地质样品中27项元素的粉末压片法x射线荧光光谱测定

本文报导了用x射线荧光光谱法—次粉末压片制样同时测定Na. Mg. Al. Si.P. S. K. Ca. Ti. V. Cr. Mn. Fe. Co. Ni. Cu. Zn. Rb. Sr. Y. Zr. Nb. Ba. Hf. Pb. Th. U等27项元素的快速分析方法。从理论上提出了新的基体效应学校正模式,首次引入了非荧光分析的物质(筒称NFAM)的新概念;并计算了理论α系数,使理论α系数在粉末压片法x射线荧光分析中获得了应用。本方法测定的对象可以是岩石,土壤和水系沉积物等地质样品。     

X－射线荧光光谱法测定道路扬尘中21种元素

本文用Ｘ－射线荧光光谱法，一次测定道路扬尘中Ｎａ等２１种元素。人工配制标样，回归法求取校准曲线常数，用散射线内标法和经验系数法校正基体效应。方法的准确度、精密度较好，分析结果令人满意。     

X Series 2 ICP-MS CCT~(ED)在食品样品超痕量元素分析中的应用

ICP-MS作为一种新兴的痕量元素检测技术正被越来越多地在食品分析中应用.ICP.MS具有检测速度快,低检出限,多元素同时检测,动态范围宽的特点,而这些优势是石墨炉原子吸收所不具备的,在食品分析中,主要存在以下几个问题:基体较为复杂,ICP-MS中存在非常明显的基体效应,这些效应影响ICP-MS测试的精度和准确性,样品消解溶液存在高含量的Ca,Mg,K,Cl和C等元素基体,其次,食品中的高含量Ca,Na和Cl等基体对待测的痕量As和Se的干扰尤为明显.     

影响环境监测结果的因素

本文讨论了一些容易忽视却普遍存在、影响环境监测结果的因素，例如采样，器皿溶出物，界面现象，空气，试剂，仪器设备性能，基体效应等。     

Effect of substrate COD/N ratio on performance and microbial community structure of a membrane aerated biofilm reactor

Two parallel carbon-membrane aerated biofilm reactors were operated at well-defined conditions to investigate the e ect of substrate COD/N ratios on the performance and microbial community structure of the bioreactor. Results showed that at substrate COD/N of 5, organic and nitrogen could be eliminated simultaneously, and COD removal degree, nitrification and denitrification e ciency reached 85%, 93% and 92%, respectively. With increasing substrate COD/N ratios, the specific oxygen utilization rates of nitrifying bacteria in biofilm were found to decrease, indicating that nitrifying population became less dominant. At substrate COD/N ratio of 6, excessive heterotrophs inhibited the activity of nitrifying bacteria greatly and thus led to poor nitrification process. With the help of fluorescence in situ hybridization (FISH), Nitrosomonas and Nitrosospira were identified as dominant ammonia-oxidizing bacteria in the biofilm at substrate COD/N of 0, whereas only Nitrosospira were detected in the biofilm at COD/N ratio of 5. Nitrospira were present as dominant nitrite-oxidizing bacteria in our study. Confocal laser scanning microscopy images revealed that at substrate COD/N ratio of 0 nitrifying bacteria existed throughout the biofilm and that at COD/N ratio of 5 they were mainly distributed in the inner layer of biofilm.     

基体效应及空白在不同校准方法中的影响和校正

空白和基体效应对于痕量分析的影响是不可忽视的.本文讨论在不同校准方法中各种空白和基体效应的影响方式及其误差的校正方法.1 基体效应和空白基体效应(matrix effect)是指试样中的基体及其它少量的非待测组份(第三元素)对待测物测量值的影响.基体效应表现在以下     

岩矿样品X射线荧光分析中多元素体系理论α系数的计算和应用

本文提出了岩矿样品X射线荧光分析中多元素体系的理论α系数的一种计算方法。假设试样由n个组分组成,其各组分平均含量为Cl(Cl=1,2,3,…k,……n),然后,假设某一组分的含量Cl相对于平均含量Cl有一微小变化量ΔC,并使每个组分相应变化一次,用基本参数法方程计算理论X射线相对强度;再按一定的数学模式计算相应的基本α系数,混合α系数和修正α系数。以实例计算了用于地质样品分析的各种理论α系数,应用于实际分析中结果令人满意。