Coprecipitation of gold(III) complex ions with manganese(II) hydroxide and their stoichiometric reduction to atomic gold (Au(0)): analysis by Mössbauer spectroscopy and XPS

To elucidate the formation process of precursor of gold-supported manganese dioxide (MnO2), the coprecipitation behavior of [AuCl4-n(OH)n](-) (n=0-4) (Au(III)) complex ions with manganese(II) hydroxide (Mn(OH)2 and the change in their chemical state were examined. The Au(III) complex ions were rapidly and effectively coprecipitated with Mn(OH)(2) at pH 9. According to the M?ssbauer spectra for gold (Au) coprecipitated with Mn(OH)2, below an Au content of 60 wt% in the coprecipitates, all of the coprecipitated Au existed in the atomic state (Au(0)), while, above an Au content of 65 wt%, part of the gold existed in the Au(III) state, and the proportion increased with increasing coprecipitated Au content. Based on the results of X-ray photoelectron spectroscopy, Mn(II) in Mn(OH)2 converted to Mn(IV) in conjunction with coprecipitation of Au(III) complex ions. These results indicate that the rapid stoichiometric reduction of Au(III) to Au(0) is caused by electron transfer from Mn(II) in Mn(OH)2 to the Au(III) complex ion through an Mn-O-Au bond.     

Capillary gas chromatographic analysis of pyrrolidinedithiocarbamate metal chelates

Pyrrolidinedithiocarbamate (PDTC) chelates of Zn(II), Cu(II), Ni(II), Co(III), Fe(III), Mn(II), Cr(III), and VO(II) were analysed by capillary GC on a DB-1701 column (30 m x 0.25 mm id) with flame ionisation detection (FID). Linear calibrations were attained within "1-30 microg/mL" for Ni(II), Fe(III), Mn(II), Cr(III), Cu(II), and VO(II), and within "2-50 microg/mL" for Co(III) and Zn(II). The limits of detection were in the "150-500 ng/mL" range, corresponding to 15-50 pg amounts reaching the FID system. The optimised method was applied to the determination of Cu(II) and Ni(II) in coins, and that of Zn(II), Cu(II), Ni(II), Fe(III), Mn(II), Cr(III), and VO(II) in pharmaceutical preparations with relative standard deviations within 1.1-5.2%. The results obtained are in good agreement with sewage water samples and the declared values for the pharmaceutical formulations, or with the results of AAS of metal contents in coins, pharmaceutical preparations, and sewage water samples.     

Determination of heavy metals at sub-ppm levels in seawater and dialysis solutions by FAAS after tetrakis(pyridine)-nickel(II)bis(thiocyanate) coprecipitation.

A coprecipitation method has been developed for the determination of Cr(III), Mn(II), Fe(III), Co(II), Cu(II), Cd(II) and Pb(II) ions in aqueous samples by flame atomic absorption spectrometry (FAAS) with the combination of pyridine, nickel(II) as a carrier element and potassium thiocyanate as an auxiliary complexing agent. The obtained coprecipitates were dissolved with nitric acid and measured by FAAS. The coprecipitation conditions, such as the effect of the pH, amounts of nickel, pyridine and potassium thiocyanate, sample volume, and the standing time of the precipitate formation were examined in detail. It was found that the metal ions studied were quantitatively coprecipitated with tetrakis(pyridine)-nickel(II)bis(thiocyanate) precipitate (TP-Ni-BT) in the pH range of 9.0 - 10.5. The reliability of the results was evaluated by recovery tests, using synthetic seawater solutions spiked with the analyte metal ions. The obtained recoveries ranged from 96 to 101% for all of the metal ions investigated. The proposed method was validated by analyses of two certified reference materials (NIST SRM 2711 Montana soil and HPS Certified Waste Water Trace Metals Lot #D532205). It was also successfully applied to seawater and dialysis solution samples. The detection limits (n = 25, 3s) were in the range of 0.01-2.44 microg l(-1) for the studied elements and the relative standard deviations were < or =6%, which indicated that this method could fully satisfy the requirements for analysis of such samples as seawater and dialysis solution having high salt contents.     

Distribution coefficients for twelve elements in oxalic acid medium on a strong anion-exchange resin

The distribution coefficients were determined for twelve elements, namely As(III), Ce(III), Cr(III), Co(II), Cu(II), In(III), Lu(III), Mn(II), Hg(II), Mo(VI), Sc(III) and Zn(II), on a strong base anion exchanger in pure oxalic acid solutions. The K_D curves are given. A scheme was developed for the chromatographic separation of five elements, namely As(III), Mn(II), Co(II), Zn(II) and Cu(II). Ce(III) can be separated from Lu(III).     

Preparation, characterization and metal sorption studies of a Chrome-Azurol-S-loaded anion-exchange resin

Chrome Azurol S (CS) was mobilized on an strongly basic anion-exchange resin (Dowex 2 x 4, in Cl(-) form) by batch equilibration. The modified resin was stable in acetate buffer solution and in 0.1 M HCl and H(2)SO(4), but it was readily degraded with 2-6 M HCl and HNO(3). Retention of Ba(II), Sr(II), Ca(II), Mg(II), Al(III), Cr(III), Zn(II), Fe(III), Ti(IV), Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) was studied using the batch equilibration method. The uptake and recovery yields were determined by using inductively-coupled plasma atomic emission spectroscopy (for Mg, Al, Cr, Ti, Fe, Mn, Ni, Zn, Cu, Cd and Pb) and atomic absorption spectrophotometry (for Ba, Sr, Ca and Co). The optimum pH value was established for performing a selective separation of Al(III) from the other metal ions. The sorption capacities of the CS-loaded resing for Al(III), Cr(III), Mg(II) (at pH 6), Fe(III) (at pH 5) and Ti(IV) (at pH 4) were 14, 2.9, 0.3, 3 and 3.9 mumoles g(-1) respectively. On this basis a method for separating Al(III) from other cations was established.     

Spectrophotometric and derivative spectrophotometric determination of aluminium with Hydroxynaphthol Blue

The reaction of aluminium(III) with Hydroxynaphtol Blue (HNB) in aqueous media at apparent pH 5.5 results in a red complex that is stable for at least 4 hr. Beer's Law is obeyed up to 1.6 microg/ml of aluminium(III) with an apparent molar absorptivity of 1.66 x 10(4) l.mol(-1). cm(-1) at 569 nm. This paper proposes procedures for aluminium(III) determination by ordinary and first-derivative spectrophotometry. The results demonstrated that the linear dynamic range is 0.03-1.60 microg/ml for ordinary spectrophotometry and 11.8-320.0 ng/ml for first derivative spectrophotometry. The HNB is not selectivity for aluminium, but the addition of EDTA allows the aluminium determination in the presence of accepted amounts of Ca(II), Mg(II), Mn(II), Ba(II), Sr(II), Cd(II), Pb(II), La(III), In(III), Bi(III) and Zn(II). The interference of Cu(II) and Hg(II) can be masked by thiosulphate. Ions such as UO(2)(II), Mo(VI), Co(II), Ti(IV) and PO(4)(III) do interfere seriously. This method was applied for aluminium determination in copper-base alloy, zinc-base alloy, magnesium-base alloy, iron ore, manganese ore, cement, dolomite, feldspar and limestone. The results indicated high accuracy and precision.     

Synthesis, characterization, solid-state structures, and spectroscopic properties of two catechol-based luminescent chemosensors for biologically relevant oxometalates

The new heteroditopic ligand 2,3-dihydroxy-N-(1,10-phenanthroline-5-yl)benzamide (H2-L3) was synthesized and coordinated to [Ru(bpy)2(phen)]2+- and [ReBr(CO)3(phen)]-type luminophores (bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline). The resulting chemosensors [Ru(bpy)2(H2-L3)]2+ and [ReBr(CO)3(H2-L3)] were fully characterized and their solid-state structures and spectroscopic properties were investigated to assess how the photophysical properties of the luminescent signaling units affect the performance of the sensors. [Ru(bpy)2(H2-L3)]2+ and [ReBr(CO)3(H2-L3)] both signal the presence and concentration of molybdate and vanadate in aqueous acetonitrile through a decrease in emission intensity. [ReBr(CO)3(H2-L3)] also detects tungstate. Due to the higher emission intensity of the Ru-based sensor, its detection limits for molybdate (43 microg L(-1)) and vanadate (24 microg L(-1)) are almost 1 order of magnitude lower than the ones achieved with the Re-based sensor. The optimum working pH of the chemosensors is determined by the pKa values of the 2-hydroxy-groups of the receptor units: pH 4 for [ReBr(CO)3(H2-L3)] and pH 3 for [Ru(bpy)2(H2-L3)]2+. Both sensors are selective: equimolar amounts of PO4(3-), SO4(2-), ReO4-, Mn(II), Fe(III), Co(II), Ni(II), Cu(II), and Zn(II) do not interfere with the detection of molybdate or vanadate.     

Using silica modified by Tiron for metal preconcentration and determination in natural waters by inductively coupled plasma atomic emission spectrometry

A new adsorbent is synthesized on the basis of silica consecutively modified by polyhexamethylene guanidine and 4,5-dihydroxy-1,3-benzenedisulfonic acid (Tiron) for the group preconcentration of Fe(III), Al(III), Cu(II), Pb(II), Zn(II), and Mn(II) followed by determination by inductively coupled plasma atomic emission spectrometry. The adsorbent in the batch mode quantitatively (recovery 98?99%) extracts Fe(III), Al(III) and Cu(II) ions at pH 4.0 and Fe(III), Al(III), Cu(II), Pb(II), Zn(II), and Mn(II) ions at pH 7.0; the time of attainment of an adsorption equilibrium does not exceed 10 min. Consecutive preconcentration at pH 4.0 and 7.0 in the batch and dynamic modes ensures the quantitative separation of Fe(III), Al(III), and Cu(II) from Pb(II), Zn(II), and Mn(II) and their separate determination. The quantitative desorption of metals was attained with 0.5?1.0 M HNO₃ (5 or 10 mL). In preconcentration from 200 mL of solution with 5 mL of a desorbing solution, the preconcentration coefficient was equal to 40. The developed procedure was used for the determination of metal ions in river waters of Krasnoyarsk Krai. The results obtained were verified by the added?found method.     

Anion exchange separation of chromium and molybdenum from iron,vanadium, uranium and other elements in malonic acid solution

Summary Anion-exchange behaviour of chromium (III) and molybdenum (VI) was studied in malonate media. They form anionic complexes with malonic acid at pH 5.6. Various eluants, such as mineral acids and their salts were tested and a selectivity scale evolved. Cr and Mo were separated from Tl(I), alkali and alkaline earth elements by selective sorption and from Co(II), Ni(II), Mn(II), Zn(II) and Cd(II) by selective washing with water. They were separated from many other elements by selective elution. The sequential separation of Fe(III) V(IV), Cr(III), Mo(VI) and U(VI) was significant.     

Adsorption of metal ions on activated carbon from aqueous solutions at pH 1-13

Adsorption of microgram amounts of 20 metal species on activated carbon powder from aqueous solutions of pH 1-13 was investigated. The species examined were Cs(I), Y(III), Ce(III), Ti(IV), Zr(IV), Cr(III), Cr(VI), Mn(II), Fe(III), Co(II), Ni(II), Ru(III), Cu(II), Ag(I), Zn(II), Cd(II), Al(III), Pb(II), Sb(III) and Bi(III).     

Coprecipitation with lanthanum phosphate as a technique for separation and preconcentration of iron(III) and lead

The usefulness of coprecipitation with lanthanum phosphate for separation and preconcentration of some heavy metals has been investigated. Although lanthanum phosphate coprecipitates iron(III) and lead quantitatively at pH 2.3, iron(II) can barely be collected at this pH. This coprecipitation technique was applicable to the separation and preconcentration of iron(III) before inductively coupled plasma atomic-emission spectrometric (ICP-AES) determination; the recoveries of iron(III) and iron(II) from spiked water samples were 103-105% and 0.2-0.7%, respectively. The coprecipitation was also useful for separation of 20 microg lead from 100 mL of an aqueous solution that also contained 1-100 mg iron. Coprecipitation of iron was substantially suppressed by addition of ascorbic acid, which enabled recovery of 97-103% of lead added to the solution, bringing the recovery to within 1.6-5.0% of the relative standard deviations. Lanthanum phosphate can also coprecipitate cadmium and indium quantitatively, although chromium(III), cobalt, and nickel and large amounts of sodium, potassium, magnesium, and calcium are barely coprecipitated at pH approximately/= 3.     

Organic acid solutions in the chromatography of inorganic ions VIII. Cation-exchange of Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II), Fe(III), Sc(III), Y(III), Eu(III), Dy(III), Ho(III), Yb(III), Ti(IV) and Nb(V) in malate media

Summary The cation-exchange behaviour of Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II), Fe(III), Sc(III), Y(III), Eu(III), Dy(III), Ho(III), Yb(III), Ti(IV) and Nb(V) in malate media at various concentrations and pH, was studied with Dowex 50 WX8 resin (200–400 mesh) in the ammonium form. Separation of Fe(III)/Cu(II), Fe(III)/Cu(II)/Zn(II), Fe(III)/Co(II)/Mn(II), Cu(II)/Ni(II)/Mn(II), Fe(III)/Cu(II)/Co(II)/Mn(II), Fe(III)/Cu(II)/Ni(II)/Cd(II), Yb(III)/Eu(III), Sc(III)/Y(III),Sc(III)/Yb(III)/Dy(III) and Nb(V)/Yb(III)/Ho(III) has been achieved, among others.This work was supported by C.N.R. of Italy.     

Determination of trace amounts of nickel, manganese, cobalt, and zinc in environmental samples after separation and preconcentration by use of polyacrylic acid/alumina sorbent

Manganese, nickel, cobalt, and zinc are elements that appear together in many real samples. In this work, a simple, rapid, and sensitive method has been used for the simultaneous separation and preconcentration of trace amounts of these elements using water-soluble polyacrylic acid on alumina as a sorbent in a glass column system. A solution containing Mn, Ni, Co, and Zn was passed through the column at pH 7, and desorption was carried with 5.0 mL of 0.03 M nitric acid. Linearity was maintained between 0.25-5.0 x 10(3), 0.04-6.0 x 10(3), 0.10-8.0 x 10(3), and 0.028-1.0 x 10(3) ng/mL for Ni, Mn, Co, and Zn, respectively, in the original solution. Eight replicate determinations of a mixture containing 1.0 microg/mL of each of the elements in the final solution gave relative standard deviations of 1.4, 1.5, 2.4, and 1.2% for Ni, Mn, Co, and Zn, respectively. The sorption capacities for Mn (mg/g sorbent) obtained were 16.0 for Mn, 9.0 for Ni, 12.0 for Co, and 10.0 for Zn. By using 5.0 mL elution solution, preconcentration factors of 400, 500, 700, and 460 could be obtained for Ni, Mn, Zn, and Co, respectively.     

Preparation and characterization of Cr(III), Mn(II), Fe(II), Co(II) and Ni(II) complexes of a hexaazadithiophenolate macrocycle

The ligating properties of the 24-membered macrocyclic dinucleating hexaazadithiophenolate ligand (L(Me))2- towards the transition metal ions Cr(II), Mn(II), Fe(II), Co(II), Ni(II) and Zn(II) have been examined. It is demonstrated that this ligand forms an isostructural series of bioctahedral [(L(Me))M(II)2(OAc)]+ complexes with Mn(II) (2), Fe(II) (3), Co(II) (4), Ni(II) (5) and Zn(II) (6). The reaction of (L(Me))2- with two equivalents of CrCl2 and NaOAc followed by air-oxidation produced the complex [(L(Me))Cr(III)H2(OAc)]2+ (1), which is the first example for a mononuclear complex of (L(Me))2-. Complexes 2-6 contain a central N3M(II)(mu-SR)2(mu-OAc)M(II)N3 core with an exogenous acetate bridge. The Cr(III) ion in is bonded to three N and two S atoms of (L(Me))2- and an O atom of a monodentate acetate coligand. In 2-6 there is a consistent decrease in the deviations of the bond angles from the ideal octahedral values such that the coordination polyhedra in the dinickel complex 5 are more regular than in the dimanganese compound 2. The temperature dependent magnetic susceptibility measurements reveal the magnetic exchange interactions in the [(L(Me))M(II)2(OAc)]+ cations to be relatively weak. Intramolecular antiferromagnetic exchange interactions are present in the Mn(II)2, Fe(II)2 and Co(II)2 complexes where J = -5.1, -10.6 and approximately -2.0 cm(-1) (H = -2JS1S2). In contrast, in the dinickel complex 5 a ferromagnetic exchange interaction is present with J = +6.4 cm(-1). An explanation for this difference is qualitatively discussed in terms of the bonding differences.     

Reactivity of M(II) metal-substituted derivatives of pig purple acid phosphatase (uteroferrin) with phosphate

The Fe(II) of the binuclear Fe(II)Fe(III) active site of pig purple acid phosphatase (uteroferrin) has been replaced in turn by five M(II) ions (Mn(II), Co(II), Ni(II), Cu(II), and Zn(II)). An uptake of 1 equiv of M(II) is observed in all cases except that of Cu(II), when a second more loosely bound Cu(II) is removed by treatment with edta. The products have been characterized by different analytical procedures and by UV-vis spectrophotometry. At 25 degrees C, I = 0.100 M (NaCl), the nonenzymatic reactions with H(2)PO(4)(-) give the mu-phosphato product, and formation constants K/M(-1) show an 8-fold spread at pH 4.9 of 740 (Mn), 165 (Fe), 190 (Co), 90 (Ni), 800 (Cu), 380 (Zn). The variations in K correlate well with stability constants for the complexing of H(2)PO(4)(-) and (CH(3)O)HPO(3)(-) with M(II) hexaaqua ions. At pH 4.9 with [H(2)PO(4)(-)] > or = 3.5 mM rate constants k(obs) decrease, and an inhibition process in which a second [H(2)PO(4)(-)] coordinates to the dinuclear center is proposed. The mechanism considered accounts for most but not all of the features displayed. Thus K(1) values for the coordination of phosphate to M(II) are in the range10-60 M(-1), whereas K(2) values for the bridging of the phosphate to Fe(III) are in the narrower range 7.8-12.4. From the fits described K(i) approximately 10(3) M(-1) for the inhibition step, which is independent of the identity of M(II). Values of k(obs) decrease with increasing pH, giving pK(a) values which are close to 3.8 and independent of M(II) (Fe(II), Zn(II), Mn(II)). The acid dissociation process is assigned to Fe(III)-OH(2) to Fe(III)-OH(-), where OH(-) is less readily displaced by phosphate.     

Silica gel modified with N-(3-propyl)-O-phenylenediamine: functionalization, metal sorption equilibrium studies and application to metal enrichment prior to determination by flame atomic absorption spectrometry.

The use of the chemically modified silica gel N-(3-propyl)-O-phenylenediamine (SiG-NPPDA) adsorbent, for the preconcentration and separation of trace heavy metals, was described. SiG-NPPDA sorbs quantitatively (90-100% recovery) trace amounts of nine heavy metals, viz., Cd(II), Zn(II), Fe(III), Cu(II), Pb(II), Mn(II), Cr(III), Co(II) and Ni(II) at pH 7-8. The sorption capacity varies from 350 to 450 micromol g(-1). Desorption was found to be quantitative with 1-2 M HNO3 or 0.05 M Na2EDTA. The distribution coefficient, Kd and the percentage concentration of the investigated metal ions on the adsorbent at equilibrium, C(M,eqm)% (Recovery, R%), were studied as a function of experimental parameters. The logarithmic values of the distribution coefficient, log Kd, ranges between 4.0 and 6.4. Some foreign ions caused little interference in the preconcentration and determination of the investigated nine metals by flame atomic absorption spectrometry (AAS). The adsorbent and its formed metal chelates were characterized by IR (absorbance and/or reflectance), potentiometric titrations and thermogravimetric analysis (TGA and DTG). The mode of chelation between the SiG-NPPDA adsorbent and the investigated metal ions is proposed to be due to the reaction of the investigated metal ions with the two nitrogen atoms of the SiG-NPPDA adsorbent. The present adsorbent coupled with flame AAS has been used to enrich and determine the nine metal ions in natural aqueous systems and in certified reference materials (RSD < or = 5%). The copper, iron, manganese and zinc present in some pharmaceutical vitamin samples were also preconcentrated on SiG-NPPDA adsorbent and determined by flame AAS (RSD < or = 4.2%). Nanogram concentrations (0.07-0.14 ng ml(-1)) of Cd(II), Zn(II), Fe(III), Pb(II), Cr(III), Mn(II), Cu(II), Co(II) and Ni(II) can be determined reliably with a preconcentration factor of 100.     

Solvent extraction of several metal ions with mercaptotropone

Mercaptotropone was synthesized from tropone, and its acid dissociation constant (K_a) and distribution coefficient (K_D) between benze and aqueous solution were spectrophotometrically determined as 5.75 (pK_a) and 2.46 (log K_D); Extraction behaviour of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pb(II), Cr(III), Fe(III), Y(III), and Zr(IV) with this reagent into benzene was examined. Cu(II) and Fe(III) were completely extracted from acidic solution, Mn(II), Co(II), Ni(II), Zn(II), Pb(II), and Zr(IV) were also extracted from intermediate pH region, a part of Cr(III) was extracted, but Y(III) was not extracted.     

Adsorption of metal ions onto Moroccan stevensite: kinetic and isotherm studies

The aim of this paper is to study the adsorption of the heavy metals (Cd(II), Cu(II), Mn(II), Pb(II), and Zn(II)) from aqueous solutions by a natural Moroccan stevensite called locally rhassoul. We carried out, first, a mineralogical and physicochemical characterization of stevensite. The surface area is 134 m2/g and the cation exchange capacity (CEC) is 76.5 meq/100 g. The chemical formula of stevensite is Si3.78Al0.22Mg2.92Fe0.09Na0.08K0.08O10(OH)2.4H2O. Adsorption tests of Cd(II), Cu(II), Mn(II), Pb(II), and Zn(II) in batch reactors were carried out at ambient temperature and at constant pH. Two simplified models including pseudo-first-order and pseudo-second- order were used to test the adsorption kinetics. The equilibrium time and adsorption rate of adsorption were determined. The increasing order of the adsorption rates follows the sequence Mn(II) > Pb(II) > Zn(II) > Cu(II) > Cd(II). The Dubinin-Radushkevich (D-R), Langmuir, and Redlich-Peterson (R-P) models were adopted to describe the adsorption isotherms. The maximal adsorption capacities at pH 4.0 determined from the D-R and Langmuir models vary in the following order: Cu(II) > Mn(II) > Cd(II) > Zn(II) > Pb(II). The equilibrium data fitted well with the three-parameter Redlich-Peterson model. The values of mean energy of adsorption show mainly an ion-exchange mechanism. Also, the influence of solution pH on the adsorption onto stevensite was studied in the pH range 1.5-7.0.     

The extraction of various metals as their anionic complexes with edta by solutions of aliquat-336 chloride in 1.2-dichloroethane

The extraction of anionic complexes of EDTA with Ca. Mg, V(IV), V(V), Cr(III), Mn(II), Mn(III), Fe(III), Co(II), Co(III), Ni, Cu(II), Zn, Cd, Hg(II), Pd(II), Pb and Bi by solutions of Aliquat-336 chloride in 1,2-dichloroethane has been studied as a function of the pH of the aqueous phase. The order and extent of the extractability varies greatly with the pH and provides a number of new possibilities for separation procedures. Thus iron(III) can be separated from many other metals in strongly alkaline solution while the extraction of V(V), V(IV), Hg(II) and Pd(II) exceeds 99% over wide pH ranges. The complex of Mn(III) with EDTA which is very unstable in aqueous solution can be preserved for up to 5 h when extracted by Aliquat-336.One of us (R. H. A1-J.) wishes to thank the Ministry of Oil of the Republic of Iraq for financial support.     

Chloroform extraction of metal ethyl xanthates from hydrochloric acid media

The chloroform extraction of 32 elements (Fe, Co, Ni, Zn, Cd, Ge, Sn, Pb, V, As, Sb, Bi, Cu, Ag, Au, Mn, Re, Ga, In, Tl, Ce, Se, Te, Cr, Mo, U, Pt, Pd, Rh, Ir, Ru and Os) from O.1-10M hydrochloric acid media in the presence of potassium ethyl xanthate has been studied. The oxidation states in which some elements react, and potential analytical separations, are discussed. Pd(II), As(III) and Se(IV) are completely extracted as ethyl xanthate complexes, Te(IV) is almost completely extracted, and Au(III) is largely extracted over the range of acid concentration investigated. Mn(II), Zn, Rh(III), Ir(IV), Ru(III), Os(IV), Cr(III), Cr(VI), Ce(III) and Ce(IV) are not extracted. Ge is partly extracted from 6-10M media as the chloro-complex. Depending on the acid concentration, the remaining elements are all partially extracted as xanthate complexes.