Determination of cobalt in P. polyphylla var. yunnanensis and S. yunnanensis by micro UV–vis spectrophotometry after deep eutectic solvent-based rapidly synergistic cloud point extraction

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.

Determination of lead in Gentiana rigescens and evaluation of the effect of lead exposure on the liver protection of the natural medicine

In this work, ultrasound-assisted rapidly synergistic cloud point extraction (UARS-CPE) and inductively coupled plasma optical emission spectrometry (ICP-OES) were combined to determine trace Pb in Gentiana rigescens Franch. ex Hemsl. (G. rigescens) samples. Under the optimal conditions, the enhancement factor (EF), limit of detection (LOD), limit of quantitation (LOQ) and precision were 33, 0.11 μg L^-1, 0.37 μg L^-1 and 1.3%, respectively. This method was applied to the analysis of G. rigescens samples, and the outcomes were in good agreement with the results determined by inductively coupled plasma mass spectrometry (ICP-MS). A mice model of immune liver injury induced by concanavalin A (ConA) was established, and the liver protection of G. rigescens and gentiopicroside (GPS) on it and the effects of various dosages of Pb exposure on its liver protection were studied. Pb at a dosage of 5 mg kg^-1 had little effect on the liver protection of G. rigescens and GPS, while 25, 125 mg kg^-1 dosages of Pb could significantly attenuate the liver protection of both. In addition, it aggravated the necrosis of hepatocytes and inflammatory cell infiltration, and these effects were dose-dependent.