Therefore, NH4OAc must be at a certain concentration to prevent background signal increase. Particularly with 80 mM NaBH4 and 1.6 M NaOH, the signals were the highest in the entire panel. However, the same panel showed the greatest sensitivity to the NaBH4 concentration. This is undesirable for the development of robust and reproducible technology for palladium quantification because NaBH4 in aqueous solution degrades even when stabilized by NaOH, and the actual NaBH4 concentration in reaction solutions may vary in day-to-day operations.