Figure 3.

Ascorbic acid_(aq) (50 µM) analyzed immediately after preparation (A) was subjected to 24 h of aging (B–E), stored in the refrigerator and protected from light (B,C) in plastic (B) and glass containers (C) or stored in daylight at room temperature (D,E) in plastic (D) and glass containers (E). The peak areas corresponding to ascorbic acid (t_R 3.1 min, 254 nm) in aged solutions were compared to the peak area of ascorbic acid in the fresh solution. The intermediate precision of the method was 3% (n = 6).