Chapter 3 - HPLC columns and trends Flashcards
Column support
Spherical/irregular, porous particles used as column packing material.
Bonded phases
Stationary phase; support material modified with functional groups.
Packing material
A term that can refer to both the support or the bonded phase.
IBW
Instrumental bandwidth or system dispersion.
Hybrid phases
Support synthesized from both inorganic and organic materials.
SPP
Superficially porous particle.
Dwell volume
Volume measured from the point of the solvents mixing in the HPLC system to the head of the column.
Most common column length
150 mm
Most common inner diameter
4.6 mm
Most common particle size
3 μm C18
Most common flow rate
1 ml/min
Most common sample loading size
1 μg
Most common sample loading size
1 μg
Most common operating pressure
3000 psi or 200 bar
Common column lifetime
2000 injections
Void volume, sample capacity, and operating flow rate are proportional to
dc2
The limit of detection for minimum detectable mass is inversely proportional to
dc2
Longer columns have _______ plate counts and yield _______ resolution.
higher; better
Since plate numbers are additive, columns can be connected in series to produce
higher efficiency and resolution at the expense of analysis time and mass sensitivity.
Silica (SiO2) is the dominant support material because of its
mechanical strength, modifiable surface chemistry, and high efficiency.
Silica based bonded phases have a pH range of
2-8
Most chromatographic supports are porous to
provide a high surface area to maximize the interaction of solutes with the bonded phase.
Traditional problem areas of silica-based RPC columns.
- Batch to batch inconsistency
- Peak tailing of basic analytes
- Short column lifetime
- pH limitations
Silanol group formula
Si-OH
