X射线荧光光谱法测定高含量有机碳样品中的钾、钠、钙、镁、硅、铝、铁、钛、锰、磷

通过事先对有机碳含量较高的样品于1000℃ 下灼烧2 h,计算其烧失量,再将灼烧后的样品经Li2 B4 O7(67％)和LiBO2(33％)的混合熔剂熔融制样后,经X射线荧光光谱仪测定,能够有效地去除因有机质含量高导致的分析结果的偏差,总体的平均相对误差从11.1％ 减少到了4.5％,而且较湿法化学分析节省时间.分析结...     

刚玉粉、高岭土、莫来石中铝、硅的测定

主要针对三种原材料中的Al含量和Si含量的分析方法进行讨论。采用容量法对其中的Al含量进行测定,在酸性溶液中,加入过量的EDTA溶液络合铝并掩蔽残余元素。在微酸性溶液中以二甲酚橙为指示剂,用氯化锌标准溶液滴定过量的EDTA,以氟化铵络合铝而游离出等量的EDTA。再用氯化锌标准溶液滴定至溶液呈橙红色即为终点。根据氯化锌标准溶液的消耗量换算出Al2O3的含量。采用重量法对其中Si含量进行测定,将熔融后的试样进行处理,使之生成硅酸沉淀。经灼烧、称重后以硫酸、氢氟酸进行挥硅处理,再灼烧称重,根据两次质量之差换算出SiO2的含量。两种分析方法均为经典化学分析方法,其分析结果准确可靠,并且具有广泛的使用性。     

X射线荧光光谱法测定除尘灰中砷、铅含量

以熔融制样法,采用X射线荧光光谱对除尘灰中的有害元素：砷、铅含量进行了测定。对样品的烧失温度进行了讨论,发现在950℃灼烧温度下灼烧2h时除碳完全。砷和铅的相对标准偏差为0.15 %和0.20 %。测试结果与化学分析法、原子吸收光谱法等相吻合。该方法制作工艺简单,分析速度快,样品可长期保存,还能满足其他元素的日常分析。     

高频红外碳硫分析仪测定含碳化硅耐火材料中碳化硅含量

采用对试样进行灼烧预处理的方法,除去游离碳,用锡粒、纯铁、钨粒作为助熔剂,并以钢铁标准样品校正仪器,高频燃烧红外吸收法测定含碳化硅耐火材料中的碳化硅含量,测定结果的相对标准偏差为1.07%(n=6),该法与化学法的测定结果较接近,精密度和准确度均满足化学分析的要求。     

熔融制样-X射线荧光光谱法测定工业硅中总硅、二氧化硅和其他杂质组分

将四硼酸锂内衬坩埚熔融制样方法应用于X射线荧光光谱法测定工业硅中总硅、二氧化硅和其他杂质组分(铝、铁、钙、镁、钛)。在熔融制样前,样品(1.000 0g)经直接灼烧(700～750℃)计算灼减量并除去样品中碳。称取上述灼烧后的样品0.200 0g,与碳酸锂1.700g和600g·L~(-1)硝酸铵溶液0.1～0.3mL混匀后移入四硼酸锂内衬坩埚中,于710～720℃预氧化10～12min。将此经预氧化的混合物及其内衬坩埚一起转移至预置有3.000g硼酸的铂金坩埚中,加入400g·L~(-1)溴化铵溶液0.1～0.4mL,于熔样机中静置熔融8min,摇动熔融12min,冷却,脱模后即得样品的玻璃片。选取测定元素的氧化物,按0.200 0g称样量模拟制备了5个校准样片,各组分的质量分数在一定范围内与其对应的X射线荧光强度呈线性关系,提出了样品中二氧化硅含量的计算公式。方法用于5个工业硅样品的分析,测定结果与湿法分析测定值相符。     

化学分析中计算含量的几种简化方法

在大规模工业性的化学分析实验室里,操作时间的缩短是大家所重视的一个问题。定量分析中百分含量的计算虽然很简单,有时只需乘上一个因数便算出待测元素的百分含量,但遇有大批样品同时计算时所累积的时间是值得考虑简省的。今分别以下列三种情况加以阐述。一、重量法在一般情况下,若称量形式为待测成分时,可称取1.000克样品,经溶样、分离、沉淀、灼烧等手续后,灼烧物的称量直接表示了该成分在此样品中所占的比率,乘上100即得百分含量。例:如某样品要测定 CaO 的百分含量,且它的称量形式也是 CaO 时,则可称取1.000克样品。样品分解后,经过必要的分离手续,再加入草酸铵作为沉淀剂使之发生 CaC_2O_4·H_2O 沉淀,过滤后进行灰化并在高温下灼烧,最后形成 CaO 称量。CaO 的净重(克数)     

熔融制样-X射线荧光光谱法测定含碳及碳化硅的铝镁质、锆质耐火材料中的7种氧化物

建立了熔融制样-X射线荧光光谱法(XRFS)测定含碳及碳化硅的铝镁质、锆质耐火材料中的二氧化锆、三氧化二铝、二氧化硅、氧化钙、氧化镁、三氧化二铁、二氧化钛等含量的方法。将样品置于950℃马弗炉内灼烧1 h以除去其中的碳。将四硼酸锂置于铂-金坩埚中熔融,旋转坩埚使熔融态四硼酸锂附着在坩埚壁上,以减少碳化硅对铂-金坩埚的腐蚀。将1.000 0 g碳酸锂、1.000 0 g硝酸锂和0.300 0 g灼烧过的样品混合,置于挂膜处理好的铂-金坩埚中,上面再覆盖2.000 0 g四硼酸锂,在程序升温条件下预氧化以去除样品中的碳化硅。加入溴化锂溶液(脱模剂),在1 120℃下熔融20 min,浇入铂-金成型模具中,制成玻璃样片,供XRFS分析。结果显示:7种氧化物的线性相关系数不小于0.999 0,检出限为28～15 123μg·g~(-1);对实际样品重复测定8次,7种氧化物测定值的相对标准偏差均小于4.0%;将方法所得结果与GB/T 16555-2017中化学湿法的进行比较,偏差基本在国家标准方法允许偏差的范围内。     

X射线荧光光谱法测定钾长石、钠长石中多种元素

采用熔融制样,以钾长石、钠长石国家标准样品为主,辅以粘土、炉渣、硅石等标准样品,配制成一系列校准标准样品,用X射线荧光光谱法测定钾长石和钠长石中的Na2O、Al2O3、SiO2、K2O、CaO、Fe2O3、TiO2的含量,结果表明:方法的相对标准偏差为0.065%～2.9%,其测定结果与标准值基本一致,准确度好,可替代湿法化学分析,适合于长石类硅铝酸盐矿物的日常分析。     

络合滴定法测定有机化合物中的锌和钴

<正> 关于有机化合物中金属元素的测定,过去多用灰化法,即将样品灼烧,称量灼烧后的残渣,再计算金属含量。在实际工作中发现灰化法并不理想。如果将金属和碳氢同时测定,称量金属氧化物产生的极小偏差就会给结果带来很大误差,有时远远超过元素分析允许的误差范围。如果把金属转变成硫酸盐又要专门的装置,且不能与碳氢同时测定,更是不便。作者最近用EDTA络合滴定法测定了有机化合物中的锌和钴,均得     

含石英脉的金矿溶解和滴定前的蒸发问题

近年来我队金分析采用氢醌滴定容量法。通过近千个样品的分析,对于含石英脉的金矿或被黄铁矿包裹的金样品的分解和滴定前的蒸发问题有如下体会。1.金矿样品的分解目前,湿法测定金,普遍以王水(1+1)分解样品。在生产实践中发现被石英脉或黄铁矿所包裹的金,如果直接用王水(1+1)分解,分析结果就偏低。其原因是:①因为石英在王水中不易分解,所以,包裹在石英内的金不能直接被王水分解;②黄铁矿经灼烧后生成氧化铁也难溶于王水。为了使此类样品中的金能被王水完全分解:1)应予先用氟化铵或氟化氢铵等作为助溶剂,与石英作用以除     

粉末压片X射线荧光光谱法测定铌铁合金中 铁、铌、硅、铝、磷

为提高铌铁合金检验效率,替代繁琐的化学湿法分析,采用粉末压片制样,利用X荧光光谱法对铌铁合金中Fe、Nb、Si、Al、P 5种主要成分进行测定。选用定值过的生产样品作为内控标准样品,主要研究制样细节对分析结果的影响,确认合适的试样粒度和压片参数,通过曲线拟合建立校准曲线。测定结果与化学湿法和电感耦合等离子体原子发射光谱法测定结果比较,各组分精密度相对标准偏差为0.48%～1.9%,准确度满足国标分析要求。     

Electron microprobe analysis of micro amount powder samples: A case study on high purity coal

For the major, minor and trace element analysis of the inorganic compounds of a Ruhr-Saar coal different preparation techniques are investigated with X-ray fluorescence analysis, electron microprobe and classical wet chemical methods minimizing sample weight at standard preparation times and analytical accuracies. Considering accuracy as well as preparation efforts, determinations by electron microprobe on small sample amounts (<50 mg) proved to be superior to the other methods.Abbreviations AAS atomic absorbtion spectrometry - EMA electron microprobe analysis - IC ion chromatography - ISE ion sensitive electrode - PHOT photometry - WCA wet chemical analysis - XRF X-ray fluorescence analysis - LTA low temperature plasma ashing - HTA high temperature ashing - l.o.i. loss on ignition     

Probenvorbereitung von Ferrolegierungen und Sintern durch Umschmelzen und Feinstmahlung

For the sample preparation of many ferroalloys in connection with their analysis by optical emission or X-ray spectrometry the recasting process has been approved. In those cases in which due to high viscosity of the melt, reactions with the refractory material of the crucible or the influence of oxygen the recasting technique is not applicable, the samples can be prepared by “wet grinding”. The following example shows the typical conditions: 60 g of a ferroalloy and 60 ml isopropanol are grinded for 5 min in a disk swing mill. The final step of preparation is done by pressing of the material received. Furthermore, oxide materials may be prepared by wet grinding. The described wet grinding process completes the other wellknown preparation techniques like remelting and chemical decomposition.     

Normalized mass mapping of Orbitrap data to define complex,polyglycerol‐based raw material compositions

Kendrick Mass Mapping of complex sample compositions, via data derived by Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) at 1 000 000 resolution, is becoming more common. The Orbitrap mass spectrometer (Fourier Transform Axially Harmonic Orbital Trapping) also uses FT methods and indirect detection, though operating at a maximum resolution of 100 000. We define the more general case of Normalized Mass Mapping to any repeating oligomer unit (e.g., C₃H₆O₂) and apply it to Orbitrap‐based mapping of a complex polyglycerol ester, 'green' raw material. Mass measurement errors showed sub‐ppm precision and accuracy in many cases, parameters that are critical to obtaining well‐defined maps. Map‐derived, raw‐material‐characterization parameters such as iodine value are compared with wet‐chemical results and show reasonable agreement for our purposes. The methodology appears applicable to raw material control and eliminates wet chemical methods. Copyright © 2010 John Wiley & Sons, Ltd.     

The Measurement of Dextran in Raw Sugars Using 1H NMR1

Abstract

In the cane sugar industry the purchase price of raw cane sugar, the product of sugar cane processing, is determined by polarimetric measurement of sucrose content in raw sugar solutions, expressed as Pol. Raw sugar generally contains more than 96% sucrose, but also contains other saccharides and non-sugars which can contribute to Pol. Dextrans, one class of polysaccharides often found in raw sugar, effect an increase in Pol and interfere with subsequent refining. The U.S. sugar refining industry can impose a penalty on the raw sugar purchase price for high dextran content. While there are several wet chemical methods for the determination of dextran in raw sugar, the results of these analyses are rarely in agreement. The existing wet chemical methods for the determination of dextran in raw cane sugar are reviewed and the results of these wet chemical analyses are compared with the results obtained from the physical measurement of dextran in raw sugar by ¹H NMR spectroscopy.     

差示分光光度法测量Cu30W70钨铜合金中钨的含量

采用传统的湿化学差示分光光度分析方法,研究了广泛用于军工、高压开关、电火花电极、电子封装的新型材料钨铜合金中钨含量的定量分析方法。由于该材料的耐腐蚀性,试样溶解是关键,实验表明采用盐酸+硝酸(9+1)、硫酸+磷酸(1+3)混合酸低温加热溶解,测定时加入草酸胺掩蔽铜的干扰,用硫氰酸胺显色。以Cu30W70为例用40%的钨为参比,配制一系列标准溶液制作工作曲线,钨含量在5~10μg/mL内服从比耳定律,方法的相对标准偏差(RSD)为1.6%,加标回收率为101.6%,适用于含钨45%以上的钨铜合金中钨的测定。     

Comparison of single- and dual-axis rotation techniques for total nitrogen in explosives by fast neutron activation analysis

Total nitrogen content in organic explosives and relate materials can be determined by fast neutron activation analysis (FNAA) to an absolute accuracy comparable to wet chemical or combustion analysis, i.e. to within less than 0.1% N. This is accomplished by dual-axis rotation of the sample and a carefully selected reference standard during neutron irradiation. The optimum reference standard is one of similar composition, density, weight and volume to the sample being analyzed. Rapid pneumatic transfer of organic explosives of low mechanical shock sensitivity poses no special safety problems. For large numbers of individual samples, a multiple sample irradiation system with single-axis rotation can be used for more rapid analysis. Precision and accuracy by this method are not as good as compared to a dual-axis rotation technique. Absolute accuracy for total nitrogen is in the order of 0.2%. This method is useful only for those reactions where the half-life of the product is long enough to allow for sequential counting of multiple samples for a single irradiation.     

便携式X射线荧光光谱法同时测定氧化锌富集物中锌铁氯镉砷

氧化锌富集物的进口能弥补我国锌矿资源的不足,但要求ZnO>50%、Fe<10%、Cl<8%、Cd<0.25%、As<0.6%。目前常采用YS/T 1171.1～10-2017《再生锌原料化学分析方法》检测氧化锌富集物中锌铁氯镉砷含量,该系列检测方法均需要繁琐的湿法样品前处理,测量过程较为冗长,不能满足氧化锌富集物大量进口时快速通关的需求。故实验建立了采用便携式X射线荧光光谱法(PXRF)同时测定氧化锌富集物中锌铁氯镉砷的方法。采用YS/T 1171.3-2017和YS/T 1171.5-2017方法对氧化锌富集物样品进行定值,然后选取21个含量具有梯度的氧化锌富集物样品作为校准样品,建立起各元素X射线荧光强度值与含量的校准曲线。各曲线相关系数在0.8164～0.9999,方法检出限为0.013%～1.95%,各元素的相对标准偏差(RSD,n=11)均小于0.05%。采用本方法和化学方法分别检测氧化锌富集物样品,各元素的本方法检测值与化学分析方法检测值的相对误差均小于20%。本方法能应用到口岸现场进口氧化锌富集物快速筛查,检测一个样品仅需1分钟测量时间,极大地加快了进口氧化锌富集物通关速度。     

Comparison of various calibration techniques for the direct spectroscopical analysis of SiC powders

Techniques for the direct analysis of powdered advanced ceramics provide an advantageous alternative to methods using wet digestion in sample preparation. The direct spectrochemical methods based on electrothermal vaporization (ETV-ICP-OES, solid-ETV-AAS, etc.) show a great similarity to the classical method of d. c. arc excitation. The calibration procedure is the major difficulty of all techniques applied for direct solid sample analysis, as there is a lack of suitable reference materials of ceramics. Consequently, it was necessary to verify various possibilities of preparation and application of model calibration samples. The results of such a calibration are compared with those using within-laboratory standards.