INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Detection of organic ionics by Ion Selective Electrodes used as an HPLC detector: applications to alkaloids in plant extracts
M.R. FERNÁNDEZ; DEVIN DAEMS; JOSEPH EVERAERT; GUY VAN CAMP; DELIA L. BERNIK ; LUC NAGELS
Congreso; VI Congreso Argentino de Química Analítica; 2011
Asociación Argentina de Químicos Analíticos
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. Several conditions such as temperature of the detection system, coating and eluent composition were varied and their effect on the response times was compared. 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 2.154±0.055 and 1.191±0.033 seconds respectively. 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 was confirmed in several chromatograms, with UV detection for comparison. 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.