A CE with contactless conductivity detection methodology using a novel background electrolyte for the separation and determination of 17 metal cations (Cs+, Rb+, K+, Ca2+, Na+, Mg2+, Mn2+, Sr2+, Li+, Ba2+, Fe2+, Pb2+, Cd2+, Zn2+, Co2+, Cu2+ and Ni2+) and ammonium has been investigated. The buffer, based on lactic acid and β-alanine, was experimentally compared with other two commonly used electrolytes, showing important improvements, such as shorter analysis times (<11 min), better electrophoretic resolutions and higher detectabilities for certain analytes, such as Fe2+ and Pb2+. The inclusion of other additives such as 18-Crown-6 and α-hydroxyisobutyric acid was studied in order to obtain the best separation of the analytes of interest. The optimised method was applied to the analysis of 11 water-based pen inks and the determination of their metal composition. The methodology was demonstrated for the comparison and differentiation of pen inks.
- Capillary electrophoresis
- Contactless conductivity detection
- Pen inks