Instrument precision was checked from six consecutive injections
of AA extracts from fruit juice and pharmaceutical preparation.
In the case of fruit juice, the intra-day (the daily) and interday
(day-to-day) RSDs obtained using HPLC were 2.2% and 2.4%,
respectively, whereas with UPLC – 1.7% and 1.9%, respectively.
For vitamin C tablets, the intra- and inter-day RSDs obtained using
HPLC were 0.4% and 0.5%, respectively; with UPLC system – 0.1%
and 0.3%, respectively (Table 1). Precision of AA determination in
pharmaceutical preparation using both methods was higher than
obtained for fruit juice. It is probably the effect of less complex
matrix of tablet than fruit juice.