Analysis of Some Trace Metals in Fish Species after Preconcentration with Congo Red on Amberlite XAD-7 Resin by Flame Atomic Absorption Spectrometry

A new procedure for separation and preconcentration of trace amounts of Cu(II), Ni(II), Fe(III), Zn(II), Cr(III), Cd(II), and Pb(II) in fish samples was proposed. The procedure is based on the adsorption of these metal ions on the column of Amberlite XAD-7 as congo red complexes prior to their determination by flame atomic absorption spectrometry (FAAS). Several factors that can affect the sorption and elution efficiency of the metal ions were investigated and optimized. The sorption was quantitative in the pH range of 6.0–9.0 for Cu(II) and Ni(II), 5.5–8.0 for Fe(III), 6.0–8.5 for Zn(II) and Cd(II), and 7.0–8.5 for Cr(III) and Pb(II). The optimum pH for simultaneous retention was 7.5. The sorption capacity of the resin was found to be 0.89, 0.72, 0.82, 0.61, 0.53, 0.84, and 0.78 mg/g for Cu(II), Ni(II), Fe(III), Zn(II), Cr(III), Cd(II), and Pb(II), respectively. The precision of the method was evaluated as the relative standard deviation obtained by analyzing a series of six replicates and below 6% for all seven elements. The validation of the method was performed by the analysis of certified reference materials. The proposed method was successfully applied to separation/preconcentration and determination of these metals in fish samples

Optimization of Ultrasound-Assisted Extraction of Antioxidants from Apium graveolens L. Seeds using Response Surface Methodology

In this study, optimum conditions for ultrasound-assisted extraction (UAE) of antioxidants from Apium graveolens L. seeds were investigated by Response Surface Methodology (RSM). A Box-Behnken Design (BBD) was used to evaluate the effect of sonication time (5, 10, 15 min), ultrasound power (60, 120, 180 W) and the ratio of extraction solvent in terms of methanol (0, 50, 100%) on antioxidant capacity. The optimal UAE conditions for the parameters investigated were 11 min of sonication time, ultrasound power of 131 W and 100% methanol as an extraction solvent. Under these conditions, UAE of antioxidants from the seeds achieved a maximum of 95.08% in respect to 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity. Additionally, the high value of the adjusted coefficient of determination (R2adj = 0.9192) and the non-significant difference between experimental and predicted values confirmed the validity of the quadratic polynomial model. Hence, UAE is a suitable, fast, economical and practical technique for the extraction of antioxidants from Apium graveolens L. seeds