For vitamin C tablets, inter- and intra-day precisions were 0.4% and 0.5%, respectively (HPLC), and 0.5%
and 0.3%, respectively (UPLC). Both methods were sensitive: LOD was 0.049 µg/mL for HPLC and 0.024
µg/mL for UPLC while LOQs were 0.149 and 0.073 µg /mL for HPLC and UPLC, respectively.