At a glance
Reverse Phase Chromatography
ScopeHydrophobic
CAPEX$200k-$1.5M
Best forSmall molecule resolution
vs
Ion Exchange
ScopeCharge-based
CAPEX$150k-$1.5M
Best forCharge separation, polishing
Decision criteria
| Criterion | Reverse Phase Chromatography | Ion Exchange | Verdict |
|---|---|---|---|
| Separation principle | Small molecule resolution | Charge separation, polishing | Hydrophobicity vs charge |
| Throughput / scale | 50-500 L/hr | 100-2,000 L/hr | IEX higher |
| Capital cost | $200k-$1.5M | $150k-$1.5M | Similar |
| Operating cost | High (solvents, denaturation) | Low (aqueous) | IEX cheaper |
| Product purity ceiling | High resolution | High resolution at low cost | Equivalent for charged molecules |
Quick verdict
Proteins: IEX. Small molecules and peptides: RP often beats IEX on resolution.
Rule of thumb: Protein over 10 kDa: never RP. Small molecule with charge handle: IEX. Small molecule without: RP.
Frequently Asked Questions
When should I choose Reverse Phase Chromatography over Ion Exchange?
Use reverse-phase for small molecules, peptides, and antibiotics — high resolution, well-validated, but denatures proteins above ~10 kDa.
When should I choose Ion Exchange over Reverse Phase Chromatography?
Use IEX as the default for proteins, charged organic acids and amino acids — all-aqueous, gentle, cheap.
Can these two techniques be used together?
Yes — for peptides and small biologics, IEX as capture and RP as polishing is standard.
Which has lower OPEX at scale?
RP needs acetonitrile / TFA — expensive solvents and waste handling. IEX uses salts and water.
Read more on each technique
Try both in your flowsheet
Build a process with each option side by side and compare yield, purity, and cost.
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