The insecticide cartap （CP） is non-fluorescent in aqueous solutions. This property makes its determination through direct fluorescent method difficult. In acidic medium and at room temperature, palmatine （PAL） can...The insecticide cartap （CP） is non-fluorescent in aqueous solutions. This property makes its determination through direct fluorescent method difficult. In acidic medium and at room temperature, palmatine （PAL） can react with cucurbit[7]uril （CB[7]） to form stable complexes, and the fluorescence intensity of the complex is greatly enhanced. Significant quenching of the fluorescence intensity of the CB[7]-PAL complex was observed with the addition of cartap. Based on the significant quenching of the supramolecular complex fluorescence intensity, a new spectrofluorimetric method with high sensitivity and selectivity was developed to determine cartap in aqueous solution. The fluorescence quenching values （AF） showed good linear relationship with cartap concentrations from 0.009 to 2.4 ~tg mL-~ with a detection limit 0.0029 ~tg mE-x. The proposed method had been successfully applied to the determination of cartap residues in grain and vegetable with recoveries of 87.4-103%. In addition, the association constants of the complexes formed between the host and the guest were determined. The competing reaction and the supramolecular interaction mechanisms between the cartap and PAL as they fight for occupancy of the CB[7] cavity were studied using spectrofluorimetry, xH NMR and molecular modeling calculations.展开更多
A highly sensitive and selective two-photon sensing scheme for detection of cartap was developed by using Au@Ag bimetallic core-shell nanoparticles.Cartap was found to induce the aggregation of Au@Ag nanoparticles and...A highly sensitive and selective two-photon sensing scheme for detection of cartap was developed by using Au@Ag bimetallic core-shell nanoparticles.Cartap was found to induce the aggregation of Au@Ag nanoparticles and up to 700-fold enhancement in two-photon photoluminescence.Huge enhancement in two-photon photoluminescence allows achieving a detection limit of as low as 0.0062 mg/kg,which is better than the conventional colorimetric methods.This two-photon sensing scheme has a broad dynamic range and displays excellent selectivity in detection of cartap against over other ten kinds of commonly used insecticides.展开更多
介绍了一种快速、灵敏、可靠的适用于茶叶样品中杀螟丹残留量的气相色谱分析方法。茶叶样品经过0.05m o l/L盐酸溶液提取,液-液分配净化,在碱性条件下用正己烷萃取提取液中的杀螟丹,用毛细管气相色谱法-微池电子捕获检测器(μ-ECD)测定...介绍了一种快速、灵敏、可靠的适用于茶叶样品中杀螟丹残留量的气相色谱分析方法。茶叶样品经过0.05m o l/L盐酸溶液提取,液-液分配净化,在碱性条件下用正己烷萃取提取液中的杀螟丹,用毛细管气相色谱法-微池电子捕获检测器(μ-ECD)测定杀螟丹的残留量。结果表明:样品的添加回收率为70.2%-92.0%,相对标准偏差小于10%,方法的检测低限为0.01m g/kg,符合农药残留分析的要求。展开更多
基金supported by the Research Fund for the Doctoral Program of Higher Education of China(20091404110001)
文摘The insecticide cartap （CP） is non-fluorescent in aqueous solutions. This property makes its determination through direct fluorescent method difficult. In acidic medium and at room temperature, palmatine （PAL） can react with cucurbit[7]uril （CB[7]） to form stable complexes, and the fluorescence intensity of the complex is greatly enhanced. Significant quenching of the fluorescence intensity of the CB[7]-PAL complex was observed with the addition of cartap. Based on the significant quenching of the supramolecular complex fluorescence intensity, a new spectrofluorimetric method with high sensitivity and selectivity was developed to determine cartap in aqueous solution. The fluorescence quenching values （AF） showed good linear relationship with cartap concentrations from 0.009 to 2.4 ~tg mL-~ with a detection limit 0.0029 ~tg mE-x. The proposed method had been successfully applied to the determination of cartap residues in grain and vegetable with recoveries of 87.4-103%. In addition, the association constants of the complexes formed between the host and the guest were determined. The competing reaction and the supramolecular interaction mechanisms between the cartap and PAL as they fight for occupancy of the CB[7] cavity were studied using spectrofluorimetry, xH NMR and molecular modeling calculations.
基金the Ministry of Education, Singapore (R-143-000-607-112)the National Research Foundation, Prime Minister’s Office, Singapore under its Competitive Research Program (NRF-CRP10-2012-04)Medium Sized Centre Programme
文摘A highly sensitive and selective two-photon sensing scheme for detection of cartap was developed by using Au@Ag bimetallic core-shell nanoparticles.Cartap was found to induce the aggregation of Au@Ag nanoparticles and up to 700-fold enhancement in two-photon photoluminescence.Huge enhancement in two-photon photoluminescence allows achieving a detection limit of as low as 0.0062 mg/kg,which is better than the conventional colorimetric methods.This two-photon sensing scheme has a broad dynamic range and displays excellent selectivity in detection of cartap against over other ten kinds of commonly used insecticides.
文摘介绍了一种快速、灵敏、可靠的适用于茶叶样品中杀螟丹残留量的气相色谱分析方法。茶叶样品经过0.05m o l/L盐酸溶液提取,液-液分配净化,在碱性条件下用正己烷萃取提取液中的杀螟丹,用毛细管气相色谱法-微池电子捕获检测器(μ-ECD)测定杀螟丹的残留量。结果表明:样品的添加回收率为70.2%-92.0%,相对标准偏差小于10%,方法的检测低限为0.01m g/kg,符合农药残留分析的要求。
