Abstract
A 3-phase liquid-liquid extraction (LLE) chip was hyphenated with nano-HPLC/ESI-MS (Fig.). Thus the purification, separation and MS detection of alkaloids was accomplished on-line. The system is solvent-efficient with a nanoLC flow rate of 200 nL/min, and chip flow rate of 500 nL/min, sample-efficient (50-330 nL sample volume) and time-efficient (saving tedious off-line sample pretreatment steps. The transfer efficiency of strychnine was above 92% in 25sec). The analyses of alkaloids in Semen strychni,
Cephaelis ipecacuanha
,
Atropa belladonna
,
Vinca minor
, and Coptidis rhizome were successfully performed. The limits of detection (LODs) of the alkaloids are lower than with conventional HPLC/ESI-MS and nano-HPLC-DAD, i.e. 5ng/mL for emetine, palmatine, vincamine, strychnine and 10ng/mL for atropine.