Multivariate optimisation of a capillary electrophoretic method for the separation of glutenins. Application to quantitative analysis of the endosperm storage proteins in wheat

A capillary electrophoretic method has been designed to allow separation of glutenins with high resolution. Several factors, such as buffer composition, running voltage and capillary temperature were optimised using factorial design and response surface methodology. On the other hand, quantification of content of glutenins and gliadins of different wheat varieties were achieved for the first time using a glutenin extract of wheat gluten and a gliadin extract as external standards, respectively, and using the lys-tyr-lys tripeptide as internal standard. The optimised method and an early reported method for the gliadin separation were validated by evaluating linearity, sensitivity, detection and quantitation limits, repeatability and precision.