Reverse-Phase Chromatography
Definition
Liquid chromatography with a non-polar stationary phase (most commonly octadecyl-bonded silica, called C18) and a polar mobile phase (water mixed with methanol or acetonitrile). The most common mode for small-molecule drug analysis because most analytes have enough hydrophobicity to retain on C18 and the aqueous mobile phase is cheap and LC-MS friendly.
Related terms
- Densitometric Scanning
- The HPTLC quantitation step. After the developed plate dries, a Camag TLC Scanner 4 sweeps a narrow slit of UV or visible...
- Diode Array Detector (DAD)
- A UV-Vis detector that records the full 190 to 800 nm absorbance spectrum of every peak as it elutes, instead of a...
- Isocratic vs Gradient Elution
- Isocratic means the mobile-phase composition stays constant through the run; simple, reproducible, but limited resolving power for wide-polarity mixtures. Gradient means the...
- Method Validation Parameters
- The numbers a forensic method must hit before it is considered fit for routine use: linearity R² > 0.999 over the working...
- Sub-2 µM Particle Column
- A UHPLC column packed with 1.6 to 1.8 µm silica particles instead of the conventional 5 µm. Smaller particles give sharper peaks...
Explained in
- HPLC, UHPLC and HPTLC for Forensic AnalysisLiquid chromatography with a non-polar stationary phase (most commonly octadecyl-bonded silica, called C18) and a polar mobile phase (water mixed with methanol...