A very simple, ultra-sensitive, highly selective and non-extractive new spectrofluorimetric method for the determination of arsenic at pico-trace levels using 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been develope...A very simple, ultra-sensitive, highly selective and non-extractive new spectrofluorimetric method for the determination of arsenic at pico-trace levels using 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been developed. PTQA has been proposed as a new analytical reagent for the direct non-extractive spectrofluorimetric determination of Arsenic (V). This novel fluorimetric reagent, PTQA becomes oxidized in a slightly acidic (0.025 - 0.1 M H2SO4) solution with Arsenic (V) in absolute ethanol to produce highly fluorescent oxidized product (λex = 303 nm;λem = 365 nm). Constant and maximum fluorescence intensities were observed over a wide range of acidity (0.025 - 0.1 M H2SO4) for the period between 2 min and 24 h. Linear calibration graphs were obtained for 0.001 - 800-μgL-1 of As, having a detection limit of 0.1-ngL-1;the quantification limit of the reaction system was found to be 1-ngL-1 and the RSD was 0% - 2%. A large excess of over 60 cations, anions and complexion 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 arsenic in several Certified Reference Materials (alloys, steels, ores, human urine, hair, nails, bovine liver and sediments) as well as in some biological fluids (human blood, urine, hair, nail and milk), soil samples, food samples (vegetables, fruits, rice, corn and wheat), solutions containing both arsenic (III) and arsenic (V) speciation and complex synthetic mixtures. The results of the proposed method for assessing biological, food and soil samples were comparable with both ICP-OES & AHG-AAS and were found to be in excellent agreement.展开更多
A new spectrofluorimetric reagent 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been synthesized and characterized through novel reaction techniques. A very simple, ultra-sensitive and highly selective non-extractive n...A new spectrofluorimetric reagent 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been synthesized and characterized through novel reaction techniques. A very simple, ultra-sensitive and highly selective non-extractive new spectrofluorimetric method for the determination of vanadium at Pico-trace levels using 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been developed. PTQA has been proposed as a new analytical reagent for the direct non-extractive spectrofluorimetric determination of vanadium (V). This novel fluorimetric reagent, PTQA becomes oxidized in a slightly acidic (0.0035 - 0.0085 M H2SO4) solution within vanadium (V) in 20% ethanol to produce highly fluorescent oxidized product (λex = 319 nm;λem = 371 nm). Constant and maximum fluorescence intensities were observed over a wide range of acidity (0.0035 - 0.0085 M H2SO4) for the period between 5 min and 24 h. Linear calibration graphs were obtained for 0.001 - 600-μg·L-1 of V, having a detection limit of 0.3-ng·L-1;the quantification limit of the reaction system was found to be 3-ng·L-1 and the RSD was 0% - 2%. 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 vanadium in several Certified Reference Materials (alloys, steels, 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 vanadium (IV) and vanadium (V) speciation and complex synthetic mixtures. The results of the proposed method for assessing biological, food and vegetable samples were comparable with inductively coupled plasma optical emission spectroscopy (ICP-OES) and atomic-absorption spectrophotometer (AAS) was found to be in excellent agreement.展开更多
A sensitive and rapid analytical procedure was established to detrmine strychnie alkaloids in diverse biological specimens. Samples were treated with hydrochloric acid to precipitate protein and scanned in thin-layer ...A sensitive and rapid analytical procedure was established to detrmine strychnie alkaloids in diverse biological specimens. Samples were treated with hydrochloric acid to precipitate protein and scanned in thin-layer chromatograpic scanner in zig-zag dual-wavelength reflection mode.Detection sensitivity for strychniue was about 0. 05 μg. Quantification recoveries were between89. 2% and 99. 5% with RSD between 2. 92% and 13. 21 %. The method was applied to investigate thedistribution or strychnine in intoxicated rats. The results showed that there were remarkable difference in organs or tissues with the aigaest concentration 4. 56±1. 41μg/g in liver. Diversification experiment proves the method also could be used to analyze other alkaloids in biological samples if theconditions slightly modified.展开更多
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 ion...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).展开更多
实时直接分析技术(direct analysis in real-time,DART)是一种在大气压环境下,利用非表面接触型热解析,对化合物进行离子化的新型软电离技术。该技术通过与样品预处理技术、质谱技术相结合,为直接、快速、无损地现场原位分析提供了一种...实时直接分析技术(direct analysis in real-time,DART)是一种在大气压环境下,利用非表面接触型热解析,对化合物进行离子化的新型软电离技术。该技术通过与样品预处理技术、质谱技术相结合,为直接、快速、无损地现场原位分析提供了一种新的途径,在农兽药残留、违禁添加成分、接触材料迁移物、生物毒素的检测方面应用广泛。该文简述实时直接分析技术的电离机理,概述该方法在常见的食品污染物检测中的应用现状和局限性,并对其未来发展方向进行展望。展开更多
文摘A very simple, ultra-sensitive, highly selective and non-extractive new spectrofluorimetric method for the determination of arsenic at pico-trace levels using 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been developed. PTQA has been proposed as a new analytical reagent for the direct non-extractive spectrofluorimetric determination of Arsenic (V). This novel fluorimetric reagent, PTQA becomes oxidized in a slightly acidic (0.025 - 0.1 M H2SO4) solution with Arsenic (V) in absolute ethanol to produce highly fluorescent oxidized product (λex = 303 nm;λem = 365 nm). Constant and maximum fluorescence intensities were observed over a wide range of acidity (0.025 - 0.1 M H2SO4) for the period between 2 min and 24 h. Linear calibration graphs were obtained for 0.001 - 800-μgL-1 of As, having a detection limit of 0.1-ngL-1;the quantification limit of the reaction system was found to be 1-ngL-1 and the RSD was 0% - 2%. A large excess of over 60 cations, anions and complexion 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 arsenic in several Certified Reference Materials (alloys, steels, ores, human urine, hair, nails, bovine liver and sediments) as well as in some biological fluids (human blood, urine, hair, nail and milk), soil samples, food samples (vegetables, fruits, rice, corn and wheat), solutions containing both arsenic (III) and arsenic (V) speciation and complex synthetic mixtures. The results of the proposed method for assessing biological, food and soil samples were comparable with both ICP-OES & AHG-AAS and were found to be in excellent agreement.
文摘A new spectrofluorimetric reagent 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been synthesized and characterized through novel reaction techniques. A very simple, ultra-sensitive and highly selective non-extractive new spectrofluorimetric method for the determination of vanadium at Pico-trace levels using 2-(α-pyridyl)-thioquinaldinamide (PTQA) has been developed. PTQA has been proposed as a new analytical reagent for the direct non-extractive spectrofluorimetric determination of vanadium (V). This novel fluorimetric reagent, PTQA becomes oxidized in a slightly acidic (0.0035 - 0.0085 M H2SO4) solution within vanadium (V) in 20% ethanol to produce highly fluorescent oxidized product (λex = 319 nm;λem = 371 nm). Constant and maximum fluorescence intensities were observed over a wide range of acidity (0.0035 - 0.0085 M H2SO4) for the period between 5 min and 24 h. Linear calibration graphs were obtained for 0.001 - 600-μg·L-1 of V, having a detection limit of 0.3-ng·L-1;the quantification limit of the reaction system was found to be 3-ng·L-1 and the RSD was 0% - 2%. 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 vanadium in several Certified Reference Materials (alloys, steels, 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 vanadium (IV) and vanadium (V) speciation and complex synthetic mixtures. The results of the proposed method for assessing biological, food and vegetable samples were comparable with inductively coupled plasma optical emission spectroscopy (ICP-OES) and atomic-absorption spectrophotometer (AAS) was found to be in excellent agreement.
文摘A sensitive and rapid analytical procedure was established to detrmine strychnie alkaloids in diverse biological specimens. Samples were treated with hydrochloric acid to precipitate protein and scanned in thin-layer chromatograpic scanner in zig-zag dual-wavelength reflection mode.Detection sensitivity for strychniue was about 0. 05 μg. Quantification recoveries were between89. 2% and 99. 5% with RSD between 2. 92% and 13. 21 %. The method was applied to investigate thedistribution or strychnine in intoxicated rats. The results showed that there were remarkable difference in organs or tissues with the aigaest concentration 4. 56±1. 41μg/g in liver. Diversification experiment proves the method also could be used to analyze other alkaloids in biological samples if theconditions slightly modified.
文摘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).
文摘实时直接分析技术(direct analysis in real-time,DART)是一种在大气压环境下,利用非表面接触型热解析,对化合物进行离子化的新型软电离技术。该技术通过与样品预处理技术、质谱技术相结合,为直接、快速、无损地现场原位分析提供了一种新的途径,在农兽药残留、违禁添加成分、接触材料迁移物、生物毒素的检测方面应用广泛。该文简述实时直接分析技术的电离机理,概述该方法在常见的食品污染物检测中的应用现状和局限性,并对其未来发展方向进行展望。
