Search

A simple solvothermal reaction was used to prepare a 3-aminopropyl-functionalized silica-gel-based adsorbent for adsorbing Pd(II) from the nitric acid solution. Scanning electron microscopy, fourier transform infrared spectroscopy, and thermogravimetry analysis were performed on the as-synthesized adsorbent to demonstrate the successful introduction of Schiff base groups. Batch experiments were used to investigate the effects of contact time, nitric acid concentration, solution temperature, and adsorption capacity. It is worth noting that the prepared adsorbent exhibited a higher affinity toward Pd(II) with the uptake approximately 100% even in a 2 M HNO3 solution. At an equilibrium time of 5 h, the maximum adsorption capacity of Pd(II) was estimated to be 0.452 mmol/g. The adsorbed Pd(II) could be completely eluted by dissolving 0.2 M thiourea solution in 0.1 M HNO3. Using a combination of particle-induced X-ray emission analysis and an X-ray photoelectron spectrometer, the adsorbed Pd was found to be uniformly distributed on the surface of the prepared adsorbent and the existing species were Pd(II) and zero-valent Pd(0). Due to the desirable performances, facile preparation method, and abundant raw material source, the prepared adsorbent demonstrated a high application potential in the recovery of Pd(II) from simulated high-level liquid waste treatment.

Constructed on the moiety of a lactam screw ring, a near-infrared fluorescent probe RCya for Pd2+ was designed under the PET mechanism and synthesized by incorporating 2,4-dihydroxybenzaldehyde as the recognition group. Dynamic detection of aqueous Pd2+ by the probe RCya could be accomplished through ion competition, linear response, fluorescence-pH/time stabilities, and other optical tests. Moreover, the high selectivity, low cytotoxicity, cell permeability, and lysosome accumulation properties of RCya enabled the imaging applications on solid-state RCya–PAN composite nanofibers and in living cells. The recognition mechanism of probe RCya toward Pd2+ was further studied through simulation calculation and MS analysis. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a fluorescent dye 1, which is able to detect selectively Pd2+ by a clear fluorescence enhancement (FE) in THF. In the presence of eight Pd2+ equivalents, we observed a fluorescence enhancement factor (FEF) of 28.3. The high Pd2+ induced FEF can be explained by an off switching of multiple quenching processes within 1 by Pd2+. In the free dye 1 a photoinduced electron transfer (PET) and energy transfer (ET) takes place and quenches the anthracenic fluorescence. The coordination of eight Pd2+ units by the alkylthio‐substituted porphyrazine receptor suppresses the PET and ET quenching process and the anthracenic fluorescence is switched on. [ABSTRACT FROM AUTHOR]

Palladium contaminants can pose risks to human health and the natural environment. Once Pd2+ enters the body, it can bind with DNA, proteins, and other macromolecules, disrupting cellular processes and causing serious harm to health. Therefore, it becomes critical to develop simple, highly selective and precise methods for detecting Pd2+ in vivo. Here, we have successfully developed the first activated second near‐infrared region fluorescence (NIR-II FL) and ratio photoacoustic (PA) probe NYR-1 for dual-modal accurate detection of Pd2+ levels. NYR-1 is capable of rapidly (< 60 s) and sensitively detection of Pd2+ in solution, providing switched on NIR-II FL 920 and ratio PA 808 /PA 720 dual-mode signal change. More notably, the probe NYR-1 was successfully used for non-invasive imaging of Pd2+ overload in mouse liver by NIR-II FL/Ratio PA dual-modality imaging technology for the first time. Thus, this work opens up a promising dual-modal detection method for the precise detection of Pd2+ in organisms and in the environment. [Display omitted] • The first dual-modality probe NYR-1 for Pd2+ detection was developed. • The probe NYR-1 could be used for the detection of Pd2+ in cells and vivo. • The probe NYR-1 was first used for dual-modality imaging of liver Pd2+ overload. • The probe NYR-1 can be used for the detection of real water samples. [ABSTRACT FROM AUTHOR]

A rapid, selective and sensitive method for the quantification of Pd (II) using spectrophotometric technique associated with Z-N'-(benzo(d)thiazol-2-yl)-N,N-dimethylformimidamide BTDF as new chelating agent is described. Yellow colored complex of Pd (II) with BTDF is formed in Britton- Robinson universal buffer of pH 9 and extracted with chloroform. The formed complex clearly illustrate an absorption at ∼384 nm and follw Beer’s law in the range of concentration between 0.5–18.0 μg ml−1 of Pd (II) with absorbance of 3.62 × 104 L mol-1 cm-1 and limit of detection (LOD) of Pd (II) 0.07 μg ml−1.The effects of different experimental parameters have been established by study the optimum conditions for the extraction and quantification of palladium ion. Density functional theory (DFT) have also been employed to compute the influence of the cation on theoretical parameters of Pd2+ complexes. The effect of donating centers was investigated theoretically which prove that Pd2+ favor coordinated with two molecules of Z-N'-(benzo(d)thiazol-2-yl)-N,N-dimethylformimidamide through two nitrogen atoms.The performance of the examined method was estimated to detect the impact of current method over the presented methods in the literature without interference effect of cations and anions. The examined method has successfully demonstrated the quantification of Pd(II) in natural and spiked water samples. [ABSTRACT FROM AUTHOR]

Herein we present a study on the preparation and properties of a hydrogel adsorbent for treatment of wasted palladium souring from actial petrochemical industrial wastewater. Chitosan was used as the raw material and acrolein as the cross-linking agent for the hydrogel (A/CS). The adsorption behaviors of the hydrogel for Pd(II) ions were characterized and analyzed. The effect of pH, temperature, adsorption kinetics, and thermodynamics were investigated. Langmuir models were employed to describe the adsorption isotherms, while the pseudo-second-order equation was applied to describe the adsorption kinetics. The experimental results demonstrated that the adsorption was a monolayer chemical adsorption, and the adsorption capacity was found to reach 505.05 mg/g under optimal conditions. In addition, FT-IR and XPS analyses, combined with MS calculations confirmed that chelation and electrostatic attraction were dominated in the adsorption process. Overall, the development of this hydrogel adsorbent will provide a practical approach to the treatment of industrial wastewater containing palladium and have great potential for practical applications. [Display omitted] [ABSTRACT FROM AUTHOR]

A new propargylated cyanostilbene has been synthesized and was found to be sensitive to Pd 2+ ions over the other metal ions tested, with a significantly lower detection limit of 9.3 ppb under mild conditions. The sensing protocol proceeds via palladium catalyzed depropargylation reaction. The probe was also explored for its potential to detect Pd 2+ in human urine and blood samples. The noted significant % age of spiked recoveries in both cases depict promising potential of 3 for practical application. Importantly, the reported sensing protocol is first time employed for the detection of Pd 2+ ions from biological fluids. [ABSTRACT FROM AUTHOR]

Mechanism diagram of continuous detection of Pd2+ and N 2 H 4 by NAT. [Display omitted] • A new fluorescence molecule with 1,2,3-triazole structure were synthesized. • This "on-off-on" fluorescent sensor can continuously detect Pd2+ and N 2 H 4. • It has good detection performance, anti-interference ability and short response time. In recent years, hydrazine hydrate has been widely used in various fields as fuel and chemical raw materials, etc. However, hydrazine hydrate is also a potential threat to living body and natural environment. The effective method is urgently needed to detect hydrazine hydrate in our living environment. Secondly, as a precious metal, palladium has attracted more and more attention because of its excellent properties in industrial manufacturing and chemical catalysis. However, its potential danger is also slowly approaching, so it is necessary to find an excellent way to detect palladium, too. Herein, a fluorescent molecule, 4,4′,4′',4′''-(1,4-phenylenebis(2H-1,2,3-triazole-2,4,5-triyl)) tetrabenzoic acid (NAT), was synthesized. Firstly, NAT has very high selectivity and sensitivity for determination of Pd2+, because Pd2+ can coordinate well with carboxyl oxygen of NAT. The detection performance of Pd2+ is that the linear range is from 0.06 to 4.50 μM and the detection limit is 16.4 nM. Furthermore, the chelate (NAT-Pd2+) can continue to be used for quantitative determination of hydrazine hydrate with a linear range of 0.05–6.00 μM and the detection limit is 19.1 nM. The interaction time of NAT-Pd2+ and hydrazine hydrate is about 10 min. Of course, it also has good selectivity and strong anti-interference ability for many common metal ions, anions and amine like compounds. At last, the ability of NAT to quantitatively detect Pd2+ and hydrazine hydrate in actual samples has also been verified and the results are very satisfactory. [ABSTRACT FROM AUTHOR]

A novel rhodamine-based fluorescent turn-on probe for the detection of Pd 2+ has been judiciously designed and developed. The probe exhibited a high selectivity and sensitivity towards Pd 2+ with efficient fluorogenic and chromogenic responses under mild conditions. The detection limit is as low as 21 nM. Furthermore, the probe has been successfully applied to image of Pd 2+ in living cells. [ABSTRACT FROM AUTHOR]

In this work, a selective Pd(II) ions chelating resin based on 2-aminobenzaldehyde modified chitosan Schiff’s base (Pd-CAZ) was synthesized through ion-imprinting technique. All the performed chemical and morphological changes during the modification and Pd(II) ion-imprinting process were investigated using instrumental techniques including FTIR, 1 H NMR, XRD and SEM. In addition, the mechanism of Pd(II) binding to the synthesized polymeric active sites was elucidated using both XPS and FTIR spectra, and the results indicated that Pd(II) ions coordinated in square planar geometry. Also, the selective extraction experiments with respect to Pd-CAZ and control non-imprinted NI-CAZ resins were performed to obtain the fundamental thermodynamic, kinetic and isotherm parameters. In all cases the adsorption was endothermic, spontaneous, fit well with pseudo-second order kinetic model and Langmuir adsorption isotherm model with maximum adsorption capacities of 275 ± 0.4 and 114 ± 0.2 mg/g for Pd-CAZ and NI-CAZ, respectively. Moreover, the regeneration and recovery experiments indicated that the resin maintain about 96% of its original activity after the fifth adsorption–desorption cycle, revealing the high economic value. [ABSTRACT FROM AUTHOR]

A novel and simple depropargylation-triggered spontaneous cyclization reaction based fluorescent turn-on chemodosimeter for the detection of Pd 2+ has been reasonably designed and developed. Based on the specific reactivity of palladium ion-promoted hydrolysis reaction, the probe exhibited a high selectivity and sensitivity for Pd 2+ with a low detection limit (53 nM, 5.7 μg/L) under physiological conditions in neutral PBS (only containing 1% organic cosolvent) without any additional reagents. [ABSTRACT FROM AUTHOR]

We report here for the first time a novel dual-fluorescence emission and electrometric sensor based on palladium ion-imprinted organosiloxane nanoparticles (Pd-imp@CDs-Pc) grafted with both carbon dots (CDs) and phthalocyanine (Pc) dye for the determination of palladium ion, Pd(II) as a target. Nanoparticles showed two emission peaks at the double excitation wavelengths of 367 and 620 nm. These peaks were assigned to emissions induced by CDs (456 nm) and Pc (698 nm). The fluorescence of Pc embedded in nanoparticles is slightly quenched, whereas the emission from CDs is distinctly quenched by Pd(II). On the other hand, Glassy Carbon Electrode (GCE), which was modified by using Pd-imp@CDs-Pc nanoparticles, displayed a sensitive electrochemical signal upon interaction with Pd(II). The reduction in emission intensity and peak current increase are both more pronounced for Pd-imp@CDs-Pc than for N-imp@CDs-Pc , which was synthesized in the absence of Pd(II), revealing a selective recognition ability of the Pd-imp@CDs-Pc. The emission ratio of fluorescence obtained at two wavelengths (F 456 /F 698) diminished and peak current increased with the increase in Pd(II) concentration in the range of 2.7–90.4 µM and 5.6–390 nM, respectively. The limits of detection (LOD) for determining Pd(II) based on ratiometric fluorescence and electrochemical measurements were found to be 0.19 µM and 2.76 nM, respectively. The nanohybrid sensor exhibited also good selectivity to Pd(II) over other interfering metal ions. Fluorescence and electrochemical experimental results confirmed that the sensor based on Pd-imp@CDs-Pc nanoparticles was distinctively responsive and selective for determining Pd(II) in tap water and artificial seawater samples. [Display omitted] • Pc synthesis and functionalization, and incorporation onto CDs through covalent bonding. • Fabrication of Pd(II)-imprinted polysiloxane nanoparticles grafted with CDs and Pc. • Encapsulated CDs-Pc as ratiometric and electrometric nanohybrid sensor for Pd(II). • Excellent selectivity and sensitivity guaranteed by ion imprinting for Pd(II) detection. [ABSTRACT FROM AUTHOR]

A new aptamer selection method using graphene oxide (GO)-adsorbed nanoparticles (GO-adsorbed NPs) was employed for specific fishing of palladium ion. High affinity ssDNA aptamers were isolated through 13 rounds of selection and the capacity of the selected DNA aptamers for palladium ion uptake was measured, clarifying that DNA01 exhibits the highest affinity to palladium ion with a dissociation constant ( K d ) of 4.60 ± 1.17 μM. In addition, binding ability of DNA01 to palladium ion was verified against other metal ions, such as Li + , Cs + , Mg 2+ , and Pt 2+ . Results of the present study suggest that future modification of DNA01 may improve palladium ion-binding ability, leading to economic recovery of palladium from water solution. [ABSTRACT FROM AUTHOR]

1,2,3-Triazole-group-containing resins for palladium ion adsorption in HCl media were prepared. The monomer, synthesized from acryloyl chloride and 3-(1,2,3-triazol-1-yl) propanol, and a crosslinker, ethylene glycol dimethacrylate, was polymerized in dimethyl sulfoxide via radical polymerization. The specific surface area decreased with increasing monomer:crosslinker molar ratio. In acidic media, the adsorption of palladium ions was greater than those of platinum and ruthenium ions, because stable complexes were formed between palladium ions and triazole groups. The maximum amount of palladium ions adsorbed was 0.41 mol/kg. [ABSTRACT FROM AUTHOR]

The environment-friendly and water-soluble polymer was prepared via ring-opening reaction between polyvinyl alcohol (PVA) and 3-epoxypropoxy fluorescein (EPF). Based on the quenching of fluorescence signals of PVA–EPF in the 520 nm wavelength and relative quenched intensity is good linear with the concentration of palladium II. A simple, rapid, sensitive, and specific detection method for palladium II is proposed. In comparison with traditionary methods, the present method is environment-friendly, stable, easy to operation, more water-soluble, and cheaper. The results suggested that PVA–EPF may offer potential as a reusable polymer sensor for palladium II ion in aqueous solution. [ABSTRACT FROM PUBLISHER]

[Display omitted] Although a number of palladium(II) probes have been developed, most of them have small Stokes shifts and lack good subcellular targeting ability. In this paper, a reaction-based probe (DCF-MPYM-Pd) has been designed and synthesized for palladium(II) detection. The probe was constructed by a fluorescein derivative as the fluorophore and an allyl ester group as the recognition group. The probe exhibited fast response time (5 min), high sensitivity and specificity. Importantly, it has a large Stokes shift and lysosomal targeting capability. In addition, it was demonstrated that the probe can be used to sense palladium(II) in living cells and can accumulate specifically in lysosomes. [ABSTRACT FROM AUTHOR]

Highlights: [•] PBA was facilely electrosynthesized in the binary solvent system containing of acetonitrile and boron trifluoride diethyl etherate. [•] “On–off” type fluorescent sensor based on this polymer for highly selective, sensitive, and practical detection of Pd2+ was designed. [•] The possible mechanism between Pd2+ and PBA has been discussed and TEM preliminary proved the proposed mechanism. [•] This fluorescent CP-based sensor has been used to practically detect Pd2+ in agricultural crops and environment samples with satisfactory results. [ABSTRACT FROM AUTHOR]

Literature thermodynamic data on species and particles existing in the heterogeneous PdO-HO system were checked for consistency, and the equilibrium constants for dissolution of palladium oxide and hydroxide in water and for Pd (aq) hydrolysis were recommended. Δ G obtained in this work for Pd(aq) sharply differs (no less than by 6 kJ/mol) from values that are reported in fundamental thermodynamic reference books and based on experimentally measured palladium electrode potential at 25°C. Detailed examination of literature data on the thermodynamic properties of compounds in the Cl-Pd(aq) system is required to account for revealed inconsistency. [ABSTRACT FROM AUTHOR]

Abstract: A series of rhodamine spiro-leuco compounds have been developed as fluorescence-enhanced sensors for optical sensing of palladium ion (Pd2+). The initial rhodamine hydrazone derivatives, RPd1-a, RPd1-b, and RPd1-c, display a good coordination to Pd2+ inducing the spirolactam-open reaction with a significant fluorescence enhancement and color generation. Different stoichiometry results, 1:2 in EtOH/H2O and 1:1 in MeOH/DCM were observed for Pd2+/RPd1-c complexation. [Copyright &y& Elsevier]

Abstract: An optimized and validated spectrophotometric method has been developed for the determination of cefixime in pharmaceutical formulations. The method is based on the complexation reaction between cefixime and palladium ion in the presence of acidic buffer solution (pH 3) in ethanol-distilled water medium at room temperature. The complex absorbed maximally at 352nm. Beer’s law is obeyed in the working concentration range of 2.5–35μg/mL with apparent molar absorptivity of 1.015×104 L/molcm and Sandell’s sensitivity of 0.001μg/cm2/0.001 absorbance unit. The limits of detection and quantitation for the proposed method are 0.175 and 0.583μg/mL, respectively. The effect of common excipients used as additives has been studied in the determination of cefixime. The proposed method has been successfully applied for the determination of cefixime in pharmaceutical formulations. The results obtained by the proposed method were statistically compared with the reference method using t and F values and found no significant difference between the two methods. [Copyright &y& Elsevier]

Abstract: One problem of carbon supported Pd (Pd/C) anodic catalyst in direct formic acid fuel cell (DFAFC) is the poor electrocatalytic stability. Considering Pd metal can be dissolved in the acidic electrolyte, the effect of the addition of Pd2+ ions in the electrolyte on the electrocatalytic stability of Pd/C catalyst for formic acid oxidation was investigated. It was found that after the Pd/C catalyst is immersed in the electrolytes with 1.0×10−4 M Pd2+ for 8 days, the electrocatalytic activity and stability of the Pd/C catalyst are higher than that of the Pd/C catalyst without immersing and with immersing in the electrolyte without Pd2+ ions. There are four reasons for obtaining high electrocatalytic performance of the Pd/C catalyst by Pd2+. (1) The existence of Pd2+ ions in the electrolyte could effectively inhibit the dissolution of Pd in the Pd/C catalyst. (2) Some Pd2+ ions would be adsorbed on the surface of Pd particles and then increase the roughness of the Pd particles. (3) Pd2+ ions adsorbed on Pd particles can make the intermediate of formic acid oxidation easy to be oxidized to CO2. (4) Pd2+ could be reduced to Pd under −0.2V and 0.8V electrode potential. Then, the new active sites are generated constantly in the process of potential scanning. Therefore, this investigation suggested a new method to improve the performance of the Pd/C anodic catalyst in DFAFC. [Copyright &y& Elsevier]

Abstract: Novel temperature-responsive copolymers of N-isopropylacrylamide and monoaza-tetrathioether derivative, were synthesized for the selective extraction of soft metal ions such as silver(I), copper(I), gold(III) and palladium(II) ion. The ratio between N-isopropylacrylamide group and monoaza-tetrathioether group in the copolymer was determined. The ratio between N-isopropylacrylamide group and monoaza-tetrathioether group varied in the range of 66:1–187:1. Each lower critical solution temperature (LCST) of the polymer solution was determined spectrophotometrically by the relative absorbance change at 750nm via temperature of the polymer solution. Metal ion extraction using the copolymer with appropriate counter anions such as picrate ion, nitrate or perchlorate ion was examined. Soft metal ions such as silver(I), copper(I), gold(III) and palladium(II) ion were extracted selectively into the solid polymer phase. The extraction efficiency of a metal ion such as silver ion increased as the increase of the ratio of the monoaza-tetrathioether group to N-isopropylacrylamide group in the polymer. The quantitative extraction of class b metal ions as well as the liquid–liquid extraction of metal ions with monoaza-tetrathioether molecule was performed. [ABSTRACT FROM AUTHOR]

We developed a facile and high-recovery system for palladium(II) ion based on complexation between trithiocyanuric acid (TCA) and melamine (Mel) through hydrogen bonding. Recovery of PdII using TCA-Mel complexation system was fast, and the recovery efficiency was greater than 90% within 1min. The maximum amount of PdII recovered by the TCA-Mel system (1.248 gPd gTCA-Mel-1) was greater than the amount recovered by previously reported materials. [ABSTRACT FROM AUTHOR]

Abstract: Palladium sensors based on two neutral ionophores, N,N′-bis(acetylacetone) cyclohexanediamine (L 1 ) and N,N′-bis(o-hydroxyacetophenone)-1,2-cyclohexanediamine (L 2 ) for quantification of palladium ions are described. Effect of various plasticizers (o-NPOE, DBP, DEP, DOP, TBP, and CN) and anion excluder, sodium tetra phenyl borate (NaTPB) has been studied. The best performance is obtained with a membrane composition of PVC:o-NPOE:ionophore (L 1 ):NaTPB of 150:300:5:5 (%, w/w). The sensor exhibits significantly enhanced selectivity towards palladium ion over the concentration range 1.0×10−8 to 1.0×10−1 M with a lower detection limit of 4.0×10−9 M and a Nernstian compliance (29.1±0.3mVdecade−1 of activity) within pH range 2.0–6.0 and fast response time of 10s. Influence of the membrane composition and possible interfering ions has also been investigated on the response properties of the electrode. Fast and stable response, good reproducibility and long-term stability of the sensor are demonstrated. The sensor has been found to work satisfactorily in partially non-aqueous media up to 20% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 4 months. Selectivity coefficients determined with fixed interference method (FIM) indicate high selectivity for palladium. The proposed electrode shows fairly good discrimination of palladium from other cations. The application of prepared sensor has been demonstrated in determination of palladium ions in spiked water sample. [Copyright &y& Elsevier]

Ion imprinted polymer (IIP) materials with nanopores were prepared by formation of ternary complex of palladium imprint ion with dimethylglyoxime (DMG) and 4-vinylpyridine (VP, functional monomer) and thermally copolymerizing with styrene (crosslinking monomer) and divinylbenzene (cross linker) and 2,2′-azobisisobutyronitrile as initiator. The synthesis was carried out with cyclohexanol as porogen and subsequently leached with 50% (v/v) HCl to obtain leached IIP particles. These leached IIP particles can now pick up palladium ions from dilute aqueous solutions. The optimal acidity for quantitative enrichment was 0.2–0.4N HCl and eluted completely by stirring for 15 min with 2×10 ml of 50% (v/v) HCl. The palladium ion imprinting polymer gave 100 times higher distribution ratio than ion recognition (blank) polymer (IRP). Further, percent extraction, distribution ratio and selectivity coefficients of palladium and other selected inorganic ions using IRP and IIP particles were determined and compared. Five replicate determinations of 50 μg of palladium in 1 l of solution gave a mean absorbance of 0.200 with a relative standard deviation of 2.12%. The detection limit corresponding to three times the standard deviation of the blank was 2.5 μg of palladium/l. [Copyright &y& Elsevier]

'of a near-infrared (NIR) fluorescent probe,' Palladium ions show many negative effects on human health via the interference with the tissue macromolecules and the function of enzymes. In this paper, a novel benzothiazolium-thioxanthene hemicyanine dye BTX-OH has been synthesized for the design of a near-infrared (NIR) fluorescent probe. The dye BTX-OH in aqueous solution showed its absorption and fluorescence emission maxima in the NIR region at 750 nm and 795 nm, respectively. The application of the dye in designing a Pd2+-selective fluorescence probe BTX-A based on a "protect-deprotect" strategy by using an allyl carbonate group as the specific Pd2+-responding site has been demonstrated. The probe BTX-A exhibited high selectivity and sensitivity for detecting Pd2+ ions. In the presence of Pd2+ ions, the probe showed an enhanced fluorescence response and accumulated specifically in lysosomes in living-cell imaging. [Display omitted] • A novel benzothiazolium-thioxanthene hemicyanine dye has been prepared. • The dye showed absorption and fluorescence maxima in the NIR region. • The dye has been applied for the design of Pd2+-selective fluorescence probe. • The Pd2+-selective fluorescence probe is accumulation in lysosomes in living-cell. [ABSTRACT FROM AUTHOR]

The conducting behavior of dendritic carbosilanes including palladium ions (Pd) has been measured. The palladium ion containing dendrimers were prepared by the addition of palladium dichloride to double-layered dendritic carbosilanes, which consist of phenylethynyl groups (−C≡CPh) on the outmost periphery as well as phenylethenyl and propyleneoxy groups (−CH=CPh− and (CH)O−) in the inner shell. By measuring conductivities, palladium ion containing dendrimers revealed an increasing tendency according to the increasing number of double bonds in the inner shells of dendritic carbosilanes. [ABSTRACT FROM AUTHOR]

In this article, a simple and rapid colorimetric sensing method was developed for the determination of palladium ions. The method is based on in situ generation of palladium nanoparticles (PdNPs) upon reduction by hydrazine which then acts as an activator on the reduction reaction of thionine by hydrazine. The formation of PdNPs was characterized by UV-Vis spectrophotometry, particle size analysis and TEM images. The reaction was followed by measuring the thionine absorbance at 599 nm with time. Several factors influencing analytical performance of the kinetic method such as concentration of reactants and electrolyte, pH of the sample solution and temperature were investigated to achieve the optimum conditions and highest sensitivity. This method showed a linear calibration curve in the concentration range of 8-1200 ng mL -1 for palladium ions. The limit of detection (LOD) was 6.5 ng mL -1 and the relative standard deviations were 3.8% and 1.3% (n = 8) for two palladium ion concentrations of 60 and 300 ng mL -1 , respectively. The method was successfully applied to the determination of palladium in river water, pond water, wastewater and soil samples., (Copyright © 2018 Elsevier B.V. All rights reserved.)