Waters Atlantis Columns - APPLICATIONS NOTEBOOK

Significance of the Topic

Study Objectives and Overview

• The rational design and optimization of Atlantis™ dC18 stationary phase to balance retention of polar and nonpolar analytes under low-pH, high-aqueous conditions.
• The development of Atlantis™ HILIC Silica stationary phase to retain very polar compounds using high-organic reversed-phase solvents in a “reverse reversed-phase” mode.
• Comparative performance across hundreds of applications, troubleshooting guidance, and scale-up strategies from analytical to preparative separations.

Methodology and Instrumentation

• High stability at low pH and under 100% aqueous mobile phases for dC18.
• Robust polar retention in >85% acetonitrile for HILIC Silica.
• Complementary selectivity between reversed-phase and HILIC modes.

• Waters Alliance series HPLC/UHPLC systems for method development and scale-up.
• Mass spectrometry platforms (Quattro micro™, Quattro Premier™, Q-Tof micro™) in ESI and APCI modes.
• Detectors such as PDA, ELSD, electrochemical (ECD), and multiple reaction monitoring (MRM) for quantitation.
• SPE sample cleanup using Oasis® HLB, MCX, MAX, and µElution plates to reduce matrix suppression and eliminate evaporation/reconstitution steps.

Main Results and Discussion

• Retention of polar pesticides (acephate, methamidophos) in river water down to <200 ng/L via dC18 and SPE cleanup with 60–90% recovery.
• Direct HILIC analysis of quaternary ammonium compounds (acetylcholine, choline, deuterated internal standard) at femtogram levels on column.
• Robust isocratic and gradient separations of pharmaceuticals (acyclovir, amoxicillin, analgesics, β-blockers) with tailing factors close to unity and reproducible retention.
• Clear separation of catecholamines, organic acids, nucleosides, peptides, antibiotics, and antioxidant compounds across both chemistries.
• Enhanced MS sensitivity and reduced source contamination by minimizing column bleed and ion suppression.
• Scalable preparative isolation using Optimum Bed Density (OBD™) columns that mirror analytical selectivity at multigram loads.

Benefits and Practical Applications

• Use a single column for both polar and nonpolar analytes, reducing method development time and instrumentation cost.
• Avoid loss of polar analytes in 100% aqueous mobile phases without column “rewetting.”
• Improve MS signal and lower detection limits by eliminating sample evaporation and reconstitution steps in HILIC workflows.
• Maintain reproducible selectivity and retention across column batches through stringent QC testing.
• Scale up methods seamlessly from analytical to preparative dimensions for compound isolation.

Future Trends and Opportunities

• Next-generation stationary phases with tailored chemistries for zwitterionic, highly charged, or ultra-polar metabolites.
• Integrated LC systems combining dC18 and HILIC switching valves for fully automated complementary separations.
• Miniaturized and high-throughput formats (µLC, chip-based) for single-cell and biofluid analysis.
• Advanced ionization interfaces and high-resolution MS to further reduce matrix effects.
• Machine-learning algorithms for intelligent method scouting and predictive retention modeling across dual-mode columns.

Conclusion

References