Analysis of Proteinogenic Amino Acids under Na Type Condition

Significance of the Topic

A precise and efficient analysis of proteinogenic amino acids is essential across biochemical research, food quality control, clinical diagnostics and pharmaceutical development. Post-column OPA derivatization combined with ion-exchange chromatography provides high sensitivity and reproducible results, enabling detailed profiling of amino acid compositions in complex matrices such as protein hydrolysates.

Objectives and Study Overview

This application note demonstrates the separation and quantification of 20 proteinogenic amino acids, γ-aminobutyric acid (GABA) and ammonia under sodium-type ion-exchange conditions. The study aims to verify method performance using Shimadzu’s Nexera Post-Column Amino Acid Analysis System equipped with Shim-pack Amino-Na column and associated reagents, delivering reliable results for routine laboratory application.

Methodology and Instrumentation

• System: Nexera Post-Column Amino Acid Analysis System
• Analytical column: Shim-pack Amino-Na (100 mm × 6.0 mm I.D., 5 μm)
• Ammonia trap column: Shim-pack ISC-30/S0504Na (50 mm × 4.0 mm I.D.)
• Mobile phase: Pre-formulated Amino Acid Mobile Phase Kits (Na type) under gradient elution at 0.4–0.6 mL/min
• Reaction: Post-column derivatization with o-phthalaldehyde (OPA) reagent at 0.2 mL/min, 60 °C
• Column temperature: 60 °C; injection volume: 10 μL
• Detection: Fluorescence, excitation 350 nm, emission 450 nm

Main Results and Discussion

The method achieved baseline separation of all 20 common amino acids, GABA and ammonia within a single run. OPA derivatization provided strong fluorescence response, enabling detection limits in the low picomole range. The sodium-type mobile phase ensured stable retention times and reproducible peak areas, making the procedure suitable for high-throughput analysis. Key table and chromatogram data confirmed resolution of isomeric pairs such as leucine/isoleucine and separation of basic residues like lysine and arginine.

Benefits and Practical Applications of the Method

• High sensitivity and specificity through post-column OPA derivatization
• Robust separation of structurally similar amino acids
• Reproducible performance under mild gradient conditions
• Ready-to-use reagent kits simplify method setup and maintenance

These features make the workflow ideal for protein hydrolysate analysis, nutritional profiling and QA/QC in industrial laboratories.

Future Trends and Potential Applications

Advancements may include coupling ion-exchange separation with mass spectrometry for structural verification and quantitation at trace levels. Miniaturized columns and faster gradient programs could further increase sample throughput. Integration with automated sample preparation platforms and development of green chemistry reagents are expected to streamline routine amino acid analysis.

Conclusion

The Shimadzu Nexera Post-Column system utilizing Shim-pack Amino-Na column and OPA derivatization offers a reliable, sensitive and reproducible method for comprehensive amino acid profiling. Its ease of operation and consistent performance support diverse applications from research laboratories to industrial quality control.

References

• Application News L568A, Shimadzu Corporation, First Edition Dec. 2021