In normal phase HPLC, the mobile phase is relatively non-polar and the. stationary phase is relatively polar. Other more general types of HPLC include partition, adsorption, ion-exchange, size-exclusion, and thin-layer chromatography.
This particular guitar loop pedal is the Boss RC-30. Simply put, a loop pedal is a device used to capture sound clips which are then played over and over again (looped) and often overdubbed. While loop machines have been around for quite a while, the idea of a guitar loop pedal is relatively recent. Instead of the traditional box controlled by the hands of a DJ, loop pedals allow guitarists to control the looping and overdub features via foot switches.
A boost pedal is one of the most useful pedals one can have. Simply put, it boosts the signal that goes into it. It can perk up a low output guitar, or bring out more character or a different quality to your amp. This is especially useful for solos where overdrive or distortion would overwhelm the tone you've got.