Determination of palladium, platinum and rhodium in geologic materials by fire assay and emission spectrography

A method is described for the determination of palladium down to 4ppb (parts per billion, 10(9)), platinum down to 10 ppb and rhodium down to 5 ppb in 15 g of sample. Fire-assay techniques are used to preconcentrate the platinum metals into a gold bead, then the bead is dissolved in aqua regia and diluted to volume with 1M hydrochloric acid. The solution is analysed by optical emission spectrography of the residue from 200 mul of it evaporated on a pair of flat-top graphite electrodes. This method requires much less sample handling than most published methods for these elements. Data are presented for G-1, W-1, and six new standard rocks of the U.S. Geological Survey. The values for palladium in W-1 are in reasonable agreement with previously published data.     

A fire-assay and wet chemical method for the determination of palladium, platinum, gold, and silver in ores and concentrates

A method is presented for the determination of palladium, platinum, gold and silver in ores and concentrates by a fire-assay and wet chemical technique. After parting of the lead assay button with dilute nitric acid, and separation of the solution from the residue, the palladium and platinum in the solution are precipitated by the addition of stannous chloride, with tellurium as collector. The resulting precipitate is combined with the gold residue and dissolved in aqua regia, then the solution is analysed for palladium, platinum and gold by atomic-absorption spectrophotometry (AAS). Silver is determined in the original solution by AAS before the reduction step.     

电感耦合等离子体原子发射光谱测定铂钯渣中铂、钯含量

铂钯属于贵金属,对于冶炼企业而言,有效回收铂钯,可以提高生产经营单位的经济效益。本文针对某铜冶炼企业工艺中产生的铂钯渣中铂、钯含量较高、难以溶解、不宜直接测定等问题,研究了一种测定铂、钯含量的新方法。首先对铂钯渣样品进行火试金熔融、富集,溶解,再用电感耦合等离子体原子发射光谱仪 (ICP-AES) 测定,方法精密度和准确度好。     

The determination of platinum and palladium in rocks and soils by electrothermal atomic absorption spectrometry of extracts of their iodo complexes

The method developed for determining platinum and palladium in rocks and soils is based on extraction of iodo complexes of these elements into methyl isobutyl ketone (MIBK), followed by electrothermal atomic absorption spectrometry of the extracts. The limit of detection is 10 ng g^?1 for platinum and 3 ng g^?1 for palladium. Analysis of the standard noble metal ore PTC-1 with recommended values of 12.7 μg g^?1 for palladium and 3.0 μg g^?1 for platinum gave precisions of 4.4% and 5.6%, respectively, and deviations of 5.0% and 1.2% from the recommended values. The method is applicable to the determination of both elements in a wide variety of rocks and soils.     

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.     

Spectrographic determination of gold and platinum metals in geological and other materials by fire-assay preconcentration

A method is described for the determination of gold, platinum, palladium, rhodium and iridium at microgram levels in geological and other materials by a combination of fire-assay preconcentration and emission spectrography. The noble metals are collected into 4-mg silver or platinum prills by a normal fire-assay technique. These prills are arced between graphite electrodes at 12 A d.c. No buffer is required to prevent ejection of the prill. Gold, platinum and palladium are determined in the silver prills and gold, palladium, rhodium and iridium in the platinum prills. Low, but reproducible, results are found for iridium. At the 0.08 ppm level an overall coefficient of variation of 11% is found. This technique is simple and rapid for the determination of the precious metals.     

火试金减杂-电感耦合等离子体原子发射光谱法（ICP-AES）法测定高冰镍的金、银、铂、钯含量

建立了火试金减杂-电感耦合等离子体原子发射光谱法（ICP-AES）测定高冰镍中金、银、铂、钯含量的分析方法。实验采用火试金富集、熔融、灰吹得到合粒,通过减杂法得到银含量,通过ICP-AES法测定得到金、铂、钯含量。金、银、铂、钯的加标回收率在99.53%-101.83%之间,相对标准偏差小于3%。此方法快速、简洁,准确度高、精密度好,能够满足高冰镍的测定需求。     

Preconcentration of Nickel(II) in White Wine Using Quinoxaline-2,3-dithiol and a Finely Divided Anion-Exchange Resin for the Determination by Solid-Phase Spectrophotometry

A simple and sensitive method for the determination of trace amounts of nickel(II) is described. The method is based on the adsorptive enrichment of nickel(II) as the complex with quinoxaline-2,3-dithiol using a finely divided anion-exchange resin, collection of the resin on a membrane filter by filtration, and direct measurement of the absorbance of the resultant circular thin layer by reflective spectrophotometry at 605 nm. In the presence of interfering cations such as copper(II) and cobalt(II) a sample solution is first filtered, after the addition of ammonium thiocyanate and Zephiramine, to extract these cations onto a membrane filter as the ion-pair precipitate formed between the metal-thiocyanate complex anions and Zephiramine cations, then nickel(II) in the filtrate is determined. Interferences from iron(III), silver(I), bismuth(III), cadmium(II), mercury(II), indium(III), palladium(II), platinum(IV), tin(IV), and zinc(II) can also be eliminated. The proposed method was applied to the determination of nickel in white wine. The concentrations of nickel found in 5-ml aliquots of 10 different wine samples were in the range 16.1-68.0 ng ml⁻¹.     

Thermal stabilization of inorganic and organically- bound tellurium for electrothermal atomic absorption spectrometry

The thermal stabilization of inorganic tellurium(IV) and organically-bound tellurium for electrothermal atomic absorption spectrometric determination of the element was studied with the use of the isotope tellurium-127m. Of the 19 metals and potassium iodide tested, 15 metals had a stabilizing effect on inorganic tellurium; among the 9 metals tested with organically-bound tellurium, only 3 exhibited an effect. The most effective metals for stabilizing inorganic tellurium were cadmium, copper, palladium, platinum and zinc, while the best agents for stabilization of organically-bound tellurium were silver, palladium and platinum; in the presence of palladium and platinum, tellurium in both forms could be heated in the graphite tube to 1050°C without losses. Attempts were made to determine tellurium in human whole blood and garlic, but the concentrations were found to be below the detection limits of 3 ng ml^-1 and 140 ng g^-1, respectively.     

Isotope dilution inductively coupled plasma quadrupole mass spectrometry in connection with a chromatographic separation for ultra trace determinations of platinum group elements (Pt, Pd, Ru, Ir) in environmental samples

An isotope dilution inductively coupled plasma quadrupole mass spectrometric (ID-ICP-QMS) method was developed for the simultaneous determination of the platinum group elements Pt, Pd, Ru, and Ir in environmental samples. Spike solutions, enriched with the isotopes 194Pt, 108Pd, 99Ru, and 191Ir, were used for the isotope dilution step. Interfering elements were eliminated by chromatographic separation using an anion-exchange resin. Samples were dissolved with aqua regia in a high pressure asher. Additional dissolution of possible silicate portions by hydrofluoric acid was usually not necessary. Detection limits of 0.15 ng x g(-1), 0.075 ng x g(-1), and 0.015 ng x g(-1) were achieved for Pt, Pd, Ru, and Ir, respectively, using sample weights of only 0.2 g. The reliability of the ID-ICP-QMS method was demonstrated by analyzing a Canadian geological reference material and by participating in an interlaboratory study for the determination of platinum and palladium in a homogenized road dust sample. Surface soil, sampled at different distances from a highway, showed concentrations in the range of 0.1-87 ng x g(-1). An exponential decrease of the platinum and palladium concentration with increasing distance and a small anthropogenic contribution to the natural background concentration of ruthenium and iridium was found in these samples.     

火试金富集-电感耦合等离子体发射光谱(ICP-OES)法测定分银渣中的铂、钯

采用火试金富集得到贵金属合粒,经王水溶解,在王水(10%)介质下采用全谱直读电感耦合等离子体发射光谱(ICP-OES)法测定分银渣中铂、钯的含量。方法精密度好,准确度高,铂、钯的加标回收率在98.4%~102%,可以很好地满足分银渣中铂、钯含量的测定。     

Simultaneous determination of palladium, platinum and rhodium by on-line column enrichment and HPLC with 5-(2,4-dihydroxyphenylazo)-rhodanine as pre-column derivatization reagent

In this paper, a new method for the simultaneous determination of palladium, platinum and rhodium ions was developed using a rapid column high performance liquid chromatography equipped with on-line enrichment technique. The palladium, platinum and rhodium ions were pre-column derivatized with DHAR to form colored chelates. The Pb-DHAR, Pt-DHAR and Rh-DHAR chelates could 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, 4.6 x 10 mm, 1.8 microm] with a 0.05 mol L(-1) of phosphoric acid solution as mobile phase. After enrichment, and by switching the six ports switching valve, the retained chelates were back-flushed by mobile phase and traveling towards the analytical column. The separation of these chelates on the analytical column [ZORBAX Stable Bound, 4.6 x 50 mm, 1.8 microm] was satisfactory with 54% acetonitrile (containing 0.05 mol L(-1) of phosphoric acid and 0.1% of tritonX-100) as mobile phase. Palladium, platinum and rhodium were separated completely within 2 min. By on-line enrichment technique, the enrichment factor of 100 was achieved, and the detection limits (S/N = 3) of palladium, platinum and rhodium reaches 1.4 ng L(-1), 1.6 ng L(-1) and 2.0 ng L(-1), respectively. This method was applied to the determination of palladium, platinum and rhodium in water, urine and soil samples with good results.     

Determination of noble metals by resonance neutron activation technique

Rhodium, palladium, platinum and iridium have been determined in silver matrix by nondestructive activation analysis upon activation with cadmium- and silver-filtered resonance neutrons. Experiments with different types of filter combinations are reported. The sensitivity of the method is 5·10⁻³% for rhodium, 5·10⁻³% for palladium, 3·10⁻²% for platinum and 5·10⁻³% for iridium.     

On the re-assessment of the optimum conditions for the determination of platinum, palladium and rhodium in environmental samples by electrothermal atomic absorption spectrometry and microwave digestion

The experimental conditions for the determination of platinum, palladium and rhodium by graphite furnace atomic absorption spectrometry (GFAAS) are re-assessed. A certified material (BCR-723) was used as a working sample and analyzed using various extraction and atomization procedures in order to find the optimal experimental conditions that enable the quantitative and reproducible detection of platinum, palladium and rhodium in environmental matrices. Evidently, literature observations regarding the atomization conditions were proven fairly adequate. However, the provision of the optimum extraction conditions revealed several parameters that lie behind the reported uncertainties. The appropriate combination between extraction conditions and atomization programs afforded a considerable improvement in the recoveries and analytical features of platinum, palladium and rhodium determination with GFAAS. Cross-examination of the analytical data with various CRMs (certified reference materials) was used to validate the robustness of the method in heterogeneous matrices bearing different element levels. Under the optimum experimental conditions the method permits the determination at concentrations as low as (LOD(3S/N)) 1.9 ng g(-1), 0.45 ng g(-1) and 0.6 ng g(-1) for Pt, Pd and Rh, respectively affording recoveries in the range of 93-101%. The method was successfully applied to the assessment of Pt, Pd and Rh accumulation in real road dust and soil samples in Greece.     

Amperometric titration of palladium, silver and copper with benzimidazol-2-ylmethanethiol, and its application to non-ferrous materials

A method is described for the determination of mg amounts of palladium, silver and copper by amperometric titration with benzimidazol-2-ylmethanethiol in acetate buifer medium (pH 4-5) at an applied potential of -0.2 V vs. the saturated calomel electrode. Direct titrations are possible in the presence of a number of foreign ions. Copper and palladium interfere mutually and in the determination of silver. Mercury(I), mercury(II) and platinum(IV) also interfere. Silver does not interfere in the determination of copper and palladium if it is first precipitated as chloride. The method has been successfully applied to the analysis of non-ferrous materials.     

Simultaneous Laser Thermal Lens Spectrometric Determination of Trace Platinum and Palladium in an Aquesous Solution

A selective and sensitive method for determination of platinum and palladium(Ⅱ）in an aqueous solution simultaneously by laser thermal lens spectrometry,based on the complex reaction of 2-(3,5-dichloropyridylazo)-5-dimethylaminoamiline(3,5-diCl-PADMA) with platinum and palladium,has been developed.It is shown that the palladium complex can be fromed at room temperature, while the platinum complex can be only formed after being heated in a boiling water bath.By using this difference of reaction temperature and the characteristic of the complexes mentioned above,the method for simultaneous determination of platinum and palladium was established in an aqueous solution without a pre-separation.The results show that the dynamic linear ranges of determination for platinum and palladium are 0.005-0.04μg/mL and 0.005-0.25μg/mL respectively,and that the detection limits are both 0.002/μg/mL.The method has been applied to the determination of platinum and palladium simultaneously in alloy and catalyst samples with satisfactory results.     

Simultaneous Determination of Palladium and Platinum by On‐Line Enrichment Followed by Rapid Column High Performance Liquid Chromatography

In this paper, a new method for the simultaneous determination of palladium and platinum ions was developed using a rapid column high performance liquid chromatograph equipped with an on‐line enrichment technique. The palladium and platinum ions were pre‐column derivatized with 5‐(p‐aminobenzylidene)‐thiorhodanine (ABTR) to form colored chelates. The Pd‐ABTR, Pt‐ABTR chelates can be absorbed onto the front of an enrichment column when they were injected into the injector and sent to the enrichment column [ZORBAX Stable Bound, 4.6 × 10 mm, 1.8 μm] with a buffer solution of 0.05 mol/L sodium acetate‐acetic acid buffer solution (pH 3.5) 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 traveled towards the analytical column. These chelates separation on the analytical column [ZORBAX Stable Bound, 4.6 × 50 mm, 1.8 μm] was satisfactory with 65% methanol (containing 0.05 mol/L of pH 3.5 sodium acetate‐acetic acid buffer salt and 0.01 mol/L of tritonX‐100) as mobile phase. The palladium and platinum were separated completely within 2 min. The detection limits (S/N = 3) of palladium and platinum are 1.4 ng/L and 1.6 ng/L, respectively. This method was applied to the determination of palladium and platinum in water and urine samples with good results.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定银钯合金中银和钯

建立健全测定银钯合金中银和钯含量的检测方法,对实现银钯合金中银和钯的高精度分析以及资源化利用有着重大意义。实验建立了电感耦合等离子发射光谱法(ICP-AES)同时测定银钯合金中银钯含量的分析方法。实验采用先加入10mL硝酸,再加入50mL过量盐酸混合,采用加热套混合消解银钯合金并混合定容在酸性浓度为18%HCl为介质中,然后通过控制不同的HCl浓度来测定银钯含量。实验结果表明：银的最佳检测酸性浓度为18%、钯的最佳酸性检测浓度为4%且该方法的加标回收率在97%-100%之间,相对标准偏差(RSD, n=10)小于2%。     

Determination of total mercury in coal fly ash by gold amalgamation cold vapour atomic absorption spectrometry

A method for the determination of total mercury in coal fly ash by gold amalgamation cold vapour atomic absorption spectrometry (CV-AAS) was optimized. Most of the experiments were performed on NBS SRM 1633a Coal Fly Ash with a certified value of 160 ± 10 ng Hg g^?1. The main attention was focused on the decomposition of the sample. The efficacy of pressure decompositions in closed silica and sealed Pyrex tubes using various combinations of acids (HNO₃, HCl, HClO₄) was compared with oxidative combustion of the coal fly ash. Notwithstanding the incomplete mineralization of the sample in sealed tubes, the results obtained showed good agreement with the certified value and results obtained by neutron activation analysis (NAA), which suggests that mercury is quantitatively released from the sample into solution. Lower results were obtained using decomposition in closed (but not hermetically sealed) silica tubes owing to losses of mercury by volatilization during decomposition. Interferences from some metal ions (nickel, lead, copper, silver, palladium, zinc and antimony) were also examined. The results showed a serious depression of the mercury signal only when gold, palladium and platinum were present at higher concentrations, which never or very seldom occur in fly ash matrices, and therefore do not represent a limitation of the method.     

Isotope dilution inductively coupled plasma quadrupole mass spectrometry in connection with a chromatographic separation for ultra trace determinations of platinum group elements (Pt, Pd, Ru, Ir) in environmental samples

An isotope dilution inductively coupled plasma quadrupole mass spectrometric (ID-ICP-QMS) method was developed for the simultaneous determination of the platinum group elements Pt, Pd, Ru, and Ir in environmental samples. Spike solutions, enriched with the isotopes ¹⁹⁴Pt, ¹⁰⁸Pd, ⁹⁹Ru, and ¹⁹¹Ir, were used for the isotope dilution step. Interfering elements were eliminated by chromatographic separation using an anion-exchange resin. Samples were dissolved with aqua regia in a high pressure asher. Additional dissolution of possible silicate portions by hydrofluoric acid was usually not necessary. Detection limits of 0.15 ng g^–1, 0.075 ng g^–1, and 0.015 ng g^–1 were achieved for Pt, Pd, Ru, and Ir, respectively, using sample weights of only 0.2 g. The reliability of the ID-ICP-QMS method was demonstrated by analyzing a Canadian geological reference material and by participating in an interlaboratory study for the determination of platinum and palladium in a homogenized road dust sample. Surface soil, sampled at different distances from a highway, showed concentrations in the range of 0.1–87 ng g^–1. An exponential decrease of the platinum and palladium concentration with increasing distance and a small anthropogenic contribution to the natural background concentration of ruthenium and iridium was found in these samples.