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A procedure for the preconcentration and determination of lead in vegetable and biological samples was developed in the continuous mode coupled to a flame atomic absorption spectrometer. Lead is quantitatively preconcentrated in acetic buffer as its diethyldithiocarbamate chelate onto a C-18 minicolumn, placed in the loop of a proportional injector, eluted by a stream of methyl isobutyl ketone and...
Direct determination of Bi, In and Pb in sea water samples has been carried out by ETAAS with Zeeman background correction using molybdenum containing chemical modifiers and tartaric acid as a reducing agent. Maximum pyrolysis temperatures and the effect of mass ratios of the mixed modifier components on analytes have been investigated. Mo+Pd+TA or Mo+Pt+TA mixture was found to be powerful for the...
In this work it was evaluated the determination of Cd and Pb in mussels by tungsten coil electrothermal atomic absorption spectrometry (TCA-AAS). A critical and comprehensive study of the effects caused by Pd, Mg, ascorbic acid, and binary mixtures of these compounds on the atomization of Cd and Pb in acid digested solutions of mussels was performed. Palladium and mixtures containing it were useful...
A procedure for lead, cadmium and copper determination in coal samples based on slurry sampling using an atomic absorption spectrometer equipped with a transversely heated graphite tube atomizer is proposed. The slurries were prepared by weighing the samples directly into autosampler cups (5-30 mg) and adding a 1.5 ml aliquot of a diluent mixture of 5% v/v HNO 3 , 0.05% Triton X-100 and 10%...
A new micelle-mediated phase separation of metal ions to preconcentrate trace levels of lead as a prior step to its determination by flame atomic spectroscopy has been developed. The methodology is based on the cloud point extraction of lead with PONPE 7.5 in the absence of chelating agent. The chemical variables affecting the sensitivity of the extractive-spectrometric procedure were evaluated in...
The design and operation of a hand-held electrochemical analyzer for field screening of trace lead are described. The stripping-based instrument meets the size, weight and power-consumption requirements of many decentralized lead testings, while maintaining the high sensitivity and reliability of centralized stripping operations. When coupled to screen-printed disposable sensors, the unit's response...
A stable chelating resin matrix was synthesized by covalently linking o-aminophenol (o-AP) with the benzene ring of the polystyrene-divinylbenzene resin, Amberlite XAD-2, through a -N N- group. Elemental analyses, thermogravimetric analysis (TGA) and infrared spectra have characterized the resulting chelating resin. It has been used to preconcentrate Cu 2+ , Cd 2+ , Co ...
A novel spherical macroporous epoxy-dicyandiamide chelating resin is synthesized simply and rapidly from epoxy resin and use for the preconcentration and separation of trace Ga(III), In(III), Bi(III), Sn(IV), Pb(II), V(V) and Ti(IV) ions from solution samples. The analyzed ions can be quantitatively concentrated by the resin at flow rate of 3.0 ml min -1 at pH 3, and can also be desorbed...
Lead hydride was generated from acid solution, containing potassium ferricyanide as an oxidizing agent, by the reaction with alkaline borohydride solution. The effects of reaction conditions (hydrochloric acid, ferricyanide and borohydride concentrations), and the lengths of reaction and stripping coils were studied. The effects of trapping temperature and argon flow rate were also investigated. Under...
A new highly sensitive, simple and low-cost methodology for the direct determination of Pb (II) with 2-(5-bromo-2-pyridylazo)-5-dimethylaminophenol in ethanolic medium has been developed. The absorption spectroscopy of the complex has been examined in detail, and the chemical variables affecting the sensitivity of procedure studied, optimized and applied to the determination of trace amounts of lead...
Different mass analysers [(quadrupole (Q), time-of-flight (TOF) and multicollector (MC) sector-field (SF)] of ions produced in an inductively coupled plasma were evaluated for the determination of lead isotope ratios in wine samples. A population of 20 wines of different origin including two reference wines from the EC Standards, Measurement and Testing Programme with concentrations varying between...
A comparative study of C 18 immobilized on silica, activated carbon and a polyurethane foam, as sorbents for Pb complexed with O,O-diethyl-dithiophosphate in a flow injection preconcentration system is reported. The complex was formed in 1.0 M HCl medium and processed in a simple system using a peristaltic pump, a manual injector-commutator and a mini-column filled with the sorbent. Using...
The electrothermal atomic absorption spectrometric determination of cadmium and lead in biological certified reference materials (CRMs) has been carried out by using NH 4 H 2 PO 4 , Ni, Pd, Ni+NH 4 H 2 PO 4 , Pd+NH 4 H 2 PO 4 and Ni+Pd+NH 4 H 2 PO 4 as chemical modifiers. A comprehensive comparison was...
The capabilities of three solid chelating reagents were compared for the preconcentration of lead and mercury in high salinity aqueous samples (sea waters). The tested materials were 7-(4-ethyl-1-methyloctyl)-8-hydroxiquinoline (Kelex 100) adsorbed on Bondapack C18 (Kelex-100/C18), 8-hydroxiquinoline immobilized on vinyl co-polymer Toyopearl gel (TSK) and the commercial polystyrene/DVB ion exchange...
Lead concentration in lake sediment samples has been determined by means of ultrasonic slurry sampling electrothermal atomic absorption spectrometry USSS-ETAAS. The soil samples were suspended (0.025-0.15% w/v slurry) in four different liquid media containing 0.5% (v/v) nitric acid, 5% (v/v) nitric acid, 0.5% nitric acid+Triton X-100 and 5% nitric acid+Triton X-100. The effects of the instrumental...
Four chelating matrices prepared by coupling Amberlite XAD-2 with chromotropic acid (AXAD-2-CA or 1), pyrocatechol (AXAD-2-PC or 2) and thiosalicylic acid (AXAD-2-TSA or 3) through azo spacer and impregnation of Amberlite XAD-7 with xylenol orange (AXAD-7-XO or 4) have been studied for enrichment of lead(II). All the four resins quantitatively sorb Pb(II) at pH 3.0-8.0 when the flow rate is maintained...
A chelating type ion exchange resin (Amberlite IRC-718), containing iminodiacetate groups as active sites, has been characterized regarding the sorption and subsequent elution of Cd, Zn and Pb, aiming to metal preconcentration from solution samples of different origins. The methodology developed is based on off-line operation employing mini columns made of the sorbent. The eluted metals were determined...
This paper reports the utilization of tetra-(4-bromophenyl)-porphyrin (T 4 BPP) as a chelating reagent using Waters Xterra RP 18 column for the on-line column enrichment and the separation of trace lead, cadmium and mercury ions by reversed-phase high-performance liquid chromatography (RP-HPLC) with photodiode array detector. When the Hg-T 4 BPP, Pb-T 4 BPP and...
A rapid and sensitive time-based flow injection (FI) method for on-line preconcentration and determination of lead by flame atomic absorption spectrometry (FAAS), using polytetrafluoroethylene (PTFE) turnings as packing material in a micro-column, has been developed. The sample was mixed on-line with ammonium pyrrolidine dithiocarbamate (APDC) and the non-charged Pb(II)-PDC complex was absorbed quantitatively...
Some drawbacks of the phosphate modifier such as reagent blank contribution and background absorption in electrothermal atomic absorption spectrometric determination of cadmium and lead are substantially alleviated by application of small amounts of phosphate, approximately 0.2 μmol (25 μg of NH 4 H 2 PO 4 or (NH 4 ) 2 HPO 4 ), on the integrated platform...
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