Atomic Absorption Spectrometry Determination Research Articles

Validation of high-resolution continuum source flame atomic absorption spectrometry for determination of selected toxic and potential toxic metals in the decontamination process of wastewater discharged in natural receivers.

A new method based on high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS) was validated for the determination of selected toxic and potentially toxic metals in wastewater resulting from mining activity. The results were compared with inductively coupled plasma optical emission spectrometry (ICP-OES). The HR-CS-FAAS method was characterized by detection limits in the range (µg L-1) 0.9(Mn)-33.6(Pb), better than ICP-OES for Cu, Fe, Ni, Co, Pb and Mn, and poorer for Cd, Zn and Cr. The Dunnett's and Tukey's statistical test showed that both methods were not affected by significant bias against certified value and between them. The recovery in HR-CS-FAAS method was in the range of 98-103% with relative extended uncertainty of 9-25%, and precision of 1.5-14.1%. The results indicated that the HR-CS-FAAS method is suitable for the determination of toxic and potentially toxic elements directly in filtered water samples without any chemical treatment.

Rapid synergistic cloud point extraction based on hydrophobic deep eutectic solvent combined with hydride generation atomic absorption spectrometry for determination of selenium in tea samples

Herein, hydrophobic deep eutectic solvents (HDESs) were created for the fast preconcentration of Se(IV) from tea samples at room temperature. A facile and rapid synergistic cloud point extraction (HDES-RS-CPE) procedure was used, followed by hydride generation atomic absorption spectrometry (HG-AAS). The selected synergistic DES included glycine and lauric acid (molar ratio 3:1). 2-hydroxy-5-p-tolylazobenzaldehyde (HTAB) and Triton X-114 were utilized as chelating reagent and non-ionic surfactant, respectively. The experimental parameters that impact extraction recovery were examined and optimized. The detection limit, quantification limit, preconcentration factor, and enhancement factor for Se(IV) under optimum circumstances were 0.02 μg L−1, 0.06 μg L−1, 125, and 149, respectively. The method exhibited analytical linearity in the range up to 700.0 μg L−1. The procedure was used effectively for the quantification of Se(IV) in tea and certified samples. Moreover, the National Environmental Method Index (NEMI), the analytical greenness scale for sample preparation (AGREEprep), and the Green Analytical Procedure Index (GAPI) criteria have been used to measure the greenness score of the extraction procedure. To further highlight the environmental friendliness of this method, a detailed evaluation has been performed.

Development of ligandless dispersive micro-solid-phase extraction method based on NH2-UiO-66 (Zr) MOF using DES eluent in determination of Cd(II) and Cu(II) ions in water and fruit juice samples

ABSTRACTA metal–organic framework (MOF) was synthesised and used for dispersive micro-solid-phase extraction of heavy metal ions from fruit juice and water sample without adding an additional complexing agent. In this work, 9 mg of the synthesised adsorbent (NH2-UiO-66 (Zr) MOF) was dispersed into 6 mL of sample solution containing Cu(II) and Cd(II) ions. Then, a synthesised deep eutectic solvent was used to elute and desorb the analytes from the surface of the sorbent. The effect of important parameters such as sorbent amount, sample solution volume, extraction time, elution solvent type and volume, desorption time, pH and salt addition on the extraction efficiency of the method was investigated. The developed procedure had linear ranges of 1–100 and 0.5–150 µg L−1 with the limits of detection of 0.37 and 0.19 µg L−1, for Cu(II) and Cd(II) ions, respectively, with flame atomic absorption spectrometry determination. To study the validity of the procedure, the concentration of the analytes was determined in a certified reference material (SPS-WW2) by the proposed method. Finally, the proposed procedure was used for the determination of the concentrations of Cu(II) and Cd(II) ions in different fruit juice and water samples.

Bioavailability Assessment of an Iron Formulation Using Differentiated Human Intestinal Caco-2 Cells.

In recent years, there has been growing interest in exploring alternative and innovative delivery systems to improve the efficacy of iron supplements, satisfying iron needs and lowering side effects. To address this issue, this study aimed at demonstrating the advantages of Ferro Supremo formulation (composed of encapsulated iron, vitamins, and micronutrients), in terms of capacity to improve iron intestinal absorption, in comparison with standard FeSO4. Hence, differentiated Caco-2 cells have been used for assessing the in vitro bioavailability and safety of FS and FeSO4. MTT experiments demonstrated that both FS and FeSO4 are not able to impair the viability of Caco-2 cells. Furthermore, the quantitative and qualitative analysis, conducted by atomic absorption spectrometry and fluorescence determinations, revealed that FS can enter, accumulate in the cytoplasm, and be transported by intestinal cells four times more efficiently than FeSO4. Our findings indicate that this formulation can be considered a valuable and efficiently good choice as food supplements for improving iron deficiency.

Ultrasound-Assisted Dispersive Magnetic Solid-Phase Extraction Using Fe3O4@Hydroxypropyl Methylcellulose Combined with Flame Atomic Absorption Spectrometry for Determination of Cadmium(II) in Food Samples

Ultrasound-Assisted Dispersive Magnetic Solid-Phase Extraction Using Fe3O4@Hydroxypropyl Methylcellulose Combined with Flame Atomic Absorption Spectrometry for Determination of Cadmium(II) in Food Samples

Pt(IV)-ion imprinted ordered mesoporous organosilica for platinum preconcentration prior to electrothermal atomic absorption spectrometry determination in geological samples

Pt(IV) ion-imprinted thiocyanato-functionalized SBA-15 material (Pt(IV)S1) was proposed for preconcentration of Pt(IV) ions from digested geological samples before its electrothermal atomic absorption spectrometry (ETAAS) determination. The ion-imprinted material exhibited very good adsorption affinity towards Pt(IV) ions. Under the optimal pH (pH = 3) the maximum static adsorption capacity for Pt(IV) was equal to 175 mg g−1. The use of Pt(IV)S1 as an adsorbent allowed for the quantitative adsorption of Pt(IV) ions from solutions with concentrations up to 25 mg L−1. The creation of ion imprinted adsorption centres resulted in an increase of the adsorption rate and selectivity towards Pt(IV) compared to the similar non-ion imprinted material. The analytical procedure was based on the adsorption of Pt(IV) ions and dissolution of the Pt-loaded sorbent in a small volume of hydrofluoric acid before its dilution with 5% hydrochloric acid and introduction into an electrothermal atomizer. The enrichment factor of the proposed procedure was 38, while the limit of quantification was 0.079 mg kg−1.

A miniaturized liquid-liquid extraction method for further Na, K, Ca, and Mg determination in crude oil by FAAS

In this study, a miniaturized liquid-liquid extraction (LLE) method for pre-concentration of Na, K, Ca, and Mg in crude oil was proposed. Analytes in crude oil were quantitatively extracted to the aqueous phase, followed by flame atomic absorption spectrometry (FAAS) determination. The following parameters were evaluated: type of extraction solution, sample mass, heating temperature and time, stirring time, centrifugation time, and the use of toluene and chemical demulsifier. Accuracy was evaluated by comparing the results obtained by the proposed method (LLE-FAAS) with those obtained after high-pressure microwave-assisted wet digestion and FAAS determination (reference values). No statistical difference was observed between the reference values and those using the optimized conditions for LLE-FAAS: 2.5 g of sample; 1000 μL of 2 mol L−1 HNO3, 50 mg L−1 of chemical demulsifier in 500 μL of toluene, 10 min of heating at 80 °C, 60 s of stirring, and 10 min of centrifugation. Relative standard deviations were lower than 6%. The limits of quantification (LOQ) were 1.2, 1.5, 5.0, and 0.50 μg g−1 for Na, K, Ca, and Mg, respectively. The proposed miniaturized LLE method presents several advantages, such as ease-of-use, high throughput (up 10 samples can be processed per 1 h), uses a high sample mass reaching low LOQs. In addition, the use of a diluted solution for extraction reduces the amount of reagents (around 40 times) and consequently laboratory residue generation, becoming an environmental friendly method. Suitable LOQs were achieved for analyte determination at low concentration even using a simple and low-cost sample preparation system (miniaturized LLE method) and a relatively low-cost determination technique (FAAS), avoiding the use of microwave ovens and more sensitivity techniques, which are required for routine analyses.

A simple spray assisted extraction/preconcentration of cadmium from sunflower oil, olive oil and hazelnut oil samples prior to flame atomic absorption spectrometry determination

In this study, an efficient and simple analytical approach for the preconcentration and extraction of cadmium from sunflower oil, olive oil and hazelnut oil samples using environmentally friendly, easy and efficient vortex assisted reverse phase spray-based fine droplet formation liquid phase microextraction (VA-RP-SFDF-LPME) prior to flame atomic absorption spectrometry (FAAS) measurement was proposed. Limit of detection (LOD)/limit of quantification (LOQ) values were calculated as 2.89/9.62 µg/kg, 2.00/6.68 µg/kg and 4.77/15.92 µg/kg for sunflower oil, olive oil and hazelnut oil, respectively. Recovery experiments were carried out for the evaluation of applicability and accuracy of the developed method. Satisfactory recovery results for hazelnut oil, olive oil and sunflower oil samples were recorded in the range of 92.8 – 111.9%, 96.6 – 108.2% and 90.0 – 105.7%, respectively. These results verified that the proposed method can be accurately applied to the hazelnut oil, olive oil and sunflower oil samples to qualify/quantify their cadmium content.

Spatio-Temporal Disposition of Micronutrients in Green Bean Grown in Sandy Mulching Soils

Currently, there is no information available about the spatio-temporal distribution of micronutrients in sandy mulching soils widely used in the southeast of Spain; therefore, in this experiment, we aimed to characterize the spatio-temporal distribution of micronutrients in the wet bulb zone in two sand-mulched soils. Four different factors were considered over the experiment: (a) soil model, (b) time sampling, (c) distance from the emitter, and (d) depth. Each soil was divided into four blocks and the soil sample per block was composed of 20 subsamples. The micronutrient concentration was determined in each soil sample through atomic absorption spectrometry determinations. To establish the relationship between factors, a multifactor ANOVA test analysis was conducted. The results obtained reported a higher micronutrient concentration in the soil profile than in the sand layer. Moreover, in the soil profile, there was a decrease in micronutrient concentration in distance for Fe (from 10.4 to 7.9 mg kg−1), Zn (from 4.0 to 3.5 mg kg−1), Mn (from 23.9 to 16.2 mg kg−1), and Cu forms (from 2.5 to 1.5 mg kg−1). Moreover, there was a decrease in micronutrients with depth for Fe (from 10.5 to 8.0 mg kg−1), Zn (from 4.0 to 3.7 mg kg−1), Mn (22.0 to 17.2 mg kg−1), and Cu (from 2.1 to 1.7 mg kg−1). Higher micronutrient concentration after green bean crop harvest was related to the highest organic matter content, with the following values for Fe (12.3 mg kg−1), Zn (4.0 mg kg−1), Mn (23.6 mg kg−1), and Cu (2.0 mg kg−1) in the soil profile. The fertigation management of the crop did not modify the micronutrient concentrations in distance in the sand layer due to the reduced exchange capacity of the sand with micronutrients.

Rapid preparation of melamine based magnetic covalent triazine polymers for highly efficient extraction of copper(II), chromium(III) and lead(II) ions from environmental and biological samples

In this work, melamine based magnetic covalent triazine polymers (MCTPs) was prepared by decoration of melamine based triazine polymers on the surface of magnetic Fe3O4@SiO2 nanoparticles. The polymer decoration is realized by nucleophilic substitution reaction between melamine (as functional monomer) and 1,4-dibromobutane (as crosslinking agent), which is simple, rapid and cost effective. The resultant MCTPs showed good affinity toward Cu2+, Cr3+ and Pb2+ with fast adsorption kinetic (7 min) and high adsorption capacities (38.3, 33.9 and 49.7 mg g−1 for Cu2+, Cr3+ and Pb2+, respectively). Besides, the prepared MCTPs can be reused after adsorption, desorption and regeneration steps, and the phase separation is highly efficient with the addition of an external magnet. Thus, MCTPs was employed as a magnetic solid-phase extraction (MSPE) sorbent for the extraction of trace Cu2+, Cr3+ and Pb2+ followed by graphite furnace atomic absorption spectrometry (GFAAS) determination. Then the extraction conditions of the above-mentioned MSPE-GFAAS method were optimized, including sample pH, extraction/elution time, sample volume, etc. Under the optimized conditions, the MCTPs based MSPE-GFAAS method exhibit the following merits: short extraction/elution time (10/3 min), high enrichment factor (125 folds) and low detection limit (2.9, 1.4 and 6.1 ng L-1 for Cu2+, Cr3+ and Pb2+, respectively). Finally, the proposed method was successfully employed for the determination of trace Cu2+, Cr3+ and Pb2+ in tap water, river water, lake water, human urine and human hair samples. The adequate recoveries of 85 ∼ 105% in spiked samples were achieved, suggesting the promising potential of MCTPs based MSPE-GFAAS method as an effective method for evaluating the environment and biological effect of metal ions.

Ultrasound-assisted dispersive micro-solid phase extraction of Pb(II) in water samples with in situ synthesis of magnetic Fe3O4-PbS nanocomposites followed by electrothermal atomic absorption spectrometry determination

Herein, an ultrasound-assisted dispersive magnetic micro-solid phase extraction (DM-μSPE) approach, along with electrothermal atomic absorption spectrometry (ETAAS) for the determination of lead at trace level in spring, well, river mineral and tap water samples was developed. The extraction step is based on the synthesis of PbS, following the sonochemical decomposition of L-cysteine used as sulphide precursor and its anchoring onto bare magnetite nanoparticles yielding the Fe3O4@PbS nanocomposite. Overall, DM-μSPE with in situ precipitation of PbS and retention onto magnetic sorbent requires a time as short as 6 min. After trapping Pb(II) as PbS, the magnetic nanocomposite was easily separated from the aqueous matrix by applying an external magnetic field and analyzed by ETAAS following slurry sampling. Different parameters involved in both the sorbent preparation/extraction and Pb quantification were optimized. Under optimal conditions, the method showed a detection limit of 0.02 μg L−1 Pb and a quantification limit of 0.07 μg L−1 Pb. The repeatability, expressed as relative standard deviation was 2% (for 0.6 μg L−1; n = 3). An experimental enrichment factor of 79 and an extraction efficiency of 99% were obtained. Finally, the method was applied for the determination of ultratrace levels of Pb(II) in spring, well, river mineral and tap water samples, showing quantitative recoveries in the range of 95–100%.

A sensitive vesicle mediated dispersive liquid-liquid microextraction of parts per quadrillion levels of beryllium from seawater samples prior to graphite furnace atomic absorption spectrometry determination

A rapid and highly sensitive vesicle mediated dispersive liquid–liquid microextraction procedure is developed for the determination of parts per quadrillion level of beryllium in seawater and air filter samples for providing its natural background and contamination levels. In this procedure, dioctylsulfosuccinate, an anionic vesicular surfactant and acetylacetone are used as dispersing and chelating agents, respectively. At pH > 9.5, beryllium forms hydrophobic beryllium-acetylacetonate complex spontaneously at room temperature. This complex is selectively filled into the vesicular cavities of dioctylsulfosuccinate and is extracted into small chloroform phase from bulk aqueous phase. The beryllium present in the chloroform phase is back extracted with dilute nitric acid and is analyzed by graphite furnace atomic absorption spectrometry. This method is applied to groundwater, seawater, coal fly ash, air filter and sea sludge samples. Under the optimized conditions, the limit of detection, limit of quantification and linear dynamic range are 10 fg mL−1, 33 fg mL−1 and 40–500 fg mL−1 for seawater; 0.15 ng g−1, 0.5 ng g−1 and 0.4–4 ng g−1 for air filter and 1.5 ng g−1, 0.39 ng g−1 and 0.4–4 ng g−1 for coal fly ash, respectively. For 1 L seawater sample an enrichment factor of 954 is achieved. Coefficient of determination (R2) is found to be 0.997. The recoveries are in the range of 94–105% at 200–500 fg mL−1. The relative standard deviations are 20%, 11%, 8% for ppq, ppt and ppb levels of Be, respectively. The accuracy of the procedure is verified by analyzing NIST SRMs 1640 and 1640a trace elements in natural water.

Ultrasound-assisted dispersive microsolid-phase extraction approach for preconcentration of trace cobalt and nickel and sensitive determination in water, food and tobacco samples by flame atomic absorption spectrometry

ABSTRACT Simpleand validated ultrasound-assisted dispersive microsolid-phase extraction (UA-DMSPE) approach for separation, and preconcentration of trace cobalt (Co(II)) and nickel (Ni(II)) ions in various water, juice, food and tobacco samples prior to their flame atomic absorption spectrometry determination (FAAS) was developed. The proposed method based on using oxidized multiwalled carbon nanotubes (ox-MWCNTs) as adsorbent and 3-(2-hydroxy-5-acetylphen-1-ylazo)-1,2,4-triazole (HAPAT) as complexing agent at pH 7.0. The effect of different parameters has been investigated and optimised. The calibration curves were linear in the ranges of 1.0–300 and 2.0–400 μg L−1 and the limits of detection were 0.30 and 0.60 μg L−1 for Co(II) and Ni(II) ions, respectively, under the optimum conditions.The preconcentration factor was 200. Co(II) and Ni(II) havemaximum sorption capacities of around 300 and 370 mg g–1, respectively. The recovery rates of the analytes ranged from 96.0 to 101%. Furthermore, relative standard deviation (RSD%) for intra-day (1.40 and 1.90%) and inter-day (1.70 and 2.10%) as repeatability for Co(II) and Ni(II), respectively. Certified reference materials (SRM 1570A spinach leaves and TMDA-52.3 fortified water) were used to verify the accuracy of the proposed preconcentration protocol. The proposed method was successfully used to determine the content of Co(II) and Ni(II) ions in a variety of real water, juice, food and tobacco samples yielding satisfactory results.

Determination of Mn(II) and Mn(VII) in beverage samples using magnetic dispersive micro-solid phase extraction coupled with solidified floating organic drop microextraction followed by graphite furnace atomic absorption spectrometry

Magnetic dispersive micro-solid phase extraction (MDMSPE) was coupled with solidified floating organic drop microextraction (SFODME) for direct separation and preconcentration of Mn(II) and Mn(VII) before graphite furnace atomic absorption spectrometry determination. MDMSPE involved use of magnetic ZnFe2O4 nanotubes for adsorbing Mn(VII). Sorbent was isolated from aqueous phase by an external magnet. Mn(II) in upper solution from MDMSPE was further enriched by SFODME. This method avoids tedious pre-oxidation/pre-reduction operation and time-consuming centrifugation/filtration step. An enrichment factor of 200-fold was obtained. Detection limits of this method were 0.005 and 0.007 ng mL−1 for Mn(II) and Mn(VII) with relative standard deviations of 4.0% and 4.8% (n = 9), respectively. This method was successfully used for detection of Mn(II) and Mn(VII) in tap water, ice tea, energy drink, mineral water, sprite drink and carbonated drink. A certified reference material of water sample was analyzed with satisfactory results. Recoveries of spike experiments ranged from 92.5 to 106%.

The amino - functionalized magnetic graphene oxide combined with graphite furnace atomic absorption spectrometry for determination of trace inorganic arsenic species in water samples

A novel adsorbent of magnetic graphene oxide (GO) chemically modified by cysteamine hydrochloride (Fe3O4@SiO2/GO-NH2) through thiol-ene click chemistry reaction was synthesized. The prepared Fe3O4@SiO2/GO-NH2 exhibit selective adsorption to As(V) with high adsorption capacity (52.66 mg g−1). Taking Fe3O4@SiO2/GO-NH2 as the adsorbents, a new method of magnetic solid phase extraction (MSPE) combined with graphite furnace atomic absorption spectrometry (GFAAS) was developed in determining trace-level inorganic arsenic species (As(III) and As(V)) in environmental water and bottled water samples. Various experimental parameters affecting the MSPE have been optimized. Under the optimal experimental parameters, the limit of detection of the established method for As(V) was 1.02 ng L−1, the relative standard deviations were 7.9% (intra-day, c = 50 ng L−1, n = 5) and 4.6% (inter-day, c = 50 ng L−1, n = 7), respectively, and the enrichment factor of the method was 392. GBW08666 and GBW08667 (certified reference material) were analyzed to confirm the accuracy of the method, and the results were matched well with the certified values. The established MSPE-GFAAS method was successfully applied in analyzing trace/ultratrace As(III) and As(V) in real water samples.

Optimization of vortex-assisted ionic liquid dispersive liquid–liquid microextraction by experimental design prior to hydride generation atomic absorption spectrometry for determination of selenium species in food, beverage and water samples

We applied novel vortex-assisted ionic liquid dispersive liquid-liquid microextraction (VA-IL-DLLME) method to preconcentration and extraction of Se(IV) ions from water, beverage and food samples. The method was optimized using central composite design combined with the response surface analysis. After extraction, inorganic selenium species (total Se, Se(IV) and Se(VI)) were determined by hydride generation atomic absorption spectrometry. 1-n-Octyl-3-methylimidazolium bis(trifluoromethane)-sulfonamide [C8mim NTf2] and tetrahydrofuran were used as the extraction and dispersive solvents, respectively. Applied vortex assisted the extractant dispersion and accelerated the mass transfer process. Obtained optimum conditions for microextraction procedure are as follows: mass of [C8mim NTf2], pH, extraction time and THF volume should be equal to 85 mg, 6.8, 15 min and 730 μL, respectively. Under these conditions, we observed linear range, limit of detection and enrichment factor equal to 5−500ng L−1, 1.5 ng L−1 and 120, respectively. We also fount linear regression coefficients in the dependence between Absorbance and Se(IV) concentration: Absorbance = 0.0652 CSe(IV) + 0.0185. We added 200 μg kg−1 of Se(IV) to selected food samples and 100 ng L−1 of Se(IV) to selected waters and beverages. Relative standard deviations and recovery values were within the ranges of 2.4–3.5 % and 92.7÷103.4 %, respectively. The optimized VA-IL-DLLME method reported here provides high extraction efficiency, fast extraction and lower detection limit without a heating step than alternative microextraction methods. This method also requires environmental solvents for determination and preconcentration of trace Se species in the selected samples. In addition, the reported VA-IL-DLLME procedure is the first method which use [C8mim NTf2] as extraction solvent for the preconcentration and separation of Se(IV) ions.

Graphite Furnace Atomic Absorption Spectrometry Determination of Trace amounts of Nickel in Water Samples after Homogeneous Liquid-Liquid Microextraction via Flotation Assistance

Graphite Furnace Atomic Absorption Spectrometry Determination of Trace amounts of Nickel in Water Samples after Homogeneous Liquid-Liquid Microextraction via Flotation Assistance

Ionic hydrophobic deep eutectic solvents in developing air-assisted liquid-phase microextraction based on experimental design: Application to flame atomic absorption spectrometry determination of cobalt in liquid and solid samples

This paper reports a new and simple microextraction procedure for cobalt determination using green ionic hydrophobic deep eutectic solvent in developing air-assisted liquid-phase microextraction and flame atomic absorption spectrometry. Thecomplexationof Co(II) ions was carried out by using dithizone solution as complexing agent at pH5.The key variables affecting microextraction steps were optimized by response surface methodology (RSM) based on central composite design. Under the optimum microextraction conditions, calibration graph was linear in the range of 0.1–500 µg L−1 Co(II) with correlation coefficient of 0.9985. Additionally, detection limit, quantitation limit and enrichment factor were found to be 0.04 µg L−1, 0.1 µg L−1 and 175, respectively. The reproducibility and repeatability were ≤ 2.9% and ≤ 3.6%, respectively. Based on the results obtained, the proposed methodology has been successfully employed for Co analysis in liquid and solid samples with recovery range of 94.2–105%.

Response surface methodology and hydrophobic deep eutectic solvent based liquid phase microextraction combination for determination of cadmium in food and water samples

In this work, an ecologically friendly, cheap, and highly efficient hydrophobic deep eutectic solvent based liquid phase microextraction procedure was developed and coupled with flame atomic absorption spectrometry for determination of cadmium. Hydrophobic deep eutectic solvent (HDES) was prepared by mixture of trihexyltetradecylphosphonium chloride and pivalic acid and used as extraction solvent. The formation of cadmium complex was achieved by sodium diethyldithiocarbamate trihydrate. Response Surface Methodology by Box–Behnken Design and three different models was used for optimizing experimental conditions and statistical analysis. Analytical parameters such as limit of detection, limit of quantification, relative standard deviation and enhancement factor were calculated as 1.6 µg L−1, 5.0 µg L−1, 3.3% and 43, respectively. Finally, the developed liquid phase microextraction method was applied to some food and water samples.

Trace measurement of lead and cadmium ions in wastewater samples using a novel dithizone immobilized metal–organic framework‐based μ‐dispersive solid‐phase extraction

A low‐cost, reliable, easy‐to‐perform, sensitive and environmentally friendly metal–organic framework (MOF)‐based μ‐dispersivesolid‐phase extraction (μ‐dSPE) method for extraction and graphite furnace atomic absorption spectrometry (GF‐AAS) determination of lead and cadmium ions in several wastewater samples was successfully developed. Initially, a zinc‐based MOF nanosorbent was prepared, immobilized with appropriate complexing agent dithizone (DTZ), characterized and eventually applied for the simultaneous extraction of the target ions. In practice, the application of the DTZ‐based MOF nanosorbent led to improvements in the extraction efficiency. After the extraction of the target ions, the desorption process, which was facilitated with vigorous agitation, was performed by applying a small amount of a desorption solvent (inorganic acid, HNO3). In the next step, concentrations of the desorbed heavy metal ions were measured using GF‐AAS. The parameters influencing the adsorption and desorption efficiencies were thoroughly evaluated followed by the establishment of optimal conditions. Under the optimum conditions, the calibration curves for respective Pb(II) and Cd(II) ions were linear over the concentration ranges 0.5–5.0 and 0.05–2.0 μg l−1. Relative recovery tests on spiked wastewater samples were performed with the results varying between 96% and 103%, whilst the analogous precisions were located in the range 1.8–3.1%. Finally, the μ‐dSPE method in conjunction with GF‐AAS was demonstrated to be fast, sensitive and cost‐effective, and could be potentially used in environmental laboratories for the surveillance of lead and cadmium ions in various wastewater samples.