Third Order Derivative Molecular Absorption Spectrophotometry Determination of Traces of Samarium With Methyl Thymol Blue - CTAB or CPB

Abstract

A sensitive and selective method is described for the determination of traces of samarium by third order derivative molecular absorption spectrophotometry (TDMAS). The method is based on the formation of a stable, blue coloured water soluble ternary complex (Metal-Chromogenic reagent-surfactant) which is formed when cetyl trimethyl ammonium bromide or cetyl pyridinium bromide is added to binary samarium-methyl thymol blue system. The influence of various instrumental parameters and reaction conditions for maximum colour development is investigated. The ternary complex detection limit is 7.5 μg of samarium present in 25 ml of final solution. Linear calibration graphs are obtained for 0–30 μg of samarium. The relative standard deviation of the procedure was calculated to be 1.6%. Gd, Tb, Dy, Ho, Tm and Lu do not interfere in TDMAS determination of samarium. Methods are described for masking other interfering analytes.     

Spectrophotometric determination of samarium(III) with chrome azurol S in the presence of cetylpyridinium chloride

A sensitive, simple method for the determination of trace amounts of samarium by spectrophotometry is described based on the formation of the samarium-chrome azurol S (CAS) complex in micellar medium. The molar absorptivities of the complexes at pH 7.5 at 505 nm were 3.6x10(4) and 1.4x10(5) l mol(-1) cm(-1) for water media and cetylpyridinium chloride (CPC), respectively. Beer's law is obeyed from 0.05-2 mg l(-1) of samarium at 505 nm as Sm-CAS-CPC complex. Optimal conditions such as reagent amounts, and pH for the samarium determination were reported. The effects of foreign ions were also investigated. The proposed method was successfully applied to the determination of samarium contents in synthetic samples.     

关于影响镧、钐与铕测定灵敏度原因的探讨

实验证明，在石墨表面上原子化时，镧、钐或铕与炽热的石墨反应生成难解离的碳化物是导致镧、钐和铕测定灵敏度低与严重记忆效应的原因。用钽探针原子化测定钐样品时，钐物种与钽氧化物之间发生反应，生成复合物SmTaO4、镶嵌于钽探针表面的裂痕内，阻碍了钐原子化，导致测定钐的灵敏度下降。     

Pre-concentration of rare earths using silica gel loaded with 1-(2-pyridylazo)-2-naphthol (PAN) and determination by energy dispersive X-ray fluorescence

The determination of a single rare earth element in a mixture with other species of this family is a very challenging problem in analytical chemistry due to the close similarity of their chemical properties. In this work, a liquid–solid extraction procedure for praseodymium, neodymium, samarium and yttrium mixtures and subsequent determination by energy dispersive X-ray fluorescence spectrometry is described. The pre-concentration procedure, which involves the use of silica modified with 1-(2-pyridylazo)-2-naphthol, permits complete recovery of the rare earths and significant sensitivity enhancement in comparison with direct determination in the aqueous phase. Determinations in quaternary mixtures show typical precisions and accuracies of 3% and 5%, respectively.     

Time discrimination in the laser fluorimetry and ultratrace determination of europium(III) and samarium(III) with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione

Efficient application of time discrimination has succeeded in substantial reduction of the detection limit of laser fluorimetry. A nitrogen laser and a pulse-gated photon counting method are combined. The detection limits for europiuni(III) and samarium(III) with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione in solution are 0.4 pg l^-1 and 0.3 ng l^-1, respectively. The results are attributed to effective removal of the short-lived unwanted signals. This technique makes possible the ultratrace determination of a fluorescent molecule in a mixture with others by making the most of the difference of their emission lifetimes. The europium(III) complex can be determined with high selectivity and sensitivity in a large excess of the samarium(III) complex     

Crystallization of new samarium polyborates

Rare earth borates are important due to their excellent properties, especially for optics. Here, we report the hydrothermal synthesis and structural determination by single-crystal X-ray diffraction of two new samarium polyborates with layered structures, being constituted by hexaborate chains. These hexaborate chains are connected by samarium polyhedra, forming dense sheets that further interact with each other by hydrogen bonding via isolated boric acid between these sheets. The third phase possesses a three-dimensional framework structure. The thermal stability of selective samples has been studied. The crystallization of samarium borate depends highly on the experimental conditions. Three samarium polyborates have been crystallized in very similar experimental conditions, clearly indicating that new lanthanide borate compounds with tailored structures may be prepared in the future by careful choice of physicochemical conditions.     

Sm对MoO3-Bi2O3催化剂性能的影响

在MoO3-B i2O3催化剂中加入稀土氧化物Sm2O3,在固定床反应器中考查了Sm2O3添加量、反应温度、异丁烯浓度、原料气流量等对异丁烯转化为甲基丙烯醛反应的影响。实验表明,添加Sm2O3可明显提高异丁烯的转化率和甲基丙烯醛的选择性。用XRD技术研究了催化剂的组成,Mo-B i-O催化剂的成分主要是B i2O3和MoO3的混合物,添加Sm后出现了Sm2Mo3O12的衍射峰,且衍射峰的强度随着Sm添加量的增加而增强。     

Application of 14 MeV neutron activation analysis to the determination of Ce and Sm markers in biological materials

The rare-earth elements are very suitable multiple particulate markers for the investigation of matter flow in the gastro-intestinal tract of animals by means of the indicator activation method. A rapid determination of cerium and samarium in biological samples is possible with the aid of a 14 MeV neutron generator. The activity of^139mCe has to be corrected for the interferences of²⁸Al and^143mSm. For the determination of samarium the radionuclides¹⁵⁵Sm and¹⁵³Sm are used. In order to increase the specific activity of these nuclides, which are produced mainly by means of nuclear reactions with thermal neutrons, the samples are irradiated inside a polyethylene moderator block. The deviation from the linearity of the calibration curve for samarium is discussed.     

Simultaneous determination of samarium, europium and terbium with quinaldic acid and phenanthroline by synchronous derivative fluorimetry

Synchronous derivative fluorescence of samarium, europium and terbium complexes with quinaldic acid and phenanthroline was examined in aqueous solution. The composition of these complexes was determined. The maximum emission wavelengths are 645 nm, 617 nm and 545 nm for samarium, europium and terbium, respectively. Under the optimal experimental conditions, the fluorescence intensity was a linear function of concentration in the range of 10-250 ppm for samarium, 0.5-50 ppm for europium and 0.5-300 ppm for terbium. Simultaneous determination of samarium, europium and terbium was successfully carried out for samarium oxide and middle rare earth mixture. The precision of the method, expressed as relative standard deviation, is within 1.1-2.5%.     

Separation/preconcentration of trace heavy metals in urine, sediment and dialysis concentrates by coprecipitation with samarium hydroxide for atomic absorption spectrometry

Multi-element determination of trace elements in urine and dialysis solutions by atomic absorption spectrometry has been investigated. Coprecipitation with samarium hydroxide was used for preconcentration of trace elements and elimination of matrix elements. To 10 ml of each sample was added 500 μl of 2 mg ml⁻¹ samarium solutions; the pH was then adjusted to 12.2 in order to collect trace heavy metals on samarium hydroxide. The precipitate was separated by centrifugation and dissolved in 1 ml of 1 mol l⁻¹ HNO₃. Coprecipitation parameters and matrix effects are discussed. The precision, based on replicate analysis, is around 5% for the analytes, and recovery is quantitative, based on analysis of spiked samples and solutions including matrix components. The time required for the coprecipitation and determination was about 30 min.     

Determination of rare earth impurities in cerium dioxide and oxalate by X-ray fluorescence technique

A method for the determination of lathanum, praseodymium, neodymium and samarium oxides in cerium dioxide has been developed. The sample in the oxalate form is mixed with the binding material (boric acid) in the ratio 1∶1 pressed to form a double layer pellet over a boric acid backing pellet and irradiated by X-rays from a tungsten tube. The secondary X-rays are dispersed with a LiF (200) crystal in a Philips PW 1220 semiautomatic X-ray fluorescence spectrometer. The intensity of fluorescent X-rays is measured by a flow proportional counter. The minimum determination limit is 0.01% for lanthanum and samarium oxides and 0.02% for praseodymium and neodymium oxides. The precision at each concentration of the standards and theoretical minimum determination limit for each element have been calculated.     

元素在石墨炉内石墨探针表面上的原子化机理研究(ⅩⅣ)─钐的原子化机理

综合运用X射线衍射、X射线光电子能谱与俄歇电子能谱等表面分析手段研究了石墨炉中石墨探针表面钐样品的原子化过程。发现在石墨炉升温过程中,钐样品先转化为Sm₂O₃,再由Sm₂O₃热分解为SmO,原子化起源于SmO的热分解;在Sm₂O₃与探针接触的表面有碳化物生成,碳化物是造成记忆效应的重要原因。     

石墨炉原子吸收光谱法测定氧化钐和氧化钆中的铕

采用衬钽片的石墨管,以石墨炉原子吸收光谱法测定了氧化钐和氧化钆中的铕。探讨了盐酸浓度,基体钐和针对铕测定的影响;考察了方法的灵敏度和精密度;建立了灵敏准确易于掌握的分析方法。 本方法不需要预先分离基体,样品经溶解后即可直接进行分析。     

协同发光效应及其分析应用研究

在研究共存元素对钐、铕、铽和镝配合物荧光发射的影响时,人们曾分别观察到这些配合物的荧光强度不但不随某些共存稀土和非稀土离子浓度的增加而降低;而是在一定浓度范围内随共存离子浓度的增加,配合物的荧光发射大大增强,利用这种效应可大大提高这类配合物的荧光分析灵敏度,我们采用自己组装的激光诱导荧光光谱测定装置,选取铕(钐)-     

激光诱导荧光光谱分析法研究 Ⅳ.钐-三氟乙酰丙酮-三正辛基膦化氧-浓乳-100的荧光特性研究及应用

采用激光诱导荧光光谱测定装置研究了Sm-三氟乙酰丙酮(TFA)-三正辛基膦化氧(TOPO)体系的激光诱导发光特性和发光机理。根据配合物体系中各组份的光谱特性和光谱能级,提出Sm-TFA-TOPO体系的能量传递机制。拟定了在农乳-100存在下,TFA-TOPO体系测定痕量钐的激光诱导荧光光谱分析新方法。不经分离,用于氧化钇和合成水样中痕量钐的测定,操作简便、快速,结果令人满意     

Stable isotope tracer marking of individual boll weevils

Summary Stable isotope markers have been used to study animal nutrition for several decades and more recently to study the foraging and cultural habits of imported fire ants. In this work, we have extended that effort to evaluate the potential for marking boll weevils, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), with the rare earth element samarium to aid in studies of insect invasion and pest eradication protocols. Neutron activation analysis (NAA) was performed on the marked boll weevils as well as plant material from the cotton squares on which the insects were fed. Samarium levels in non-dosed insects average about 20 ng/g or about 100 pg total element per insect. Our computed average determination limit was 36 pg samarium/weevil. The determination limit for cotton plant squares and leaves averaged 3.5 ng/g and 8.2 ng/g, respectively. These initial results indicate the NAA method is capable of identifying individual marked insects which have assimilated 1 ng of samarium, a ten-fold increase in content over average blank values.     

影响钽探针原子化法测定钐灵敏度原因的实验研究

用扫描电镜和Ｘ－射线衍射分析研究ＳｍＣｌ３，在钽探针表面原子化时，发现了由于ＳｍＴａＯ４嵌入钽探针而形成镶嵌结构，它影响了测定的灵敏度，并由实验结果说明了衬钽技术的重要性。     

Spectrophotofluorimetric determination of terbium, europium and samarium with pivaloyltrifluoroacetone and tri-n-octylphosphine oxide in micellar solution of nona-oxyethylene dodecyl ether

The fluorescence intensities of terbium, europium and samarium complexes with several beta-diketone derivatives in the absence and presence of tri-n-octylphosphine oxide (TOPO) in micellar solution of nona-oxyethylene dodecyl ether (BL-9EX) were examined. The spectrophotofluorimetric determination of terbium (1.5-1500 ng/ml) has been investigated with pivaloyltrifluoroacetone (PTA) and TOPO in 0.5% micellar solution (pH 3.8-4.5) of BL-9EX. The excitation and emission wavelengths were 309 and 542 nm, respectively. Europium and samarium could be determined by a similar method.     

DBM—MSA光度法测定化妆品中铅

为建立一个新的测定化妆品中铅的分光光度法,在0．24mol／L的磷酸介质中,铅与DBM—MSA{3-[（2-磺酸基苯）偶氮]-6-[2,6-二溴-4-甲基苯）偶氮]-4,5-二羟基-2,7-萘二磺酸}反应形成1：2的蓝色配合物,在波长630nm处比色测定。结果表明,铅量在0—1μg／mL范围内符合比耳定律;样品测定的相对标准偏差为1．24％～4．59％,标准加入回收率为95．0％～107．0％,化妆品中共存物质不干扰测定,方法简便,选择性好,结果满意。     

Synthesis of (E)-α,β-unsaturated ketones with total or high diastereoselectivity by using samarium diiodide or triiodide

(E)-α,β-Unsaturated ketones are obtained by reaction of α-chloro-β-hydroxy ketones with samarium diiodide or with samarium triiodide with total or high diastereoselectivity and in good yield.