Recent developments in modifying polypropylene hollow fibers for sample preparation

• We review four ways of modifying hollow fibers of polypropylene.
• We review applications of hollow-fiber-based solid-phase microextraction (HF-SPME).
• Modified HF-SPME has advantages over conventional SPME.

Polypropylene hollow fibers (PPHFs) are usually applied for HF liquid-phase microextraction and have proved effective in various applications. By modifying PPHFs with sorbents, they can be used for solid-phase microextraction, and the method is novel, efficient and economical. This article mainly reviews the modification of PPHFs using carbon nanotubes, graphene, ceramic metal oxides and self-synthesized polymers.