Flame Atomic Absorption Spectrometric Analysis Research Articles

Tergitol@SiO2@Fe3O4 magnetic nano-material and experimental design methodology: An effective and selective adsorbent for solid phase microextraction and flame atomic absorption spectrometric analysis of lead in different matrixes

In current paper, we synthesized a new and functional magnetic Tergitol@SiO2@Fe3O4. The synthesized magnetic nano-material was characterized in detail using transmission electron microscopy, energy dispersive spectrometer, X-ray photoelectron spectroscopy, and fourier transform infrared spectrometer. Then, the applicability of the synthesized nano-material to the separation and preconcentration of Pb(II) ions was investigated prior to flame atomic absorption spectrometric determination. In order to ensure efficient and selective extraction of Pb(II), major variables such as pH, adsorbent amount, and adsorption time were optimized by multivariate methodology based on Box-Behnken design. Under the optimized conditions, linearity, detection limit, enhancement factor, and relative standard deviation (RSD%) were 0.2–250 µg L−1, 0.07 µg L−1, 84, and 1.8%, respectively. Accuracy and precision of the optimized method were investigated by using two certified reference materials (INCT-TL-1-tea leaves and SRM-1643e Trace elements in water), and good recoveries (94.7–103.9%) with low RSDs were achieved. Finally, the optimized method was successfully applied for the determination and separation of lead in different matrixes.

Magnetised and sulfide functionalised zinc oxide nanocomposite for dispersive micro-solid-phase extraction of lead (II) and cadmium (II) in water samples

ABSTRACT In this study, a dispersive micro-solid-phase extraction (D-µ-SPE) technique was developed prior to flame atomic absorption spectrometric analysis of trace amounts of lead and cadmium in waters. For this purpose, a magnetized and sulphide functionalised zinc oxide nanocomposite (Fe3O4/ZnO@S NC) was effectively synthesised through sol-gel and sono-chemical methods. The surface phenomena, size, shape, elemental composition as well as electromagnetic interactions of the synthesised nanomaterials were characterised by Fourier transform infrared spectroscopy, X-ray-diffraction, transmission electron microscopy, scanning electron microscopy-energy dispersive X-ray spectrometry, and ultraviolet-visible spectroscopy. Experimental parameters that can affect the adsorption and desorption of the metal ions such as pH, adsorbent dose, sample volume, eluent type, concentration and volume, shaking time and speed, and ionic strength were optimised. Under the optimum conditions, preconcentration factor of 48.2 for Pb(II) and 51.5 for Cd(II), limit of detection of 1.1 µg/L for Pb(II) and 0.4 µg/L for Cd(II), and >80% recovery values were obtained. The precision of the D-µ-SPE method was also evaluated by calculating the inter- and intra-day relative standard deviation of seven replicate measurements and <10% were obtained. Finally, the developed D-µ-SPE method was successfully applied for the determinations of lead and cadmium in different real-world water samples. Therefore, the D-µ-SPE is simple, fast and sensitive and hence, highly recommended for the enrichment of metal ions from various types of waters.

Fabrication of calixarene-grafted magnetic nanocomposite for the effective removal of lead(II) from aqueous solution

ABSTRACTMagnetic nanocomposites adorned with calixarene were successfully prepared by immobilizing diethanolamine functionalized p-tert-butylcalix[4]arene (DEA-Calix) onto silica-coated magnetic nanoparticles (MNPs). The synthesis, surface morphology, purity, elemental composition and thermal stability of newly prepared nanocomposites were analyzed using FT-IR spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), X-ray diffractometer (XRD), thermal gravimetric analysis (TGA) and vibrating sample magnetometer (VSM). Magnetic solid-phase adsorption (MSPA) was employed to explore the adsorption behavior of DEA-Calix-MNPs towards Pb(II) from water samples prior to its flame atomic absorption spectrometric analysis. The essential analytical factors governing the adsorption efficiency such as solution pH, mass of adsorbent, concentration and contact time have been investigated and optimized. The results depict that DEA-Calix-MNPs has excellent adsorption efficiency 97% (at pH 5.5) with high adsorption capacity of 51.81 mg g–1 for Pb(II) adsorption. Additionally, kinetic and equilibrium studies suggested that Pb(II) adsorption process follows a pseudo-second-order model and Langmuir isotherms, respectively. Real sample analysis also confirmed field applicability of the new DEA-Calix-MNPs adsorbent.

Extraction and preconcentration of trace Al and Cr from vegetable samples by vortex-assisted ionic liquid-based dispersive liquid–liquid microextraction prior to atomic absorption spectrometric determination

In the study, a simple, and efficient microextraction approach, which is termed as vortex-assisted ionic liquid-based dispersive liquid–liquid microextraction (VA-IL-DLLME), was developed for flame atomic absorption spectrometric analysis of aluminum (Al) and chromium (Cr) in vegetables. The method is based on the formation of anionic chelate complexes of Al(III) and Cr(VI) with o-hydroxy azo dye, at pH 6.5, and then extraction of the hydrophobic ternary complexes formed in presence of cetyltrimethylammonium bromide (CTAB) into a 125 μL volume of 1-butyl-3-methylimidazolium bis(trifluorosulfonyl)imide [C4mim][Tf2N]) as extraction solvent. Under optimum conditions, the detection limits were 0.02 µg L−1 in linear working range of 0.07–100 µg L−1 for Al(III), and 0.05 µg L−1 in linear working range of 0.2–80 µg L−1 for Cr(VI). After the validation by analysis of a certified reference material (CRM), the method was successfully applied to the determination of Al and Cr in vegetables using standard addition method.

Efficient determination of some potentially toxic metal ions from real samples via modified nano-γ-alumina-based solid-phase extraction followed by flame atomic absorption spectrometric analysis

ABSTRACTIn the current research work, trace amounts of the Ni(II), Cu(II), Ag(I) and Zn(II) ions in water, cabbage and pomegranate juice were determined via the solid-phase extraction approach based on a new selective adsorbent in the continuous mode followed by flame atomic absorption spectrometry. This efficient and safe sorbent was easily prepared from the immobilisation of 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-BrPADAP), as a selective chelating agent, onto nano-γ-alumina coated with sodium dodecyl sulphate. Nano-γ-alumina was successfully synthesised by the solution combustion procedure and was subsequently analysed by various techniques including SEM, XRD and BET. The parameters involved in the metal ions extraction including the sample pH and volume, amount of sorbent, flow rates of the sample and the eluent, and type and concentration of the eluting agent were optimised. Under the optimal operating conditions, the proposed sample preparation method provided the good linear dynamic ranges (LDRs) 6–300, 4–300, 4–110 and 4–300 µg L−1 for the Ni(II), Cu(II), Ag(I) and Zn(II) ions, respectively, with the correlation of determinations (R2s) higher than 0.99. The detection limit (LOD) and repeatability (RSD%) values (n = 8) obtained were found to be in the ranges of 1.50–2.00 µg L−1 and 4.44–5.52%, respectively. The calculated enrichment factors were found to be 166.6, 166.6, 200 and 200 for the Cu(II), Ag(I), Ni(II) and Zn(II) ions, respectively. According to the adsorption studies, the Freundlich isotherm and the pseudo-second-order model showed reasonable fits to the experimental data. Also, thermodynamic studies demonstrated that the adsorption process was spontaneous and exothermic.

Bovine serum albumin-Cu(II) hybrid nanoflowers: An effective adsorbent for solid phase extraction and slurry sampling flame atomic absorption spectrometric analysis of cadmium and lead in water, hair, food and cigarette samples

Herein, the synthesis of bovine serum albumin-Cu(II) hybrid nanoflowers (BSA-NFs) through the building blocks of bovine serum albumin (BSA) and copper(II) ions in phosphate buffered saline (PBS) and their use as adsorbent for cadmium and lead ions are reported. The BSA-NFs, for the first time, were efficiently utilized as novel adsorbent for solid phase extraction (SPE) of cadmium and lead ions in water, food, cigarette and hair samples. The method is based on the separation and pre-concentration of Cd(II) and Pb(II) by BSA-NFs prior to determination by slurry analysis via flame atomic absorption spectrometry (FAAS). The analytes were adsorbed on BSA-NFs under the vortex mixing and then the ion-loaded slurry was separated and directly introduced into the flame AAS nebulizer by using a hand-made micro sample introduction system to eliminate a number of drawbacks. The effects of analytical key parameters, such as pH, amount of BSA-NFs, vortexing time, sample volume, and matrix effect of foreign ions on adsorbing of Cd(II) and Pb(II) were systematically investigated and optimized. The limits of detection (LODs) for Cd(II) and Pb(II) were calculated as 0.37 μg L−1 and 8.8 μg L−1, respectively. The relative standard deviation percentages (RSDs) (N = 5) for Cd(II) and Pb(II) were 7.2%, and 5.0%, respectively. The accuracy of the developed procedure was validated by the analysis of certified reference materials (TMDA-53.3 Fortified Water, TMDA-70 Fortified Water, SPS-WW2 Waste Water, NCSDC-73349 Bush Branches and Leaves) and by addition/recovery analysis. The quantitative recoveries were obtained for the analysis of certified reference materials and addition/recovery tests. The method was successfully applied to the analysis of cadmium and lead in water, food, cigarette and hair samples.

Extraction of Zinc, Copper, and Lead Ions with a Zeolite Loaded by a Multidentate Schiff Base Ligand Followed by Flame Atomic Absorption Spectrometric Analysis

A multi-element preconcentration–separation technique for metal ions is established. The procedure is based on complex formation of metal ions with Bis(2-hydroxy-1-naphtaldimine)-N-diethylentriamine (BHNDT) on nanoporous Analcime as sorbent followed by their determination using flame atomic absorption spectrometry. The effects of analytical parameters like pH, flow rates, eluent types, and sorption capacity on the recoveries of metal ions are investigated. In order to predict the extraction ability of BHNDT for different metallic ions, DFT method is used to compute the binding energies of the cations to the title Schiff base compound. The calculated binding energies are in good agreement with the observed extraction power of the Shiff-base ligand.

Application of silica gel 60 loaded withAspergillus niger as a solid phase extractor for the separation/preconcentration of chromium(III), copper(II), zinc(II), and cadmium(II)

Sorption properties of silica gel 60 loaded with fungi cells characterized as Aspergillus niger were evaluated for trace enrichment of Cr(III), Cu(II), Zn(II), and Cd(II) from various water samples prior to the description of flame atomic absorption spectrometric analysis. The proposed SPE method is cheap, simple, highly sensitive, accurate, and selective for enrichment of analytes. The effect of experimental parameters, such as pH of sample solution, amount of solid phase, eluent type, and volume of sample solution on the recovery of the metal ions has been investigated. The effect of diverse ions was also investigated. The recoveries of Cr(III), Cu(II), Zn(II), and Cd(II) under the optimum experimental conditions were 98 +/- 2, 98 +/- 3, 99 +/- 2, 100 +/- 2%, respectively, at the 95% confidence level. The analytical detection limits were found to be 3.1, 1.6, 1.1, and 1.4 microg/L for Cr(III), Cu(II), Zn(II), and Cd(II), respectively. The proposed enrichment method was applied to the determination of analytes in Atatürk Dam, Egirdir Lake, and tap-water samples. The analytes were determined with a relative error lower than 8% in various water samples. The method has been validated by analyzing spiked water samples.

The use of Agrobacterium tumefacients immobilized on Amberlite XAD-4 as a new biosorbent for the column preconcentration of iron(III), cobalt(II), manganese(II) and chromium(III)

A microorganism Agrobacterium tumefacients as an immobilized cell on a solid support was presented as a new biosorbent for the enrichment of Fe(III), Co(II), Mn(II) and Cr(III) prior to flame atomic absorption spectrometric analysis. Amberlite XAD-4 was used as a support material for column preconcentration. Various parameters such as pH, amount of adsorbent, eluent type and volume, flow rate of sample solution, volume of sample solution and matrix interference effect on the retention of the metal ions have been studied. The optimum pH for the sorption of above mentioned metal ions were about 6, 8, 8 and 6, respectively. The loading capacity of adsorbent for Co(II) and Mn(II) were found to be 29 and 22 μmol g −1, respectively. The recoveries of Fe(III), Co(II), Mn(II) and Cr(III), under the optimum conditions were found to be 99 ± 3, 99 ± 2, 98 ± 3 and 98 ± 3%, respectively, at the 95% confidence level. The limit of detection was 3.6, 3.0, 2.8 and 3.6 ng ml −1 for Fe(III), Co(II), Mn(II) and Cr (III), respectively, by applying a preconcentration factor of 25. The proposed enrichment method was applied for metal ion determination from water samples, alloy samples, infant foods and certified samples such as whey powder (IAEA-155) and aluminum alloy (NBS SRM 85b). The analytes were determined with a relative error lower than 10% in all samples.

An optimised single-reagent method for the speciation of chromium by flame atomic absorption spectrometry based on surfactant micelle-mediated methodology.

The toxicity of chromium in the environment is dependent on the species in which it exists. This paper outlines a method for the analysis of the oxidation states of Cr employing a suitable chelating agent and the cloud point phenomenon for Cr(VI) and total Cr analysis. The method involves preconcentration of metal chelates followed by air-acetylene flame atomic absorption spectrometric analysis. The chelating agent chosen for this task is the ammonium pyrrolidinedithiocarbamate, which reacts with either Cr(VI) or total Cr under specific experimental conditions. The condensed surfactant phase with the metal chelate(s) is introduced into a flame atomic absorption spectrometer, whereby discrimination of Cr species is feasible by calculating the Cr(III) concentration from the difference between total Cr and Cr(VI). A multivariate design was employed to study the variables affecting the overall analytical performance for total Cr assay. The analytical curves are rectilinear up to 100 micrograms l-1 for both oxidation states of the metal. The limits of detection are 0.6 microgram l-1 and the relative standard deviation (n = 5) at a concentration of 30 micrograms l-1 for both species is around 2.0%. The method was validated by analysing BCR 544 reference material certified for both Cr species. High recoveries in the range 96-107% were attained for the environmental and biological samples tested.

Application of Emulsions for Direct Flame Atomic Absorption Spectrometric Analysis of Organic Liquids

The proportion of aerosol desolvatation in sample introduction in different volatility systems and the possibility of solvent-type-independent sample introduction based on nebulization of O/W type macroemulsions were investigated. It was found that desolvatation governs sample introduction if the volatility of the solvent is high and the aerosol concentration in the chamber is small. O/W type macroemulsions, which can eliminate the differences of nebulization and aerosol desolvatation, were considered. Due to the insufficient stability of this type of emulsion, a vapor trap needs to be coupled into the sample introduction line to get good identity of the values of absorbance measured in different solvents. Using O/W type microemulsions, the emulsion stability problem can be eliminated; however, the analytical signals remain solvent type dependent.

Extraction system for flame atomic absorption spectrometric analysis of high-purity bismuth compounds

Two new ligands, 2-(2-benzoxazolyl)cyanoacetaldehyde and 2-(2-benzoxazolyl)malonaldehyde are proposed for extractive separation and preconcentration. The extraction behaviour of Ag, Bi, Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, Pd, Pt, Sb and Zn with respect to pH, salt concentration and the presence of various masking agents was studied. A simple extraction procedure for the analysis of high-purity bismuth compounds was developed.

Observations on the limitation imposed by interferences in flame atomic-absorption spectrometry at high analyte concentrations

When burner rotation or an absorption line of poorer sensitivity is used in flame atomic-absorption spectrometric analysis, care must be taken to establish the absence of fresh or increased interferences at higher concentrations of the analyte element. At high concentrations, sulphate was found to cause severe depressions in the determinations of magnesium, cobalt and nickel, although under normal conditions the interference is negligible. The risk of substantial error can be reduced either by dilution of samples and standards, or by taking measurements by using the upper part of a fuel-lean flame that is burning on a slot burner with a triangular cross-section, or by adding a suitable releasing agent.