Polymeric wheat endosperm proteins, especially the high-molecular-weight
glutenin subunits (HMW-GS), are probably the most interesting protein
fraction giving the essential information about bread-making quality of wheat
flour. A relatively new method that shows a great potential for a fast,
reliable and automatable analysis of protein purity, sizing and
quantification is microfluidic or Lab-on-a-Chip (LoaC) capillary
electrophoresis. This work was aimed to explore the possibilities of
implementation of LoaC method to analysis of protein samples isolated from a
Serbian common wheat variety, emphasizing the steps that might bring
uncertainties and affect reproducibility of obtained glutenin subunits
quantitation results. A good resolution of protein bands in a molecular
weight range of 14.0 to 220.0 kDa was achieved. The reproducibility of HMW-GS
sizing and quantitation were good, with the average coefficient of variation
values of 1.2% and 12.2%. The ratio of HMW-GS to low-molecular-weight
glutenin subunits (LMW-GS) was about 20%. The investigation ruled out
influences of the extract solution addition and the buffer addition steps of
the applied method, as well as the individual chip influence on GS
quantitation results. However, there was statistically significant difference
between HMW-GS quantitation results of multi-step and one-step extraction
procedures applied prior to glutenin subunits extraction step.