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Ultra-sensitive quantification of copper in food and water samples by electrochemical adsorptive stripping voltammetry Texte intégral
2013
Goudarziafshar, Hamid | Nikoorazm, Mohsen | Mortazavi, Sayede Shima | Abbasi, Shahryar | Farmany, Abbas
A new electrochemical adsorptive stripping voltammetry method was developed for the determination of trace amounts of copper in food and water samples. The study of electrochemical behavior of Cu ion indicated that Cu(II) and Schiff base formed a complex in H3BO4-NaOH buffer solution (pH = 7.25). An accumulation potential of -100 mV (vs Ag/AgCl) was applied while the solution was stirred for 60 s. The response curve was recorded by scanning the potential, and the peak current of -0.31 V (vs Ag/AgCl) was recorded. The peak current and concentration of copper accorded with linear relationship in the range of 0.04-120 ng mL(-1). The relative standard deviation (for 12 ng mL(-1) of copper) was 1.73 %, and the detection limit was 0.007 ng mL(-1). The possible interference of some common ions was studied. The proposed method was applied to the determination of copper in water, rice, wheat, tea, milk, and tomato with satisfactory results.
Afficher plus [+] Moins [-]Dispersive liquid-liquid microextraction coupled with digital image colorimetric analysis for detection of total iron in water and food samples Texte intégral
2017
Peng, Bo | Chen, Guorong | Li, Kai | Zhou, Min | Zhang, Ji | Zhao, Shengguo
A simple and low cost assay for total iron in various samples based on dispersive liquid-liquid microextraction (DLLME) coupled with digital scanning image analysis was proposed. Orthogonal experiment design was utilized to optimize the amount of extraction solvent and disperser solvent, O-phenanthroline concentration and buffer pH. Under the optimum conditions, the calibration curve was linear over the range of 0.047–1.0μgmL−1 (R2>0.99) of iron. The limit of detection (LOD) for iron was 14.1μgL−1 and limit of quantification (LOQ) was 46.5μgL−1. The relative standard deviations for seven replicate determinations of 0.5μgmL−1 of iron was 3.75%. The method was successfully applied for analysis of total iron in water and food samples without using any spectral instrument and it could have a potential industrial impact in developing fast and portable devices to analyze the iron content in water and certain foods.
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