INDUSTRIAL APPLICATIONS OF CAPILLARY ZONE ELECTROPHORESIS MASS-SPECTROMETRY

Capillary zone electrophoresis was coupled on-line via a tricoaxial sheath flow interface with a benchtop quadrupole mass spectrometer (CZE-MS) equipped with a (pneumatically assisted) electrospray ionization source. Experimental parameters were optimized for operation in the negative-ion scan mode. The system was applied to the fingerprinting of an alkylsulphate detergent, to the identification of an impurity in a chloramine-T disinfectant, to the characterization of a complex polyethoxylated alkylphosphate emulgator, to the analysis of phenoxy acid herbicides and to the impurity profiling of MCPP. The optimized system was found to fully maintain the CZE separation performance, showing up to I million theoretical plates for the low-molecular-mass analytes studied. The sensitivity in the full-scan mode was typically in the picogram range and sufficient for the separation and identification of minor impurities in these industrial chemicals, down to the 0.1% level. In addition, the feasibility of on-column transient isotachophoresis (ITP-CZE-MS) under high electroosmotic flow conditions has been demonstrated for sample preconcentration and subsequent identification of trace impurities.