Corn-like stationary phase for solid phase microextraction prepared by electro-assisted deposition of sol-gel/silica nanoparticles composite

Polydopamine-coated magnetic Spirulina nanocomposite for efficient magnetic dispersive solid-phase extraction of aflatoxins in pistachio

An efficient adsorbent was synthesized and used in magnetic dispersive solid phase extraction (MDSPE) of aflatoxins B1, B2, G1, and G2 at trace levels in pistachio prior to analysis by HPLC equipped with a fluorescence detector. Spirulina (Sp) algae was first magnetized, followed by surface modification with dopamine (Dp). The adsorbent was characterized using FT-IR, XRD, FE-SEM, EDX, VSM, and BET analyses. The effects of different analytical parameters on the extraction performance were evaluated. Under optimal conditions, good limits of detection (LODs) and quantifications (LOQs) were achieved in the ranges of 0.02-0.07 and 0.06-0.21 ng g^-1, respectively. The RSDs were 5.9, 6.3, 5.6, and 7.3% for AFB1, G1, B2, and G2, respectively. The proposed method was successfully used to determine AFs in pistachio samples and acceptable recoveries in the range of 72-95% were obtained.

Arsenic Removal from Mining Effluents Using Plant-Mediated, Green-Synthesized Iron Nanoparticles

Arsenic contamination in industrial and mining effluents has always been a serious concern. Recently, nano-sized iron particles have been proven effective in sorptive removal of arsenic, because of their unique surface characteristics. In this study, green synthesis of iron nanoparticles was performed using a mixed extract of two plant species, namely Prangos ferulacea and Teucrium polium, for the specific purpose of arsenic (III) removal from the aqueous environment. Results of UV-visible spectrometry, X-ray powder diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) analyses confirmed the formation of iron nanoparticles from Prangos ferulacea (Pf) and Teucrium polium (Tp) extracts. The synthesized Fe nanoparticles morphology was studied via microscopy imaging. The particle size was 42 nm, as assessed by dynamic light scattering (DLS) analysis. Adsorption experiments were also designed and performed, which indicated 93.8% arsenic removal from the aqueous solution at 200 rpm agitation rate, 20 min agitation time, pH 6, initial concentration of 0.1 g/L, and adsorbent dosage of 2 g/L. Adsorption isotherm models were investigated, and the maximum uptake capacity was determined to be about 61.7 mg/g. The kinetic data were best represented by the pseudo-second kinetic model (R2 = 0.99). The negative value of Gibbs free energy, the enthalpy (−7.20 kJ/mol), and the entropy (−57 J/mol.K) revealed the spontaneous and exothermic nature of the adsorption process. Moreover, the small quantity of the activation energy confirmed the physical mechanism of arsenic adsorption onto iron nanoparticles and that the process is not temperature sensitive.