A sensitive and highly efficient method for the determination of losartan potassium (LOS) in the presence of hydrochlorothiazide (HCTZ) via a combination of magnetic solid phase extraction (MSPE) and fluorometry techniques is suggested.

Hexamethylenetetramine covalently immobilized on silica-coated magnetic nanoparticles is prepared and characterized by XRD, FT-IR, SEM, and VSM. According to SEM pictures, the nanoparticles are mostly spherical in shape, and their size is approximately 46 nm. The catalytic performance of these magnetic nanoparticles for the synthesis of bis(indolyl)methanes was investigated. The catalyst was readily recycled by the use of an external magnetic field and can be reused four times without significant loss of activity. Graphical AbstractKeywords Magnetically retrievable Á Nano-hybrid Á Bis(indolyl)methanes Á Solventfree Á Silica Á Hexamethylenetetramine

In this study, the polyaniline–magnetite (PA@Fe3O4) hollow nanocomposite was synthesized by a chemical polymerization technique, and magnetite nanoparticles were deposited on the polyaniline hollow shell.