scholarly journals Flame atomic absorption spectrometric determination of trace amounts of lead, cadmium and nickel in different matrixes after solid phase extraction on modified multiwalled carbon nanotubes

2010 ◽  
Vol 8 (3) ◽  
pp. 662-668 ◽  
Author(s):  
S. Mohammadi ◽  
D. Afzali ◽  
D. Pourtalebi

AbstractThe potential of modified multiwalled carbon nanotubes (a solid-phase extraction sorbent), for the simultaneous separation and preconcentration of lead, cadmium and nickel; has been investigated. Lead, cadmium and nickel, were adsorbed quantitatively; on modified multiwalled carbon nanotubes (in the pH range of 2–4). Parameters influencing, the simultaneous preconcentration of Pb(II), Ni(II) and Cd(II) ions (such as pH of the sample, sample and eluent flow rate, type and volume of elution solution and interfering ions), have been examined and optimized. Under the optimum experimental conditions, the detection limits of this method. for Pb(II), Ni(II) and Cd(II) ions, were 0.32, 0.17 and 0.04 ng mL−1 in original solution, respectively. Seven replicate determinations, of a mixture of 2.0 μg mL−1 lead and nickel, and 1.0 μg mL−1 cadmium; gave a mean absorbance of 0.074, 0.151 and 0.310, with relative standard deviation 1.7%, 1.5% and 1.2%, respectively. The method has been applied, to the determination of trace amounts of lead, cadmium and nickel; in biological and water samples, with satisfactory results.

2020 ◽  
Vol 16 (4) ◽  
pp. 381-392
Author(s):  
Ayman A. Gouda ◽  
Ali H. Amin ◽  
Ibrahim S. Ali ◽  
Zakia Al Malah

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.


2018 ◽  
Vol 41 (12) ◽  
pp. 2613-2622 ◽  
Author(s):  
Javier González-Sálamo ◽  
Javier Hernández-Borges ◽  
María del Mar Afonso ◽  
Miguel Ángel Rodríguez-Delgado

NANO ◽  
2014 ◽  
Vol 09 (04) ◽  
pp. 1450054 ◽  
Author(s):  
XIAOYING DENG ◽  
XIAOQING CHEN ◽  
XINYU JIANG

We report a novel solid-phase extraction adsorbent for the preconcentration of three phthalate esters (PAEs) from aqueous samples. The material was obtained by modifying multiwalled carbon nanotubes (MWCNTs) with mesoporous silica. The structural characterization of the adsorbent was conducted by Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM) and N 2 adsorption–desorption measurement, which confirmed the successful coating of mesoporous silica on MWCNTs and the adsorbent possessing large surface and porous structure. The effects of adsorbent amount, type and volume of eluent and sample pH on extraction efficiency were optimized. Following extraction, the PAEs were quantified by high performance liquid chromatography (HPLC). Under optimal conditions, the recoveries ranged from 89.8% to 96.3%. The calibration plot was linear in the 3–1000 ng⋅mL-1 concentration range, with correlation coefficients ranging from 0.9993 to 0.9995. The repeatability of the method, expressed as relative standard deviation (RSD), ranged from 3.8% to 7.7% (for n = 5). Limits of detection (LODs) were between 0.28 ng mL-1 and 0.53 ng⋅mL-1. The relative recoveries (RR) for spiked river water, pond water and tap water samples were in the ranges of 80.9–98.0%, 82.7–96.1% and 88.3–95.5%, respectively. The results showed that the method obviously had a large potential for preconcentration and determination of PAEs in environmental samples.


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