Solvent Extraction Separation of Palladium (II) and Platinum(IV) with Mesityl Oxide.

Khopkar, S. M.

doi:10.1021/ac60234a051

Cited by 14 publications

(4 citation statements)

References 13 publications

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“…The ability to form and extract the DEDTC complexes of Pt(II), Pd(II), and Rh(II1) from dilute acidic aqueous solutions of the metal was critical for development of a useful method. For this, and all discussions not specifically addressing the acidity of the Reports indicate that in some cases, an added ionic salt will enhance extraction (38,39). A variety of ionic salt concentrations were evaluated with respect to the complexation/ extraction ability of NaDEDTC for an 80 ng/mL aqueous Pd(I1) solution.…”

Section: Chromatography Of Pure Precious Metal Chelatesmentioning

confidence: 99%

“…Reports indicate that in some cases, an added ionic salt will enhance extraction (38,39). A variety of ionic salt concentrations were evaluated with respect to the complexation/ extraction ability of NaDEDTC for an 80 ng/mL aqueous Pd(II) solution.…”

Section: Dedtc Complexesmentioning

confidence: 99%

“…of the DEDTC complexation were slowed considerably. Khopkar (39) studied the solvent extraction of Pd(II) and Pt(IV) with mesityl oxide and found that the addition of chloride ion in acidic solution increased the ability of the metal complexes to be extracted into the organic phase. The increased extraction was attributed to the chloride acting as a salting-out agent, increasing the distribution ratio.…”

Section: Dedtc Complexesmentioning

confidence: 99%

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Determination of low levels of rhodium and palladium as their solvent extracted dithiocarbamate complexes by liquid chromatography

Mueller¹,

Lovett²

1985

Anal. Chem.

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High-performance iiquld chromatography with UV detection can be used to determine trace levels of Pd( I I ) and Rh( I I I) in aqueous solution after complexation with sodium diethyidithiocarbamate. Successful low-level extraction of the precious metal complexes Into chloroform depends on the ionic strength of the aqueous phase. The use of 2 M sodium bromide in the extraction step results In high efficiency of metal complex extraction (>95 % ) for Pd( I I ) and Rh( I I I). Detection limits for Pd( I I ) and Rh( I I I) from aqueous solution are 2.7 ng/mL and 2.8 ng/mL, respectively. Complexation and extractlon conditions for the determlnatlon of Pd( I I ) and Rh( I I I ) appear to have a limited pH dependence. Trace levels of Pd in Pt powder (58 pg/g) and In an aqueous Pt atomic absorption standard solution (21 ng/mL) have been determlned. A Pt/Rh alloy (90%/10%) has been analyzed for Rh content. The analyses show high reproducibility and high sensitivity. Pd( I I ) can be determined in the presence of large amounts of Pt because the Pt( I V ) diethyidithlocarbamate complex is charged and is not extracted lnto the chloroform.The analytical applications of dithiocarbamates for trace metal determinations are well documented (1-3). The ability of dithiocarbamates to form metal complexes with a large variety of trace metals and the properties of these complexes make dithiocarbamates useful reagents in trace-metal analysis. In general, metal complexes of dithiocarbamates are thermodynamically stable and their formation is kinetically fast (4). The solubility of the metal complexes is low in aqueous solution, but high in organic solvents such as chloroform and 4-methyl-2-pentanone. Solvent extraction of dithiocarbamate complexes has thus been extensively exploited as a preconcentration technique in atomic absorption spectrometry (5-7). In addition, the large molar absorptivities of metal dithiocarbamate complexes make them useful for colorimetric trace metal determinations (8).In recent years, the use of high-performance liquid chromatography (HPLC) trace-metal analysis has grown in popularity. A number of recent reviews regarding the HPLC of metal complexes has been published (9-11). The use of dithiocarbamates for the analytical determination of trace metals has been a logical progression in the analytical use of dithiocarbamates.A variety of separation conditions, detectors, and a number of different dithiocarbamates have been used. Both reverse-phase (12-18) and normal-phase (19-22) chromatographic techniques have been utilized. The method of de; tecting the eluted metal complex has also been varied. Electrochemical (23-26) and atomic spectrometric (27) detection systems have been evaluated to some extent, but UV-vis absorption is by far the most used detection method. In addition, both on-line complexation (25,26) and prechromatographic complexation and extraction procedures have been used.This work involves the low-level determination of precious metals by the HPLC of their diethyldithiocarbamate (DEDTC) complexes....

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Section: Chromatography Of Pure Precious Metal Chelatesmentioning

confidence: 99%

Section: Dedtc Complexesmentioning

confidence: 99%

Section: Dedtc Complexesmentioning

confidence: 99%

See 1 more Smart Citation

Determination of low levels of rhodium and palladium as their solvent extracted dithiocarbamate complexes by liquid chromatography

Mueller¹,

Lovett²

1985

Anal. Chem.

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“…The effect of diverse ions on the solvent extraction of beryllium (10.9 pg) from 0.5M hydrochloric acid and 5M ammonium thiocyanate using 50% tributyl phosphate was studied. The tolerance limit was calculated as described earlier (13). The results are shown in Table II.…”

Section: Resultsmentioning

confidence: 99%

Diluted tributyl phosphate as an extractant for beryllium as its thiocyanate complex

Kalyanaraman¹,

Khopkar²

1975

Anal. Chem.

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50% Tributyl phosphate-toluene was used for the quantitative extraction of beryllium from 0.5M hydrochloric acid containing 5M ammonium thiocyanate. Beryllium was stripped from the organic phase with 1M sodium hydroxide and determined colorimetrically at 510 nm as its complex with Eriochrome Cyanine R.Although several extractants are available for the solvent extraction of beryllium, they have only limited applications (1) . The d-diketones had no special advantages (2). Diethyl ether was used in fluoride (3) and thiocyanate (4) media but the extraction was incomplete. Trioctylamine in methyl isobutyl ketone (5) was used for its separation from acidic solutions.Tributyl phosphate (6) was used for the extraction of beryllium but the method had no practical utility as the extraction was possible only from 0.1M hydrochloric acid and 14M lithium chloride. Further, the extraction was not quantitative. A similar attempt was made to use tributyl phosphate as an extractant (7) in the presence of salicylic acid with no advantage.Many transition elements were extracted as their thiocyanate complexes with tributyl phosphate as the extractant(2) . Sekine (8) extracted americium from 5M sodium thiocyanate with 5% tributyl phosphate in hexane. Similarly, De and Sen (9) utilized the thiocyanate system for the solvent extraction of some transition elements such as cobalt, copper, and iron with tributyl phosphate.An attempt was made to extract beryllium from thiocyanate media with 50% tributyl phosphate, using toluene as the diluent. This paper describes such a method for the solvent extraction of beryllium. The method proposed is simple, rapid, selective, and applicable at microgram concentrations. The procedure was extended for the analysis of beryllium in beryl. EXPERIMENTALApparatus and Reagents. A Spektromom 204 spectrophotometer with 10-mm matched quartz cells, a Type FEK-57 photoelectric filter photometer, and Cambridge pH meter with glass and calomel electrodes were used.The tributyl phosphate, bp 143 °C, was from British Drug House, England (BDH). About 1.241 grams of beryllium nitrate tetrahydrate (BDH Ana-laR) was dissolved in 100 ml of distilled water containing 1 ml of nitric acid. The solution was standardized gravimetrically (10). It contained 0.545 mg/ml of beryllium. The diluted solution containing 5.45 Mg/ml of beryllium was prepared from stock solution by appropriate dilution.Eriochrome Cyanine R. (E. Merck, Germany) was an 0.1% a ueous solution.General Procedure. An aliquot of the solution containing 10.9 Mg of beryllium was taken. Then enough hydrochloric acid and ammonium thiocyanate were added to make their concentrations 0.5M and 5M, respectively, in a total volume of 25 ml. The sample was then transferred to a separatory funnel and extracted with 10 ml of 50% tributyl phosphate in toluene for 5 minutes at room temperature. The two layers were allowed to settle and separate.Beryllium was stripped from the organic phase by shaking it twice with 15 ml of 1M sodium hydroxide. To the aqueous phase, 3 ml of con...

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Two-electron oxidation of N,N,N′,N′-tetramethyl naphthidine in acetonitrile The reactivity of its dication to aromatic nucleophilic substitution by pyridine

Miras

Silber

Sereno

1986

Journal of Electroanalytical Chemistry and Interfacial Electroc

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Solvent Extraction Separation of Palladium (II) and Platinum(IV) with Mesityl Oxide.

Cited by 14 publications

References 13 publications

Determination of low levels of rhodium and palladium as their solvent extracted dithiocarbamate complexes by liquid chromatography

Determination of low levels of rhodium and palladium as their solvent extracted dithiocarbamate complexes by liquid chromatography

Diluted tributyl phosphate as an extractant for beryllium as its thiocyanate complex

Two-electron oxidation of N,N,N′,N′-tetramethyl naphthidine in acetonitrile The reactivity of its dication to aromatic nucleophilic substitution by pyridine

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