Initially, efforts were made to identify phenolic compounds by
separating on C18 column using HPLC. The extracts obtained from
each variety were separated into 5–8 peaks. Efforts to identify
these peaks by comparing the retention times of authentic standards
of phenolic acids, or spiking with known phenolic acids did
not help in identifying the peaks, as there were little variations
with retention times. This is mainly due to the complex nature of
polyphenols.