Use case. You need one LC–MS / MS platform method to cover a diverse metabolite panel that includes glucose, pyruvate, taurocholic acid, γ‑glutamylcysteine, glycochenodeoxycholate, glycerol‑3‑phosphate, spermidine, taurine, and S‑adenosyl‑L‑methionine (SAM).

Many of these analytes are highly polar / ionizable and are not well retained in traditional reversed phase (RP); the recommended approach is the Cogent Diamond Hydride™ column operated in Aqueous Normal Phase (ANP).

Why Diamond Hydride™ and ANP?

• ANP retention is strong for polar species (e.g., sugars, amino acid derivatives, bile salt conjugates, phosphorylated metabolites), enabling simultaneous analysis of compounds that would elute near void volume in RP. 

• The column tolerates volatile, MS‑friendly additives and can be tuned by the organic/water ratio, supporting discovery and targeted assays within the same platform.

Mobile‑Phase Systems & Additives

Because the panel spans multiple functional groups (neutral, zwitterionic, cationic polyamines, anionic phosphates/bile salts), no single additive is universally optimal. Recommended sequence for screening:

1. 10 mM ammonium acetate in both channels (A & B) → good general starting point; supports negative and positive ESI.

2. 0.1% formic acid in both channels → sharpens basic/cationic species (e.g., spermidine) and can improve symmetry; positive ESI oriented. 

3. pH “split” option: ammonium acetate in one channel and formic acid in the other to create a mild pH differential (effective for multiplex panels when selectivity is tight). 

4. Additional candidates to screen: ammonium formate (10 mM) or acetic acid (0.1%) when fine‑tuning ionization/retention. 

Tip for complex matrices: Include 50% isopropanol or 50% methanol in Solvent A to help continuously wash strongly adsorbed matrix components and extend column lifetime—particularly useful for biofluids or food extracts. 

Starter Gradient (ANP, LC–MS Compatible)

Column: Cogent Diamond Hydride™ (TYPE‑C Silica)
Solvent A: 50:50 DI water/methanol + 0.1% formic acid (v/v/v)
Solvent B: acetonitrile + 0.1% formic acid (v/v)

Notes by class (examples):

• Sugars (glucose), small acids (pyruvate), taurine, SAM: typically strong ANP retention; will elute as water increases—monitor in ESI± per ionization behavior. 

• Bile salt conjugates (taurocholic acid, glycochenodeoxycholate): amphipathic; often benefit from ammonium acetate for negative‑mode response and improved peak shape. 

• Phosphorylated species (glycerol‑3‑phosphate): frequently show improved retention in acetate/formate buffers and negative ESI. 

• Polyamines (spermidine): may sharpen with 0.1% FA (positive mode).

Injection & Sample Considerations

• Injection solvent: For ANP, keep the diluent high in organic (≥70% ACN) with a small water fraction matching the starting mobile phase; this minimizes band broadening/peak splitting for strongly retained polar species. (General ANP practice consistent with column guidance.) 

• Matrix management: Using 50% MeOH or 50% IPA in Solvent A (as above) plus a low‑%B wash segment helps desorb matrix between runs, maintaining reproducibility over long sequences. 

Troubleshooting Quick Wins

• Low retention of very polar targets: Increase initial %B (more ACN), or reduce early water content; consider 10 mM ammonium acetate and negative ESI for acids/phosphates. 

• Peak tailing for bases (e.g., spermidine): Switch to 0.1% FA system, or use the pH‑split configuration to stabilize ionization while preserving ANP retention. 

• Carryover / matrix buildup: Maintain (or lengthen) the low‑%B hold after the gradient to aggressively wash; ensure Solvent A contains 50% MeOH or IPA as recommended. 

Summary

For mixed‑polarity metabolite panels that include highly polar analytes, the Cogent Diamond Hydride™ in ANP with MS‑friendly additives offers a practical single‑method solution. Start with 10 mM ammonium acetate or 0.1% formic acid (and consider a mild pH split if needed), use a high‑organic start with a matrix‑wash hold, and include 50% MeOH/IPA in Solvent A to preserve performance over complex sample sets.