Optimization of High-Pressure-Assisted Extraction of Cadmium and Lead from Kelp (Laminaria japonica) Using Response Surface Methodology

Magnetic Solid Phase Extraction of Lead (II) and Cadmium (II) From Water Samples Using ZnO@Fe3O4 Nanoparticles Combined With Flame Atomic Absorption Spectrometry Determination

A new magnetic solid phase extraction method was developed utilizing magnetically enhanced zinc oxide (ZnO@Fe3O4) nanoparticles for the separation and enrichment of lead (II) and cadmium (II) before sample determination through flame atomic absorption spectrometry. The ZnO@Fe3O4 nanoparticles synthesized by the hydrothermal method were characterized by x-ray diffraction, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. The experimental factors like pH (6.0), eluent type and concentration (1 M nitric acid for lead (II), 1 M hydrochloric acid for cadmium (II)), adsorbent amount (150 mg for lead (II), and 200 mg for cadmium (II)), sample volume (5 mL), and extraction time (5 min for lead (II), and 10 min for cadmium (II)) were optimized. Under the optimization conditions, limits of detection of 2.36 and 7.86 µg/L for lead (II) and cadmium (II) were obtained with a wide concentration range from 50 to 5000 µg/L, respectively. The presented method was successfully applied to real water samples with spiked recoveries in the range of 99.2%-101% for lead (II) and 99.6%-100% for cadmium (II).

Fe3O4-SiO2-MIL-53 (Fe) nanocomposite for magnetic dispersive micro-solid phase extraction of cadmium (II) at trace levels prior to HR-CS-FAAS detection

A magnetic metal-organic framework Fe3O4-SiO2-MIL-53 (Fe) nanocomposite was synthesized for magnetic dispersion micro-solid phase extraction (M-d-µSPE) of cadmium in water, spice, chocolate, tea, and tobacco samples prior to the detection by flame atomic absorption spectrometry. Fe3O4-SiO2-MIL-53 (Fe) nanocomposite fabricated using the solvothermal technique was characterized using a field emission scanning electron microscope and X-ray diffraction. The extraction efficiency of the method was improved by optimizing the experimental factors. After optimization, the linearity range for Cd (II) was 4.3-500 µgL-1. The limits of detection and quantification were 1.3 and 4.3 µgL-1, respectively. The presented magnetic dispersion-micro solid phase extraction method was applied to Cd (II) analysis in food and some environmental samples.

Multi-Response Optimization of Pyrrolizidine Alkaloids Removal from Chrysanthemum morifolium by High-Pressure Extraction

As an ingredient in various foods, Chrysanthemum morifolium flower is popular due to its multiple health benefits. Pyrrolizidine alkaloids (PAs) are hepatotoxic secondary metabolites in Chrysanthemum family. Effects of high-pressure extraction (HPE) on PAs removal efficiency, as well as the retention efficiency of functional components, including chlorogenic acid, luteolin-7-β-D-glucopyranoside, 3,5-dicaffeyl quinic acid and total flavonoids, were investigated and optimized using response surface methodology (RSM). Pressure (0.1-200 MPa), numbers of cycles (1-5) and acetic acid concentration (0-10%) were chosen as the independent variables. The results indicated that the pressure was the most significant factors affecting all responses. The optimum HPE for removing Pas and retaining functional components were set at 124 MPa, with one cycle and with an acetic acid concentration of 10%. After comparing the experimental optimum values and predicted optimum values, the validity of RSM model was proved.