Flame Atomic Absorption Spectrometric Detection Research Articles

Starch-modified nickel ferrite nanoparticles as a magnetic nano-bio adsorbent for the extraction and determination of lead in water and Moringa oleifera samples

In this work, nickel ferrite magnetic nanoparticles were synthesized using a facile hydrothermal method. The surface modification of the prepared nanoparticles was carried out using cross-linked starch as a good stabilizer and biopolymer. The as-prepared nickel ferrite-starch nano-bio composite was characterized using numerous techniques, and introduced as a novel adsorbent. The initial experimental results indicated that the adsorbent has a good capability to extract lead ions (Pb(II)) from aqueous solutions. Hence, the adsorbent was applied for dispersive magnetic solid-phase extraction of Pb(II) before flame atomic absorption spectrometric detection. Some variables affecting the extraction efficiency such as sample volume (250.0mL), pH (6.5), type and eluent concentration (0.3molL1 nitric acid), amount of the adsorbent (200mg), extraction time (15min), and desorption time (15min) were investigated and optimized. Moreover, the adsorption capacity (35.50mgg1), stability and reusability (80 extraction/desorption cycles), and selectivity of the adsorbent towards the analyte were studied. In the optimized conditions, the linear dynamic range of the constructed calibration graph is between 0.5 and 140.0ngmL1. The limit of detection and limit of quantification of the method are 0.12 and 0.40ngmL1, respectively. The average intra-day and inter-day relative standard deviations (for n=6 and 5.0, 50.0 and 100.0ngmL1 Pb(II) concentration) are 2.02% and 3.72%, respectively. To validate the method, the certified reference material NIST SRM 1643e was analyzed, and the method was used for the pre-concentration and determination of lead ions in different sections of Moringa oleifera medicinal plant and several water samples. The acceptable relative recovery values between 98.0 and 102.7% were attained for the spiked samples, approving the ignorable matrix effect of the method.

Zn-doped MoO3 nanorods for dispersive solid phase extraction of trace Pb(II) from water and food samples

A rapid, and environmentally friendly dispersive solid phase extraction method based on Zn-doped MoO3 nanorods for efficient extraction of trace level of Pb(II) from water and food samples was established before high-resolution continuum source flame atomic absorption spectrometric detection. The sorbent characterization studies were carried out using BET, FE-SEM, XRD, and FT-IR techniques. To achieve effective phase separation and accurate analytical data, the adsorption and desorption procedures have been precisely adjusted. The presented approach demonstrated a wide working range (9.3–500 µg L−1), a relatively low detection limit (3.1 µg L−1), and very good extraction recoveries (90–104%) under optimum conditions. The matrix effect was investigated by the addition of interference ions. The presence of many different anions and cations in the environment did not lead to negative results and selectivity towards the analyte was observed. The method was validated by the analysis of certified reference materials (TMDA - 64.3 and INCT-OBTL-5). The enhancement factor has been determined as 10.9. The suggested method worked efficiently to extract and determine Pb(II) from water, tea, and oil samples.

Speciation of Chromium by Magnetic Solid Phase Microextraction Using an Activated Charcoal-Molybdenum (IV) Selenide-Magnetite Composite with Flame Atomic Absorption Spectrometric (FAAS) Detection

A simple and sensitive magnetic solid phase extraction (MSPE) method was developed for the separation-preconcentration and speciation of Cr in water samples. The system is based on the adsorption of Cr (VI)-ammonium pyrrolidinedithiocarbamate (APDC) complex on the activated charcoal@MoSe2@Fe3O4 composite. Total chromium has also been determined after the conversion of Cr (III) to Cr (VI) by oxidation with KMnO4. Cr (III) was determined as the difference between the total content of the Cr and Cr (VI). For quantitative recoveries, the effects of solution pH, adsorbent amount, volume of the sample, ligand volume, eluent type, and volume and effect of foreign ions were investigated. The limit of detection and limit of quantification for Cr was 0.36 ng mL−1 and 1.19 ng mL−1, respectively. The procedure was applied for the determination and speciation of chromium in water samples.

Dispersive solid phase microextraction (DSP-μE) by using nanodiamond@Bi2MoO6 composite for the separation-preconcentration of Pb(II) in food and water samples

A nanodiamond@Bi2MoO6 nanocomposite was synthesized using a hydrothermal procedure. The nanodiamond@Bi2MoO6 was characterized using various techniques like BET, FT-IR, FESEM, EDX, and XRD. It was used as an adsorbent for dispersive solid phase microextraction (DSP-μE) of Pb(II) at ultra-trace levels prior to its flame atomic absorption spectrometric detection. The analytical parameters such as pH values, adsorbent dose, eluent concentration, eluent volume, eluent time, and sample volume on the quantitative recoveries of lead(II) on nanodiamond@Bi2MoO6 were optimized. Additionally, matrix effects were investigated. The LOD, LOQ, and PF were calculated as 1.75 μg L-1, 5.85 μg L-1 and 16.7, respectively. The validation of the DSP-μE procedure was checked by using certificated reference material (CRM) Wheat Gluten RM8418 and BCR Estuarine water 505 for satisfactory with 98.5 to 102.4 % recovery results. The new DSP-μE procedure was applied to be successful for Pb determination in instant noodles and water samples. The concentration of Pb(II) in instant noodles samples ranged between 23 and 194 µg kg−1. In water samples, Pb(II) concentration was observed in the range of 7.95–8.05 and 123.3–142.7 µg/L, tap water, and industrial water respectively. The estimated daily intake of total Pb(II) in the food (noodles/serving i.e., noodles, seasoning spices, water) was come out as 4.27– 16.12 µg kg−1 day−1 and compared with PTDI level.

Magnetic solid‐phase extraction of nickel(II) as the 2‐(5‐bromo‐2‐pyridilazo)‐5‐(diethylamino)phenol chelate on magnetite@methacrylic ester copolymer prior to high‐resolution–continuum source flame atomic absorption spectrometric detection

A Fe3O4@ Diaion HP‐2MG resin was used for separation-preconcentration and determination of trace Ni(II) as the 2‐(5‐bromo‐2‐pyridilazo)‐5‐(diethylamino)phenol (PADAP) chelate. Nickel determination was performed by high‐resolution–continuum source flame atomic absorption spectrometry (HR-CS FAAS). Among the parameters affecting the recoveries of Ni(II) on the Fe3O4@ Diaion HP-2MG, the pH, resin mass, and sample volume were optimized. The influence of matrix ions upon the analyte recovery was evaluated and the tolerance limit was determined for common ions. The Fe3O4@ Diaion HP-2MG resin was used 15 times without any degradation in performance. The limit of detection, the limit of quantification, and preconcentration factor were 15.0 µg L−1, 49.0 µg L−1, and 100 respectively. The accuracy of the developed method was validated by the analyzing certified reference materials (NIST 1573a tomato leaves and TMDA-64.3 fortified water). The developed procedure was applied to natural water and food samples.

Ag modified ZnO nanoflowers for the dispersive micro-solid-phase extraction of lead(II) from food and water samples prior to its detection with high-resolution continuum source flame atomic absorption spectrometry

Ag modified ZnO nanoflowers were synthesized by using hydrothermal method and used as dispersive micro-solid phase extractant for separation and preconcentration prior to its flame atomic absorption spectrometric detection. The Ag modified ZnO nanoflowers has been characterized by FT-IR, XRD, FESEM, EDX and BET. The factors effecting extraction efficiency like pH, Adsorbent dose, sample volume, eluent concentration, eluent volume was optimized. Matrix effects were also studied. The limit of detection and preconcentration factor (PF) were calculated as 8.52 μg L−1, and 100, respectively. The presented dispersive micro-solid phase extraction technique was validated using GBW07424 (GSS-10) soil and GBW07425 (GSS-11) soil certificated reference materials (CRMs) with satisfactory recovery results. The presented dispersive micro-solid-phase extraction (d-μSPE) procedure was successfully applied to food and water samples.

One-pot synthesis of nickel oxide/nickel ferrite nanocomposite and application to dispersive magnetic solid-phase extraction of zinc(II) ions in water and milk samples

An inorganic magnetic nanocomposite named nickel oxide/nickel ferrite (NiO/NiFe2O4) was synthesized using a one-pot hydrothermal method. After successful synthesis and characterization of the nanocomposite, it was applied as a novel adsorbent for dispersive magnetic solid-phase extraction and pre-concentration of zinc(II) ions followed by flame atomic absorption spectrometric detection. The developed method was validated by exploring the affecting parameters, including the amount of the adsorbent (100 mg), sample volume (150.0 mL), sample pH (6.0), adsorption time (15 min), type and eluent concentration (acetic acid 2.0 M), and desorption time (15 min). In the optimal condition, the calibration graph is linear in the concentration range of 0.3–20.0 ng mL1 with a satisfactory determination coefficient of 0.9996. The limit of detection and limit of quantification of the method are 0.04 and 0.13 ng mL1, respectively. The precision of the method in the term of intra-day and inter-day relative standard deviation with six replicates are 1.5% and 3.5%, respectively. A certified reference sample was analyzed applying the developed method and the results confirmed its high accuracy. The applicability of the method was also assayed by determination of Zn(II) ions in various water and milk samples, and the acceptable relative recovery values (96.0–102.0%) were obtained for the spiked samples.

Determination of Cadmium in Water Samples by Automated Flow-Batch Cloud Point Extraction (CPE) Hyphenated to High-Resolution Continuum Source Flame Atomic Spectrometry (HR-CS FAAS)

A computer-controlled multicommuted flow-batch system is reported that allows for the online cloud point extraction of metal ions followed by high-resolution continuum source flame atomic absorption spectrometric (HR-CS GFAAS) detection. This approach combines reduced sample and reagent consumption and a short analysis time with the increased precision and sensitivity characteristic of flow-batch analysis and modern extraction techniques. As proof of concept, cadmium in aqueous solutions was determined by the formation of a hydrophobic complex [Cd(PAN)2]. Parameters related to complex formation (pH, pyridyl-azo-naphthol-PAN concentration, complexation time), cloud point extraction (Triton X-114 concentration, electrolyte composition, rich phase trapping), and the multicommuted flow-batch system (flow rates, timing control) were optimized. A small column packed with hydrophobic cotton was used as the interface between the extraction and detection stages to stack the cadmium-containing rich phase in a short plug. Optimized parameters led to a 5.0 to 75.0 µg L−1 linear range, 1.3 µg L−1 limit of detection, 4.3 µg L−1 limit of quantification and 1.8% coefficient of variation (n = 12). Accuracy was evaluated by analyzing a certified reference material EP-H (drinking water) and by recovery tests employing tap water, groundwater, mineral water, and reuse water samples.

Ultrasound assisted magnetic solid phase extraction of copper(II) and lead(II) in environmental samples on Magnetic Activated Carbon Cloth

ABSTRACT Copper (II) and lead (II) ions are complexed with 1-nitroso-2-naphthol and preconcentrated on the magnetic activated carbon cloth prior to its flame atomic absorption spectrometric detection. Analytical parameters such as model solution pH, adsorbent amount, eluent type and volume, ligand amount, sample volume and matrix effect were determined. As a result of these studies, quantitative recovery of analyte ions was obtained at pH 4.0. Quantitative recovery was observed with 2 mL 3 M HNO3 solution as eluent. The developed method has been applied to various water and food samples and the accuracy of the developed method has been confirmed by certified reference material analysis and addition recovery studies. The method has been applied to the separation and preconcentration of copper (II) and lead (II) ions in water and food samples.

Selective aptamer conjugation to silver-coated magnetite nanoparticles for magnetic solid-phase extraction of trace amounts of Pb2+ ions.

Herein, a novel aptamer-functionalized magnetic adsorbent was developed and combined with magnetic solid-phase extraction (MSPE) for the specific enrichment of Pb2+ ions prior to flame atomic absorption spectrometric detection. First, silver-coated magnetite core–shell nanoparticles (Fe3O4@Ag MNPs) were synthesized by the chemical reduction of silver ions on the surface of magnetite nanoparticles. After that, the selective DNA aptamer against Pb2+ was conjugated on the surface of the synthesized nanoparticles to form aptamer-modified magnetic nanoparticles (Fe3O4@Ag-APT). The characterization of the prepared adsorbent was performed through SEM imaging, XRD, FT-IR, EDX, and DRS instruments. The influence of the various experimental parameters on the adsorption and desorption steps in MSPE was investigated via Taguchi experimental design to optimize different parameters. Under the optimized conditions, the Pb2+ calibration graph was linear in the range of 33–1000 μg L−1. The relative standard deviation (RSD%) of the method for six replicates containing 100 μg L−1 of Pb2+ ions was 0.34%. Furthermore, the limit of detection (LOD) and the limit of quantification (LOQ) were 10 μg L−1 and 33.3 μg L−1, respectively. Finally, the applicability of the proposed method was successfully confirmed by preconcentration and determination of trace amounts of Pb2+ ions in tap and seawater samples. We showed a proof of concept for Fe3O4@Ag-APT as an efficient bio-adsorbent, offering a promising strategy for the specific binding/removal of toxic heavy metal ions.

Magnetic dispersive solid phase extraction of lead(II) as dithizone chelates in food and environmental samples on Fe3O4@XAD-8 prior to its flame atomic absorption spectrometric detection

ABSTRACT A magnetic dispersive solid phase extraction method has been developed using Fe3O4@XAD-8 adsorbent to separate and preconcentrate Pb (II) ions as dithizone chelates from environmental samples. Fe3O4@XAD-8 was characterised by SEM, FT-IR and BET methods. Analytical parameters such as pH, adsorbent amount, ligand volume, eluent type and volume, model solution volume and matrix effects which are effective on method recovery are optimised. Limit of detection (LOD) and limit of quantification (LOQ) values were 0.048 µg mL−1 and 0.159 µg mL−1, respectively. The accuracy of the developed method has been proven by TMDA – 64.2 certified reference material and addition-recovery studies in water samples. Lead content of some food and water samples was determined by using the developed dispersive magnetic solid-phase extraction method.

A selective and sensitive procedure for magnetic solid-phase microextraction of lead(II) on magnetic cellulose nanoparticles from environmental samples prior to its flame atomic absorption spectrometric detection

A solid-phase microextraction (SPME) procedure has been proposed for the extraction of a trace amount of lead from the environmental samples using magnetic cellulose nanoparticles (Cell-MNPs) as adsorbent material. Synthesized cell-MNPs was characterized by FTIR, SEM—EDX, XRD, and BET. Different analytical parameters were optimized such as pH, adsorbent amount, adsorption time, desorption time, eluent type, eluent volume, model solution amount, and matrix ions effects for the selective and sensitive extraction of lead (II) from the environmental samples. The limit of detection and limit of quantification were found to 8.9 and 29.7 µgL−1 for the lead (II). Cell-MNPs was successfully applied for solid-phase extraction of lead (II) from the water and tea samples.

An efficient green microextraction method of Co and Cu in environmental samples prior to their flame atomic absorption spectrometric detection

ABSTRACT A dispersive liquid-liquid microextraction procedure (DLLME) was developed and validated for the determination of cobalt and copper in environmental samples by flame atomic absorption spectrometry. The optimisation parameters of DLLME procedure including amount of chelating reagent (0.05 mg dithizone), pH (6), extraction type and volume (250 µL chloroform) and dispersive solvent (1000 µL acetone), matrix effect was investigated. Several validation variables, such as limit of detection and quantification, linearity, recovery, precision and trueness were also tested. The quantification limits of Co and Cu were found to be 9.01 and 6.14 µg L−1, respectively. The enrichment factor was 20. The trueness of the method was tested by analysis of certificated reference material (BCR-715) for Cu and calculated less than −1.11% with the relative error. The presented green microextraction method was profitably applied to real samples and the spiked recoveries calculated were more than 95% with the relative standard deviation less than 8.4%.

Application of Co3O4 nanoparticles as an efficient nano-sorbent for solid-phase extraction of zinc(II) ions

In this research, a solid-phase extraction (SPE) method based on application of cobalt oxide nanoparticles (Co3O4 NPs) as a novel nano-sorbent was developed for preconcentration and extraction of zinc(II) ions from various real samples followed by flame atomic absorption spectrometric (FAAS) detection. Co3O4 NPs were simply synthesized via a thermal treatment of cobalt hydroxide after a precipitation method, and its structure and morphological properties were studied by Fourier transform infrared spectrometry, X-ray diffraction, and scanning electron microscopy. The effect of various parameters influencing the extraction recovery of Zn(II) ion such as extraction time, pH, amount of the nano-sorbent, sample volume and elution conditions were studied and optimized. Applying optimum conditions for SPE procedure, the limit of detection was 0.25 ng mL‒1 and the calibration graph was linear in the concentration range of 0.4‒32 ng mL‒1 with a correlation coefficient of 0.9951. The method intra- and inter-day precisions, calculated by performing five replicates at the concentration level of 20 ng mL‒1, were obtained 2.3% and 2.6%, respectively. The applicability of the developed SPE-FAAS method was evaluated by its application for measuring zinc concentration in various samples including tap water, river water, well water, milk and powder milk samples, and the relative recoveries were obtained in the range of 94.5‒103.5% for the spiked samples.

Nickel oxide/chitosan nano-composite as a magnetic adsorbent for pre-concentration of Zn(II) ions

Abstract In this work, a magnetic nickel oxide/chitosan nanocomposite was fabricated by a facile precipitation approach. The structure and morphological properties of the prepared nano-material were characterized via X-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy and energy dispersive X-ray spectroscopy. The prepared nanocomposite was used as a nano-sorbent for the magnetic solid-phase extraction (MSPE) of the trace amounts of zinc (Zn(II)) ions from aqueous solutions followed by flame atomic absorption spectrometric (FAAS) detection. Several factors influencing the extraction efficiency of Zn(II) ions such as pH, extraction time, amount of the nano-sorbent, elution conditions and sample volume were investigated and optimized. Under optimized conditions, the calibration curve with a liner dynamic range of 0.35–15 ng mL−1 was attained. The preconcentration factor and limit of detection were 100 and 0.12 ng mL−1, respectively. The method precision was evaluated with seven replicates at the concentration level of 5 ng mL−1 and the relative standard deviations of 2.8% and 3.1% were obtained for intra-day and inter-day repeatability, respectively. The applicability of the developed MSPE-FAAS method for the measurement of Zn(II) ions was validated by analyzing the certified reference material NIST SRM 1549. Zinc(II) ion concentration was measured in various real samples including tap water, river water, well water, milk and powder milk using the method, and satisfactory relative recovery values were acquired for the spiked samples.

Magnetic dispersive solid-phase extraction based on graphene oxide/Fe3 O4 @polythionine nanocomposite followed by atomic absorption spectrometry for zinc monitoring in water, flour, celery and egg.

Magnetic graphene oxide nanocomposite has been proposed as a promising and sustainable sorbent for the extraction and separation of target analytes from food matrices. Sample preparation based on nanocomposite presents several advantages, such as desired efficiency, reasonable selectivity and high surface-area-to-volume ratio. A new graphene oxide/Fe3 O4 @polythionine (GO/Fe3 O4 @PTh) nanocomposite sorbent was introduced for magnetic dispersive solid-phase extraction and flame atomic absorption spectrometric detection of zinc(II) in water, flour, celery and egg. To fabricate the sorbent, an oxidative polymerization of thionine on the surface of magnetic GO was applied, while polythionine was simply employed as a surface modifier to improve extraction yield. The properties of the sorbent were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis, vibrating sample magnetometry and Fourier transform-infrared spectroscopy. The calibration curve showed linearity in the range of 0.5-30 ng mL-1 . Limits of detection (S/N = 3) and quantification (S/N = 10) were 0.08 and 0.5 ng mL-1 , respectively. The method was applied for trace-level determination of Zn(II) in water and food samples, and its validation was investigated by recovery experiments and analyzing certified reference material. © 2018 Society of Chemical Industry.

Switchable solvent based liquid phase microextraction of palladium coupled with determination by flame atomic absorption spectrometry

ABSTRACTA switchable solvent-based micro-extraction method for pre-concentration and separation of ultratrace palladium was developed prior to its flame atomic absorption spectrometric detection. Reverse change of hydrophilicity of N,N-dimethylcyclohexylamine (DMA) was achieved by reaction with carbonated water. The hydrophilic bicarbonate salt of the protonated DMA was used as extractant for palladium complexed with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP). Formation of the hydrophobic form of switchable solvent from hydrophilic form of switchable solvent phase was achieved by addition of sodium hydroxide into the extractant-sample solution. The effect of key parameters affected extraction recovery was studied and optimised by using Plackett–Burman design, central composite design and three dimension (3D) surfaces response. The calibration plot was linear in the range 0.015–1.6 mg L−1 of palladium with a correlation coefficient of 0.999. The limit of detections values of palladium for liquid and solid samples were 4.28 μg L−1 and 0.54 µg g−1, respectively. The pre-concentration factor was 37.5. The accuracy was confirmed by determination of palladium in certified reference material. The procedure was also applied for determination of palladium content of real samples as automotive catalytic converter, roadside dust, sea water and river water.

Preconcentration and extraction of lead ions in vegetable and water samples by N-doped carbon quantum dot conjugated with Fe3O4 as a green and facial adsorbent

Magnetically N-doped Carbon quantum dots has been synthesized via a simple chemical method and applied as a sorbent for the preconcentration and extraction of trace amounts of Pb2+ from water and vegetable samples followed by flame atomic absorption spectrometric detection. The nanoparticles were characterized by X-ray diffraction, UV–vis spectra, Fourier transform infrared spectroscopy, vibrating sample magnetometer analysis and transmission electron microscopy. A central-composite design was used to find the optimum conditions for the preconcentration procedure through response surface methodology. The effects of various parameters such as the pH value, adsorption time, amount of adsorbent, desorption conditions (type, concentration and volume of the eluent and desorption time), sample volume and interfering ions have been studied. Under the optimized conditions, the calibration graph was linear in the range of 0.3–300μgL−1 (R2=9992). The detection limit and pre-concentration factor were found to be 0.082μgL−1 and 265, respectively.

Nanodiamond/MoS2 nanorod composite as a novel sorbent for fast and effective vortex-assisted micro solid phase extraction of lead(II) and copper(II) for their flame atomic absorption spectrometric detection

This study is a report on the synthesizing nanodiamond/MoS2 nanorod composite using the hydrothermal method and its application as adsorbent in micro solid phase extraction of lead(II) and copper(II) prior their determination through flame atomic absorption spectroscopy. The nanodiamond/MoS2 nanorod composite was characterized using Raman spectroscopy, BET surface analysis and scanning electronic microscopy (SEM). The optimal conditions including amount of used adsorbent, pH, vortex time, elution condition and volume investigated. Quantitative recoveries for both analytes were obtained at pH3.0. The preconcentration factor is 35, and the sorption capacity of synthesized adsorbent for lead(II) and copper(II) is 19.87 and 49.33mgg−1. The relative standard deviation is 0.9 and 1.5% for lead(II) and copper(II) at a level of 200μgL−1 (n=6), and the detection limit is 42 and 22μgL−1 for lead(II) and copper(II), respectively. The procedure accuracy was proved via analyzing the standard reference materials (SPS-WW2 Waste water Level 2 and TMDA-53.3). The presented procedure was applied for the determination of copper and lead contents of the water samples from Turkey.

1-nitroso-2-naphthol impregnated multiwalled carbon nanotubes (NNMWCNTs) for the separation-enrichment and flame atomic absorption spectrometric detection of copper and lead in hair, water, and food samples

1-nitroso-2-naphthol impregnated multiwalled carbon nanotubes (NNMWCNTs) for the separation-enrichment and flame atomic absorption spectrometric detection of copper and lead in hair, water, and food samples