|SOFT - TIAFT 1998||Poster Session 4||Friday October 9, 1998|
SCREENING FOR BARBITURATES BY CAPILLARY ELECTROPHORETIC TECHNIQUES|
Carolien M. Boone, Jan Piet Franke, Rokus A. De Zeeuw, Kees Ensing
University Centre for Pharmacy, Groningen Utrecht Institute of Drug Exploration, Ant. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
|In Systematic Toxicological Analysis (STA), powerful analytical methods are required to screen samples for the presence of toxicologically relevant substances. Capillary Electrophoresis (CE) is a modern separation technique which provides outstanding efficiency and fast analysis. Our objective was to evaluate and compare two CE techniques, namely Capillary Zone Electro-phoresis (CZE) and Micellar Electrokinetic Chromatography (MEKC) for STA. Initially, the methods were developed for a group of 25 barbiturates.
To enhance the reproducibility of the data and to create a standardisable identification parameter, migration times were converted to effective mobilities, which were then corrected with 5 external reference barbiturates. The data were used to evaluate the Identification Power (IP) of the methods by calculating the Mean List Length, Discriminating Power and Discriminating Number.
The CE methods were very promising for the application in STA, providing fast analyses (within 5 min for CZE and 10 min for MEKC). The two methods showed low correlation and hence complement each other. Also, especially the CZE method showed low correlation with existing RP-HPLC and GC for STA. Reproducibilities were significantly improved using corrected effective mobilities instead of migration times. Both methods had good IP's but combinations of methods such as CZE plus MEKC, HPLC or GC and MEKC plus GC provided considerably better IP's than the individual methods.
Finally, CZE and MEKC appeared to be very favourable in STA when analysing a group of structurally similar compounds. In further studies, the two methods (CZE and MEKC) will be evaluated for compounds from different chemical classes.