便携式全反射X荧光同时测定清洁水体中多种元素

应用便携式全反射X射线荧光分析仪,以Sc作内标,同时测定清洁水体中的Cu、Zn、Cr、Fe、Mn、Co、Ni,在X射线管电压30kV,管电流200μA,测定时间100s的条件下,运用点滴支持工具,方法检出限为3.1-5.1μg/L.地表水水样分析结果与ICP-Ms法相符,精密度较好,加标回收率在95％-123％之间.     

Simultaneous Extraction and Atomic Absorption Spectrometric Determination of IB Group Elements (Cu,Ag, Au) from Aqueous Thiocyanate/2,2′-Dipyridyl-2-Pyridylhydrazone (Dpph) Solutions

Abstract

A quantitative simultaneous extraction procedure of copper, silver and gold cations from aqueous thiocyanate solutions into Methyl Isobutyl Ketone (MIBK) is described. the effects of pH, thiocyanate and 2,2′-Dipyridyl-2-py-ridylhydrazone (DPPH) concentration were studied. Tolerance amounts for many diverse cations and anions have been determined. Finally, a procedure for the determination of IB Group elements is recommended, by extaction-AAS.     

液相色谱串联质谱法测定水产品中的敌百虫残留量

将水产品样品经乙腈提取,正已烷除脂,旋转浓缩后采用液相色谱串联质谱法进行定性、定量分析。线性范围为5—100μg/kg,线性相关系数为0.9987,定性检出限1.7μg/kg,定量检出限3.5μg/kg。在鳗鱼、虾和罗非鱼3种不同样品基质中进行添加浓度为10,20,50μg/kg的验证实验,回收率在77.2%—87.5%之间,相对标准偏差(RSD)在5.4%—8.3%之间,并对敌百虫的质谱裂解进行了分析。本法快速简单,高效,灵敏度高,符合检测要求。     

有机无机肥配施黑土胡敏酸结构光谱学特征

土壤有机质是土壤的重要组成部分,在土壤肥力、环境保护、农业可持续发展等方面都具有重要作用。腐殖质作为土壤有机质的主体,对土壤的一系列性质和形态产生影响,其数量、组成和性质可以反映一定的成土条件和过程,是土壤肥力的重要指标。由于腐殖质分子组成的不确定性,各种方法均存在一定的局限性,优化寻求更为准确可靠的腐殖酸表征方法已成为当前研究的热点。施肥方式改变土壤中胡敏酸的组成与结构,但短期的影响程度难以用常规的测定技术检测出来。利用38年的黑土长期定位试验,通过腐殖质组分HA的分离和纯化,多种光谱分析方法的联合应用,从物质结构的角度分析土壤中单施有机肥和有机无机肥配施对黑土HA有机化合物的分子结构变化的影响。分析显示,M和MNPK施肥处理较CK处理均可提高土壤有机碳和HA含量,增加土壤中HA的总反应热、中温放热值、2920/1720值、脂族C含量、f450/500值,表明单施有机肥和有机无机肥配施后土壤HA芳构化程度降低,脂族含量增加,结合简单化,但M施肥处理增加幅度小于MNPK施肥处理。分析结果表明：多种光谱技术的联合应用,可以相互认证其结果的准确性。同时试验结果也证明有机无机肥配施较单施有机肥,更能提高土壤有机碳和土壤HA的脂族C含量,增加作物产量,培肥地力。     

Cu^2＋与胆固醇相互作用的光谱分析研究

以分光光度法（ＳＡ），原子吸收光谱分析（ＡＡＳ）、电感耦合等离子体原子发射光谱法（ＩＣＰ－ＡＥＳ）以及红外光谱分析（ＩＲ）考察了水溶液中Ｃｕ＾２＋与胆固醇的要艇。不同分析方法均得出相同结果，Ｃｕ＾２＋与胆固醇二者间存在表面吸附作用，这种作用在近生理条件下较为显著。     

The stucco decorations from St. Lorenzo in Laino (Como, Italy): The materials and the techniques employed by the “Magistri Comacini”

The paper reports a cross-cutting and systematic approach to the analytical study of Baroque stucco decorations by Italian artists known as “Magistri Comacini”. Samples from the Church of St. Lorenzo in Laino (Como, Italy) were analysed using chemical and mineralogical techniques and the results interpreted with the help of art historians in order to enlighten the artistic techniques. The characterisation of the binder, aggregate and organic fractions was carried out through optical microscopy, scanning electron microscopy with microprobe, X-ray powder diffraction, Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry and laser ablation mass spectrometry equipped with plasma source spectrometry. The results on major, minor and trace components ascertained various recipes. In particular, the investigation of the finishing layers corroborated hypotheses of attribution and chronology and stressed the different skills of the artists working in the building, shedding a light on details of the decoration technique.     

主成分分析在某型柴油机光谱数据分析中的应用

通过改变气缸套和活塞间隙,设计了6种工作状态,获得了某型6缸柴油机在每种工作状态下不同负荷时的润滑油样本共计69个,采用超谱M型原子发射光谱仪分析21种元素浓度。应用主成分分析法,分别以分析元素和润滑油样本为研究对象,基于权系数和主成分得分,对光谱数据进行了元素分类和样本分类。发现应用主成分分析法分析油液光谱数据能比较理想地对元素进行分类,该分类的3种主成分反映了5种类型的元素组合即磨损元素Fe,Cr,Cu,Al和Pb,含量较高的添加剂元素Na,Zn,P,Ca和Mg,含量较低的添加剂元素Ba和B,润滑油主成分元素C和H和干扰元素Ni,Ti,Mo,V和Ag等。不仅如此,主成分分析法对样本的分类较好地区分了来自柴油机不同的气缸套—活塞设计间隙的油样。研究表明应用主成分分析法分析润滑油光谱分析数据可揭示不同元素的来源、监测工况和诊断磨损故障。     

红外光谱定量分析中的一种变量聚类偏最小二乘算法

偏最小二乘算法( Partial least squares, PLS)可以很好地解决分析数据中的变量共线性问题,在光谱分析,尤其是近/中红外及拉曼光谱的定量分析中应用广泛。针对PLS存在的有效信息提取和噪声抑制问题,提出一种变量聚类重加权的PLS算法。通过对光谱的各波数变量进行聚类并分别建模,然后集成为全谱模型。通过对计算并赋予各子类不同的权重,根据对模型的贡献对变量进行重加权,从而提高算法的预测精度。汽油中的辛烷值预测和烟草中的烟碱含量预测两组近红外数据验证表明,所提出算法优于经典的PLS算法,其RMSEP在两组数据中分别降低32%和22%,在光谱数据的定量分析中具有潜在的应用优势。     

The role of certified reference materials in ensuring the quality of spectrochemical measurements – the present status in Romania

 The objective of quality assurance programme for spectrochemical measurements is to reduce the measurement errors to accepted limits. Reference materials are being widely used as measurement standards in the fields of industrial production, environmental protection and clinical chemistry, and are playing an important role in ensuring the quality of measurement results. This paper presents some aspects, practices and examples of the activity of the Reference Materials Laboratory of the National Institute of Metrology, Bucharest, in the field of spectrochemical measurements. An attempt to describe the role and use of reliable certified reference materials to ensure the quality of spectrochemical measurements is presented. A short review of the locally available certified reference materials used in spectrochemical measurements is given. The use of reference materials data in estimating the measurement uncertainty is discussed. An interlaboratory comparison, recently organized in Romania, is also presented as a useful response to the need for quality assurance of spectrochemical results. Received: 20 March 1999 / Accepted: 25 February 2000