Selective Flotation-Spectrophotometric Procedure for the Trace Analysis of Palladium(II) in Different Matrices

Abstract

The determination of palladium under microgram concentration levels is generally hampered by insufficient sensitivity of the techniques used and or by a matrix effect. With the introduction of techniques, sensitivity problems have been drastically reduced.There are chemical and physical methods to increase the sensitivity and decreasing matrix effects, such as extraction 1,2 or preconcentration by solvent evaporation; however, in the presence of complex matrices with very low concentration of the analyte, these methods are seldom effective and are considered to be unsatisfactory. However, the development of a sensitive, accurate, precise and fast procedure using less sophisticated instruments is a vital process.The formation of extractable chelates of Pd(II) with dithizone 3 and dithiocarbamate 4 has been applied to the separation of Pd(II) from other platinum metal ions. Also, the extraction of Pd(II) halide complexes affords convenient separation.5 Oxime derivatives have also been used for extraction and the spectrophotometric determination of Pd(II).Flotation techniques are recommended as good separation and preconcentration 6-8 tools with most of the advancing factors previously mentioned. Recently, the flotation-separation step can be analytically completed spectrophotometrically 9 or by a suitable technique, such as atomic absorption spectrometry. 10 Such techniques acquire analytical importance as the flotation-separation step is selectively completed.Although many spectrophotometric methods have been reported for the determination of Pd(II) 6-8 , a simple, rapid and economical flotation-spectrophotometric method has been developed for the concentration and determination of trace Pd(II) in different matrices using HOL as a surfactant and HHB as a chelating reagent. This reagent is more sensitive and specific than many of the reagents reported for Pd(II). 3,4 Moreover, this method involves the determination of trace Pd(II) after selective separation by floatation, those eliminating the effect of foreign ions and increasing the sensitivity. Also, the direct determination of Pd(II) in the surfactant phase decreases its determination time and loss during the determination. Another advantage of the present investigation is that the data obtained spectrophotometrically were attained by the simplest colorimetric analysis method.A literature survey showed that ion-flotation followed by a spectrophotometric determination of Pd(II) is rarely reported.11,12 Also, no attempt has been found for using HHB in this concern. Fortunately, in this investigation, HHB finds its role for a direct spectrophotometric determination of Pd(II), and also gives high performance in the preconcentration of Pd(II) via its flotation as HHB-Pd colligend. Experimental ReagentsPalladium stock solutions were prepared by dissolving 1 g PdCl 2 (Merck) in 3 ml HCl followed by dilution to 250 ml using doubly distilled water or ethanol. For the analysis of simulated ores, a Pd stock solution was prepared by dissolving 1 g of Pd wire in few ml of ...

Development of a flotation method for preconcentration-separation of trace amounts of some metal ions in plant tissues prior to their FAAS determinations

“…In addition, the viscosity of the surfactant-rich phase increases, leading to poor sensitivity. 34,35 At lower CTAB concentrations (below 0.005% w/v), the preconcentration efficiency of the complex was very low, probably due to assemblies that were inadequate to quantitatively entrap the hydrophobic complex and float the complex. …”

“…Many factors influence to perform a proper flotation, but an important role has the collector with its colloid nature. [30][31][32][33][34] According to our knowledge there is still not reported any method in the literature, based on the simultaneous flotation of transition and heavy metal ions using Schiff's bases ligand. Therefore, in detail it was decided to develop an efficient method for the extraction and preconcentration of trace amounts of some metal ions from aqueous media using bis(2-hydroxyacetophenone)-1,4-butanediimine (BHABDI) and determination by FAAS.…”

Separation via Flotation, Spectrophotometric Speciation, and Determination of Vanadium(IV) in Wastes of Power Stations

“…[9][10][11][12][13][14][15][16][17][18] Consequently, such a process enabled and facilitated the spectrophotometric determination of the analyte.…”

“…On the other hand, methods for the separation and preconcentration of metals by flotation, followed by their spectrophotometric determination, have increased in popularity in recent years. [9][10][11][12][13][14][15][16][17][18] A literature survey showed that ion-flotation followed by spectrophotometric determination of V(IV) is rarely reported. 19 Also, no attempt has been found for using 1-(2-hydroxy-4-methoxybenzophenone)-4-phenylthiosemicarbazone (HMBPT) in this concern.…”

Simultaneous preconcentration flotation-separation and spectrophotometric determination of thorium, lanthanum and yttrium in some geological and enviromental samples

“…Among several preconcentration techniques, interactions based on chelate formation have received considerable attention due to their simplicity and ability to attain high enrichment factor [17,18]. Much attention has been given to the preconcentration and separation of heavy metals from environmental, biological and pharmaceutical samples by flotation techniques [19][20][21][22][23][24]. In this respect, the adoption of a flotation methodology has been shown to give accurate and reproducible results, together with simple, rapid analytical processing and low chemical blanks.…”