Magnetic Solid-Phase Extraction Using Fe₃O₄@SiO₂ Magnetic Nanoparticles Followed by UV-Vis Spectrometry for Determination of Paraquat in Plasma and Urine Samples

Abstract

A rapid and simple method was optimized and validated for the separation and quantification of paraquat, a frequently used herbicide and a leading cause of fatal poisoning worldwide, at trace levels with UV-Vis spectrophotometry in plasma and urine samples by direct magnetic solid-phase extraction. Fe3O4@SiO2 nanoparticles (NPs) were used as the magnetic solid-phase extraction agents and the paraquat absorbed on NPs was eluted using NaOH and ascorbic acid. Upon optimization, paraquat could be extracted and concentrated from various samples by 35-fold. The linear range, limit of detection (LOD), correlation coefficient (R), and relative standard deviation (RSD) could reach 15.0–400.0 μg/L, 12.2 μg/L, 0.9987, and 0.65% (n = 5, c = 40.0 μg/L), respectively. The Fe3O4@SiO2 NPs could be reused up to five times. The method was successfully applied to the determination of paraquat in urine and plasma at different hemoperfusion numbers in a local hospital for the patient of paraquat poisoning. The experiment result could not only enable immediate medical intervention but also benefit patients' survival.

Facile Synthesis of Magnetic Biochar Derived from Burley Tobacco Stems towards Enhanced Cr(VI) Removal: Performance and Mechanism

“…After the biochar was modified with FeCl 3 , a new peak at 572 cm −1 conforming with the ferric oxide (Fe 3 O 4 or γ-Fe 2 O 3 ) was presented in the spectra of MBTS, indicating that the tobacco stem biochar was successfully modified with FeCl 3 , which is in accordance with the XRD characterization result. As for the MBTS adsorbed Cr spectra, the peak of nearly 580 cm −1 conforms with the representative Fe-O vibration [31], which that after the adsorption of Cr(VI) by the ferric oxides on MBTS, a redox reaction occurred, which reduced Cr(VI) to Cr(III), while the chemical valence of iron changed, then and Fe-O vibration occurred. Figure 2c shows that MBTS disperses in a water suspension and can be magnetically separated.…”

Antibacterial and plant growth-promoting properties of novel Fe3O4/Cu/CuO magnetic nanoparticles

“…2b , confirming the existence of Fe on the surface of FC as Fe 2+ and Fe 3+ ions. 29 The spectral peaks 530.8 and 529.5 eV in O 1s match the O 2− element in CuO and Fe 3 O 4 , 28 indicating that the Fe 3 O 4 /CuO composites included Cu 2+ , Cu, O 2− , Fe 2+ and Fe 3+ .…”

“… 22,27,29 Due to the fact that bacterial resistance mechanisms depend on the expression of resistance genes in plasmid DNA proteins, the more protein in the cell wall, the more probable that resistance gene expression is activated. 29 As a result, S. aureus is more susceptible to the FC.…”

Separation and Determination of Paraquat and Diquat in Human Plasma and Urine by Magnetic Dispersive Solid Phase Extraction Coupled with High-Performance Liquid Chromatography

“…Although PQ and DQ could be absorbed by CoFe 2 O 4 @SiO 2 MNPs under the pH of 7.0–12.0, the reduced product of PQ and DQ reacted with the strong alkaline (NaOH solution) could not be absorbed by CoFe 2 O 4 @SiO 2 MNPs [ 29 ]. Therefore, 2.0 mol/L of NaOH solution was chosen as the eluent.…”