A facile solid-phase extraction (SPE) method based on bare Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 NPs) was developed to capture cinnamic acid (CA) from a well-known traditional Chinese medicine, Ramulus cinnamomi, for high performance liquid chromatography (HPLC) analysis. The as-prepared Fe 3 O 4 NPs were characterized via Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Several parameters that influence CA extraction rate, such as the amount of Fe 3 O 4 NPs, shaking time, methanol content, eluent pH, and elution time, were investigated. The experimental results show that the CA extraction was 86.9% at optimal condition, and the mass yield of CA extraction was found to be 0.00021%. This study demonstrates that the developed CA extraction method is simple, cheap and environmentally friendly. Therefore, the proposed method has a potential for CA separation and purification from complex biological samples.

In this work, rare-earth composite as an optical upconversion temperature dual mode sensing is practically demonstrated. NaGdF 4 :Yb 3+ /Er 3+ /Zn 2+ phosphor was synthesized by the solvothermal method. The phase purity, crystal structure and morphologies were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The enhancement of upconversion luminescence is achieved by aliovalent doping in Zn 2+ co-doped NaGdF 4 : Yb 3+ /Er 3+ phosphors. The temperature sensing behaviours based on the luminescence intensity and luminescence lifetime in phosphors are recorded in the temperature range from 75 to 297 K, and the maximum sensitivity is obtained as 13.4 × 10 −3 K −1 at 75 K and 2.52 × 10 −3 K −1 at 225 K, respectively.