Planar solid phase extraction—A new clean-up concept in multi-residue analysis of pesticides by liquid chromatography–mass spectrometry

Planar solid phase extraction clean-up for pesticide residue analysis in tea by liquid chromatography–mass spectrometry

Determination of caffeine, theobromine and theophylline in Mate beer and Mate soft drinks by high-performance thin-layer chromatography

Screening for total ergot alkaloids in rye flour by planar solid phase extraction–fluorescence detection and mass spectrometry

Screening for mineral oil saturated and aromatic hydrocarbons in paper and cardboard directly by planar solid phase extraction and by its coupling to gas chromatography

Polyethyleneimine as weak anionic exchanger adsorbent for clean-up in pesticide residue analysis of fruits and vegetables