INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Potentiometric detection in flow systems: an HPLC and FIA study for plant alkaloids.
FERNÁNDEZ, MARCELO R.; DAEMS, DEVIN; EVERAERT, JOSEPH; VAN CAMP, GUY; BERNIK, DELIA L.; NAGELS, LUC
Congreso; XVII Congreso Argentino de Fisicoquimica y Quimica Inorganica; 2011
Asociacion Argentina de Investigacion Fisicoquimica
Introduction: Some 12,000 plant secondary products (many of them aromatic) have been isolated, and this amount is estimated to be only 10% of the products present. Also some 10,000 plant alkaloids were already identified. Alkaloids can be differentiated from other secondary plant metabolites by their positive charge at physiological (or lower) pH. Objectives: - Develop a sensor capable of detecting the presence of alkaloids in plant extract. - Analyse its kinetics behaviour and applicability as HPLC detector. Results: In the present study, we developed a potentiometric HPLC detector which selectively detects the positively charged alkaloids from phenolic compounds present in a plant extract. The characteristics of the detector, such as selectivity, sensitivity, calibration curve behaviour, speed of response were studied in FIA, using the sensorgram methodology. The detectors response is typical for a surface phenomenon dependent system, showing on and off kinetics. Response speeds are described by a double exponential function. These response times (t90) were calculated for cocaine on and off kinetics being 14.6±1.1 and 1.8 ±0.1 seconds respertivelly. Alkaloids as cocaine, ergocorine, solanidine and metergoline can be easily detected at concentrations of 2.5 10-7M, 7 10-7M, 1 10-7M and 1.7 10-7M in HPLC respectively. The detectors ability to be used as an alkaloids detector in HPLC is shown in several chromatograms, with UV detection for comparison. Conclusions: Alkaloids can be sensitively detected and differentiated from other secondary plant compounds in a plant extract without pre-purification. Potentiometry and UV peak shape matching shows the applicability of this detector in HPLC.