Flame Atomic Absorption Spectrometric Determination Research Articles

A MWCNTs@CuAl2O4@SiO2 Nanocomposite for the Speciation of Cr(III), Cr(VI), and Total Chromium Prior to High-Resolution Continuum Source Flame Atomic Absorption Spectrometric Determination

A solid-phase microextraction (SPME) method had been applied to speciate chromium in natural and wastewater samples. MWCNTs@CuAl2O4@SiO2 nanocomposite was synthesized by sol–gel and calcination methods and then characterized using SEM, FTIR, and XRD techniques. MWCNTs@CuAl2O4@SiO2 was used to extract Cr(VI) as pyrrolidine dithiocarbamate chelates. Some analytical parameters involving pH, ligand (APDC) and adsorbent amounts, sample initial and final volume, and the effects of matrices were tested and optimized. For the oxidation of Cr(III) to Cr(VI), potassium permanganate was used, and after that, the presented method was applied to determine the total chromium levels. The calculations were carried out to obtain Cr(III) concentration by finding differences between total chromium and Cr(VI) concentrations. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 6.2 µg L−1 and 20.8 µg L−1, respectively. The proposed method was successfully applied for chromium speciation in wastewater samples.

Micro-solid phase extraction of lead (II) on ionic liquid impregnated Sepabeads SP70 resin (IL-SP70) in water and food samples

Sepabeads SP70 resin was impregnated with ionic liquid (BMIMPF6) was used for micro-solid phase extraction of lead(II) prior to its microsampling flame atomic absorption spectrometric determination. The optimum values of experimental parameters such as adsorbent amount, ligand amount, pH, eluent type and concentration, eluent volume, sample volume on recovery of lead were optimized as 5.0 mg, 0.15 mg, 7, HCl, 2 M, 0.4 mL, 50 mL, respectively. The analytical data of the method under optimal condition are as follows; limit of detection (LOD) (3 s/m, N: 10): 0.21 μg L−1, limit of quantification (LOQ) (10 s/m, N: 10): 0.69 μg L−1, preconcentration factor (PF): 125, and relative standard deviation (RSD%): 1.43%. The accuracy of the developed method was checked by addition-recovery tests to real samples and analysis of certified reference materials (Environment Canada TMDA-53.3 (fortified water) and 1570a trace elements in spinach leaves). The recovery values of these analyses are in the range of 90–98%. The method was successfully applied to determination of lead level of food and water samples.

Su örneklerindeki Pb(II)-vitamin B6 komplekslerinin Bulutlanma Noktası Ekstraksiyonu

This study mainly centered on the preconcentration and flame atomic absorption spectrometric determination of lead ions by cloud point extraction (CPE) procedure. Complexation of Pb2+ and vitamin B6 prior to its preconcentration by cloud point extraction was achieved in the method. The solution pH, surfactant and vitamin B6 concentrations, interfering ions, incubation temperature and sample volume were optimized. The limit of quantication (LOQ) and limit of detection (LOD) values of the method were found as 7.88 and 25.99 respectively. The validation of the CPE method was achieved by the analyte adding (known concentration of Pb2+) to water samples such as natural spring waters and mineral waters.

Determination of Cobalt (II), Copper (II), Lead (II), and Zinc (II) with Preconcentration by 8-Hydroxyquinoline-Coated Magnetic Nanoparticles (MNPs) and Microinjection Sampling–Flame Atomic Absorption Spectrometry (MIS–FAAS)

The separation and preconcentration for trace cobalt(II), copper(II), lead(II), and zinc(II) were investigated with magnetic solid phase extraction using Fe3O4 nanoparticles coated with 8-hydroxyquinoline as a new adsorbent prior to their microinjection sampling–flame atomic absorption spectrometric (MIS–FAAS) determination. The synthesized 8-hydroxyquinoline-coated Fe3O4 magnetic nanoparticles (Fe3O4-8HQ MNPs) were characterized by Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and vibrating sample magnetometry (VSM). The analytical parameters including pH, type of eluent, eluent volume, eluent concentration, adsorption and desorption times, mass of adsorbent, and foreign ion effects were investigated. The analyte ions were quantitatively recovered at pH 8.0 and eluted with 1 M nitric acid. The developed method was applied to pharmaceuticals, wastewater, and a composite material with recoveries from 92% to 98%. The method was validated using NIST certified reference material (CRM) QCP-QCS-1. The results of the CRM solution were compared with those obtained by inductively coupled plasma–mass spectrometry (ICP–MS) and shown to be compatible.

Novel determination of copper(II) in natural waters by solid-phase extraction (SPE) flow-injection (FI) flame atomic absorption spectrometry (FAAS)

A novel functionalized silica gel with the Schiff base of N-{[3-[(3-aminopropyl)amino]propyl}-2-hydroxy-benzaldimine was fabricated and utilized for flow-injection (FI) solid-phase extraction (SPE) of Cu(II) ions with flame atomic absorption spectrometric determination in environmental water samples. The practical factors on the FI-SPE of Cu(II) ions, including flow rates and volumes of sample and eluent solutions, eluent type and concentration, sample pH, and matrix ions, were studied. The maximum absorbance of Cu(II) ions was obtained using sample solutions at pH 7.0 at 5.0 mL min−1 with elution by 500 µL of 1.0 M HCl. Batch adsorption capacity of the functionalized silica gel for Cu(II) ions was 24.7 ± 0.3 mg g−1. The developed FI-SPE method was successfully validated by the determination of Cu(II) in water certified reference materials, including water-trace elements (NWTM-15.2) and Ontario Lake water (NWTMDA-54.4). Cu(II) levels in environmental samples such as tap, river, and sea water were successfully determined using the reported FI-SPE method.

Preconcentration of Nickel by Magnetic Solid-Phase Extraction (MSPE) as the 2-(5-Bromo-2-Pyridylazo)-5-Diethylamino-Phenol (PADAP) Chelate upon Multiwalled Carbon Nanotubes (MWCNTs) with Determination by Flame Atomic Absorption Spectrometry (FAAS)

A magnetic solid phase extraction (MSPE) method for nickel as the 2-(5-bromo-2-pyridylazo)-5-diethylamino-phenol (PADAP) chelate was established prior to flame atomic absorption spectrometric (FAAS) determination. Magnetic multiwalled carbon nanotubes were used as the adsorbent. Analytical parameters affecting the extraction efficiency of nickel such as pH of the medium (8.0), mass of adsorbent (8.0 mg), eluent concentration and volume (4.0 mL of 1 M HNO3), extraction time (6.0 min), and model solution volume (20 mL) were optimized. In addition, matrix effects were investigated. The preconcentration factor was 5. The relative standard deviation was less than 5%. A standard addition recovery study was performed on water samples to evaluate the accuracy of the method and certified reference materials were used for validation. The limits of detection (LOD) and quantitation (LOQ) were 7.1 µg L−1 and 24.4 µg L−1, respectively. The proposed method was applied to determine nickel in tobacco samples.

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.

Flame atomic absorption spectrometric determination of multi element in apricot and soil samples after wet and microwave digestion method

Iron, copper, zinc, manganese, nickel, cobalt, lead, cadmium and chromium in various apricot and soil samples were determined by atomic absorption spectrometry in this study. Microwave digestion method and wet ashing method efficiency were compared for digestion of the samples. Recovery values were nearly found quantitative. The analysis results were evaluated. The accuracy of the digestion procedures was confirmed by analyzing Montana Soil and Apple Leaves certified reference materials. There are no important differences between digestion methods. The results were compared with literature values. Relative standard deviations were found below 10 %. Heavy metal levels in analyzed samples were not found toxic limits.

An automatic on-line sorptive extraction platform for palladium determination in automobile exhaust catalysts based on a PTFE-turnings packed column, flow injection analysis and flame atomic absorption spectrometry

ABSTRACT A novel simple sensitive and effective on-line flow injection column preconcentration platform using poly-tetrafluoroethylene turnings as sorbent was developed prior to flame atomic absorption spectrometric (FAAS) determination of palladium in vehicle exhaust catalysts, hydrogenation catalysts and environmental water samples. The method is based on the sorption of palladium(II)-diethyldithiophosphate, which was found to be more effective than dithiocarbamate ones. Methyl isobutyl ketone (MIBK) was used as eluent prior atomisation and quantification. All parameters like pH, DDPA concentration, flow rates, preconcentration time that affect the sensitivity of the method as well as interferences of other metals were investigated in detail. The enhancement factor calculated as 114 for 60 s preconcentration time while the sampling frequency as 40 h−1. The detection limit was 0.9 μg L−1 and the relative standard deviation (RSD) was 2.8% at 20.0 μg L−1 concentration level. The accuracy of the proposed method was estimated by analysing certified reference material and spiked environmental samples. The analytical features of the method were compared with other on-line column preconcentration methods reported in the literature.

Vortex-assisted magnetic solid phase extraction of Pb and Cu in some herb samples on magnetic multiwalled carbon nanotubes.

This study is the development of a new solid phase extraction method based on using magnetic multiwalled carbon nanotubes impregnated with 1-(2-pyridylazo)2-naphthol (PAN) for separation, preconcentration, and flame atomic absorption spectrometric determination of Pb(II) and Cu(II). Optimization of the method was done by investigating pH effect, amount of magnetic multiwalled carbon nanotubes impregnated with PAN, eluent type and volume, matrix effects, and volume of the sample. The optimum adsorbent amount was found to be 75 mg and the optimum pH value was found as 5.5. The detection limits were 16.6 μg L-1 for Pb(II) and 18.9 μg L-1 for Cu(II). The relative standard deviations (RSD%) were less than 4%. Two certified reference materials: SPS-WW2 wastewater and NCS-DC73349 (bush branches and leaves) were used to test the validation of the method. The method was successfully applied to the analysis of Pb(II) and Cu(II) ions in daisy, mint, paprika, sage, rosemary, daphne leaves, heather, green tea, andViburnum opulussamples.

Chemically modified rice husk as an effective adsorbent for removal of palladium ions

Bio-matrix of rice husk and Mobil Composition of Matter No. 41 (MCM-41) was modified with alizarin red S for preconcentration of Pd2+ prior flame atomic absorption spectrometric determination. The prepared bio-matrix (RH@MCM-41@ARS) was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope, energy dispersive X-ray spectrometer (SEM/EDX) and surface area studies. The impact of different parameters (solution pH, amount of sorbent, contact time, sample volume, initial Pd2+ concentration and diverse ions) on the uptake of Pd2+ were evaluated. The maximum adsorption capacity of Pd2+ onto RH@MCM-41@ARS was 198.2 mg g−1 at optimum conditions. Applying the optimized procedure as a preconcentration step led to limit of detection of 0.13 μg L−1 and dynamic analytical range up to 500 μg L−1. The sorbent was regenerated by 0.5 mol L−1 thiourea for at least 10 cycles without significant reduction of adsorption capacity. The method was applied for preconcentration of Pd2+ from real samples.

Preconcentration and separation of Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) in environmental samples on cellulose nitrate membrane filter prior to their flame atomic absorption spectroscopy determinations

ABSTRACT A new and sensitive enrichment membrane filtration method was applied for the preconcentration and separation of trace amounts of Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) ions from environmental (water and food) samples prior to their flame atomic absorption spectrometric (FAAS) determinations. The method was based on the collection of analyte ions as quinalizarin complexes on cellulose nitrate membrane filter and then eluted using nitric acid. The concentration levels of Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) ions in the final solutions were determined by FAAS. Various analytical parameters which affect the collection and determination of metal ions including pH, amounts of quinalizarin, sample volume, type and size of the membrane filter, flow rates and matrix effects were investigated. The analyte ions recovery values were measured and found to be in the range of 95–101%. The relative standard deviation (RSD%) was measured to determine the precision of the proposed approach and was found to be ≤5.0%. The detection limits for the proposed method were in the range of 0.1–0.7 μg L−1. The preconcentration factors were 100 and 125 for (Cd(II), Co(II), Cu(II) and Ni(II)) and Pb(II), respectively. The validation of the proposed method was verified by the analysis of certified reference materials. Satisfactory results for separation and preconcentration trace levels of the analyte ions in water and food samples.

Micelle Mediated Extraction and Flame Atomic Absorption Spectrometric Determination of Trace Amounts of Copper in Different Mushroom Species

A micelle mediated separation and preconcentration method for flame atomic absorption spectrophotometric (FAAS) determination of Cu was developed. The method is based on complex formation between Cu and 1-(2-pyridylazo)-2-naphthol and cloud point extraction with Tergitol NP-7 surfactant prior to FAAS determination. The parameters affecting quantitative extraction of copper, including pH, surfactant and ligand concentrations, incubation time and temperature, were examined and optimized. Under optimum conditions, interference effects of other ions were studied, and tolerance ratios of interference ions were given. Under the optimal conditions, detection and quantitation limits were found as 3 and 8 μg/L, respectively. Linear dynamic range for Cu2+ was determined to be 0.13–1.5 μg/mL. Relative standard deviations were below 6% throughout the experiments. Enhancement factor was determined as 25. Applicability of the method was proved by analysis of standard reference materials. The developed method was applied to determine trace copper contents in different mushroom species.

Flame atomic absorption spectrometric determination of total chromium and cadmium in bean samples after ultrasonic-assisted microextraction using ionic liquid Aliquat-336

A new and rapid microextraction approach termed as ultrasonic-assisted ionic liquid-based microextraction (UA-ILME) was developed using ionic liquid Aliquat-336 as extraction solvent for the extraction of chromium and cadmium in bean samples collected from different regions in Turkey. The total amounts of analytes in the samples were measured by flame atomic absorption spectrophotometry. The basis of the extraction step is based on the complexation of Cr(III) and Cd(II) with diethyldithiocarbamate at pH 4.0. The hydrophobic ternary complexes containing analytes were then rapidly extracted from the sample solution to the ionic phase under the ultrasonic effect using tricaprylylmethylammonium chloride (Aliquat-336). Some experimental variables (pH, ligand amount, extraction solvent volume, ultrasound time, extraction temperature and sample volume) were optimized in detail. Following the optimization steps, the limits of detection (LODs, 3Sblank/m) for Cr(III) and Cd(II) were calculated as 0.45 ng mL−1 with linear range of 1.5–380 ng mL−1 and 0.25 ng mL−1 with linear range of 0.8–220 ng mL−1, respectively. Enrichment factors and average recoveries were ranged from 125.8–96.4 to 92.7–106.5%, respectively. The accuracy and precision of the method were validated by analyzing a certified reference material and spiked recovery tests. The UA-ILME method was successfully applied to the determination of Cd and Cr in the samples, highlighting that the matrix ions under consideration do not affect the extraction and determination steps.

Green Dispersive Micro Solid-Phase Extraction using Multiwalled Carbon Nanotubes for Preconcentration and Determination of Cadmium and Lead in Food, Water, and Tobacco Samples

Background: Cadmium (Cd2+) and lead (Pb2+) have acute and chronic effects on humans and other living organisms. In the present work, new, green and accurate dispersive micro solid-phase extraction (DμSPE) method for the separation and preconcentration of trace amounts of cadmium (Cd2+) and lead (Pb2+) ions in various food, water and tobacco samples collected from Saudi Arabia prior to its Flame Atomic Absorption Spectrometric (FAAS) determinations was developed. Methods: The proposed method was based on a combination of oxidized multiwalled carbon nanotubes (O-MWCNTs) with a new chelating agent 5-benzyl-4-[4-methoxybenzylideneamino)-4H- 1,2,4-triazole-3-thiol (BMBATT) to enrich and separate trace levels of Cd2+ and Pb2+. The effect of separation parameters was investigated. The validation of the proposed preconcentration procedure was performed using certified reference materials. Results: Analyte recovery values ranged from 95-102%, indicating that the method is highly accurate. Furthermore, precision was demonstrated by the relative standard deviation (RSD < 3.0%). The limits of detection were 0.08 and 0.1 μg L−1 for Cd2+ and Pb2+ ions, respectively. The preconcentration factor was 200. Conclusion: The proposed method was used for the estimation of Cd2+ and Pb2+ ion content in various real samples, and satisfactory results were obtained. The proposed method has high adsorption capacity, rapid adsorption equilibrium, extremely low LODs, high preconcentration factors and shortens the time of sample preparation in comparison to classical SPE.

Fabrication and characterization of SiO2@Fe3O4@nanodiamonds for vortex-assisted magnetic solid-phase extraction of lead in cigarette samples prior to FAAS detection

A novel, speed and accurate vortex-assisted magnetic solid-phase extraction procedure for separation–preconcentration and flame atomic absorption spectrometric determination of lead at trace levels has been proposed. Silica-coated magnetic nanodiamonds (SiO2@MNDs) as magnetic solid-phase extractor were fabricated and characterized by Fourier transform infrared spectroscopy, X-ray diffraction spectrometry and scanning electron microscopy. Pb(II) could be easily separated from the aqueous solution on the SiO2@MNDs by using a neodymium magnet. Analytical factors affecting the recoveries of Pb(II) such as pH, adsorbent amount, type and volume of eluent and sample volume were optimized. The preconcentration factor, the precision (RSD %, n = 5), the limit of detection and the limit of quantification were 5, 5.3%, 40.8 and 135 µg L−1, respectively. The effects of matrix ions have been investigated. The presented extraction method has been applied for the determination of lead in cigarette samples and Bush Branches and Leaves certified reference material. Quantitative recoveries changing from 94 to 106% were obtained for accuracy studies.

N-Octanol-Induced Phase Separation of Triton X-100 for the Extraction of Trace Silver from Environmental Samples with Flame Atomic Absorption Spectrometric Determination

A novel and simple cloud point extraction (CPE) method for detecting trace silver has been built up with flame atomic absorption spectrometry (FAAS) through adding proper amount of n-octanol into Triton X-100 resulting in an obvious decrease of the cloud point. In the method, rhodanine was chosen as chelating agent for the preconcentration of silver. The influence of major experimental parameters such as pH, chelating agent concentration, surfactant concentration, equilibration temperature and time on the extraction of silver from aqueous solutions was investigated and optimized. Under the optimal conditions, the minimum detection was 0.18 μg/L (3σ), while the preconcentration factor could reach up to 42. The well-pleasing results of standard reference sediment analysis manifested perfect accuracy and sensitivity of the method. Also, the presented method was applied to determine the trace silver in sediment and environmental water samples with satisfactory results.

A novel deep eutectic solvent microextraction procedure for enrichment, separation and atomic absorption spectrometric determination of palladium at ultra-trace levels in environmental samples

A dispersive deep eutectic solvent microextraction procedure for the separation and preconcentration of palladium from environmental samples has been established prior to its flame atomic absorption spectrometric determination. The deep eutectic solvent (DES) was prepared by mixing disodium 4,5-dihydroxy-1,3-benzenedisulfonate, hydroxyl ammonium chloride, FeCl3 and phenol resulting in homogenous solution which used directly for the extraction of palladium. The analytical parameter including pH, amount of deep eutectic solvent and sample volume were optimized. The developed microextraction procedure was found to have tolerance for the common matrix ions in real samples. The optimization studies resulted in pH was suitable at 6.0 with sample volume up to 35 mL. The preconcentration factor was 116. The detection limit was found as 1.18 µg·L−1. The presented microextraction method was applied to determination of palladium in marble mine and catalytic converter samples.

Co-microprecipitation/flotation of trace amounts of cadmium from environmental samples through its complexation with iodide and neutralization with cetyltrimethylammonium bromide in the presence of perchlorate ions

ABSTRACTA fast, cost-effective and reliable method is presented for separation and preconcentration of trace amounts of cadmium based on co-precipitation and flotation prior to its flame atomic absorption (AAS) spectrometric determination. Cadmium (II) was complexed with iodide and neutralized with cetyltrimethylammonium bromide (CTAB) in the presence of perchlorate ions. This resulted in the formation of a bulky precipitate containing the ternary complex of CdI4(CTA)2, floating on the top of the solution. The aqueous layer was then simply drained out, the floated layer was dissolved in 1.0 mL of acetonitrile, and its Cd content was determined by flame atomic absorption spectrometry. The parameters affecting the designed separation method such as KI, CTAB, and ClO4− concentration, pH, ionic strength, volumes of sample and dissolving solvent, and extraction time were studied and optimized. For preconcentration of 200 mL of the sample, the calibration graph was linear in the range of 1–30 μg L−1 of cadmium with a correlation coefficient of 0.9997, enhancement factor of 194 and a limit of detection of 0.18 μg L−1. The relative standard deviation for seven replicate determinations at 20 μg L−1 levels of cadmium was found to be 2.1%. The effect of the presence of different common cations and anions on the separation and determination of Cd(II) by the developed method was studied. The method was successfully applied to the determination of trace amounts of Cd(II) ions in different types of real samples including tap water, polluted industrial wastewater, dust, and soil with the recoveries in the range of 95.3 to 103.4.

Graphene Oxide Supported on Amberlite Resin for the Analytical Method Development for Enhanced Column Preconcentration/Sensitive Flame Atomic Absorption Spectrometric Determination of Toxic Metal Ions in Environmental Samples

Graphene oxide (GO)-layered nanosheets with a two-dimensional carbon lattice is linked to styrenic carbon of porous XAD polymeric resin via an azo spacer arm without utilizing any oxygen-containing functionality for the first time. The adopted synthesis approach makes all of the epoxy, hydroxyl, carbonyl, and carboxyl groups on the axial and basal planes of the GO sheet available for coordination with metal ions, and the introduction of hydrophilic character as result the highest preconcentration factor for Pb (500) was observed among the GO composites used as a solid-phase extractant in column operation. The developed analytical methodology using XAD–GO for the preconcentration of Pb, Cd, and Zn ions permits the use of an economically viable less sensitive atomic absorption spectrometry for their trace determination in water samples because of the enhanced quantification limit. The application of polymer-immobilized GO in a column sorts out the problem of escape of toxic GO into the environment, and unde...