原子吸收法测定地质样品中的金、铂、钯

地质样品组分复杂,各元素含量范围变化大,金、铂、钯存在量甚微。样品需经分离富集后测定。作者曾实验在磷酸介质中,用甲基异丁基酮萃取吸收法测定金。本文着重介绍在此基础上以双十二烷基二硫乙二酰二胺—石油醚—氯仿混合溶剂分别萃取钯和铂。本法避免了试样组分对金、铂、钯的影响,可测0.03克/吨金或钯,0.1克/吨铂,分析结果的变动系数:金为5,钯为6.2,铂为7.7。     

二乙烯苯和丙烯腈聚合物浸渍磷酸三丁酯为固定相萃取色谱法富集分离铂与金

报道了以GDX501（二乙烯苯和丙烯腈的聚合物）型树脂浸渍磷酸三丁脂（TBP）为固定相，用萃取色谱法使微量铂、金与常见贱金属分离。富集在色谱柱上的铂与金分别用0.25mol/L HNO-0.5mol/L NaClO3溶液和0.1mol/L HCl-0.2mol/L硫脲溶液连续洗脱并用原子吸收光谱法进行测定。铂与金的回收率分别为89.5%-113.9%和90.1%-105.3%。     

硫醚萃取金(Ⅲ)的研究

本文研究几种对称或不对称硫醚从盐酸介质中萃取金的行为及其机理,讨论了硫醚分子结构与萃取过程的热力学函数间的关系。还考察了钯和铂对萃取金的影响,表明试剂有较高的选择性。     

丙醇-氯化钠双水相体系萃取分离铂、钯、铑、金中的铱及其吸收光谱分析研究

提出了一种丙醇－氯化钠双水相体系萃取铱的分离－吸收光谱分析方法，在HCl介质中基于铱生成三氯亚锡酸络阴离子动力学速率与铂、钯、铑、金差异使铱与铂、钯、铑、金分离，其后在KI介质中萃取铱使其与贱金属基体分离，研究了在丙醇萃取相中铱的吸收光谱分析，并应用于实际样品中铱的测定。     

丙醇-硫酸铵-水液-液体系萃取分离铂、钯、铑和金

研究了丙醇－（NH4）2SO4－水液－液体系对铂（Ⅱ）,钯（Ⅱ）,铑（Ⅲ）和金（Ⅲ）氯化亚锡络阴离子的萃取行为及体系在盐酸介质中的分相条件。实验表明在盐酸介质中体系可同时萃取铂（Ⅱ＿,钯（Ⅱ）,铑（Ⅲ）和金（Ⅲ）,对铂,钯,铑 和金的萃取率分别为99．4％,99．0％,98．3％和99．8％,方法可用于从贱金属中分离铂,钯,铑,金,对阳极泥,砂铂矿,废催化剂样品的分离分析结果与其它方法相符。     

用P_(350)萃取分离微量金

在盐酸介质中,用P_(350)作为新型萃取剂,研究了微量金与大量铂族元素、铜及重金属元素的分离,证实了同一体系中反相薄层色谱所得出的结论,并考查了该体系中若干盐类的盐析效应,得出金的分配比和盐析剂阳离子的离子势及浓度之间有如下经验关系: D=e+f[M]~(?)·Z/r 结合罗丹明B法,成功地用于阳极泥、水溶液氯化渣、纯铜、纯银和大量铂、钯存在下金的萃取分离和测定,获得良好结果。     

二正辛基硫醚(DOS)在贵金属分析中的应用 Ⅰ、DOS-二甲苯萃取原子吸收测定矿石中的微量金、钯(银)

烷基硫醚和烷基亚砜是近几年才逐步应用于分析化学中的一类新型萃取剂。这类萃取剂对贵金属(以及铀钍、稀土)有极好的选择性。有人用二烷基二硫醚R-S-S-R等多种不同结构的烷基硫化物萃取金、银、钯,除金、银、钯外,其它元素几乎都不被萃取。我们曾试验用含有烷基硫化物的大蒜浸液(甲苯溶液)萃取金、银、铂、钯,萃取效果是很好的。此外,用石油硫化物萃取贵金属也是很有效的。     

用新铜试剂——甲基橙萃取分光光度法测定微量银

用新铜试剂——甲基橙萃取分光光度法(以下简称NMO法)测定微量银,国内外尚未见报导。微量银的测定,普遍采用双硫腙法、原子吸收法和试金法。前一种方法,微克量的汞、金、钯、铂(Ⅱ),克量的铜有严重干扰。后两种方法受仪器设备的限制。为此,我们在资料的基础上,试验了以NMO法测定微量银。本文研究了用该体系分光光度法测定银的适宜萃取条件,共存组份的干扰及络合物的组     

用二乙基二硫代磷酸作贵金属的萃取分离

本文研究了用二乙基二硫代磷酸作萃取剂时,一些贵金属的萃取行为。文中着重考查了铂在萃取过程中的行为,并研究了萃取的适宜条件。实验表明,由于光化学反应,铂会部分进入有机相,只要避免光照,铂可定量留于水相,根据研究的结果,提出了一个大量钯、银与少量铂、铑、铱萃取分离的方法,方法简便快速。此法能应用于钯、银合金中铂、铑铱的分析。     

苄基十四烷基二甲基氯化铵(Zeph)在贵金属分析中的应用——Ⅰ.Zeph萃取富集、石墨炉原子吸收法连续测定矿石中微量金、铂、钯

本文发现Zeph在酸介质中,能定量萃取微量金、铂、钯,从而与大量的铁、铜、钴、镍、铬(Ⅲ)、钙、镁、铝、铅等元素分离。有机相可直接用石墨炉原子吸收法连续测定。该法可用于富集和测定矿石中xx～0.00x克/吨的金和钯,xx～0.0x克/吨的铂。矿石中常见的30种金属离子不干扰测定。操作较简便、快速,精密度和准确度满意。     

Extraction of gold, palladium and platinum from chloride, bromide and iodide solution with di-n-octyl sulphide (DOS) in cyclohexane

The extraction of gold, palladium and platinum from hydrochloric acid, hydrobromic acid and iodide media by solutions of di-n-octyl sulphide in cyclohexane was examined. From distribution data it was concluded that the monosolvates AuX(3).DOS and disolvates PdX(2).2DOS are extracted. Extraction of platinum was efficient only from iodide solutions; a disolvate PtI(4).2DOS was formed. The possibility of separation of gold and palladium from platinum by extraction from bromide or chloride solutions and simultaneous extraction of palladium and platinum from an iodide medium was demonstrated.     

Extraction with long-chain amines-IV Separation and colorimetric determination of gold

A highly selective method, almost free from interferences, for extraction of gold(III) from sulphuric acid into a chloroform solution of trioctylamine (TOA) is described. The yellow extract is then measured at 325-330 nm. Gold can be determined in the presence of platinum. The method has been applied to the determination of gold in waste dumps. A more sensitive method is based on reaction of the gold with diphenylcarbazide after the separation of the gold from the TOA-chloroform extract. The violet colour is stable and is measured at 560 nm.     

Simultaneous determination of palladium, platinum, rhodium and gold by on-line solid phase extraction and high performance liquid chromatography with 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine as pre-column derivatization regents

In this paper, 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine (HNATR) was synthesized. A new method for the simultaneous determination of palladium, platinum, rhodium and gold ions as metal-HNATR chelates was developed using a rapid analysis column high performance liquid chromatography equipped with on-line solid phase extraction technique. The samples (Water, human urine, geological samples and soil) were digested by microwave acid-digestion. The palladium, platinum, rhodium and gold ions in the digested samples were pre-column derivatized with HNATR to form colored chelates. The Pd-HNATR, Pt-HNATR, Rh-HNATR and Au-HNATR chelates can be absorbed onto the front of the enrichment column when they were injected into the injector and sent to the enrichment column [Zorbax Stable Bound, 10 mm x 4.6 mm, 1.8 microm] with a buffer solution of 0.05 mol L(-1) phosphoric acid as mobile phase. After the enrichment had finished, by switching the six ports switching valve, the retained chelates were back-flushed by mobile phase and travelling towards the analytical column. These chelates separation on the analytical column [Zorbax Stable Bound, 10 mm x 4.6 mm, 1.8 microm] was satisfactory with 72% acetonitrile (containing 0.05 mol L(-1) of phosphoric acid and 0.1% of Triton X-100) as mobile phase. The palladium, platinum, rhodium and gold chelates were separated completely within 2.5 min. Compared to the routine chromatographic method, more then 80% of separation time was shortened. By on-line solid phase extraction system, a large volume of sample (10 mL) can be injected, and the sensitivity of the method was greatly improved. The detection limits (S/N=3, the sample injection volume is 10 mL) of palladium, platinum, rhodium and gold in the original samples reaches 1.4, 1.8, 2.0 and 1.2 ng L(-1), respectively. The relative standard deviations for five replicate samples were 2.4-3.6%. The standard recoveries were 88-95%. This method was applied to the determination of palladium, platinum, rhodium and gold in human urine, water and geological samples with good results.     

Extraction chromatographic separation of platinum(IV) from real samples and associated elements

 The extraction behavior of platinum(IV) was studied with N-n-octylaniline as a function of different parameters, such as pH, concentrations of weak acids, mineral acids, reagents and elution time. A selective method was developed for the extraction chromatographic studies of platinum(IV) and its separation from several metal ions with N-n-octylaniline (liquid anion exchanger) as a stationary phase on silica gel. The quantitative extraction of platinum(IV) was observed with 0.067 mol/L N-n-octylaniline and 0.015 mol/L ascorbic acid at pH 1.0. Metal ion was stripped from the column with water and determined spectrophotometrically with stannous chloride method. The proposed method is free from the interference of a large number of cations and anions. Platinum(IV) was separated from pharmaceutical preparations, alloys and synthetic mixtures. Mutual separation scheme was developed for platinum(IV), palladium(II) and gold(III). The log-log plot of N-n-octylaniline concentration versus the distribution ratio indicates that the probable extracted species is ［RR′NH+2 ］· Pt(C6H7O6)－3.     

Studies on the extraction of platinum metals with tri-iso-octylamine from hydrochloric and hydrobromic acid: separation and determination of gold, palladium and platinum

The extraction of Pd(II), Rh(III), Ir(III), Au(III) and Pt(IV) from hydrochloric and hydrobromic acid with 5% tri-iso-octylamine solution in carbon tetrachloride has been studied. The gold extract from hydrochloric acid is yellow and absorbs at 325 nm, the palladium compound is red and absorbs at 290 nm and 467 nm, and the platinum compound is blood-red and shows absorption at 268 nm. The gold, palladium and platinum extracts from hydrobromic acid are crimson. reddish brown and blood-red, with maximum absorption at 260, 345 and 300 nm respectively. Methods have been devised for the separation of gold from platinum and for its determination and also for the simultaneous determination of palladium and platinum.     

Solvent extraction of gold with N-substituted benzoylthioureas

Summary Benzoylthioureas are excellent reagents for the solvent extraction of gold. Very effective separations of gold from platinum group metals and base metals are possible due to control of the extraction parameters. The best results, a fast extraction and low residual gold concentrations <1 g/l are obtained with N,N-Di-n-hexylbenzoylthiourea/toluene.     

Extraction of palladium and platinum with trioctylphosphine oxide (TOPO) in various solvents from hydrochloric and hydrobromic acid media

The extraction of palladium and platinum with trioctylphosphine oxide (TOPO) in cyclohexane, chloroform, methyl isobutyl ketone (MIBK) and 2,2′-dichlorodiethyl ether (DCDE) from hydrochloric and hydrobromic acids in dependence on the concentration of the acids and the extractant has been investigated. The obtained relation have been discussed and the possibilities of the separation of palladium, platinum, gold and their simultaneous extraction have been pointed out.     

THE SYNTHESIS OF TRISELENOCARBONATE COMPLEXES OF PLATINUM

The addition of dichloromethane solutions of carbon diselenide to liquid ammonia containing suspensions of platinum bis-phosphine dichlorides [PtCl₂(PR_X)_n] (n = 2, (PR_X) = PMe₃, PMe₂Ph, PMePh₂, and PPh₃, n = 1, (PR_X) = dppm, dppe, dppp, dppf) gives, after evaporation of the ammonia and extraction of the reaction residues with dichloromethane, the appropriate platinum bis-phosphine triselenocarbonate complexes in reasonable yields (40–60%).     

STUDIES OF ADHESION OF METAL PARTICLES TO SILICA PARTICLES BASED ON ZETA POTENTIAL MEASUREMENTS

The zeta-potentials of silica, copper, platinum and gold particles have been measured as a function of pH. The isoelectric points were found to be at pH 3.0, 5.8, 3.0 and 3.5, respectively. In the pH range 3.0 to 5.8 copper and silica particles are oppositely charged and accordingly the coating of silica with copper particles could be demonstrated. In the case of gold and platinum the sign of the charge is such that direct adhesion to silica particles cannot be expected and this was also demonstrated in the case of platinum.