Hepes is a widely used buffer in biological studies. There is only one restriction in the use of this buffer, because it interferes with the Folin protein assay. In cell culture media, it is employed as a substitute for the bicarbonate buffer at a concentration of 25 mM or as a supplement to the bicarbonate buffer (concentration 10 - 15 mM). The addition of 20 mM HEPES to TBE buffer improves the migration behaviour of certain samples in the SSCP analysis (single-strand conformation polymorphism), with a higher resolution especially if small differences in the sequences between certain bands are wanted (5).