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Abstract A new low-cost material is presented for the first time, aiming to study the sorption process for the stir-bar sorptive extraction (SBSE) technique. The bars were made using a composition of a commercial epoxy resin and montmorillonite, under different compositions and a final ratio of 70% (epoxy) and 30% (montmorillonite) was employed, providing the best mechanical and chemical resistance. A PTFE support was developed to hold the bars permitting the magnetic stirring, without turbulent behavior even under long times of stirring at 1000 rpm. The bars were employed to study the sorption of the herbicide atrazine (ATZ), and the best extraction conditions were: sample volume 20.0 mL, pH 6.0, extraction time of 15 min, room temperature, stirring speed of 100 rpm, and 10.0% (w v-1) NaCl. This preliminary evaluation suggests that the modified bars could be employed for ATZ sorption, affording close to 71% of ATZ removal, and presented robust characteristics to be used at least 80 times.
Subject(s)
Atrazine/chemistry , Herbicides/chemistry , Microscopy, Electron, Scanning , Sorption DetoxificationABSTRACT
Background and Objective: Digital media can be considered as an important element of life for today's children and adolescents since theyspend a lot of time using it. This increased use of digital media is associated with poor behavior and health status. Society in general andpractitioners in public health in particular should promote digital media use strategies through health education. This study is aimed atevaluating the impact of using digital technology on children physical, social and behavior health. Methodology: This is a descriptive studywhich was conducted at the primary health care centers of Tabuk. Through purposive sampling, 300 people were included in the study. Aquestionnaire and a checklist were used as the tools for data collection. Results: There was a significant relationship between theattachment to technology and both physical and psychological health of the studied children. There was also a significant differencebetween the awareness of mothers regarding both negative and positive effects of technology and total effects of technology at the pre andpost-intervention stages. Conclusion: Using technology had an impact on both physical and psychological health of children, and there wasan improvement in mothers’ awareness in this regard. This reflects the key role of health education on improving the awareness of mothersabout the effects of using technology on the health of their children.
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Microchip electrophoresis is emerging as a highly promising method for portability and fast analysis with minimum amount of analytes. This paper reviewed the recent development of microchip electrophoresis, and discussed the structures,materials,processing technologies,surface modification,experimental methods, and application on ion detection. The existing issues and prospects of future study were also discussed.
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A new derivative of ordered mesoporous carbon (GSH-CMK-3) has been prepared by chemical modification and functionalization of ordered mesoporous carbon with glutathione. The composite was fully characterized by means of Fourier transforming infrared spectroscopy (FT-IR), scanning electron microscope (SEM) image and thermogravimetric analysis (TGA). GSH-CMK-3 showed favorable chemical stability, thermal stability and excellent adsorption performance toward Cd2+and a maximum adsorption capacity of 87.87 mg/g was achieved. The adsorption kinetic follows pseudo-second-order adsorption model. In a sequential injection mini-column separation system, 0. 006 mol/L sulfourea (in 0. 2 mol/L HNO3) was adopted as eluent and the elution efficiency was 96%. With a sample volume of 1000 μL and 50 μL of eluate, an enrichment factor of 17.3 was obtained. A procedure for on-line selective separation and preconcentration of trace Cd2+was developed by graphite furnace atomic absorption spectrometry. Along with a detection limit of 1.9 ng/L (n=7,3σ) and a linear range of 0.05-0.20 μg/L, a RSD of 2.9% (n=13,100 ng/L) was achieved. The method was validated by analyzing Cd2+in a certified reference material GBW08608.
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The sample introduction system of a cool vapor atomic fluorescence spectrometer made domestically was modified for taking the mercury vapor which was pre-concentrated in a capture mercury gold cartridge as gold amalgam generated on-line by pyrolyzing atmospheric particulate collected from an air conditioner. The temperatures that applied) to sample pyrolyzer to generate elemental mercury and capture mercury gold cartridge to release mercury from amalgam were 700-750 ℃ and 550 ℃, respectively. The carrier Ar flow rate was 120 mL/min. The method detection limit was 1 pg, mercury content showed a linear relationship in 0-1.5 ng), and RSD was 2.2%. The method was validated by determining mercury in the national soil standards) GBW07410. The method was Applied to determine the mercury content in the atmospheric particulate from a hospital air conditioner.
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An ion chromatography procedure, employing an IonPac AC15 concentrator column was used to investigate on line preconcentration for the simultaneous determination of inorganic anions and organic acids in river water. Twelve organic acids and nine inorganic anions were separated without any interference from other compounds and carry-over problems between samples. The injection loop was replaced by a Dionex AC15 concentrator column. The proposed procedure employed an auto-sampler that injected 1.5 ml of sample into a KOH mobile phase, generated by an Eluent Generator, at 1.5 mL min-1, which carried the sample to the chromatographic columns (one guard column, model AG-15, and one analytical column, model AS15, with 250 x 4mm i.d.). The gradient elution concentrations consisted of a 10.0 mmol l-1 KOH solution from 0 to 6.5 min, gradually increased to 45.0 mmol l-1 KOH at 21 min., and immediatelly returned and maintained at the initial concentrations until 24 min. of total run. The compounds were eluted and transported to an electro-conductivity detection cell that was attached to an electrochemical detector. The advantage of using concentrator column was the capability of performing routine simultaneous determinations for ions from 0.01 to 1.0 mg l-1 organic acids (acetate, propionic acid, formic acid, butyric acid, glycolic acid, pyruvate, tartaric acid, phthalic acid, methanesulfonic acid, valeric acid, maleic acid, oxalic acid, chlorate and citric acid) and 0.01 to 5.0 mg l-1 inorganic anions (fluoride, chloride, nitrite, nitrate, bromide, sulfate and phosphate), without extensive sample pretreatment and with an analysis time of only 24 minutes.
A metodologia analítica foi desenvolvida empregando coluna pré-concentradora AC15 em linha na cromatografia iônica na determinação simultânea de ânions orgânicos e inorgânicos, com uso de coluna de guarda AG15 e analítica AS15, 250 x 4 mm i.d. (Dionex Corp.). O gradiente de concentração do eluente foi fixo em 10,0 mmol.l-1 KOH nos tempos de retenção de 0 até 6,5 min, seguido do aumento da concentração até 45,0 mmol.l-1 KOH a 21 min, imediatamente retornando e mantendo a concentração inicial até o tempo total de análise de 24 min. Os compostos foram separados com boa resolução e deslocados para uma cela de detecção de condutividade elétrica acoplada a um detector eletroquímico. O emprego da coluna pré-concentradora em linha apresentou vantagens analíticas na determinação de rotina dos íons na faixa linear de 0,01 até 1,0 mg l-1 (r=0,9989) de ácidos orgânicos (acético, propiônico, fórmico, butírico, glicólico, pirúvico, tartárico, ftálico, metanossulfônico, valérico, maleico, oxálico e cítrico) e 0,01 até 5,0 mg.l-1 (r=0,9987) de ânions inorgânicos (fluoreto, cloreto, nitrito, brometo, nitrato, sulfato, clorato e fosfato) sem pré-tratamento da amostra. Um tempo de análise de 24 min e limite de detecção de 5 µ.l-1 foram obtidos para os ânions orgânicos ácido ácetico, ácido fórmico, ácido butírico, ácido glicólico, ácido valérico, ácido cítrico e de 10 µg.l-1 para ácido propiônico, piruvato, ácido tartárico, ácido ftálico, ácido metasulfônico e ácido maleico. Para os ânions inorgânicos 2 µg.l-1 de fluoreto, cloreto, nitrato, brometo, sulfato e 10 µg.l-1 de clorato, nitrito e fosfato foram estimados, segundo metodologia sugerida por IUPAC.
Subject(s)
Chromatography , AnionsABSTRACT
Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva, the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic silica capillary when it was used to concentrate catecholamines.
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Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva, the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic silica capillary when it was used to concentrate catecholamines.
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Objective To establish a new method for the determination of chromium (Ⅵ) in printing and dyeing wastewater. Methods A combined technique was employed for the determination of chromium (Ⅵ) by flow injection on-line separation and preconcentration on a micro column packed with alumina(acidic form) and inductively coupled plasma-atomic emission spectrometry (ICP-AES).The effect of acidity,concentration of eluent and coexistence ion on separation and enrichment was detected.Results The detection limit was 0.72 ?g/L.The LOQ was 2.38 ?g/L.RSDs were 1.45%～2.12%.The recovery rates were 96.0%-104.0%.The concentration enhancement of chromium (Ⅵ) was 10 times for 45 s sample loading.Analytic frequency was 33 samples one hour. Conclusion This method is sensitive,rapid and applicable to the determination of chromium (Ⅵ) in dyeing wastewater.