◽  
Food Samples ◽  
Soil Samples ◽  
Complexing Agents ◽  
Linear Calibration

A new spectrophotometric reagent, salicylaldehyde-orthoaminophenol (Sal-OAP) has been synthesized and characterized for the determination of selenium through novel reaction techniques. Also, a new highly selective, and sensitive spectrophotometric method for the nano-trace determination of selenium using salicylaldehyde-orthoaminophenol (Sal-OAP) has been developed. Sal-OAP undergoes reaction in a slightly acidic solution (0.0001-0.0002 M H2S04) with selenium (IV) to give an orange-red chelate, which has an absorption maximum at 379 nm. The reaction is instantaneous and absorbance remains stable for over 24 h. The average molar absorption co-efficient and Sandell’s sensitivity were found to be 6.4×105 L/mol.cm and 1.0 ng/cm2 of, respectively. Linear calibration graphs were obtained for 0.001-40.000 mg/Lof Se having detection limit of 0.1 µg/L and RSD 0-2 %. The stoichiometric composition of the chelate is 1:2 (Se:Sal-OAP). 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 developed method was successfully used in the determination of selenium in several Certified Reference Materials (Alloys, steels, human urine, bovine liver, drinking water, tea, milk, soil, and sediments) as well as in some environmental waters (Potable and polluted), biological fluids (Human blood, urine, hair, and milk), soil samples, food samples (Vegetables, rice, and wheat) and pharmaceutical samples (Tablet and syrup) and solutions containing both selenium (IV) and selenium (VI) as well as complex synthetic mixtures. The results of the proposed method for assessing biological, food and vegetables and soil 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 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 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 highly sensitive and selective spectrofluorimetric method for the determination of molybdenum at pico-trace levels in various matrices using N-(pyridin-2-yl)-quinoline-2-carbothioamide

2021 ◽  
Vol 12 (1) ◽  
pp. 1-12
Author(s):  
Muhammad Jamaluddin Ahmed ◽  
Ayesha Afrin ◽  
Muhammad Emdadul Haque
Keyword(s):  
Certified Reference Materials ◽  
Biological Fluids ◽  
Reaction System ◽  
Bovine Liver ◽  
Food Samples ◽  
Complexing Agents ◽  
Linear Calibration ◽  
Spectrofluorimetric Method ◽  
Wide Range

A new spectrofluorimetric reagent N-(pyridin-2-yl)-quinoline-2-carbothioamide (PQTA) has been synthesized and characterized. A very simple, ultra-sensitive, and highly selective, and non-extractive new spectrofluorimetric method for the determination of molybdenum at pico-trace levels using PQTA has been developed. This novel fluorimetric reagent PQTA, becomes oxidized in a slightly acidic (0.0025-0.05 M H2SO4) solution with molybdenum (VI) in absolute ethanol to produce a highly fluorescent oxidized product (λex = 300 nm; λem= 377 nm). Constant and maximum fluorescence intensities were observed over a wide range of acidity (0.0025-0.0500 M H2SO4) for the period between 2 min and 24 h. Linear calibration graphs were obtained for 0.001-600 μg/L of Mo having a detection limit of 0.15 ng/L; the quantification limit of the reaction system was found to be 1.5 ng/L and the RSD was 0-2%. A large excess of over 60 cations, anions, and complexing agents like chloride, phosphate, azide, tartrate, oxalate, and SCN- etc. do not interfere in the determination. The developed method was successfully used in the determination of molybdenum in several Certified Reference Materials (Alloys, steel, serum, bovine liver, drinking water, soil, and sediments) as well as in some environmental waters (Potable and polluted), biological fluids (Human blood, urine, hair, and milk), soil samples and food samples (Vegetables, rice, and wheat) solutions containing both molybdenum (VI) and molybdenum (V) ions. 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.

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 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.

scholarly journals Automatic simultaneous determination of copper and lead in biological samples by flow injection/stripping voltammetric analysis

1993 ◽  
Vol 15 (4) ◽  
pp. 121-125 ◽  
Author(s):  
Andrés Izquierdo ◽  
M. D. Luque de Castro ◽  
Miguel Valcárcel
Keyword(s):  
Simultaneous Determination ◽  
Flow Injection ◽  
Certified Reference Materials ◽  
Stripping Voltammetry ◽  
Bovine Liver ◽  
Good Precision ◽  
Voltammetric Analysis ◽  
Statistical Studies ◽  
Determination Of Copper

An automatic-continuous method for the simultaneous determination of copper and lead based on flow injection analysis (FIA) and stripping voltammetry (SV) is proposed. The method affords the determination of the analytes at the ng/ml level (linear ranges 0.64 to 64.0 ng/ml and 2.1 to 62.2 ng/ml for copper and lead, respectively) with good precision (r.s.d. values smaller than 4%). The selectivity of SV allows the method to be applied to the determination of these analytes in bovine liver fresh samples and certified reference materials from the National Institute for Standards and Technology and the Community Bureau of Reference. The performance of the method was assessed by repeatability and validation statistical studies.

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.

A simple spectrophotometric method for the determination of trace levels of molybdenum in industrial, environmental, biological and soil samples using benzoylacetone-benzoylhydrazone

2014 ◽  
Vol 6 (7) ◽  
pp. 2282-2293 ◽  
Author(s):  
M. Jamaluddin Ahmed ◽  
M. Nasir Uddin ◽  
Tasnima Zannat ◽  
Salma Sultana
Keyword(s):  
Spectrophotometric Method ◽  
Soil Samples

A simple, ultra-sensitive and highly selective direct spectrophotometric method for the determination of trace amounts of molybdenum(vi) with benzoylacetone-benzoylhydrazone (Bzac-BH) has been developed.

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