An automated and self-cleaning nano liquid chromatography mass spectrometry platform featuring an open tubular multi-hole crystal fiber solid phase extraction column and an open tubular separation column

•A self-cleaning nano liquid chromatography mass spectrometry platform is presented.•Multi-channeled polymer layer open tubular column as solid phase extraction column.•Poly(styrene-co-octadecene-co-divinylbenzene) stationary phases.•An open tubular column for separation of small compounds was employed.

An open tubular (OT) sample preparation/separation platform was developed. A multi-channel polymer layer open tubular (mPLOT) solid phase extraction (SPE) column was prepared by wall-coating the 126 channels (8 μm inner diameter (ID) each) of a crystal fiber capillary with an organic polymer, namely poly(styrene-co-octadecene-co-divinylbenzene) (PS-OD-DVB). The mPLOT SPE was coupled on-line with a 10 μm × 2 m poly(styrene-co-divinylbenzene) (PS-DVB) OT liquid chromatography column with nanospray mass spectrometry (OTLC-MS). Compared to using monolithic/particle-packed SPEs, mPLOT-SPE-OTLC allowed both fast loading and sufficient refocusing on the OT analytical column of small model compounds (sulfonamides ≈ 300 Da). Using automatic filtration/filter back-flushing (AFFL) plumbing, the mPLOT SPE column gave a constant and low back-pressure ≈35 bar at 0.5 μL/min. Surprisingly large sample volumes (10 μL) were possible to be injected using a 12 cm mPLOT.