To achieve accuracy/recovery, aliquots of samples were
diluted to final concentrations of 2.0, 6.0 and 10.0 gmL−1 of
standard ascorbic acid and 20.0 gmL−1 of nicotinic acid on the
mobile phase. To obtain intra- and inter-run precision, samples
were diluted to final concentration of ascorbic acid of 6.0, and
20.0gmL−1 of nicotinic acid [21,24–27].