Determination of four parabens in cosmetics by high-performance liquid chromatography with magnetic solid-phase and ionic dispersive liquid–liquid extraction

Abstract

To determine the trace amount of four benzoic acid esters in cosmetics, ionic dispersive liquid–liquid microextraction (DLLME) and magnetic solid-phase extraction were combined and optimized. After solvent optimization, 1-octyl-3-methylimidazolium hexafluorophosphate was selected as the extraction solvent to form hydrophobic droplets in the process of ionic DLLME, followed by removal of ions from the sample solution containing Fe3O4@GO nano-materials. The magnetic nano-materials were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometer. Some parameters affecting the efficiency of extraction were optimized using Box-Behnken design. Under optimized conditions, the limit of detection for all the preservatives was less than 0.135 mg/L and the accuracy ranged from 88.5% to 101%. This technology could determine the trace amount of preservatives in cosmetics with comparatively higher accuracy and sensitivity.

Open Tubular Column Immobilized with Covalent Organic Frameworks for Rapid Separation of Small Molecular Compounds by Capillary Electrochromatography

“…Of course, the performance and mechanism of the TpBD COF immobilized capillary needs to be further studied and explored to broaden its application field. To evaluate the current method, it was compared with the previously reported analytical methods [33,[38][39][40][41][42][43][44][45][46][47]. As shown in Table 7, the method in this work was found to be very rapid (baseline separation of the analytes studied within 6 min), simple (only phosphate buffer as separation media), sensitive and accurate (recovery rate 92.44-103.41%).…”