Silica-coated modified magnetic nanoparticles (Fe3O4@SiO2@(BuSO3H)3) as an efficient adsorbent for Pd2+ removal.

It is crucial to fabricate cost-effective and efficient strategies for monitoring and eliminating hazardous metals in the water supplies. Among the many techniques, adsorption is one of the most powerful and facile ways for eliminating pollutants from effluents. It is also crucial to engineering high-performance low-cost adsorbents. In this regard, herein, Fe3O4@SiO2@(BuSO3H)3 as a modified core-shell magnetic silica nanoparticle embodies good selectivity to extract toxic metal ions from aquatic media. The present work investigated the removal performance of the magnetic adsorbent towards Pd2+ cation amongst the other heavy metal ions including Co2+, Pb2+, Hg2+, Cd2+, Cu2+, Zn2+ in aqueous solution. The flame atomic absorption spectrometry (FAAS) was utilized to assess the removal efficiency of the adsorbent. Several experimental parameters including elution condition, initial Pd(II) concentration, adsorbent dosage, initial pH of the solution, and contact time were explored to achieve the optimal conditions. The data of adsorption were very well with the Langmuir isotherm model, according to the adsorption isotherm mechanism experiments. In conclusion, this study lays the way for the development of novel magnetic adsorbents with high removal efficiencies for the removal of toxic metal ions from aqueous environment.

Polystyrene-coated magnetic nanoparticles based dispersive solid phase extraction for the determination of cadmium in cigarette ash prior to slotted quartz tube flame atomic absorption spectrometry system.

A sensitive, accurate and simple analytical method was developed to determine cadmium by slotted quartz tube-flame atomic absorption spectrometry after preconcentration/extraction with polystyrene coated magnetic nanoparticles based dispersive solid phase extraction. The surface of Fe3O4 based magnetic nanoparticles was modified with polystyrene to yield higher selectivity and sensitivity in adsorption efficiency of cadmium. The nanoparticles were dispersed into the aqueous solution to extract/separate cadmium. Significant parameters of the method including magnetic nanoparticle amount, mixing effect, effect of ionic strength, eluent concentration and sonication period were optimized to achieve optimal conditions for the analyte. The limit of detection and quantification values of the developed method were found to be 0.62 and 2.1 ng/mL, respectively. Under the optimum conditions, enhancement of the detection power for cadmium were calculated as 102 folds for the developed method. The developed method was then applied to cigarette ash to test its accuracy and applicability. Total cadmium was found to be between 402 and 450 ng/g in the ashes of different cigarette brands commercially available in Turkey. The accuracy of quantifying cadmium in the complex ash samples was enhanced by using the matrix matching calibration strategy. The developed method provides sensitive and selective determination of cadmium at ng/mL levels even at complex cigarette ash samples. High percent recovery results (90-102%) were obtained from spiked real samples.

Preconcentration of trace amount Cu(II) by solid-phase extraction method using activated carbon-based ion-imprinted sorbent.

In this study, preconcentration conditions of trace amounts of copper ions were investigated with solid-phase extraction (SPE) method by synthesizing activated carbon-based ion-imprinted sorbent (Cu(II)-IAC) with a novel and selective approach. Flame atomic absorption spectrometry (FAAS) was used for the determination of metal ions concentrations. For the characterization of the sorbents, scanning electron microscopy, energy dispersive X-ray (SEM/EDX) analysis, and Fourier transform infrared spectroscopy (FTIR) were used. Optimum conditions for the SPE procedure, various parameters such as pH value, eluent type and concentration, sample volume, sample flow rate, adsorption capacity, and selectivity were studied. The adsorption isotherm was analyzed by Freundlich and Langmuir isotherm, and the maximum adsorption capacity was found to be 142.9 and 312.5 mg/g for activated carbon-based nonimprinted (Cu(II)-non-IAC) and Cu(II)-IAC sorbents, respectively from the Langmuir isotherm. Limit of determination (LOD) and limit of quantification (LOQ) values were found to be 0.038 and 0.113 µg/L, respectively for Cu(II)-IAC sorbent, and the results were compared with the literature. The accuracy and validity of the proposed method were evaluated by the determination of Cu(II) ions from tap water samples and certified reference materials (CRMs) (soft drinking water ERML-CA021e and NIST 1643e) analysis. Good and quantitative recoveries were obtained for the spiked analysis.

Determination of essential elements in beverages, herbal infusions and dietary supplements using a new straightforward sequential approach based on flame atomic absorption spectrometry.

A simple method based on FAAS was developed for the sequential multi-element determination of Cu, Zn, Mn, Mg and Si in beverages and food supplements with successful results. The main absorption lines for Cu, Zn and Si and secondary lines for Mn and Mg were selected to carry out the measurements. The sample introduction was performed using a flow injection system. Using the choice of the absorption line wings, the upper limit of the linear range increased up to 110mgL-1 for Mg, 200mgL-1 for Si and 13mgL-1 for Zn. The determination of the five elements was carried out, in triplicate, without the need of additional sample dilutions and/or re-measurements, using less than 3.5mL of sample to perform the complete analysis. The LODs were 0.008mgL-1 for Cu, 0.017mgL-1 for Zn, 0.011mgL-1 for Mn, 0.16mgL-1 for Si and 0.11mgL-1 for Mg.

Preconcentration of Cu(II), Co(II), and Ni(II) using an Optimized Enrichment Procedure: Useful and Alternative Methodology for Flame Atomic Absorption Spectrometry.

In this paper, a new solid phase extraction procedure is described for Cu(II), Co(II), and Ni(II). Silica gel which was coated with N,N'-bis(4-methoxysalicylidene) ethylenediamine (MSE) is used as a sorbent. Three independent variables were optimized using central composite design (CCD) for sorption and elution of metal ions. The optimum values of sorption and elution variables allowed simultaneous preconcentration of the ions in same conditions as follows, for sorption, pH 6.9, flow rate 5.4 mL min(-1), sample volume 50.0 mL, and for elution, flow rate 2.6 mL min(-1), eluent concentration 1.0 mol L(-1), eluent volume 5.0 mL. The detection limits (LOD) were found to be 1.1 µg L(-1) for Cu(II), 7.4 µg L(-1) for Co(II), and 7.5 µg L(-1) for Ni(II) and preconcentration factor was 200 for each of the ions. The accuracy of the method was tested with Lake Ontario water and multi-element standard solution. The proposed method was also applied to various water samples. The proposed method can be alternatively suggested as accurate, precise, easy, and a cheap method for Cu(II), Co(II), and Ni(II) determination.

Determinação sérica de lítio: comparação das metodologias de espectrometria de emissão e de absorção atômica / Determination of serum lithium: comparison between atomic emission and absorption spectrometry methods

Introduction: The therapeutic monitoring of lithium, through concentration measurements, is important for individual dose adjustment, as a marker of treatment adherence and to prevent poisoning and side effects. Objectives: Validate and compare two methods - atomic emission and atomic absorption - for the determination of lithium in serum samples. Methodology: Parameters such as specificity, precision, accuracy, limit of detection (LOD) and linearity were considered. The atomic absorption spectrometer was used, operating in either emission or absorption mode. For the quantitative comparison of 30 serum samples from patients with mood disorder treated with lithium, the results were submitted to Student's t-test, F-test and Pearson's correlation. Results: The limit of quantification (LOQ) was established as 0.05 mEq/l of lithium, and calibration curves were constructed in the range of 0.05-2 mEq/l of lithium, using aqueous standards. Sample preparation time was reduced, what is important in medical laboratory. Conclusion: Both methods were considered satisfactory, precise and accurate and can be adopted for lithium quantification. In the comparison of quantitative results in lithium-treated patients through statistical tests, no significant differences were observed. Therefore the methods for lithium quantification by flame atomic absorption spectrometry (FAAS) and flame atomic emission spectrometry (FAES) may be considered similar...

Introdução: A monitorização terapêutica por meio da determinação sérica de lítio é importante para proporcionar o ajuste individual da dose, como marcador de adesão e para prevenir intoxicações. Objetivos: Validar e comparar duas metodologias, a de emissão e a de absorção atômicas, para determinação de lítio em amostras de soro. Metodologia: Foram determinados parâmetros de especificidade, precisão, exatidão, limite de detecção e linearidade a fim de validar as metodologias para determinação de lítio. Foi utilizado espectrômetro de absorção atômica, funcionando no modo de emissão ou de absorção. Para comparação das metodologias foram utilizados os testes estatísticos (teste t de Student, o teste F e a correlação de Pearson) nos resultados quantitativos de 30 amostras de soro sanguíneo de pacientes que faziam uso terapêutico de lítio para o controle do transtorno de humor bipolar (THB). Resultados: Foram estabelecidos um limite de quantificação de 0,05 mEq/l de lítio e curvas de calibração de 0,05 a 2 mEq/l de lítio, construídas utilizando padrões aquosos, com redução no tempo de preparo das amostras, principalmente para ser utilizado em laboratório de análises clínicas. Conclusão: Os dois métodos foram considerados satisfatórios, precisos e exatos e podem ser adotados para a quantificação do lítio. Na comparação dos dois métodos por testes estatísticos em amostras de pacientes tratados com o fármaco, não foram observadas diferenças significativas entre os resultados encontrados. Desta forma, os métodos para quantificação do lítio por espectrometria de absorção atômica em chama (FAAS) e espectrometria de emissão atômica em chama (FAES) podem ser considerados semelhantes...

Simultaneous preconcentration of cadmium and lead in water samples with silica gel and determination by flame atomic absorption spectrometry.

A new method that utilizes pretreated silica gel as an adsorbent has been developed for simultaneous preconcentration of trace Cd(II) and Pb(II) prior to the measurement by flame atomic absorption spectrometry. The effects of pH, the shaking time, the elution condition and the coexisting ions on the separation/preconcentration conditions of analytes were investigated. Under optimized conditions, the static adsorption capacity of Cd(II) and Pb(II) were 45.5 and 27.1mg/g, the relative standard deviations were 3.2% and 1.7% (for n = 11), and the limits of detection obtained were 4.25 and 0.60 ng/mL, respectively. The method was validated by analyzing the certified reference materials GBW 07304a (stream sediment) and successfully applied to the analysis of various treated wastewater samples with satisfactory results.