Determination of Cadmium in Water Samples by Automated Flow-Batch Cloud Point Extraction (CPE) Hyphenated to High-Resolution Continuum Source Flame Atomic Spectrometry (HR-CS FAAS)

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.

Innovative approaches in cloud-point extraction

Cloud-point extraction (CPE) is a pre-treatment technique for the extraction and preconcentration of different chemical compounds, such as metal ions, pesticides, drugs, phenols, vitamins etc., from various samples. CPE is based on the phenomenon of two phases (micellar and aqueous) forming after the heating of an aqueous isotropic solution of a non-ionic or zwitterionic surfactant above the cloud-point temperature. If analytes are added to the surfactant solution under suitable conditions, they should be extracted into the micellar phase, also called the surfactant-rich phase. Recently, the traditional CPE procedure is being increasingly replaced by improved CPE procedures. In this study, recent advances in CPE over the last three years (2020 - 2022), including the application of various innovative approaches, are reviewed. In addition to the basic principle of CPE, alternative extraction media in CPE, CPE supported by various auxiliary energies, a different modified CPE procedure and the use nanomaterials and solid-phase extraction in combination with CPE are presented and discussed. Finally, some future trends for improved CPE are presented.