1,720,993 research outputs found
Analytical Applications of Phase-selective 2nd Harmonic Alternating-current Polarography - Simultaneous Determination of Indium(iii) and Cadmium(ii)
No full textPeak Resolution in the Determination of Cobalt and Nichel by Differential Pulse and Alternating Current adsorption Voltammetry
No full textThe simultaneous determination of cobalt(II) and nlckel(II) by differential pulse adsorption voltammetry and fundamental and second harmonic alternating current adsorption voltammetry was compared In the case of very high element concentration ratios. The measurements were carried out In 0.5 M ammonia buffer-1 X 10−4 M dimethyiglyoxlme (DMG) as the supporting electrolyte, employing a semistationary mercury electrode with a drop time of 180-240 s (the long lasting sessile drop mercury electrode) as the working electrode. The accuracy of the analytical procedure was checked by the analysis of the standard reference materials: stainless steel (AISI 321) SRM 121-d and highly alloyed steel (Eurostandard 281-1). The precision, expressed as the relative standard deviation, and the detection limits were also reported for each voltammetric technique. The selectivity of the above-mentioned three techniques was found to Increase in the following order: second harmonic alternating current adsorpti..
Characterization of heroins based on their content of major, minor traces, and ultratraces of metals measured by atomic absorption spectrometry
No full textcharacterization of heroin
La tecnica ETA-AAS Zeeman nella determinazione di elementi in traccia presenti come impurezze nei farmaci: il caso di un antibiotico
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Size-elemental characterization of suspended particle matter by split-flow thin cell fractionation and slurry analysis-electrothermal atomic absorption spectrometry
No full textAn analytical methodology for characterizing SPM (Suspended Particle Matter) from natural waters, by using the coupling between the SPLITT (Split-Flow Thin) cell separation and elemental spectroscopic identification, is presented. The results of a systematic study about the validation of the direct slurry elemental analysis by ETAAS (Electrothermal Absorption Atomic Spectroscopy), are reported for Al and Fe determination in mineral particulates, considered as representative models of the real SPM.
Slurry determination of like-clay particle materials results to be accurate in the particle size range up to 25 m, provided that slurry concentrations satisfies conditions for quantitative sampling.
The evaluation of the coupled SPLITT-ETAAS technique is then considered for the dimensional and elemental characterization of the same samples.
The developed procedure has been applied to a real sample of SPM from Po river, where trace elements of environmental interest have been determined for the whole fraction in the dimensional range 0.2 - 25 m, and for some sub-fractions obtained by SPLITT fractionation
Determination of metals in multicomponent system by differential pulse and alternating current anodic stripping voltammetry
No full textA combination of sensitive and selective voltammetric methods, namely differential pulse (DPASV) and fundamental and second harmonic alternating current anodic stripping voltammetry (ACASV) were found to be very suitable techniques for the simultaneous determination of metal species having half-wave potentials close to one another. The simultaneous determination of traces of CuII, BIII, SbIII, PbII, CdII and SnII is described using 0.1 M HCl as the supporting electrolyte with the subsequent addition of 0.02 M EDTA or 1.0 M NaOH (for the analysis of CuII, SbIII and SnII, respectively). A semistationary mercury electrode (long lasting sessile drop mercury electrode) was used as the working electrode. A saturated calomel electrode (SCE) and a platinum electrode were used as the reference and auxiliary electrodes, respectively. The analytical procedure was verified with the analysis of standard reference material NBS-SRM 631 Spectrographic Zinc Spelter LV1. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were 3 to 5%, while the detection limits were of the order of 10-8 to 10-10 M in the case of element examined
Bioaccumulation of heavy metals by aquatic macroinvertebrates along the Basento river in the south of Italy
No full textIn this study, the occurrence of toxic heavy metals (As, Cd, Cr, Cu, Pb, and Zn) and relative bioaccumulation in biota samples were investigated in a freshwater ecosystem, the Basento river, one of the main aquatic systems in the south of Italy, which over the last years has been transformed into a sink of urban and industrial wastes. Therefore, the levels of arsenic, cadmium, chromium, copper, lead, and zinc were determined in water, sediments, and tissues of some macroinvertebrate—which are natural assessment endpoints for the evaluation of ecological risk in aquatic systems. Statistical analysis was performed for a comparative evaluation of bioaccumulation among various macroinvertebrates, according to different feeding guilds
Application of Second Harmonic Alternating Current Anodic Stripping Voltammetry in the Simultaneous Trace and Ultratrace Metal Determination of a Multicomponent System
No full textSecond harmonic alternating current voltammetry coupled with anodic stripping techniques has been used for the simultaneous determination of lead(II), tin(II), and thallium(I) (elements which, in common supporting electrolytes exhibit similar half-wave potentials). The supporting electrolyte was 0.1 M HClO4 for the Pb-Tl couple with the subsequent addition of EDTA (0.02 M) for measuring the tin ion. Once conditions for the experimental measurements were optimized, calculation was done for the various concentration ratios for which one could determine one element in the presence of the other two; the maximum experimental error was 5%. These concentration (c) ratios were as follows: CSn : CPb = 43:1; CSn : CTl = 32:1 (HClO40.1 M)and CTl:CSn = 45:1; Ctl:CPb = 156:1 (HClO4 0.1 M plus EDTA 0.02 M). Precision and accuracy data (3–5%) are also reported and expressed, respectively, as the relative standard deviation and relative error. The detection limit for each element proved to be around 10−8 M. The standard addition technique improved the resolution of the alteranting current voltammetric method, even in the case of very high concentration ratios
Determination of Elements in Biological Material by Inductively Coupled Plasma Atomic Emission Spectrometry with Sampling of a Carbonaceous Slurry
No full textSequential inductively coupled plasma atomic emission spectrometry was used to determine Mg, Ca, K, Na, Fe, Mn, Cu and Zn in five different National Institute of Standards and Technology Standard Reference Materials, by nebulising their carbonaceous slurries obtained by simply warming these matrices with concentrated sulphuric acid using a temperature programme up to 350 °C and gently boiling them for a short period of time. The method has been tested on similar matrices in previous studies, utilising flame atomic absorption spectrometry and electrothermal atomic absorption spectrometry. The results show good precision, expressed as relative standard deviation, s,% (often less than 5%) and accuracy, expressed as relative error, e,% (1-6%). The detection limits for each element are also reported.Sequential inductively coupled plasma atomic emission spectrometry was used to determine Mg, Ca, K, Na, Fe, Mn, Cu and Zn in 5 different National Institute of Standards and Technology Standard Reference Materials (pine needles, dried skim milk, wheat flour, citrus leaves and bovine liver), by nebulizing their carbonaceous slurries obtained by simply warming these matrices with conc. sulphuric acid using a temp. programme up to 350°C and gently boiling them for a short period of time. The method has been tested on similar matrices in previous studies, utilizing flame AAS and electrothermal AAS. The results show good precision, expressed as relative s.d., s, percentage (often <5%), and accuracy, expressed as relative error, e, percentage (1-6%). The detection limits for each element are also reported
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