Novel mixed hemimicelles based on nonionic surfactant–imidazolium ionic liquid and magnetic halloysite nanotubes as efficient approach for analytical determination

The co-adsorption of mixed nonionic surfactant and imidazolium-based ionic liquid, Triton X100 (TX100), with 1-cetyl-3-methylimidazolium bromide (C 16 mimBr) adsorbed onto the surface of magnetic halloysite nanotubes (MHNTs) was used as an efficient adsorbent for simultaneous determination of amlodipine and nimodipine in urine. The designed adsorbent was characterized by TEM, TGA, FTIR, and DLS analysis methods. All the parameters that influence the extraction efficiency are optimized with the aid of response surface methodology (RSM). The effects of nonionic surfactant TX100 with different structures of ionic-liquid-coated MHNTs were investigated. Under optimum conditions, extraction recoveries of amlodipine and nimodipine were in the range of 73.8–81.2 and 94.3–96.1%, with RSDs ( n  = 3) of 2.6–5.5% in spiked urine samples, respectively. The adsorption mechanism principal of mixed hemimicelles was discussed in this study. The limit of detection obtained for analytes was < 0.002 μg·mL −1 . To our knowledge, this was the first attempt using a mixed hemimicelle solid-phase extraction (SPE) based on MHNTs and nonionic surfactant and imidazolium-based ionic liquid for the simultaneous determination of amlodipine and nimodipine in biological samples. ᅟ