X射线荧光光谱(XRF)法测定绿泥石中镁、铝、硅、磷、钾、钙、钛、铁元素含量

建立了X射线荧光光谱法测定绿泥石中镁、铝、硅、磷、钾、钙、钛、铁元素含量的快速分析方法。以标准物质及标准物质与基准试剂氧化镁、氧化钙人工混合配制标样的方法建立标准工作曲线,重点讨论了熔剂和脱模剂的选取。最佳熔样条件：采用8.0g四硼酸锂和偏硼酸锂混合熔剂(质量比67: 33)+0.8g样品并添加溴化锂作为脱模剂,熔样温度1100℃,熔样时间10min。该方法相对标准偏差(n=12)均小于5.57%,绿泥石样品测定结果与化学法一致,硅酸盐标准物质测定结果均满足不确定度要求。     

ICP-AES测定南红玛瑙中剧毒元素As、Cd、Cr、Pb、Sb含量的研究

文章研究报道了电感耦合等离子体发射光谱法测定南红玛瑙中As、Cd、Cr、Pb、Sb元素含量的分析方法。通过对前处理方法的确定、分析线的选择、基体干扰方面的研究,确定了分析条件,并对比研究了标准曲线法与标准加入法在测定方面的异同。标准加入法与标准曲线法的测定结果相近,但标准曲线法的测定结果总是比标准加入法的测定结果小。在标准加入法中,各元素加标回收率在93.6％～103％之间,测定值的相对标准偏差(RSD_n=6)小于10％;在标准曲线法中,各元素加标回收率在90.2％～103％之间,各元素的相对标准偏差(RSD _n=6)也均小于10％。基体效应对标准曲线法测定存在一定的影响,但不十分明显。标准加入法可以很好地减轻基体效应的干扰,但不可大批量测定样品。因此,在分析控制质量要求允许范围内,可采用标准曲线法对南红玛瑙中剧毒元素As、Cd、Cr、Pb、Sb的含量进行测定。     

直读光谱法检测铝合金中硅、锰、镁、锌的标准曲线优化

为了使直读光谱法检测铝合金中硅、锰、镁、锌的标准曲线适应不同系列铝合金样品,减少测量误差,将仪器预置标准曲线细分至10条,即将1条高含量预置标准曲线细分为7条,将1条低含量预置标准曲线细分为3条。通过检测大量铝合金光谱标准样品,将检测结果与标准值进行线性拟合,得出的截距和斜率分别用于调整细分标准曲线的截距A₀和斜率A₁,并使用标准样品进行验证。结果表明,标准曲线细分和优化后,硅、锰、镁和锌的检测结果更加接近证书值,测量误差更小,所考察的标准样品中,最低含量的硅、锰、镁、锌的绝对误差分别从0.002 6%降至0.000 9%、从0.001 0%降至0.000 0%、从0.005 0%降至0.000 2%、从0.005 1%降至0.000 3%;最高含量的硅、锰、镁、锌的绝对误差分别从0.070%降至0.001%、从0.13%降至0.01%、从0.33%降至0.14%、从0.49%降至0.09%。     

直读光谱法测定CD4MCu不锈钢中碳、镍、铬、铜、钼

应用光电直读光谱法测定了不锈钢(CD4MCu)中碳、镍、铬、铜及钼5种元素。通过下述三项措施提高了方法的准确度和精密度:共存元素的干扰校正;增加制作各元素的标准工作曲线时所用的标准样品数,用了两套标准共13块光谱分析用标准样品;选择样块上合适部位作为光谱激发点。上述5种元素的测量范围(质量分数)依次为0.02%～0.35%,3.50%～28.0%,6.50%～32.0%,0.05%～5.0%及0.05%～4.0%。对方法的精密度做了试验,测得相对标准偏差(n=11)为碳4.8%,镍、铬、钼0.4%,铜2.3%。应用此方法分析了5个不锈钢(CD4MCu)样品,所测得数据与用GB标准中化学法所测得的结果完全一致。     

电感耦合等离子体发射光谱(ICP-OES)法测定不锈钢中的硅、锰、磷、铬、镍、钼、铜

用HCl-HNO3混和酸溶解不锈钢样品,用钇为内标物质,使用标准样品绘制工作曲线,用电感耦合等离子体发射光谱(ICP-OES)法测定了不锈钢中的硅、锰、磷、铬、镍、钼、铜。在选定的操作条件下,对不锈钢标准样品按实验方法进行测定,标准样品的测定值与标准值基本吻合。元素质量分数在0.01%～0.10%时,相对标准偏差(n=11)RSD5%;质量分数大于0.10%,RSD 1%。同时测定不锈钢中的硅、锰、磷、铬、镍、钼、铜元素的含量,操作简单、快速、灵敏度高,结果令人满意。     

ICP-AES法同时测定锰矿石中铁、铝、钛、钙、镁、磷、钡、铅的含量

锰矿石样品用HNO3-HF-HClO4酸溶除硅后,对采用ICP-AES法测定其中的铁、铝、钛、钙、镁、磷时,同时测定钡、铅的相关条件进行了试验。主要对酸溶样能否分解重晶石或天青石等含钡矿物进行了探讨,测定了3个国家级标准样品。测定结果与标准值吻合。用标准加入法测得的钡和铅的回收率分别为96．0％-100．5％,97．1％～100．0％。用该法对含钡量较高的澳大利亚锰矿进行分析,测定结果的相对标准偏差为0-82％,并将测定结果与X荧光光谱法测定结果进行了比对。     

X射线荧光光谱法测定催化剂中的铁、镍、铜、钒

介绍用X射线荧光光谱法测定催化裂化催化剂中重金属Fe、Ni、Cu、N含量的分析方法。以未使用过的催化剂为载体配制标准样品,使标准样品与样品的基体基本一致,减少了基体效应的影响。待测元素的线性范围分别为：Fe0.30%～2.50%,Ni0.10%～1.20%,Cu0.02%～0.20%,V0.05%～0.30%,相关系数均为0．9999,测定结果的相对标准偏差小于2％。该方法的测定结果与原子吸收法的测定结果相吻合。     

无公害蔬菜、灌溉水、种植土壤中Pb、As、Cd、Cr的测定

采用原子吸收光谱法测定了广西区内几个无公害生产基地土壤、蔬菜、水样中Pb、As、Cd、Cr的含量,RSD＜7％,回收率在94％－110％之间。用本法测定GBW 08302土壤标准物质,测得值与推荐值基本一致。     

《化学分析计量》征稿、征订、征集广告启事

《化学分析计量》杂志是由中国兵器工业第五三研究所主办、国家标准物质研究中心协办的技术类刊物 ,主要报道我国化学分析计量行业的法规、政策、标准、管理经验和技术经济发展动态 ;化学分析计量专业技术、学术论文 ;标准物质及分析测试的研究成果 ;分析计量仪器的新产品、新技术、仪器检定、维修经验 ;本专业文献综述和信息等。本刊读者对象主要为化学计量、分析测试、标准物质研究、分析计量仪器开发与生产、检定与维修等领域的技术人员、管理人员、营销人员及高等院校师生等。本刊发行量大 ,广告宣传效果好。本刊国内外公开发行 ,国内统…     

ICP-AES法同时测定玻璃组份中的Ca、Mg、Ti、Fe、Pb、Cd、Al、Si、B、Zn、Cu元素

建立了一种用电感耦合等离子发射光谱(ICP-AES)法测定玻璃成份的简便、快速、准确、精密度好的方法．研究了样品的处理、标准样品的配制、谱线干扰等问题,并采用和基体匹配的方法消除基体的影响,进行了标准样品的分析、对照、精密度等试验,均取得了满意的结果．     

Determination of Mo, Zn, Cd, Ti, Ni, V, Fe, Mn, Cr and Co in crude oil using inductively coupled plasma optical emission spectrometry and sample introduction as detergentless microemulsions

A procedure to prepare crude oil samples as detergentless microemulsions was optimized and applied for the determination of Mo, Zn, Cd, Si, Ti, Ni, V, Fe, Mn, Cr and Co by ICP OES. Propan-1-ol was used as a co-solvent allowing the formation of a homogeneous and stable system containing crude oil and water. The optimum composition of the microemulsion was crude oil / propan-1-ol / water / concentrated nitric acid, 6 / 70 / 20 / 4 w/w/w/w. This simple sample preparation procedure together with an efficient sample introduction (using a Meinhard K3 nebulizer and a twister cyclonic spray chamber) allowed a fast quantification of the analytes using calibration curves prepared with analyte inorganic standards. In this case, Sc was used as internal standard for correction of signal fluctuations and matrix effects. Oxygen was used in the nebulizer gas flow in order to minimize carbon building up and background. Limits of detection in the ng g^− 1 range were achieved for all elements. The methodology was tested through the analysis of one standard reference material (SRM NIST 1634c, Residual Fuel Oil) with recoveries between 97.9% and 103.8%. The method was also applied to two crude oil samples and the results were in good agreement with those obtained using the acid decomposition procedure. The precision (n = 3) obtained was below 5% and the results indicated that the method is well suited for oil samples containing low concentrations of trace elements.     

基于主成分和支持向量机浓度参量同步荧光光谱油种鉴别

基于浓度参量同步荧光光谱技术,对不同溢油类型不同油源原油样品集、引入外扰相似油源样品集进行光谱数据采集,获取其浓度同步荧光光谱矩阵Concentration-Synchronous-Matrix-Fluorescence(CSMF),利用主成分分析方法对两套不同层次的原油相关样品集进行了多类分类识别。结果表明:主成分载荷图可以很好地反映各个原油相关样品在油源上的相似程度,结合支持向量机可以实现不同溢油类型及不同油源原油的准确分类,对于引入风化和海水外扰相似油源溢油样品集,两类分类区分的结果远远高于多类分类识别的结果。通过详细的主成分分析讨论,为溢油油种鉴别提供了一种利用多类分类识别,逐步缩减嫌疑样本数量,最后通过两两分类实现溢油样品准确识别的新思路。     

The determination of lead, nickel and vanadium in Saudi Arabian crude oil by sequential injection analysis/inductively-coupled plasma mass spectrometry

The coupling of sequential injection with inductively-coupled plasma mass spectrometry as an analytical tool for trace element detection is described. The technique is applied for determining the concentrations of lead, nickel and vanadium at part per billion levels in sample solutions of Saudi arabian crude oils. A microemulsion crude oil sampling procedure and a standard addition method using oil-soluble organo metallic salts of trace elements were used. A reference oil sample (NBS 1634b) was analyzed to obtain the accuracy and precision of the method. Results showed percentage recovery values of 98.2%, 95.7% and 101.4% and standard deviations of 2.9%, 1.5% and 2.0% for lead, nickel and vanadium respectively. The method is sensitive, requires only small sample volumes and is quick.     

基于费谢尔判别法的原油、燃料油鉴别技术研究

对原油、燃料油的鉴别方法进行了研究.以来自不同国家和地区的30个原油样品以及不同产地、不同种类的24个燃料油样品中的正构烷烃(n-C7～30)、植烷(Ph)、姥鲛烷(Pr)的含量构成训练集.借助SPSS 16.0进行费谢尔(Fisher)判别分析,建立Fisher判别函数.将判别变量值代入后,得到样本的空间位置,再计算样本至各组重心的距离,据此判断分类情况.结果表明,Fisher判别法可以很好地用于原油和燃料油的鉴别,具有快速、准确等特点.     

Trace Metals Determination by Wet Ashing ICP/MS in Saudi Arabian Crude Oils

Abstract

The effect of metallic traces present in crude oils has raised a major concern to develop aquantitative analytical method. A Wet-Ashing procedure has been used for sample pretreatment to determine Al, Cd, Fe, K, Li, Mn, Ni, Pb, Sn and V in five (5) Saudi Arabian crude oil samples as multi-elements by Sciex elan ICP/MS. The relative standard deviation was found not more than 3% for five replicate samples.     

Prediction of physical–chemical properties of crude oils by 1H NMR analysis of neat samples and chemometrics

In this work, we report the feasibility study to predict the properties of neat crude oil samples from 300‐MHz NMR spectral data and partial least squares (PLS) regression models. The study was carried out on 64 crude oil samples obtained from 28 different extraction fields and aims at developing a rapid and reliable method for characterizing the crude oil in a fast and cost‐effective way. The main properties generally employed for evaluating crudes' quality and behavior during refining were measured and used for calibration and testing of the PLS models. Among these, the UOP characterization factor K (K_UOP) used to classify crude oils in terms of composition, density (D), total acidity number (TAN), sulfur content (S), and true boiling point (TBP) distillation yields were investigated. Test set validation with an independent set of data was used to evaluate model performance on the basis of standard error of prediction (SEP) statistics. Model performances are particularly good for K_UOP factor, TAN, and TPB distillation yields, whose standard error of calibration and SEP values match the analytical method precision, while the results obtained for D and S are less accurate but still useful for predictions. Furthermore, a strategy that reduces spectral data preprocessing and sample preparation procedures has been adopted. The models developed with such an ample crude oil set demonstrate that this methodology can be applied with success to modern refining process requirements. Copyright © 2012 John Wiley & Sons, Ltd.     

Effect of Inorganic Solids,Wax to Asphaltene Ratio,and Water Cut on the Stability of Water-in-Crude Oil Emulsions

The formation of stable water-in-crude oil emulsions during petroleum production and refinery may create sever and costly separation problems. It is very important to understand the mechanism and factors contributing to the formation and stabilization of such emulsions for both great economic and environmental development. This article investigates some of the factors controlling the stability of water-in-crude oil emulsions formed in Burgan oil field in Kuwait. Water-in-crude oil emulsion samples collected from Burgan oil filed have been used to separate asphaltenes, resins, waxes, and crude oil fractions. These fractions were used to prepare emulsion samples to study the effect of solid particles (Fe₃O₄) on the stability of emulsions samples. Results indicate that high solid content lead to higher degree of emulsion stability. Stability of emulsion samples under various waxes to asphaltenes (W/A) ratios have also been tested. These tests showed that at low W/A content, the emulsions were very stable. While at a wax to asphaltene ratio above 1 to 1, the addition of wax reduced emulsion stability. Stability of emulsion samples with varying amount of water cut has also been investigated. Results indicated that stability and hence viscosity of emulsion increases as a function of increasing the water cut until it reaches the inversion point where a sharp decline in viscosity takes place. This inversion point was found to be approximately at 50% water cut for the crude oils considered in this study.     

Sample preparation methods for subsequent determination of metals and non-metals in crude oil—A review

In this review sample preparation strategies used for crude oil digestion in last ten years are discussed focusing on further metals and non-metals determination. One of the main challenges of proposed methods has been to overcome the difficulty to bring crude oil samples into solution, which should be compatible with analytical techniques used for element determination. On this aspect, this review summarizes the sample preparation methods for metals and non metals determination in crude oil including those based on wet digestion, combustion, emulsification, extraction, sample dilution with organic solvents, among others. Conventional methods related to wet digestion with concentrated acids or combustion are also covered, with special emphasis to closed systems. Trends in sample digestion, such as microwave-assisted digestion using diluted acids combined with high-efficiency decomposition systems are discussed. On the other hand, strategies based on sample dilution in organic solvents and procedures recommended for speciation analysis are reported as well as the use of direct analysis in view of the recent importance for crude oil field. A compilation concerning sample preparation for crude oil provided by official methods as well as certified reference materials available for accuracy evaluation is also presented and discussed.     

Direct olive oil authentication: detection of adulteration of olive oil with hazelnut oil by direct coupling of headspace and mass spectrometry, and multivariate regression techniques

Control of adulteration of olive oil, together with authentication and contamination, is one of the main aspects in the quality control of olive oil. Adulteration with hazelnut oil is one of the most difficult to detect due to the similar composition of hazelnut and olive oils; both virgin olive oil and olive oil are subjected to that kind of adulteration. The main objective of this work was to develop an analytical method able to detect adulteration of virgin olive oils and olive oils with hazelnut oil by means of its analysis by a headspace autosampler directly coupled to a mass spectrometer used as detector (ChemSensor). As no chromatographic separation of the individual components of the samples exists, a global signal of the sample is obtained and employed for its characterization by means of chemometric techniques. Four different crude hazelnut oils from Turkey were employed for the development of the method. Multivariate regression techniques (partial least squares and principal components analysis) were applied to generate adequate regression models. Good values were obtained in both techniques for the parameters employed (standard errors of prediction (SEP) and prediction residual error sum of squares (PRESS)) to evaluate its goodness. With the proposed method, minimum adulteration levels of 7 and 15% can be detected in refined and virgin olive oils, respectively. Once validated, the method was applied to the detection of such adulteration in commercial olive oil and virgin olive oil samples.     

Systemic analysis of structures and contents of nitrogen-containing compounds and other non-hydrocarbons in crude oils in conjunction with chemometric resolution technique.

A method is described for the systemic identification and quantitative analysis of nitrogen-containing compounds and other non-hydrocarbons in crude oils. The pre-fractionation of a crude oil sample into 7 fractions was performed by di-adsorption column chromatography using neutral aluminum oxide and silica gel. A subsequent high-resolution separation of individual components was achieved by using capillary column gas chromatography, and compound types were detected by a mass spectrometer. In conjunction with a chemometric method, the compounds in the fractions were further resolved or separated, which made it possible to identify some nitrogen-containing compounds and other non-hydrocarbons in crude oils. To a certain extent, this method could relieve the difficulty of classical analysis in identifying those species with very low contents or incompletely separation, particularly in the cases where authentic standards were not available for addition into the unknown samples in order to reveal what indeed existed in them. The structures and contents of 168 nitrogen-containing compounds in one crude sample and 60 non-nitrogen-containing compounds in one of non-hydrocarbon fractions of this oil sample were determined, and the addition-recovery examination of some standard compounds showed that the analytical veracity was satisfactory.