Trace Lead In Environmental Samples Research Articles

Switchable hydrophilicity solvent-based preconcentration for ICP-OES determination of trace lead in environmental samples

In this work, switchable hydrophilicity solvent-based extraction (SHSE) was combined with inductively coupled plasma-optical emission spectrometry (ICP-OES) for the determination of trace lead (Pb) in environmental water and soil samples. During the phase transformation of SHSE, the organic phase appeared to capture the target analytes effectively. The resultant sample solution was heated to remove the organic phase, realizing the successful combination with ICP-OES. The sensitivity was obviously improved by adding non-ionic surfactant Triton X-114 (TX-114) and the sensitization factor of 3.8 was achieved. Under the optimal conditions, the limit of detection (LOD) and enhancement factor (EF) were 0.07 μg/L and 38, respectively. The established method was applied to analyze environmental samples and certified reference material with satisfactory results. The analytical results of environmental samples were in great agreement with those obtained by inductively coupled plasma-mass spectrometry (ICP-MS). The established method provides a promising, simple and sensitive approach for the determination of trace Pb in environmental samples.

Synthesis, Characterization and Selective Recognition of Lead Using a New Ion Imprinted Polymer Material

A new ion-imprinted polymer (IIP) material was synthesized by copolymerization of 4-vinylpyridine(VP) as monomer, ethylene glycol dimethacrylate(EGDMA) as crosslinking agent and 2,2΄-azobisisobutyronitrile(AIBN) as initiator in the presence of Pb–1,5-diphenylcarbazone(Pb-DHCB) complex. Blank non-imprinted polymer (NIP) were prepared under identical conditions without the use of lead imprint ion. The synthesized polymers were characterized by IR spectroscopy and elemental analyzer techniques. Of the several polymers synthesized, only the imprinted polymer formed with binary complex of Pb2+–DHCB showed quantitative enrichment of lead ion from aqueous solution. The relative standard deviation of the five replicate determinations of Pb (II) was3.26%. The detection limit for 150 mL of sample was 1.6 µg L-1 using flame atomic absorption spectrometry. The developed method was successfully applied to the determination of trace lead in environmental samples with satisfactory results.

On-line solid-phase extraction using alizarin violet functionalized silica gel for determination of trace lead in environmental samples and wastewater by sequential injection spectrophotometry

Trace of Pb(II) has been on-line separated and enriched from environmental samples and wastewater by using the self-made alizarin violet functionalized silica gel micro-column coupling with a sequential injection sampling technology. The determination is based on the color reaction of Pb(II) with iodide and crystal violet to form an ionic association complex in the presence of polyvinyl alcohol and hydrochloric acid. The use of the microcolumn can prevent the interference of most familiar metal ions, and therefore improve the selectivity and sensitivity of this analytical technique. The proposed method was used for the determination of Pb(II) in environmental samples and wastewater. No statistically significant difference was observed between the results determined by the present method and atomic absorption spectrometry.

Application of Factorial Design and Doehlert Matrix for Determination of Trace Lead in Environmental Samples by On-line Column Preconcentration FAAS Using Silica Gel Chemically Modified with Niobium(V) Oxide

In this study a new method for Pb determination in water using solid phase extraction coupled to a flow injection system and flame atomic absorption spectrometry was developed. The sorbent used for Pb preconcentration and extraction was silica gel chemically modified with niobium(V) oxide. Flow and chemical variables of the system were optimized through a multivariate procedure. The factors selected were buffer type, eluent concentration, and sample and eluent flow rates. It was verified that the aforementioned factors as well as their interactions were statistically significant at the 95% confidence level. The effect of foreign ions was evaluated using a fractionary factorial experimental design. The detection limit was 0.35 microg L(-1) and the precision was 1.6%. Results for recovery tests using different environmental samples were between 90 and 104%. Certified reference materials were analyzed in order to check the accuracy of the proposed method.