For most reversed-phase solid phase extraction applications using a silica-based SPE media, cartridges are initially conditioned using an organic solvent such as methanol, followed by rinsing with water or a buffer.
Peak shape issues at the apex of a peak are typically related to detector saturation. This symptom can be observed as flattening and/or noise at the peak apex.
The boiling point is the temperature where liquid has enough energy that molecules transferring into the vapor phase exert a pressure that is equal to the outside pressure. This allows molecules anywhere—not just the surface—to transfer to the gas phase.