Trap Chemistry Reference
Choosing a trap starts with what the method needs to retain, remove or concentrate. The packing material comes first; then operating pressure, sample load and the available cartridge configuration determine the product choice. This reference explains the different chemistry names used across Optimize trap families.
From application to product
Method / workflow → Packing material → Operating pressure → Sample load & capacity → Product & part number
A familiar phase name is a useful starting point, but packing selectivity and method suitability must be checked before a particular product is selected. See Sample Concentration & Desalting for the complete selection path.
1. Start with the method and packing
The examples below help narrow the chemistry question without restricting an application to one hardware family.
Concentrate or desalt peptides
The Optimize Trapping Guide describes polymeric reversed-phase packing with C8-like retention for peptide concentration and salt removal. Current catalog labels worth comparing include Peptide Concentration & Desalting Trap, Peptide and Peptide ES-C18.
Concentrate or desalt proteins
The guide describes large-pore polymeric reversed-phase packing with C4-like retention. Product phase labels include Protein Concentration & Desalting Trap and Protein; verify the exact packing and conditions.
Concentrate or desalt small molecules
The guide describes a historical hydrophilic C18 silica (ODS-AQ) method. Current catalog phase labels also include Small Molecule, C18AQ and C18, but these are distinct identities, not established equivalents to that historical method.
Remove detergents
SDS and non-ionic detergent removal use different trapping approaches. Current application-specific names include Small Molecule SDS Removal Trap and NID (Non-Ionic Detergent) Removal Trap. Choose by the detergent and what must be retained.
Fractionate peptides / 2D LC
The documented tandem workflow uses an SCX (Strong Cation Exchange) Trap stage followed by a Peptide Concentration & Desalting Trap stage. The approved route for this complete workflow is OPTI-TRAP; generic SCX alone does not establish an equivalent route.
Other sample types: For oligonucleotides or unfamiliar matrices, first establish whether the target or the contaminant should bind. No standard oligonucleotide-to-cartridge configuration is established by the current guide. Ask Optimize about the packing.
2. Recognize application-specific packing names
The names in this section identify particular Optimize application packings. Keep them distinct when comparing other products with shorter or similar phase names.
Peptide Concentration & Desalting Trap
OPTI-TRAP application-specific packing. Historical guide: polymeric reversed-phase with C8-like retention. The comparison describes behavior, not a generic C8 identity.
Protein Concentration & Desalting Trap
OPTI-TRAP application-specific packing. Historical guide: polymeric reversed-phase with C4-like retention; distinct from a generic C4 or Protein phase.
SCX (Strong Cation Exchange) Trap
OPTI-TRAP application-specific identity used in the documented tandem peptide-fractionation workflow. It remains distinct from generic SCX offered elsewhere.
Small Molecule SDS Removal
Application-specific SDS-removal identity. The OPTI-TRAP product page names its option Small Molecule SDS Removal Trap; it is not generic Small Molecule, SAX or SCX.
Non-Ionic Detergent Removal
Application-specific non-ionic detergent-removal identity. The OPTI-TRAP product page names its option NID (Non-Ionic Detergent) Removal Trap; generic NID is a separate catalog label.
Useful distinction: A packing can have retention behavior similar to a familiar phase without being the same material. The relevant question is whether the particular packing supports the intended retention, wash and elution method.
3. Find the phase in a current trap family
These are cataloged phase labels, not a method-equivalence chart. The product selector determines which packing, phase and bed-volume combinations are available. Pressure is a system or configuration limit, not a guarantee for every listed packing.
OPTI-TRAP
Up to 1,500 psi • 0.5, 5 and 50 µL bed volumesListed phase names: SCX (Strong Cation Exchange) Trap; Peptide Concentration & Desalting Trap; Protein Concentration & Desalting Trap; NID (Non-Ionic Detergent) Removal Trap; Small Molecule SDS Removal Trap; Small Molecule (generic catalog option); Custom.View OPTI-TRAP product options
OPTI-LYNX Micro
Up to 6,000 psi • 4, 10, 20 and 40 µL bed volumesListed phase names: C18; C18AQ; C8; C4; SCX; SAX; DVB; DVB/SCX; NID; Peptide; Protein; Cyano; Small Molecule; Custom.View OPTI-LYNX Micro product options
Original OPTI-LYNX
Up to 6,000 psi • 4, 10, 20, 40 and 100 µL bed volumesListed phase names: C18; C18AQ; C8; C4; Phenyl; Cyano; SCX; SAX; DVB; DVB/SCX; Custom.Orderable legacy family: planned for discontinuation. No specific successor has been established.View Original OPTI-LYNX product options
EXP Trap
System rated to 20,000+ psi • 4, 10, 20, 40 and 100 µL standard bed volumesListed phase names: C18; C8; C4; HILIC; RP-Amide; Penta-HILIC; Phenyl-Hexyl; PFP; ES-CN; SAX; SCX; Protein; Peptide ES-C18; Custom.Pressure exception: 30.0 µm Protein configuration is limited to 6,000 psi.View EXP Trap product options
EXP2 Stem Trap
Nano-flow • 0.17, 0.33, 0.68, 1.5 and 2.6 µL bed volumesListed phase names: C18; C8; C4; HILIC; RP-Amide; Penta-HILIC; Phenyl-Hexyl; PFP; ES-CN; SAX; SCX; Peptide; Peptide ES-C18; Custom.Hardware seals to 8,700+ psi hand-tight or 20,000+ psi wrench-tight, subject to configuration limits. The 10.0 µm Peptide option is limited to 6,000 psi and is distinct from Peptide ES-C18.View EXP2 Stem Trap product options
Next screen: Once the packing meets your method, compare pressure, sample load and bed size. Bed volume is not the same as maximum sample volume or guaranteed analyte capacity. Use the Trap Compatibility & Holder Reference to confirm physical fit before choosing the part number.
Packing pH ranges and particle sizes
Use these packing characteristics as a reference after choosing the retention mechanism required by your method. Product-family columns are kept separate because similar phase labels do not necessarily mean the same packing or method suitability.
On a narrow screen, scroll within the table to compare all four trap families.
| Phase / packing label | pH range | OPTI-TRAP | OPTI-LYNX Micro | EXP2 Stem Trap | EXP Trap |
|---|---|---|---|---|---|
| C18 | 2–9 | — | 5 µm, 40 µm | 2.7 µm, 3 µm, 5 µm | 2.7 µm, 3 µm, 5 µm |
| SCX | 2–7 | 12 µm | 40 µm | 3 µm | 3 µm |
| C4 | 2–9 | — | 40 µm | 3 µm | 3 µm |
| C8 | 2–9 | — | 40 µm | 2.7 µm, 3 µm, 5 µm | 2.7 µm, 3 µm, 5 µm |
| SAX | 1–14 | — | 40 µm | 3 µm | 3 µm |
| ES-CN | 1–8 | — | — | 5 µm | 5 µm |
| HILIC | 1–8 | — | — | 2.7 µm, 3 µm, 5 µm | 2.7 µm, 3 µm, 5 µm |
| Penta-HILIC | 2–9 | — | — | 5 µm | 5 µm |
| Peptide ES-C18 | 1–8 | — | — | 2.7 µm | 2.7 µm |
| PFP | 2–8 | — | — | 5 µm | 5 µm |
| Phenyl-Hexyl | 2–9 | — | — | 2.7 µm, 3 µm, 5 µm | 2.7 µm, 3 µm, 5 µm |
| RP-Amide | 2–9 | — | — | 2.7 µm | 2.7 µm |
| NID | 2–7.5 | 12 µm | 12 µm | — | — |
| Peptide | 1–14 | 15–20 µm | 15–20 µm | — | — |
| Protein | 1–13 | 30 µm | 30 µm | — | — |
| Small Molecule | 2–7.5 | 12 µm | 12 µm | — | — |
| C18AQ | 2–9 | — | 40 µm | — | — |
| DVB | 2–13 | — | 30 µm | — | — |
| DVB/SCX | 2–13 | — | 60 µm | — | — |
| Custom Request custom packing |
Depends on packing | We can pack custom materials for your application. Tell us what packing material and trap configuration you need. | |||
How to read this reference: An em dash (—) means the source worksheet does not list a size for that family; it is not confirmation that a product is unavailable. Listed particle sizes do not establish every online-orderable phase-and-bed-volume combination. Verify the exact selected product configuration.
Technical limits: These pH ranges describe the named packing phases and do not override the compatibility or pressure limitations of the complete cartridge, holder, fittings, solvents, or method. For OPTI-TRAP, application-specific names such as Peptide Concentration & Desalting Trap, Protein Concentration & Desalting Trap, SCX (Strong Cation Exchange) Trap, and NID (Non-Ionic Detergent) Removal Trap must remain distinct from shorter phase labels in other families. The special EXP2 Stem Peptide and EXP Trap Protein options retain their published 6,000 psi configuration limits; their packing-material identification is under separate review.
4. Other similarly named phases
Peptide, Peptide ES-C18 and Peptide Concentration & Desalting Trap are separate names; likewise, Phenyl is distinct from Phenyl-Hexyl, and Cyano from ES-CN. Choose the exact packing and configuration documented for your method rather than treating a familiar-sounding label as an automatic replacement.
5. Historical and legacy terminology
Older Optimize publications remain useful for interpreting established methods and installed equipment. They are not, by themselves, current orderable product selections.
Small Molecule Concentration & Desalting Trap / ODS-AQ
Historical Optimize guide identity for small-molecule concentration and desalting. Its relationship to present-day generic Small Molecule or C18AQ options remains unverified.
ISRP Protein Removal Trap
A historical internal-surface reversed-phase protein-removal approach. Current availability and configuration have not been established; contact Optimize for present-day requirements.
EXP2 Nano Trap — discontinued
Legacy Nano literature lists C18, C8, C4, HILIC, Phenyl-Hexyl, PFP, ES-CN, Penta-HILIC, RP-Amide, Peptides ES-C18, SAX, SCX and Custom. EXP2 Nano is separate from current EXP2 Stem; no automatic interchangeability or replacement mapping is established.
Older OPTI-TRAP shorthand: historical listings may use Protein, Peptide, NID, SCX or Small Molecule without the complete application-specific names. Check the full current identity instead of silently treating the short and long labels as interchangeable.
From chemistry to an orderable product
Once the packing is identified, compare the actual pressure at the trap, flow, sample volume and mass, and packed-bed volume. Match the cartridge and holder using the Trap Compatibility & Holder Reference; then select the specific available packing, size and part number on the family product page. For pressure-limited configurations, use the lowest applicable hardware or packing limit.
Technical references and related applications
Need help matching a packing to your method? Tell us what you need to retain or remove, the sample type, your operating pressure and approximate sample load. Contact Optimize Technologies for help finding an appropriate packing and cartridge configuration.