NACE-DAD method
The current work investigated the CE method for the separation of β-agonists (i.e.,
clenbuterol, salbutamol and terbutaline). The use of factorial design for the development of CE
methods is powerful as it enables full control of the effects of the design variables. Results from the
factorial design experiment indicated that BGE ionic strength and the amount of acetonitrile were the
main affecting factors and their interactions were significant for the separation of β-agonists.
Although factorial experimental designs at two levels did not provide the optimal conditions, it
represented an understanding on the influence of several variables on the separation condition and
their trends and behavior. The final optimized NACE condition was obtained from a compromise of
the four key responses (resolution, plate, tailing factor and migration time). The optimized NACE
condition is summarized as the following.