Table 1. Results of the MS determined equilibrium association constants at three different concentrations for all combinations of the five drugs and the four duplexes studied.

Duplex	C0 (µM)	Hoechst 33258		Hoechst 33342		DAPI		Netropsin		Berenil
		K1 (M–1)	K2 (M–1)	K1 (M–1)	K2 (M–1)	K1 (M–1)	K2 (M–1)	K1 (M–1)	K2 (M–1)	K1 (M–1)	K2 (M–1)
AAAA	2	1.1 × 107	3.6 × 105	2.2 × 106	NDa	3.4 × 106	1.3 × 105	4.8 × 106	NDa	2.7 × 105	NQb
	4	2.1 × 107	8.8 × 105	1.1 × 107	NQb	2.7 × 106	8.6 × 104	2.5 × 106	NDa	1.7 × 105	3.6 × 104
	10	5.2 × 106	9.0 × 104	6.5 × 106	7.6 × 104	1.8 × 106	5.8 × 104	1.8 × 106	NDa	1.8 × 105	1.8 × 104
		1.2 × 107	4.4 × 105	6.6 × 106		2.6 × 106	4.1 × 104	3.0 × 106		2.1 × 105	2.7 × 104
ATAT	2	2.5 × 107	7.4 × 105	1.8 × 107	NDa	3.3 × 106	8.7 × 104	2.4 × 106	NDa	7.6 × 105	7.2 × 104
	4	4.2 × 107	8.9 × 105	1.4 × 107	2.4 × 105	2.4 × 106	7.5 × 104	1.2 × 106	NDa	6.8 × 105	4.3 × 104
	10	2.0 × 107	7.1 × 105	2.1 × 107	5.3 × 105	2.0 × 106	2.6 × 104	7.0 × 105	NDa	5.3 × 105	2.9 × 104
		2.9 × 107	7.8 × 105	1.8 × 107	3.8 × 105	2.6 × 106	6.3 × 104	1.4 × 106		6.6 × 105	4.8 × 104
AATT	2	8.7 × 107	4.6 × 104	7.0 × 107	NDa	5.4 × 106	NDa	4.4 × 106	NDa	3.7 × 105	NDa
	4	9.7 × 107	2.6 × 105	6.1 × 107	NDa	2.6 × 106	NDa	2.2 × 106	NDa	2.5 × 105	NDa
	10	8.0 × 107	2.0 × 105	4.8 × 107	NDa	1.4 × 106	NDa	1.3 × 106	NDa	2.6 × 105	3.1 × 104
		8.8 × 107	1.7 × 105	6.0 × 107		3.0 × 106		2.6 × 106		2.9 × 105
DK	2	3.7 × 107	NDa	9.7 × 107	NDa	4.8 × 106	NDa	4.8 × 106	NDa	3.4 × 105	NDa
	4	2.8 × 107	NDa	5.2 × 107	NDa	2.7 × 106	NDa	2.7 × 106	NDa	3.1 × 105	NDa
	10	3.7 × 107	NDa	6.9 × 107	NDa	1.3 × 106	NDa	1.0 × 106	NDa	2.6 × 105	NDa
		3.4 × 107		7.3 × 107		2.9 × 106		2.8 × 106		3.0 × 105

The mean values of the measurements at three concentrations are indicated in bold.

^aND, not detected (signal-to-noise ratio < 3).

^bNQ, not quantified (3 < signal-to-noise ratio < 10).