Lynn S. Adler and Rebecca E. Irwin. 2005. Ecological costs and benefits of defenses in nectar. Ecology 86:2968–2978.

Appendix A. Methods of HPLC-MS analysis of Gelsemium nectar samples.

Sample treatment:

Lyophylized sample + 500µL MeOH

HPLC:

Column: Merck LiChroCART RP-18 (5 µm, 250 mm × 4 mm)

Mobile phase: A: water + 0,1% formic acid and B: Acetonitril

Linear gradient from 30 to 100% acetonitril in 20 min

Flow rate: 1 mL/min

Detection wavelength DAD: 280 nm

Mass spectrometer:

Capillary voltage: 3.50 kV

Cone voltage: 45 V

Source temperature: 120°C

Flow rate: 100µL/min

Injection volume: 20µL

Sample amount was estimated from total ion current using a response factor.