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Alaa S. Amin - One of the best experts on this subject based on the ideXlab platform.
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Utility of solid phase extraction for colorimetric determination of lead in waters, vegetables, biological and soil samples
Journal of Industrial and Engineering Chemistry, 2018Co-Authors: Zakia Al-mallah, Alaa S. AminAbstract:Abstract A highly sensitive, selective and rapid method for the determination of lead based on the reaction of lead(II) with 5-(4′-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione (CPAHPD) and the solid phase extraction of the Pb(II)–CPAHPD complex with Amberlite XAD-2000 was developed, in the presence of pH 5.6 buffer solution and Triton X-114 medium. CPAHPD reacts with lead to form a violet complex with a molar ratio of 2:1 (CPAHPD to lead). This complex was enriched by the solid phase extraction with Amberlite XAD-2000. An enrichment factor of 500 was obtained by elution of the complex from the resin with a minimal amount of Isopentyl Alcohol (0.2 mL). In Isopentyl Alcohol medium, the molar absorptivity of the complex is 1.13 × 106 L mol−1 cm−1 at 647 nm. Beer’s law is obeyed in the range of 5.0–160 ng mL−1 in the measured solution. The relative standard deviation for 10 replicate samples of 50 ng mL−1 level is 1.26%. The detection and quantification limits reaches 1.5 and 4.7 ng mL−1 in the original samples. The presented procedure was successfully applied for determination of lead content in real samples such as vegetables, waters, biological and soil samples with satisfactory results.
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Solid Phase Extraction and Spectrophotometric Determination of Palladium with 1-(2-benzothiazolylazo)-2-hydroxy-3-naphthoic Acid
Analytical Chemistry Letters, 2017Co-Authors: Nader Hassan, Alaa S. AminAbstract:AbstractA selective, sensitive, and fast procedure to determine palladium depended on the sensitive reaction of palladium(II) with 1-(2-benzothiazolylazo)-2-hydroxy-3-naphthoic acid (BTAHN) coupled with solid phase extraction (CPE) of the BTAHN - Pd(II) chelate with a reversed phase polymer-based C18 cartridge was developed. In 5.0 M hydrochloric acid solution and cetyl trimethyl ammonium bromide (CTAB) medium, BTAHN reacts with palladium(II) to form a deep violet complex with a mole ratio 2:1 {BTAHN to Pd(II)}. The complex was enriched by CPE with a reversed phase polymer-based C18 cartridge. An enrichment factor of 500 was achieved by elution of the complex form the cartridge with least volume of Isopentyl Alcohol. Beer’s law was obeyed in the concentration range of 0.02 - 0.85 μg mL–1. The molar absorptivity of the complex was 2.61 × 105 L mol–1 cm–1 at 669 nm. The detection and quantification limits were calculated and found to be 6.3 and 19.65 ng in the original samples, respectively. For 0.4 μg mL–1...
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Study on the solid phase extraction and spectrophotometric determination of cobalt with 5-(2-benzothiazolylazo)-8-hydroxyquinolene
Elsevier, 2014Co-Authors: Alaa S. AminAbstract:A highly sensitive, selective and rapid method for the determination of cobalt based on the rapid reaction of cobalt(II) with 5-(2-benzothiazolylazo)-8-hydroxyquinolene BTAHQ and the solid phase extraction of the Co(II)-BTAHQ complex with C18 membrane disks were developed. In the presence of pH = 6.4 buffer solution and cetylpyridenium chloride (CPC) medium, BTAHQ reacts with cobalt to form a deep violet complex with a molar ratio of 1:1 (cobalt to BTAHQ). This complex was enriched by the solid phase extraction with C18 membrane disks. An enrichment factor of 100 was obtained by elution of the complex from the disks with a minimal amount of Isopentyl Alcohol. In Isopentyl Alcohol medium, the molar absorptivity of the complex is 2.42 × 105 L mol−1 cm−1 at 658 nm. Beer’s law is obeyed in the range of 0.01–0.38 μg mL−1 in the measured solution. The relative standard deviation for 11 replicate samples of 0.20 μg mL−1 level is 1.37%. The detection and quantification limits reach 3.1 and 9.7 ng mL−1 in the original samples. This method was applied for the determination of cobalt in biological, water, soil and pharmaceutical preparation samples with good results
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Study on the solid phase extraction and spectrophotometric determination of cobalt with 5-(2-benzothiazolylazo)-8-hydroxyquinolene
Arabian Journal of Chemistry, 2014Co-Authors: Alaa S. AminAbstract:A highly sensitive, selective and rapid method for the determination of cobalt based on the rapid reaction of cobalt(II) with 5-(2-benzothiazolylazo)-8-hydroxyquinolene BTAHQ and the solid phase extraction of the Co(II)-BTAHQ complex with C18 membrane disks were developed. In the presence of pH = 6.4 buffer solution and cetylpyridenium chloride (CPC) medium, BTAHQ reacts with cobalt to form a deep violet complex with a molar ratio of 1:1 (cobalt to BTAHQ). This complex was enriched by the solid phase extraction with C18 membrane disks. An enrichment factor of 100 was obtained by elution of the complex from the disks with a minimal amount of Isopentyl Alcohol. In Isopentyl Alcohol medium, the molar absorptivity of the complex is 2.42 · 10 5 L mol � 1 cm � 1 at 658 nm. Beer's law is obeyed in the range of 0.01-0.38 l gm L � 1 in the measured solution. The rela- tive standard deviation for 11 replicate samples of 0.20 l gm L � 1 level is 1.37%. The detection and quantification limits reach 3.1 and 9.7 ng mL � 1 in the original samples. This method was applied for the determination of cobalt in biological, water, soil and pharmaceutical preparation samples with good results. a 2011 Production and hosting by Elsevier B.V. on behalf of King Saud University.
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Study of the solid phase extraction and spectrophotometric determination of nickel using 5-(4′-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione in environmental samples
Journal of Saudi Chemical Society, 2012Co-Authors: Alaa S. Amin, Amirah S. Al-attasAbstract:Abstract A rapid, sensitive and selective method for the determination of nickel based on the rapid reaction of nickel(II) with 5-(4′-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione (CPAHPD) and the solid phase extraction of the Ni(II)–CPAHPD complex with C18 membrane disks has been developed. In the presence of pH 6.8 buffer solution and cetylpyridinium bromide (CPB) medium, CPAHPD reacts with nickel to form a red complex of a molar ratio of 1:1 (nickel to CPAHPD). This complex was enriched by solid phase extraction (SPE) with C18 membrane disks. An enrichment factor of 100 was obtained by elution of the complex from the disks with the minimal amount of Isopentyl Alcohol. The molar absorptivity and Sandell sensitivity of the complex was 3.11 × 105 L mol−1 cm−1 and 0.0189 ng cm−2, respectively at 549 nm in the measured solution. Beer's law was obeyed in the range of 0.01–0.37 μg mL−1, while that obtained by Ringbom plot was in the range of 0.025–0.35 μg mL−1. The detection and quantification limits were calculated and found to be 0.003 and 0.01 μg mL−1. The proposed method was applied to the determination of nickel in water, food, biological and soil samples with good results.
Li Zhang - One of the best experts on this subject based on the ideXlab platform.
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ORIGINAL PAPER Impact odorants of Chardonnay dry white wine from Changli County (China)
2014Co-Authors: Li ZhangAbstract:Abstracts Effect of volatile compounds ’ contribution to the overall aroma of Chardonnay wines from Changli County was first investigated in this research. Wine aroma compounds were extracted by solid-phase micro-extraction fibers, then they were submitted to gas chromatography-mass spectrometry (GC–MS). A total of 41 volatile com-pounds were identified and quantified. In the volatiles detected, higher Alcohols, esters and fatty acids are the main chemicals. According to their odor active values (OAVs), 13 volatile compounds were considered to be the powerful impact odorants of this wine. They are b-dama-scenone, Isopentyl acetate, phenethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl lactate, ethyl decanoate, Isopentyl Alcohol, 2-phenyl-ethanol, hex-anoic acid, octanoic acid and n-decanoic acid. Odor descriptions of the impact volatiles suggested that Char-donnay wines from Changli County was a pleasant floral and fruity odor product
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Volatile compounds of young Cabernet Sauvignon red wine from Changli County (China)
Journal of Food Composition and Analysis, 2008Co-Authors: Yong-sheng Tao, Hua Wang, Li ZhangAbstract:Abstract Some 69 volatile compounds of young red wines from Vitis vinifera cv . Cabernet Sauvignon in Changli County (China), were identified by GC–MS. HS-SPME (headspace solid-phase microextraction) was used to extract and concentrate volatile and semi-volatile compounds in the wine. Higher Alcohols made up about 46% of the total level of volatiles and this group was mainly composed of isobutyl Alcohol, 2-phenyl ethanol, 1-propanol and Isopentyl Alcohol. Acetates and ethyl esters make up 51% of the total volatiles, of which acetates made up 5% and ethyl esters 46%. Fatty acids made up 1.6% of the total volatiles. Among the small quantity of detected volatiles, there were five terpenes, one norisoprenoid ( β -damascenone), seven fatty acid esters of higher Alcohols, two carbonyl compounds, one volatile phenol and one sulfur compound. This represent 1.3% of total volatiles. Considering all the volatiles detected, higher Alcohols and acetates and ethyl esters are the main contributors to young Cabernet Sauvignon wine in Changli County. Terpenes and β -damascenone also contributed to the overall flavor and aroma of the wine.
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Impact odorants of Chardonnay dry white wine from Changli County (China)
European Food Research and Technology, 2007Co-Authors: Yong-sheng Tao, Hua Wang, Li ZhangAbstract:Effect of volatile compounds’ contribution to the overall aroma of Chardonnay wines from Changli County was first investigated in this research. Wine aroma compounds were extracted by solid-phase micro-extraction fibers, then they were submitted to gas chromatography-mass spectrometry (GC–MS). A total of 41 volatile compounds were identified and quantified. In the volatiles detected, higher Alcohols, esters and fatty acids are the main chemicals. According to their odor active values (OAVs), 13 volatile compounds were considered to be the powerful impact odorants of this wine. They are β-damascenone, Isopentyl acetate, phenethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl lactate, ethyl decanoate, Isopentyl Alcohol, 2-phenyl-ethanol, hexanoic acid, octanoic acid and n-decanoic acid. Odor descriptions of the impact volatiles suggested that Chardonnay wines from Changli County was a pleasant floral and fruity odor product.
V K Gupta - One of the best experts on this subject based on the ideXlab platform.
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extraction spectrophotometric determination of nitrite using 1 aminonaphthalene 2 sulphonic acid
Analyst, 1991Co-Authors: Rachana Kaveeshwar, Lata Cherian, V K GuptaAbstract:A simple and highly sensitive extraction–spectrophotometric method for the determination of nitrite is described. The method is based on diazotization of o-nitroaniline with nitrite and subsequent coupling with 1-aminonaphthalene-2-sulphonic acid in acidic medium to yield a red dye with an absorption maximum at 545 nm. The dye could be extracted into Isopentyl Alcohol, whereupon its absorption maximum shifted to 530 nm. Beer's law is obeyed in the range 0.08–0.68 and 0.01–0.08 ppm of nitrite in the aqueous and extraction systems, respectively. The molar absorptivity and Sandell's sensitivity were found to be 5.46 × 104 dm3 mol–1 cm–1 and 0.0008 µg cm–2, and 4.83 × 105 dm3 mol–1 cm–1 and 0.00009 µg cm–2 in the aqueous and extraction systems, respectively. The method is free from the interferences of Cu and Fe which are the normal interferents in other methods. The method was applied successfully to the determination of nitrite in polluted water.
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Extraction–spectrophotometric determination of nitrite using 1-aminonaphthalene-2-sulphonic acid
Analyst, 1991Co-Authors: Rachana Kaveeshwar, Lata Cherian, V K GuptaAbstract:A simple and highly sensitive extraction–spectrophotometric method for the determination of nitrite is described. The method is based on diazotization of o-nitroaniline with nitrite and subsequent coupling with 1-aminonaphthalene-2-sulphonic acid in acidic medium to yield a red dye with an absorption maximum at 545 nm. The dye could be extracted into Isopentyl Alcohol, whereupon its absorption maximum shifted to 530 nm. Beer's law is obeyed in the range 0.08–0.68 and 0.01–0.08 ppm of nitrite in the aqueous and extraction systems, respectively. The molar absorptivity and Sandell's sensitivity were found to be 5.46 × 104 dm3 mol–1 cm–1 and 0.0008 µg cm–2, and 4.83 × 105 dm3 mol–1 cm–1 and 0.00009 µg cm–2 in the aqueous and extraction systems, respectively. The method is free from the interferences of Cu and Fe which are the normal interferents in other methods. The method was applied successfully to the determination of nitrite in polluted water.
B. S. M. Kumar - One of the best experts on this subject based on the ideXlab platform.
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Pararosaniline as a New Chromogen for the Extractive Spectrophotometric Determination of Trace Amounts of Hydrogen Sulfide in Air
Journal of AOAC International, 1993Co-Authors: B. S. M. Kumar, Natesan BalasubramanianAbstract:Abstract A sensitive spectrophotometric method for the determination of trace amounts of hydrogen sulfide H2S) in air, after fixing in a zinc acetate–disodium ethylenediaminetetraacetate–sodium hydroxide solution, is described. The reaction of iodate with the fixed H2S in the presence of acid and an excess of chloride leads to the formation of ICI2 ions. The resulting IC-2 species forms an ion par with pararosaniline cation, and the product is extracted into Isopentyl Alcohol. The color system obeys Beer’s law over the range of 0 to 5.0 μg H2S. The molar absorption coefficient of the color system is 1.8 × 104 L mol-1 cm-1 . The coefficient of variation is 3.3% for 10 determinations at 3.0 μg H2S. The effect of interfering gases on the determination is discussed. The method was applied to the determination of residual amounts of H2S present in a laboratory fume cupboard, and results were compared to those obtained by the widely used methylene blue method. The current method can be used to determine residues as low as 0.2 μg H2S.
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Extractive spectrophotometric determination of trace amounts of sulfur dioxide in air
Journal of AOAC INTERNATIONAL, 1992Co-Authors: B. S. M. Kumar, Natesan BalasubramanianAbstract:A sensitive spectrophotometric method was developed for the determination of trace amounts of sulfur dioxide (SO{sub 2}) in air after SO{sub 2} has been fixed in a buffered formaldehyde solution. The reaction of iodate with the fixed SO{sub 2} in the presence of an acid an an excess of chloride leads to the formation of ICI{sub 2} ions. The resulting ICI{sub 2} species forms an ion-pair with pararosaniline cation; the product is extracted into Isopentyl Alcohol and measured spectrophotometrically at 560 nm. The color system obeys Beer`s law over the range 0-40 {mu}g SO{sub 2}. The color is stable for 72 h from the time of extraction. The molar absorption coefficient of the color system is 4.5 {times} 10{sup 3}Lmol{sup {minus}1}cm{sup {minus}1}. The coefficient of variation is 3.6% for 10 determinations at 20 {mu}g SO{sub 2}. The effect of interfering gases on the determination is discussed. The method was applied to the determination of SO{sub 2} at low concentrations, and the results obtained were compared with the widely used West and Gaeke method. The method can be used to determine as low as 2 {mu}g SO{sub 2}. 12 refs., 2 figs., 2 tabs.
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Extraction-spectrophotometric determination of sulphur dioxide
Analyst, 1991Co-Authors: Natesan Balasubramanian, B. S. M. KumarAbstract:A sensitive spectrophotometric method for the determination of trace amounts of sulphur dioxide after fixing in a modified buffered formaldehyde solution is described. The reaction of iodate with sulphur dioxide in the presence of acid and excess of chloride leads to the formation of ICI which is stabilized as the ICI–2 ion. The species formed reacts with 2′,7′-dichlorofluorescein to form 2′,7′-dichloro-4′,5′-diiodofluorescein and is extracted into a solvent mixture of 15% Isopentyl acetate in Isopentyl Alcohol. The colour system obeys Beer's law in the range 0–40 µg of sulphur dioxide. The relative standard deviation is 3.5% for ten determinations of 15 µg of sulphur dioxide. The effect of interfering gases on the determination is discussed. The method has been applied to the determination of sulphur dioxide at low concentrations and the results obtained were compared with the widely used pararosaniline method. The method can be used to determine as low as 2 µg of sulphur dioxide.
Natesan Balasubramanian - One of the best experts on this subject based on the ideXlab platform.
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Pararosaniline as a New Chromogen for the Extractive Spectrophotometric Determination of Trace Amounts of Hydrogen Sulfide in Air
Journal of AOAC International, 1993Co-Authors: B. S. M. Kumar, Natesan BalasubramanianAbstract:Abstract A sensitive spectrophotometric method for the determination of trace amounts of hydrogen sulfide H2S) in air, after fixing in a zinc acetate–disodium ethylenediaminetetraacetate–sodium hydroxide solution, is described. The reaction of iodate with the fixed H2S in the presence of acid and an excess of chloride leads to the formation of ICI2 ions. The resulting IC-2 species forms an ion par with pararosaniline cation, and the product is extracted into Isopentyl Alcohol. The color system obeys Beer’s law over the range of 0 to 5.0 μg H2S. The molar absorption coefficient of the color system is 1.8 × 104 L mol-1 cm-1 . The coefficient of variation is 3.3% for 10 determinations at 3.0 μg H2S. The effect of interfering gases on the determination is discussed. The method was applied to the determination of residual amounts of H2S present in a laboratory fume cupboard, and results were compared to those obtained by the widely used methylene blue method. The current method can be used to determine residues as low as 0.2 μg H2S.
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Extractive spectrophotometric determination of trace amounts of sulfur dioxide in air
Journal of AOAC INTERNATIONAL, 1992Co-Authors: B. S. M. Kumar, Natesan BalasubramanianAbstract:A sensitive spectrophotometric method was developed for the determination of trace amounts of sulfur dioxide (SO{sub 2}) in air after SO{sub 2} has been fixed in a buffered formaldehyde solution. The reaction of iodate with the fixed SO{sub 2} in the presence of an acid an an excess of chloride leads to the formation of ICI{sub 2} ions. The resulting ICI{sub 2} species forms an ion-pair with pararosaniline cation; the product is extracted into Isopentyl Alcohol and measured spectrophotometrically at 560 nm. The color system obeys Beer`s law over the range 0-40 {mu}g SO{sub 2}. The color is stable for 72 h from the time of extraction. The molar absorption coefficient of the color system is 4.5 {times} 10{sup 3}Lmol{sup {minus}1}cm{sup {minus}1}. The coefficient of variation is 3.6% for 10 determinations at 20 {mu}g SO{sub 2}. The effect of interfering gases on the determination is discussed. The method was applied to the determination of SO{sub 2} at low concentrations, and the results obtained were compared with the widely used West and Gaeke method. The method can be used to determine as low as 2 {mu}g SO{sub 2}. 12 refs., 2 figs., 2 tabs.
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Extraction-spectrophotometric determination of sulphur dioxide
Analyst, 1991Co-Authors: Natesan Balasubramanian, B. S. M. KumarAbstract:A sensitive spectrophotometric method for the determination of trace amounts of sulphur dioxide after fixing in a modified buffered formaldehyde solution is described. The reaction of iodate with sulphur dioxide in the presence of acid and excess of chloride leads to the formation of ICI which is stabilized as the ICI–2 ion. The species formed reacts with 2′,7′-dichlorofluorescein to form 2′,7′-dichloro-4′,5′-diiodofluorescein and is extracted into a solvent mixture of 15% Isopentyl acetate in Isopentyl Alcohol. The colour system obeys Beer's law in the range 0–40 µg of sulphur dioxide. The relative standard deviation is 3.5% for ten determinations of 15 µg of sulphur dioxide. The effect of interfering gases on the determination is discussed. The method has been applied to the determination of sulphur dioxide at low concentrations and the results obtained were compared with the widely used pararosaniline method. The method can be used to determine as low as 2 µg of sulphur dioxide.
