Table 4.

Results of the repeatability test.

Ionization Mode	ESI+		ESI–
Additive	AA	AF	AA	AF
ND** peaks	14	7	11	11
Median peak area	692,901	1,036,833	663,922	2,994,235
Median area RSD*	29 max–min 49–8	10 max–min 53–2.8	17 max–min 90–6	8.7 max–min 45–5
Mean RT shift	11 s	10 s	16 s	9 s

*Relative Standard Deviation. **Not Detected.