Determination of trace metals in waters and compost by on-line precipitation coupled to flame atomic absorption spectrophotometry or ion chromatography
ABSTRACT A general rapid on-line preconcentration method for the determination of trace metals coupled to flame atomic absorption spectrophotometry (FAAS) or ion chromatography (IC) with spectrophotometric detection is described. The method is based on the on-line precipitation of metal hydroxides with sodium hydroxide and their dissolution in a small volume of nitric acid solution. All the chemical and physical variables that affect the efficiency of metal precipitation and elution in the flow injection system have been studied. The detection limits obtained by FAAS are 0.1, 0.3, 0.5 and 0.5 μg l−1 for Zn, Cu, Ni and Pb, respectively. When the on-line precipitation is coupled to IC with post-column derivatization with the spectrophotometric reagent 4-(2-pyridylazo) resorcinol (PAR), the detection limits are 3, 1, 5, 3, and 3 μg l−1 for Cu, Zn, Ni, Co and Mn, respectively. The proposed general method was successfully applied to determine independently the above mentioned metals in compost and tap and river water samples.
SourceAvailable from: Rodolfo G Wuilloud[Show abstract] [Hide abstract]
ABSTRACT: The progress in flow‐injection (FI) on‐line separation and preconcentration employing knotted reactors (KRs) as a sorption medium for organometallic complexes associated to atomic spectrometry techniques is reviewed in this article, focusing the attention on the more frequently complexing agents used. In the last years, the KR has demonstrated to be an excellent alternative in the FI on‐line preconcentration procedures; the on‐line preconcentration and separation of different metallic species on the inner walls of the KR have been developed utilizing diverse organic and inorganic reagents. The choice of complexing reagents, the coupling of the FI preconcentration system to atomic spectrometry techniques, and the application of the methodologies developed to different samples are discussed.Applied Spectroscopy Reviews 01/2005; 40(1):71-101. DOI:10.1081/ASR-200038313 · 3.11 Impact Factor
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ABSTRACT: A flow injection analysis system with on-line enrichment was developed for simultaneous determination of trace levels of Cu2+, Ni2+, Zn2+, Co2+, Mn2+, Cd2+, Pb2+ and Fe3+, by high-performance ion chromatography (HPIC) with spectrophotometric detection. It is a highly sensitive and low cost alternative methodology. Ion Pac CS5A was used as the analytical column with eluent composition of sodium nitrate 160mM and oxalic acid 36mM. Quantification after post-column reaction with PAR allows detection limits between 0.5 and 5.0ppb to be attained. The total analysis time is less than 30min. The proposed procedure was compared with a large volume direct injection method using loop volumes up to 5mL. Both procedures were applied to the analysis of heavy metals in the PM10 fraction of atmospheric particulate samples. Airborne pollutants such as nickel and cobalt can be quantified in 24h samples of particulate matter at concentrations of a few ngm−3.Chromatographia 10/2006; 64(9):537-542. DOI:10.1365/s10337-006-0068-7 · 1.37 Impact Factor
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ABSTRACT: Multiwalled carbon nanotubes (MWNTs) have been widely used for the enrichment of trace important pollutants in environment because of its large specific surface area, high extraction efficiency, and easy operation. In this study, a solid phase extraction method was established to determine nickel (Ni(2+)), cobalt (Co(2+)) and mercury (Hg(2+)) ions using MWNTs as the adsorbent and sodium diethyldithiocarbamate (DDTC) as the chelating agent. The final analysis was performed on a high performance liquid chromatography (HPLC). The factors that may influence the extraction efficiency were optimized in detail including the type and volume of elution solvent, sample pH, volume of chelating agent solution, and volume of sample solution, etc. The experimental results indicated that good linear relationship between peak area and the concentration of the ions was achieved in the range of 0.1-100μgL(-1), 0.1-50μgL(-1), and 2.7-300μgL(-1) for Ni(2+), Co(2+), and Hg(2+), respectively. The precision was determined by calculating the relative standard deviation (R.S.D.) values that were in the range of 6.2-11.7% under the optimal conditions. The detection limits of Ni(2+), Co(2+), and Hg(2+) were in the range of 0.04-0.9μgL(-1) (S/N=3). The presented method was applied for the determination of the metal ions mentioned above in real water samples, and satisfied results were achieved. All these indicated that proposed method will be a good alternative tool for monitoring the target ions in environmental samples in the future.Journal of Chromatography A 08/2014; 1360. DOI:10.1016/j.chroma.2014.07.084 · 4.26 Impact Factor