粉末压片-X荧光光谱法测定过磷酸钙中硫含量

硫是过磷酸钙中重要营养指标之一,为准确快速测定过磷酸钙中硫的含量,试验采用粉末压片-X荧光光谱法,将过磷酸钙试样充分干燥后研磨至粒度小于74 μm,采用硼酸镶边,在压力18 Mpa条件下保压30 s,制成样片。通过在过磷酸钙样品中添加不同质量的纯物质硫酸钙（质量分数范围1.52 %～17.21 %）,经过专用混匀设备混合均匀后,与试样压片相同条件下压制标准样片,作为过磷酸钙中硫的标准样品,建立硫标准曲线,曲线线性相关系数R2为0.9995,采用经验系数法校正干扰,建立了粉末压片-波长色散X射线荧光光谱法测定过磷酸钙中硫含量的方法, 方法检出限为0.002 %。对3个不同硫含量的过磷酸钙样品采用本实验方法重复测量7次,RSD在1.4 %~3.1 %,方法精密度性好,同时用高温燃烧红外光谱法和电感耦合等离子发射光谱法对比,三者测量结果相对极差小于2.0 %,测量结果无显著性差异。此方法不需要对样品进行熔融或溶解,样品制备简单,数据准确度和稳定性好,分析效率高,适合大批量样品中硫的测定。     

Determination of As, Sb, Se, Te and Bi in milk by slurry sampling hydride generation atomic fluorescence spectrometry

A simple and fast analytical procedure has been developed for the determination of As, Sb, Se, Te and Bi in milk samples by hydride generation atomic fluorescence spectrometry (HG-AFS). Samples were treated with aqua regia for 10 min in an ultrasound water bath and pre-reduced with KBr for total Se and Te determination or with KI and ascorbic acid for total As and Sb, the determination of Bi being possible in all with or without pre-reduction. Slurries of samples, in the presence of antifoam A, were treated with NaBH₄ in HCl medium to obtain the corresponding hydrides, and AFS measurements were processed in front of external calibrations prepared and measured in the same way as samples. Results obtained by the developed procedure compare well with those found after microwave-assisted complete digestion of samples. The proposed method is simple and fast, and only 1 ml of milk is needed. The values obtained for detection limit are 2.5, 1.6, 3, 6 and 7 ng l⁻¹ for As, Sb, Se, Te and Bi respectively in the diluted samples, with average relative standard deviation values of 3.8, 3.1, 1.9, 6.4 and 1.2% for three independent analysis of a series of commercially available samples of different origin. Data found in Spanish market samples varied from 3.2±0.3 to 11.3±0.2 ng g⁻¹ As, from 3.1±0.2 to 11.6±0.4 ng g⁻¹ Sb, from 10.7±0.5 to 25.5±0.4 ng g⁻¹ Se, from 0.9±0.2 to 9.4±0.6 ng g⁻¹ Te and from 11.5±0.1 to 27.7±0.4 ng g⁻¹ Bi.     

Study of biofilm formation by total-reflection X-ray fluorescence spectrometry

A total reflection X-ray fluorescence spectrometric method was developed for elemental analysis of natural biofilms grown on polycarbonate substrates in the Lake Velence. For the duration of 9 weeks long growing period, two substrates were removed weekly from the lake and investigated by analytical and algological methods. The total biomass production achieved its highest value after 7 weeks. Ca, Sr and Ti, as well as Fe, Mn, K and Zn showed their maximum concentrations in the biofilms after 5 and 6-7 weeks, respectively. The enrichment factors of the 6 weeks old biofilm for the detected seven elements amounted to 10³-10⁴. The recommended colonization time for biomonitoring of the Lake Velence is 6 weeks applying polycarbonate substrates.     

X射线荧光光谱法测定金红石中主次组分

采用Li2B4O7和LiBO2的混合熔剂(67∶33)熔融制样,波长色散X射线荧光光谱法测定金红石中TiO2,TFe,P,SiO2,Al2O3,MnO,CaO,Cr2O3,MgO,ZrO2,HfO2等组分。实验中样品和熔剂的质量比为1∶14,以溴化锂(LiBr)作脱模剂,采用高频熔炉在1 150℃熔融90s进行制样,所得熔片均匀、强度高、成型良好。方法用于金红石实际样品的测定,结果同参考值或化学分析方法的结果相吻合,相对标准偏差(RSD,n=10)P为3.8%、Al2O3为2.8%,其它均小于2%,能够满足实际测定工作的需要。     

X射线荧光光谱法测定重整铂催化剂中氯

建立重整铂催化剂中氯的X射线荧光光谱测定方法。通过研磨机将铂催化剂研磨至粒径小于75 μm的颗粒,采用仪器压片制样,通过测量不同氯含量样品的计数率,建立铂催化剂中氯含量与计数率的线性关系。氯的质量分数在0.85%~1.04%范围内与计数率成良好的线性关系,相关系数为0.9995,检出限为0.0076%。样品加标回收率为96.2%~104.2%,测定结果的相对标准偏差小于2%(n=6)。该法测定结果与电位滴定法相吻合。该方法精密度高,分析速度快,满足重整装置生产调整的要求。     

X射线荧光光谱法测定地质样品中的硫和氟

采用粉末压片制样-X射线荧光光谱法研究地质样品中硫(S)和氟(F)元素的快速测定方法。通过分级过筛实验优化确定样品粒度,探讨样品粒度对测定结果的影响,并进行实际样品和标准物质验证。结果显示,样品粒度为85μm时,经实际样品和标准物质验证,测定结果与化学值和标准认定值相符,且相对标准偏差(RSD)均小于2%。方法具有准确度高、检出限好、测试范围宽、简便快速等优点,能确保样品分析结果的准确性,实现了地质样品中S和F的快速测定。     

X-ray fluorescence determination of As, Bi, Co, Cu, Fe, Ni, Pb, Se, V and Zn in natural water and soil extracts after preconcentration of their pyrrolidinedithiocarbamates on cellulose filters

A simple method for the elements preconcentration on thin-layer paraffin-treated cellulose filters was proposed. It was found that pyrrolydinedithiocarbamates of As(III), Bi, Cd, Co, Cu, Fe(III), Ni, Pb, Se(IV), V(V) and Zn obtained after mixing of sample (3-5 ml min⁻¹) and reagent (0.7-1.0 ml min⁻¹) streams were quantitatively recovered from 100 ml sample. The sample acidity was adjusted to pH 4.8-5.2 for preconcentration of Cd, Co, Cu, Fe(III), Ni, Pb, V(V) and Zn, and to 2 M HCl for preconcentration of As, Bi and Se. The optimum reagent concentration was found to be 0.1%. The elements were determined on the filters by X-ray fluorescence spectrometry. The detection limits achieved were 0.1-4.0 μg of element on the filter. Relative standard deviation (R.S.D.) was not higher than 0.08 while determining 5-50 μg of elements on filter. Accuracy and precision of the technique proposed were evaluated by the analysis of spiked natural samples.     

X射线荧光光谱法测定钠冰晶石的主要化学成分

选用国家标准样品和高纯物质配制实验用标准样品,采用混合熔剂(67%Li2B4O7+33%LiBO2)熔融制样,使用X射线荧光光谱法测定钠冰晶石中SiO2、Fe2O3、MgO、CaO、K2O、TiO2、P2O5、Na、F、Al各组分的含量,实验结果表明,各组分的相对标准偏差(RSD)在0.57%~6.5%,与第三方实验室对比测定结果表明,方法可以满足工厂检测要求。     

Extended fine structure in characteristic X-ray fluorescence: A novel structural analysis method of condensed systems

An oscillation similar to that in extended X-ray absorption fine structure (EXAFS) is found in characteristic X-ray fluorescence spectra, originating from a quantum interference effect during the X-ray emission process in a solid. We observe the oscillating fine structure in the radiative Auger X-ray fluorescence spectra of aluminum metal. The Al-Al interatomic distances are successfully reproduced by the Fourier transform of the fine structure. Thus, the present method has the potential to become a convenient alternative to EXAFS measurement for light elements.     

Simultaneous determination of traces of iron, cobalt, nickel, copper, mercury and lead in water by energy-dispersive x-ray fluorescence spectrometry after preconcentration as their piperazino-1,4-bis(dithiocarbamate) complexes

A bidentate chelating agent has been proposed to preconcentrate seven metal ions dissolved in an aqueous sample for their simultaneous determination using energy-dispersive x-ray fluorescence spectrometry. The metal ions are precipitated as their polymeric piperazino-1,4-bis(dithiocarbamate) chelates, which are then collected by vacuum filtration on a Millipore membrane filter for direct examination by x-ray fluorescence analysis. Iron, cobalt, nickel, copper and zinc are determined by means of their K x-rays and mercury and lead by means of their L x-rays. A detection limit in the μg1⁻¹ range can be achieved for all metals tested in 250-ml water samples with a counting time of 600 s. Effective precipitation of all metals occurs at pH 6–7. The recoveries of eight analyses of the metals in a multielement standard using the proposed method ranged from 97 to 105% and the precision ranged from 2.3 to 3.1%. High concentrations of calcium and magnesium do not interfere with the method. The method is simple, sensitive and accurate, and has been used for the simultaneous determination of the seven metals under study in environmental samples and synthetic mixtures.     

X射线荧光光谱法快速测定FeSiB非晶合金薄带中硅、硼、铁

提出了以自制的标准样品,采用单点法绘制校准曲线,利用X射线荧光光谱仪测定FeSiB非晶薄带样品中硅、硼和铁的含量。对于4个FeSiB非晶合金薄带样品中硅、硼和铁进行了10次测定,其分析结果的相对标准偏差分别为0.4%~0.5%、1.3%~4.2%和0.2%~0.4%。方法的分析结果与火花源原子发射光谱法、化学重量法和电感耦合等离子体原子发射光谱(ICP-AES)法的测定值吻合较好。方法快速、简便,薄带样品无需制样,适用于FeSiB非晶合金薄带的快速成分分析。     

Preconcentration of rare earth quinolin-8-ol complexes onto activated carbon and determination by first-order derivative x-ray fluorescence spectrometry

A method is described for the determination of traces of rare earths using energy-dispersive x-ray fluorescence spectrometry (EDXRF) after preconcentration of their quinolin-8-ol complexes on activated carbon. Various parameters that influence the adsorptive preconcentration of rare earths on activated carbon, viz., pH, amounts of activated carbon and quinolin-8-ol, time of stirring and aqueous phase volume, were systematically studied. A numerical method based on a simple least-squares procedure using a fifth-order polynomial with 25 consecutive values was developed for smoothing and differentiation of EDXRF data which were previously digitized and averaged. First-order derivative EDXRF in conjunction with adsorptive preconcentration of activated carbon enables down to 10 ng ml^?1 of each rare earth element to be determined.     

波长色散X射线荧光光谱法测定钴精矿中钴、铜和锰含量

采用高纯氧化物经四硼酸锂和偏硼酸锂熔融制备人工标准样品,以氧化镱为内标,制作校准曲线,建立了波长色散型X射线荧光光谱法测定钴精矿中钴、铜、锰元素的分析方法。重点研究了混合熔剂、试样稀释比、氧化剂和内标选择、方法检出限、方法准确度和精密度等,结果表明,各元素校准曲线线性范围宽,相关系数均大于0.999, 钴、铜、锰元素检出限分别达到0.002%、0.001%和0.001%,测试准确度和精密度可靠,方法满足行业检测需求。     

Determination of sulphur in uranium matrix by total reflection X-ray fluorescence spectrometry

The possibility of sulphur determination in uranium matrix by total reflection x-ray fluorescence spectrometry (TXRF) has been studied. Calibration solutions and samples of sulphur in uranium matrix were prepared by mixing uranium in form of a standard uranyl nitrate solution and sulphur in the form of Na₂SO₄ standard solution, prepared by dissolving Na₂SO₄ in Milli-Q water. For major element analysis of sulphur, it was determined without separation of uranium whereas for the trace level determinations, uranium was first separated by solvent extraction using 30% tri-n-butyl phosphate (TBP) in dodecane as an extractant. In order to countercheck the TXRF results, a few samples of Rb₂U(SO₄)₃, a chemical assay standard for uranium, were diluted to different dilutions and sulphur content in these solutions were determined. The TXRF determined results for trace determinations of sulphur in these diluted solutions were counterchecked after addition of another uranium solution, so that sulphur is at trace level compared to uranium, separating uranium from these solution mixtures using TBP extraction and determining sulphur in aqueous phase by TXRF. For such TXRF determinations, Co was used as internal standard and W Lα was used as excitation source. The precision and accuracy of the method was assessed for trace and major element determinations and was found to be better than 8% (1σ RSD) and 15% at a concentration level of 1 μg/mL of sulphur measured in solutions whereas for Rb₂U(SO₄)₃, these values were found to be better than 4 and 13%, respectively.     

能量色散-X射线荧光光谱测定中草药痕量镉、铅、铜

为寻求一种能够直接对中草药中重金属进行快速检测的方法,采用压片法对样品进行前处理,建立了能量色散-X射线荧光光谱法快速检测中草药中痕量重金属镉、铅、铜元素的方法。在20 min即可完成检测,镉、铅、铜检出限分别为0.072、0.207、0.340 mg/kg,测试结果表明与原子吸收和ICP-MS相比,本方法数据稳定性和准确度良好,具有快速、准确、简单的优点,能够满足药典中对重金属元素的限量要求,适用于现场快速检测与质量控制检测。     

X射线荧光光谱法测定Zn镀层质量厚度及计算谱线选择问题研究

用X射线荧光光谱法测定了Fe基上Zn镀层的质量厚度；研究了厚度不同时选用不同谱线计算对测定结果的影响，发现在镀层质量厚度较小时（约〈14mg／cm^2）测量Zn元素的Kα线，质量厚度较大时选择Zn的Kα和Fe的Kα线共同计算，用纯元素和相似标样校正测定结果之间的偏差最小；用纯元素作校正标样测定了3个标准样品的Zn镀层质量厚度，计算结果与标准值符舍得较好。     

X射线荧光光谱法快速测定FeSiB非晶薄带中Si,B,Fe的含量合金薄带中硅硼铁

提出了以自制的标准样品,采用单点法绘制校准曲线,利用X射线荧光光谱仪测定FeSiB非晶薄带样品中硅、硼和铁的含量。对于4个FeSiB非晶合金薄带样品中硅、硼和铁进行了10次测定,其分析结果的相对标准偏差分别为0.4~0.5%,1.3~4.2%和0.2~0.4%。本方法的分析结果与火花源原子发射光谱法、化学重量法和ICP-AES的测定值吻合较好。本方法快速、简便,薄带样品无需制样,适用于FeSiB非晶合金薄带的快速成分分析。     

X射线荧光光谱法快速测定费托蜡中铁

通过对费托蜡(合成蜡、渣蜡)创新制样与装样、测试条件优化,利用仪器自带的基本参数法无标样半定量分析软件,建立了X射线荧光光谱(XRF)测定费托蜡中Fe的方法。测定的相对标准偏差<1%、典型分析时间10 min/样,无需标样。与ICP-AES测定结果相比较,相对误差低于10%,同时降低了蜡样测试对仪器真空度或分光晶体产生的不良影响。     

Determination of trace elements in Syrian medicinal plants and their infusions by energy dispersive X-ray fluorescence and total reflection X-ray fluorescence spectrometry

X-ray fluorescence (XRF) and total-reflection X-ray fluorescence (TXRF) techniques suited well for a multi-element determination of K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr in some Syrian medicinal plant species. The accuracy and the precision of both techniques were verified by analyzing the Standard Reference Materials (SRM) peach-1547 and apple leaves-1515. A good agreement between the measured concentrations of the previously mentioned elements and the certified values were obtained with errors less than 10.7% for TXRF and 15.8% for XRF. The determination of Br was acceptable only by XRF with an error less than 24%. Furthermore, the XRF method showed a very good applicability for the determination of K, Ca, Mn, Fe, Cu, Zn, Rb, Sr, and Br in infusions of different Syrian medicinal plant species, namely anise (Anisum vulgare), licorice root (Glycyrrhiza glabra), and white wormwood (Artemisia herba-alba).     

单波长激发-能量色散X射线荧光光谱法检测蔬菜中多种重金属元素

为实现蔬菜中多种元素的快速检测,利用单波长激发-能量色散X射线荧光光谱仪（MW-EDXRF）,建立了蔬菜中As、Pb、Cd、Cr、Ni、Cu、Zn、Rb、Mn等元素的快速检测方法。对XRF的激发时间、载样量、样品压片等条件进行了优化,结果显示当累积激发时间达到600 s、载样量为2 g、样品压片15 Mpa保持60 s时,可以实现XRF最优检测性能。在最优条件下,As、Pb、Cd、Cr、Ni、Cu、Zn、Rb、Mn的检出限（LOD）分别为0.07 mg/kg、0.07 mg/kg、0.07 mg/kg、0.32 mg/kg、0.32mg/kg、1.2 mg/kg、0.4 mg/kg、0.08 mg/kg、0.3 mg/kg;对菠菜、葱、胡萝卜、豆角、番茄、姜、空心菜、莲藕、芹菜、蒜等蔬菜样品测定11次的相对标准偏差（RSD）在3%~10%,表明方法具有良好的精密度;测定5种蔬菜基体标准物质的回收率在93%~119%,与微波消解电感耦合等离子体质谱法（ICP-MS）测定结果对比的线性回归系数（R2）>0.99（Cu的R2=0.9838）,表明方法具有良好的检测准确度。同时,该仪器仅有不到10 kg,不需要样品消解处理,检测时间在10 min左右,非常适合蔬菜多种重金属的现场快速筛查。