Table 1. The peak area ratios of 8-OHdG obtained in different mobile phase A additives conditions.

Mobile phase A additives	Peak area ratios
	MRM modea	Full scan modeb
0.1% CH3COOH	3.2	1.0
0.1% HCOOH	1.2	0.7
2 mM NH4HCO3	1.0	0.4
2 mM HCOONH4	0.8	0.4
2 mM HCOONH4/HCOOH, pH = 3.5	0.6	0.5
2 mM HCOONH4/NH4OH, pH = 9.5	0.7	0.5
2 mM CH3COONH4	0.9	0.5
2 mM CH3COONH4/CH3COOH, pH = 5.0	0.9	0.8
2 mM CH3COONH4/NH4OH, pH = 9.0	0.7	0.6

^aThe peak area ratios of 8-OHdG were obtained by other eight types of mobile phase vs mobile phase with NH₄HCO₃ as an additive.

^bThe peak area ratios were calculated as peak area of [8-OHdG + H]⁺/(peak area of [8-OHdG + Na]⁺ + peak area of [8-OHdG + K]⁺).