An AES method has been proposed for micro elements analysis in Chinese herbal medicine and the pretreatments of samples are discussed in detail.The method is proved accurate by analyzing peach leaves with the level of...An AES method has been proposed for micro elements analysis in Chinese herbal medicine and the pretreatments of samples are discussed in detail.The method is proved accurate by analyzing peach leaves with the level of the national standard substance and by comparing results using different methods∶ Thedata obtained are accurate and reliable and the method can be used for detemin10 kinds of micro elements in Chinese herbal medicine.展开更多
为了实现了电容式传感器和其他信号处理电路之间的接口,提出了一种电容式传感器接口电路。该接口电路基于开关电容技术,采用采样电荷结构,并在其前端读出电路采用采样开关噪声消除技术,在0.35μm 2P-4 M CMOS标准工艺下设计并流片实现,...为了实现了电容式传感器和其他信号处理电路之间的接口,提出了一种电容式传感器接口电路。该接口电路基于开关电容技术,采用采样电荷结构,并在其前端读出电路采用采样开关噪声消除技术,在0.35μm 2P-4 M CMOS标准工艺下设计并流片实现,且特别适用于开环或力平衡闭环电容式微加速度计和振动角速度陀螺仪应用。测试结果表明:在1 MHz的采样时钟下,该接口电路取得了约5.35 aF的电容分辨率和约0.173 aF.Hz-1/2的噪声基底。展开更多
目的:建立微量样品羟自由基(·OH)的检测方法,并用于新疆葡萄树伤流液及金银花茶、罗布麻茶、茉莉茶、竹叶茶等样品的检测。方法:采用Mn2+-H2O2-EBT法,检测波长为560 nm,在2 m L的比色皿中,取缓冲溶液(Na B4O7-Na OH)300μL,EBT 120...目的:建立微量样品羟自由基(·OH)的检测方法,并用于新疆葡萄树伤流液及金银花茶、罗布麻茶、茉莉茶、竹叶茶等样品的检测。方法:采用Mn2+-H2O2-EBT法,检测波长为560 nm,在2 m L的比色皿中,取缓冲溶液(Na B4O7-Na OH)300μL,EBT 120μL,Mn2+300μL,H2O2150μL,将体系体积用水补充至2.0 m L。Mn2+-H2O2-EBT法可作为检测抗氧化物质抗氧化活性的有效可行方法之一,为验证该方法对微量样品抗羟自由基(·OH)活性实时检测的可行性,以抗坏血酸对照。结果:实验结果表明,新疆葡萄树伤流液、金银花茶、罗布麻茶、茉莉茶和竹叶茶均具有较强的清除羟自由基(·OH)的生物活性功能,是一种很好的天然抗氧化及自由基清除剂。结论:微量样品抗羟自由基检测方法可行,实现吸光度测定的同时,对少量样品进行实时、恒温及震荡在线检测,连续观察吸光度的变化。展开更多
Highly precise and reliable determination of heavy metals in soil micro-arthropod tissues remains a challenge because of the small size of the animals and their typical low abundance in metal-contaminated agricultural...Highly precise and reliable determination of heavy metals in soil micro-arthropod tissues remains a challenge because of the small size of the animals and their typical low abundance in metal-contaminated agricultural soils. The present study sought to develop a method for cadmium （Cd） determination in soil micro-arthropods by optimizing the sample digestion procedure, reducing sample weight, modifying sample pre-treatment and validating the methodology with field samples. The optimized digestion conditions comprised a sample mass of 50-150 μg, digestion reagent of nitric acid：hydrogen peroxide （3：1）, digestion temperature of 105 ℃, digestion period of 3 h and digestion volume of 30 μL. Defecation of the standard Collembola Folsomia candida （92 h） and the indigenous Collembola Onychiurus yodai （42 h） and ultrasonic cleaning of F. candida increased the accuracy of Cd determination. The recovery of Cd using the refined procedure was 98.9% and the limits of detection and quantification were 0.002 and 0.008 μg L-1, respectively. The within-batch precision values were 〈 3%. The Cd concentrations in the tissues of the Collembola Isotorna sp. collected from a range of metal-contaminated fields determined by the improved method were consistent with the Cd concentrations in the field soils. The results indicate that the optimized method can be used for more accurate or reliable determination of Cd concentrations in soil micro-arthropod tissues.展开更多
文摘An AES method has been proposed for micro elements analysis in Chinese herbal medicine and the pretreatments of samples are discussed in detail.The method is proved accurate by analyzing peach leaves with the level of the national standard substance and by comparing results using different methods∶ Thedata obtained are accurate and reliable and the method can be used for detemin10 kinds of micro elements in Chinese herbal medicine.
文摘目的:建立微量样品羟自由基(·OH)的检测方法,并用于新疆葡萄树伤流液及金银花茶、罗布麻茶、茉莉茶、竹叶茶等样品的检测。方法:采用Mn2+-H2O2-EBT法,检测波长为560 nm,在2 m L的比色皿中,取缓冲溶液(Na B4O7-Na OH)300μL,EBT 120μL,Mn2+300μL,H2O2150μL,将体系体积用水补充至2.0 m L。Mn2+-H2O2-EBT法可作为检测抗氧化物质抗氧化活性的有效可行方法之一,为验证该方法对微量样品抗羟自由基(·OH)活性实时检测的可行性,以抗坏血酸对照。结果:实验结果表明,新疆葡萄树伤流液、金银花茶、罗布麻茶、茉莉茶和竹叶茶均具有较强的清除羟自由基(·OH)的生物活性功能,是一种很好的天然抗氧化及自由基清除剂。结论:微量样品抗羟自由基检测方法可行,实现吸光度测定的同时,对少量样品进行实时、恒温及震荡在线检测,连续观察吸光度的变化。
基金supported by the National High Technology Research and Development Program of China (No. 2012AA101402-2)the National Natural Science Foundation of China (Nos. 41271264, 41325003)
文摘Highly precise and reliable determination of heavy metals in soil micro-arthropod tissues remains a challenge because of the small size of the animals and their typical low abundance in metal-contaminated agricultural soils. The present study sought to develop a method for cadmium （Cd） determination in soil micro-arthropods by optimizing the sample digestion procedure, reducing sample weight, modifying sample pre-treatment and validating the methodology with field samples. The optimized digestion conditions comprised a sample mass of 50-150 μg, digestion reagent of nitric acid：hydrogen peroxide （3：1）, digestion temperature of 105 ℃, digestion period of 3 h and digestion volume of 30 μL. Defecation of the standard Collembola Folsomia candida （92 h） and the indigenous Collembola Onychiurus yodai （42 h） and ultrasonic cleaning of F. candida increased the accuracy of Cd determination. The recovery of Cd using the refined procedure was 98.9% and the limits of detection and quantification were 0.002 and 0.008 μg L-1, respectively. The within-batch precision values were 〈 3%. The Cd concentrations in the tissues of the Collembola Isotorna sp. collected from a range of metal-contaminated fields determined by the improved method were consistent with the Cd concentrations in the field soils. The results indicate that the optimized method can be used for more accurate or reliable determination of Cd concentrations in soil micro-arthropod tissues.
