. Author manuscript; available in PMC: 2010 Apr 27.

Published in final edited form as: Magn Reson Med. 2006 Apr;55(4):836–847. doi: 10.1002/mrm.20818

Table 1.

Exchange Constants for the Various pH's for PLL and the G5 PAMAM Dendrimer Obtained from Linewidth, WEX, QUEST, and QUESP

pH	x_CA (×10³) exp.	LW k_sw (Hz)	WEX k_sw^a (Hz)	QUEST k_sw^a (Hz)		QUESP k_sw^a (Hz)

				Numerical	Analytical	Numerical^c	Analytical
G5 PAMAM
8.1	1.368	580	—	521 ± 24	454 ± 13	550 + 200/−150	436 + 268/−131
7.6	1.307	382	305 + 98/−73	415 + 85/−104	316 + 54/−41	350 ± 50	300 + 73/−54
7.0	1.488	165	202 + 59/−48	161 ± 17	155 ± 17	175 ± 25	151 ± 26
6.7	1.456	115	128 + 37/−31	153 ± 15	133 ± 15	150 ± 25	132 ± 20
6.3	1.634	90	83 ± 13	78 ± 6	74 ± 6	75 ± 25	64 ± 11
5.6	1.346	27	39 ± 4	45 ± 3	41 ± 2	37 ± 12.5	37 ± 3
PLL
7.9	0.656	1211	—	1257 + 500/−400	782 ± 47	1250 ± 550	788 + 482/−378
7.7	0.579	639	—	660 + 143/−100	552 ± 17	650 ± 150	534 + 186/−124
7.3	0.674	398	404 + 153/−106	410 ± 70	379 ± 14	450 ± 150	379 + 98/−77
6.7^b	1.044	133	122 ± 15	151 ± 24	140 ± 8	125 ± 50	121 ± 11
6.5	1.035	71	89 ± 10	81 ± 10	83 ± 7	75 ± 25	79 ± 6
6.0	0.907	39	48 ± 1	49.8 ± 4	52 ± 3	50 ± 12.5	45 ± 8

Errors were obtained using the F statistic and the 95% confidence limits.

PLL 30 kDa.

Fit using Eqs. [10–15] to a grid of solutions every 25 Hz.