The effects of different sodium hydroxide concentrations of carmine on peak area were investigated using the standard solution. The concentration of NaOH solution was studied at 0.01, 0.02, 0.03, 0.04, 0.05, and 0.06 M (Fig. 3). The peak area of carmine increased when NaOH concentration increased to 0.05 M. On the other hand, when the concentration of NaOH reached 0.06 M, the area of carmine significantly decreased by 16%, which might have