Spectrophotometric determination of palladium with 2-mercaptobenzoxazole

A new spectrophotometric method for the determination of palladium is described using 2-mercaptobenzoxazole as reagent. The color reaction has a sensitivity of 0.08 μg of Pd per cm² for log I₀/I = 0.001 and obeys Beer's law from 2 to 40 p.p.m. The effects of pH, time, order of addition of the reagents, temperature and diverse ions were investigated. The procedure was applied to synthetic solutions containing palladium plus a variety of foreign ions.     

A highly sensitive spectrophotometric determination of palladium with chromal blue g and cetyltrimethylammonium chloride

A new spectrophotometric method for the determination of palladium with chromal blue G (Color Index 43835) and cetyltrimethylammonium chloride is described. The sensitivity of the color reaction between palladium and chromal blue G is greatly increased in the presence of cetyltrimethylammonium chloride. The palladium complex has maximal absorbance at pH 3.2–3.8 and at 670 nm. Beer's law is obeyed over the range 0.08–1.4 p.p.m. palladium; the molar absorptivity is 1.01 · 10⁵ l mol^-1 cm^-1 at 670 nm and the sensitivity is 1·10^-3 μg Pd cm^-2. The mole ratio of palladium and chromal blue G in the complex in the presence of cetyltrimethylammonium chloride is 1:3. Only scandium interferes when sodium fluoride is used as masking agent.     

The determination of palladium by atomic absorption spectroscopy

A commercial atomic absorption apectrophotometer was used without modification to establish the most suitable operating, conditions for the determination of palladium. A study of the effect of organic solvents miscible with water, and of acids was then carried out. In general, organic solvents led to increased sensitivity. With a complex of palladium, Pd(py)₂Cl₂, in 50% ethanol, the sensitivity was also enhanced and, with a hexone solution of the complex, Pd(py)₂(SCN)₂, amounts of palladium below 2 p.p.m. could be determined.     

Amperometric determination of palladium with 2-(o-Hydroxyphenyl) Benzoxazole

Summary A method for the amperometric determination of palladium is presented, which involves the formation of a palladium-2-(o-hydroxyphenyl) benzoxazole inter complex salt. The method is primarily recommended for the accurate determination of palladium in solutions containing only traces of other platinum elements. Of the several diverse ions studied, only iridium interfered seriously with the determination of palladium; however, this element is easily removed from palladium according to the standard procedure². The data obtained in the amperometric investigation of the palladium-2-(o-hydroxyphenyl) benzoxazole interaction were in agreement with the results obtained in the gravimetric study of the same reaction⁷.     

Spectrophotometric determination of palladium : Bismuthiol ii as an analytical reagent

A method for the spectrophotometric determination of palladium with bismuthiol 11 is described. The colour reaction is instantaneous and at 20–30° the system is stable for about 24 hours when maintained at a pH between 3 and 10. The colour system shows no sharp peak of maximum absorption but measurements can be made at any wavelength between 410 mμ and 430 mμ, preferably at 420 mμ. In this region the system obeys Beer's law at a palladium concentration of 0.4 μg to 80μg per ml. The sensitivity of the reaction is 0.0t6μg palladium per cm² (practical) or o 01 μg and 0.012μg of palladium per cm² at 410 mμ and 420 mμ respectively (Sandell). Acetone and methyl cellosolve stabilize the system. Excess of reagent and a large number of cations and anions are completely without effect. The composition of the complex in solution, which agrees well with that of the isolated compound, is Pd(C₈H₅N₂S₃)₂ with an average dissociation constant of 2.8$\text{.}\text{?}$10^-12 at 25°.     

Spectrophotometric determination of palladium using 4-methyl-l ,2-cyclohexanedionedioxime

A procedure for the determination of palladium with 4-methyl-1,2-cyclohexanedionedioxime by an extraction -spectrophotometric method has been developed. Interference by coppcr(II), cobalt(Il), iron(II), or iron(III) can be eliminated by suitable masking agents. Ruthenium(III) must be absent or separated prior to the determination of palladium. The molar absorptivity of the bis(4-methyl-1,2-cyclohexanedionedioximato-N,N') palladium(II) complex has been calculated and found to be 1.51?10⁴ 1/moles-cm in chloroform at 280 mμ.     

Spectrophotometric determination of palladium with glyoxime and chloroform extraction

Palladium(II) reacts with glyoxime in a 1:2 mole ratio to form a yellow water-insoluble chelate, which is soluble in chloroform; the solution has an absorption maximum at 397 mμ. Absorbance measurements at 397 mμ allow determination of the palladium glyoximate in solution. The maximum amount of palladium is extracted at pH 1.0. Platinum(II), iridium(III), gold(III), and phosphate cause some positive interference, and iron(II, III) causes negative interference; the interferences can be eliminated by masking with EDTA. The species extracted has been shown to be identical with that used to prepare the original palladium glyoximate chloroform solution. With EDTA and multiple extractions, the method is satisfactory for the determination of palladium in the presence of other platinum-group elements and many other cations.     

Extraction and flame spectrophotometric determination of palladium and rhodium

Solvent extraction methods involving toluene, chloroform, 4-methyl-2-pentanone and pentyl acetate were studied for palladium and rhodium chelates. The palladiurn-salicylaldoxime chelate was extracted quantitatively into 4-methyl-2-pentanone at pH 3. The rhodium-diethyldithiocarbamate chelate was completely extracted into 4-methyl-2-pentanone at pH 8. The optimum combustion conditions for each of the organic extracts were then studied. The position of maximum emission intensity in the flame mantle was determined for each chelate and solvent system ; readings were taken at 363.5 mμ for palladium, and 369.2 mμ for rhodium. For palla-dium, when 4-methyl-2-pentanone was used instead of water as solvent, the emission intensity increased 21-fold. For rhodium, this kctone increased the sensitivity 27 times compared with water. A method is suggested for the separation and determination of palladium and rhodium in the same sample.     

Spectrophotometr1c determination of palladium : Bismuthiol i as an analytical reagent

The reagent, bismuthiol l, has been successfully utilized for the spectrophotometric determination of palladium. The colour reaction is instantaneous and the system is stable for at least 24 hours in the pH range 6 to 10 but shows no sharp peak of maximum absorption. The system obeys Beer's law at a palladium concentration of 0.8 μg to 8.0 μg per ml at any wavelength between 400 mμ and and 410 mμ giving a sensitivity of 0.08 μg of palladium per cm² (practical); 0.01 μg of palladium per cm² (sandell). Ethyl alcohol stabilizes the system against any deviation due to appearance of turbidity. A large excess of the reagent and almost all thc cations and anions, except platinum, gold, copper, chromium, iron, mercury, silver, thallium, uranium, vanadate and cyanide, do not interfere. By applying job's method of continuous variation it was found that the complex contains thc reactants in 1 : 1 ratio and that the average value of the dissociation constant of the complex is 3.2$\text{.}\text{?}$ 10^-5 at 25°.     

Comparative study of magnesium nitrate,palladium nitrate and reduced palladium for the direct determination of mercury in sea water by electrothermal atomization atomic absorption spectrometry

A comparative study of different chemical modifiers in graphite furnace atomic absorption spectrometry for the direct determination of mercury in sea water samples, in synthetic sea water sample of high (72.8%) and low 34.2%) salinity and in aqueous solutions, was carried out. The use of reduced palladium produces better results. The mixture of palladium nitrate and ascorbic acid, gives the best limit of detection (1.9 gl^–1). The use of reduced palladium and magnesium nitrate produced excellent recoveries (close to 100%) in the whole salinity range for all mercury concentration tested. The use of palladium nitrate alone or combined with magnesium nitrate gave good recoveries with respect to a real sea water sample for low salinities. The interference from the major components of sea water were completely removed by using reduced palladium and magnesium nitrate modifiers. Thus, a single calibration curve with synthetic sea water may be applied to the analysis of sea water samples of widely differing salinities.     

Prochlorperazine bismethanesulfonate as a new reagent for the spectrophotometric determination of palladium

A simple, rapid, and selective method for the determination of palladium is described. The orange-red palladium(II)-prochlorperazine bismethanesulfonate complex in the presence of hydrochloric acid-sodium acetate buffer exhibits maximum absorbance at 480 nm with a molar absorptivity of 4.32 × 10³ liters mol^?1 cm^?1. The sensitivity of the reaction is 24.62 ng cm^?2. The system obeys Beer's law over the concentration range 0.4–20 ppm of palladium with an optimum concentration range of 1–19 ppm. The apparent stability constant of the complex is found to be log K = 5.3 ± 0.1 at 27 °C. The effects of pH, time, temperature, order of addition of reactants, reagent concentration, and interferences from various ions are reported. The proposed method offers the opportunity to carry out the determination at room temperature without the need for an extraction step. The method is also found to be suitable for the determination of palladium in jewelry alloy.     

Extractive photometric determination of palladium with o-mercaptobenzoic acid

A procedure is described for the extractive photometric determination of palladium(II) with o-mercaptobenzoic acid. The reagent forms a yellow complex having maximum absorption at 365–370 mμ. The complex is quantitatively extractable with chloroform in the presence of pyridine at pH 5.2–7.2. The color develops immediately at room temperature and is very stable. Beer's law conforms over the range of 0.37–5.86 ppm of palladium. Most of the cations do not interfere in the presence of ascorbic acid and EDTA. Gold and silver are effectively masked with excess of thiocyanate prior to the addition of ascorbic acid and EDTA. Many common anions do not interfere. The molar absorptivity and Sandell sensitivity are 16.7 × 10³ and 0.0065 μg/cm². The reagent forms a 2:1 complex with palladium. The proposed method is simple, rapid, and selective for the determination of palladium(II).     

Gravimetric determination and radiochemical separation of palladium(II) with ethyl-α-isonitrosoacetoacetate

The use of ethyl-ga-isonitrosoacetoacetate (HEINA) for determination of palladium is reported. Pd can be estimated quantitatively from 0.5M to 2M HCl solution. Accurate results are obtained in 1M solution with an accuracy better than 1%. Decontamination values against platinum metals and other metals usually associated with Pd are greater than 10⁵. The time required for gravimetric determination is about an hour, for radiochemical separation about 25 min and the recovery is better than 90%.     

Spectrophotometric determination of palladium: A comparative study of 2-mercaptobenzothiazole and 2-mercaptobenzimidazole as analytical reagents

As spectrophotometric reagents for palladium 2-mereaptobenzothiazole and 2-mereaptobenzothiazole behave more or less in the same way. Colour system formed by them at a pH region of 3.0 to 6.5 obey Beer's law at 380 mμ palladium concentration of 0.4 to 6.0 mμ per ml and the optimum range with the minium is from 1.6 to 4.0 μg of palladium per ml at 30.1% and 35.8% treansmission with 2-mereaptobenzothiazole and 2-mereaptobenzothiazole respectively. By applying job's method it was found that in solution the ratio of metal to reagent in the complexes is 1:2 and that the dissociation constants of the order of 10^-12.     

Application of non-steroidal anti-inflammatory drugs for palladium determination

A highly sensitive spectrophotometric method for palladium determination using piroxicam and tenoxicam as new chromogenic reagents has been developed. In the presence of sodium lauryl sulfate (SLS), palladium reacts with piroxicam (PX) or tenoxicam (TX) to form stable yellow orange complexes in an acetate buffer solution of pH 5.0 at 424 nm and 426 nm with molar absorptivity of 7.16 × 10⁴ L mol⁻¹ cm⁻¹ and 1.20 × 10⁵ L mol⁻¹ cm⁻¹, respectively. Sandell sensitivity, detection, and quantitation limits were also calculated. Optimum conditions were evaluated considering pH, reagent concentration, time, temperature, and surfactant concentration. The complex system conforms to Beer’s law over the range of 0.07–1.28 μg mL⁻¹ palladium. The stoichiometric ratio and stability constant were also evaluated. Tolerance limits of many cations and anions were determined. Finally, the proposed method was applied successfully in the determination of palladium in jewellery, anode mud, synthetic mixtures, catalysts, and alloy samples.     

Indirect complexometric determination of palladium usingl-histidine as masking agent

An indirect complexo-titrimetric method is described for the determination of palladium in the presence of other metal ions, L-histidine being used as the masking agent. Palladium(II) and other metal ions are initially complexed with an excess of EDTA and the surplus EDTA titrated with standard zinc sulfate solution at pH 4.5–5.5 using xylenol orange as indicator. An excess of 1 % L-histidine solution is then added, and the released EDTA is titrated with standard zinc sulfate solution. Accurate and reproducible results were obtained for 2–15 mg of Pd with relative errors 0.4% and standard deviations < 0.02mg. Sn(IV) and Au(III) interfere, but can be easily masked. The method is successfully applied for the determination of palladium(II) in alloy compositions.     

Extractive spectrophotometric determination of palladium from acidic high activity nuclear waste

A simple and rapid method for spectrophotometric determination of palladium from highly acidic and highly radioactive nuclear waste using -benzoin oxime (ABO) as extractant and isobutyl methyl ketone (hexone) as diluent has been developed. The method can be employed over a wide range of nitric acid concentrations and for palladium concentrations in the range of 1·10^–5M to 4·10^–4M in the organic phase. The molar absorptivity was found to be 4·10³l·mol^–1·cm^–1. Influence of various heavy metal ions, fission products and corrosion products was studied. The method was found to give a precision and accuracy better than 4% at 100 g of palladium.     

Extractive spectrophotometric determination of palladium using 2-(2-hydroxyimino-1-oxoethyl)furan

A rapid, simple, selective and sensitive method for the determination of palladium in trace amounts has been developed, based on the reaction of 2-(2-hydroxyimino-1-oxoethyl)furan [-isonitroso-2-acetyl-furan] with the metal ion in acetic acid. The intense yellow complex is quantitatively extractable into chloroform, whose absorbance is measured at 425 nm. The method is free from the interference of a large number of other metal ions. It obeys Beer's law in the range 0.0–3.8 g Pd mL^–1 with Sandell's sensitivity of 0.003 g Pd cm^–2. The ratios of metal to ligand in the extracted complex are 1:1 and 1:2. The analysis of various samples has been carried out with satisfactory and reproducible results.     

Cloud-point extraction,preconcentration, and spectrophotometric determination of palladium in water samples

The possibility of using Thio-Michler's Ketone (TMK), 4,4′-bis(dimethylamino) thiobenzophenone, for palladium(II) concentrated by micellar extraction at the cloud-point temperature, and later spectrophotometric determination, was investigated. Under the optimum conditions, preconcentration of 50?mL of water samples in the presence of 0.1% (w/v) octylphenoxy polyethoxy ethanol (Triton X-114), 2?×?10^?6?mol?L^?1?TMK and 1?×?10^–3?mol?L^?1 buffer solution (pH?=?3.0) gave the limit of detection of 0.47?ng?mL^?1, and the calibration graph was linear in the range of 2–50?ng?mL^–1. The recovery under optimum working conditions was higher than 97%. The proposed method has been applied to the spectrophotometric determination of palladium(II) in natural water samples after cloud-point extraction with satisfactory results.     

The determination of platinum and palladium in copperbased standard reference materials by neutron activation analysis

The determination of palladium and platinum by n.a.a. in 100-1 μg g^?1 Pd-Cu and Pt-Cu alloys is described. To avoid systematic errors, standards with approximately the same shape and composition as the samples were prepared by quantitative deposition of the noble metals from dilute hydrochloric acid medium on copper powder; after ignition in hydrogen, the powder was pressed to standard pellets. Platinum was determined by i.n.a.a. via ¹⁹⁹Au. For palladium an instrumental analysis via ¹¹¹Ag was possible only for the 100 μg g^?1 samples. For the lower concentrations copper was removed by cation exchange and palladium was determined via the ¹⁰⁹Pd-^109mAg isotopes. The precision for each analysis was 2–3 % relative. The accuracy was checked by comparison with results from other laboratories.