In order to investigate the individual and inhomogenous cellular response, e.g. 
to external stimuli, single cell analysis is mandatory and may provide new 
cognitions in proteomics as well as in other fields of systems biology in the 
future. Here, we report on novel chip architectures for single cell analysis 
based on full body quartz glass microfluidic chips (QG chips) that extend our 
previous studies in polydimethylsiloxane (PDMS) chips, and enhance the detection 
sensitivity of native UV laser-induced fluorescence (UV-LIF) detection. 
Detection of a 10nM tryptophan solution with an S/N ratio of 11.9, which gives a 
theoretical limit of detection of 2.5 nM (with S/N=3), was possible. With these 
optimizations the three proteins alpha-chymotrypsinogen A, ovalbumin and 
catalase each at a concentration of 100 microg/mL (equal to 4 microM, 0.4 microM 
and 2.2 microM) were injected electrokinetically and could be separated with 
nearly baseline resolution. Furthermore, fluorescence spectra (excitation 
wavelength, lambda(ex) = 266 nm) clearly demonstrate the favourable properties 
like the very high UV transparency and the nearly vanishing background 
fluorescence of the QG chips as compared to PDMS chips and to PDMS quartz window 
(PQW) chips. Finally we exploit the improved sensitivity for single cell 
electropherograms of Spodoptera frugiperda (Sf9) insect cells.