Using Thiol-Capped Gold Nanoparticles in the Background Solution of MEKC to Concentrate and Separate Neutral Steroids

In this study, it was aimed to use micellar electrokinetic chromatography (MEKC) to concentrate and separate neutral steroids (Δ⁴-androstene-3,17-dione, testosterone, progesterone, and testosterone propionate). It was aimed to study the impact of background solution (BGS) parameters on MEKC concentration and separation. These included sodium dodecylsulfate concentration, buffer concentration, pH, and the presence of organic solvent. Salt contents of the sample matrix and the operation conditions of the capillary electrophoresis system, i.e., voltage and temperature, have also been investigated. The addition of thiol-capped Au nanoparticles (NPs) to the BGS and how this affected the concentration and separation of the steroids was investigated. It was found that the migration time window of the steroids widened upon the increased concentration of these NPs present in the BGS. All of the tested steroids were separated well, showing limits of detection values ranging from 11.8 to 16.4 μg L^?1.