The HPLC and LC/MS were then used to analyze the extract. This
was repeated for dyes collected from other parts of the note
including the national emblem, Great Hall of the People, marble
pillar, text, and numbers (Fig. 1). Different ratios of methanol–
water–acetic acid-ion pairing reagent were studied for their effects
on the separation of the dye components in the red inks (Table 1).
The ratio most commonly used was 65:35:1.25:0.25.