A series of substituted naphthopyran derivatives are synthesized via the three-component condensation reaction of aromatic aldehydes,malononitrile and naphthol promoted by alkaline ionic liquid(OH).This proposed metho...A series of substituted naphthopyran derivatives are synthesized via the three-component condensation reaction of aromatic aldehydes,malononitrile and naphthol promoted by alkaline ionic liquid(OH).This proposed method is efficient and environmentally friendly.展开更多
The process of ultrasound-assisted dispersive liquid-liquid microextraction(USADLLME) was successfully applied for the extraction and preconcentration of trace copper from water samples,prior to flame atomic absorptio...The process of ultrasound-assisted dispersive liquid-liquid microextraction(USADLLME) was successfully applied for the extraction and preconcentration of trace copper from water samples,prior to flame atomic absorption spectrometry(FAAS).In the proposed approach,1-(2-pyridylazo)-2-naphthol(PAN) was used as a chelating agent and carbon tetrachloride was selected as extraction solvent.Under the optimized experimental conditions(extraction solvent volume:80 μL;pH=5.00;PAN amount:10-6 mol;extraction time:15 min and extraction temperature:40°C),an enrichment factor of 14.3 was obtained from only 6.00 mL of water sample.The calibration graph was linear in the range of 10.00～500.00 μg/L with a detection limit of 0.85 μg/L.The relative standard deviation(RSD) for eleven replicate measurements of 20.00 and 400.00 μg/L of copper were 3.71 and 3.20%.The method was applied to the analysis of tap,river,and sea water samples and good spiked recoveries over the range of 90.4～100.5% were obtained.展开更多
文摘A series of substituted naphthopyran derivatives are synthesized via the three-component condensation reaction of aromatic aldehydes,malononitrile and naphthol promoted by alkaline ionic liquid(OH).This proposed method is efficient and environmentally friendly.
文摘The process of ultrasound-assisted dispersive liquid-liquid microextraction(USADLLME) was successfully applied for the extraction and preconcentration of trace copper from water samples,prior to flame atomic absorption spectrometry(FAAS).In the proposed approach,1-(2-pyridylazo)-2-naphthol(PAN) was used as a chelating agent and carbon tetrachloride was selected as extraction solvent.Under the optimized experimental conditions(extraction solvent volume:80 μL;pH=5.00;PAN amount:10-6 mol;extraction time:15 min and extraction temperature:40°C),an enrichment factor of 14.3 was obtained from only 6.00 mL of water sample.The calibration graph was linear in the range of 10.00～500.00 μg/L with a detection limit of 0.85 μg/L.The relative standard deviation(RSD) for eleven replicate measurements of 20.00 and 400.00 μg/L of copper were 3.71 and 3.20%.The method was applied to the analysis of tap,river,and sea water samples and good spiked recoveries over the range of 90.4～100.5% were obtained.
