Analysis of Free Amino Acids and Organic Acids

Significance of the Topic

The analysis of free amino acids and organic acids is fundamental in fields ranging from food quality control to clinical diagnostics. Accurate quantification of these low–molecular‐weight compounds informs metabolic profiling, nutritional monitoring, and biochemical research.

Objectives and Overview

This application note evaluates the performance of the Shim-pack GIS CN reversed-phase column for simultaneous separation and detection of representative amino acids (asparagine, aspartic acid) and organic acids (fumaric acid, maleic acid). The aim is to demonstrate resolution, sensitivity, and robustness under a simple isocratic protocol.

Methodology and Used Instrumentation

Methodology:

• Stationary Phase: Shim-pack GIS CN column (250 mm L × 4.6 mm I.D., 5 μm).
• Mobile Phase: 20 mM potassium dihydrogen phosphate buffer, adjusted to pH 4.0 with phosphoric acid.
• Flow Rate: 1.0 mL/min.
• Column Temperature: 40 °C.
• Detection: UV absorbance at 210 nm.
• Injection Volume: 5 μL.
• Analyte Concentrations: Asparagine and aspartic acid at 0.75 mg/mL; fumaric and maleic acids at 0.01 mg/mL.

Used Instrumentation:

• Shim-pack GIS CN reversed-phase column, P/N 227-30263-07.
• High-performance liquid chromatograph equipped with UV detector.

Main Results and Discussion

The four target analytes were baseline‐resolved in a single run under isocratic conditions. Both amino acids showed strong retention and sharp peaks, whereas the smaller organic acids eluted later with good peak symmetry. UV detection at 210 nm provided adequate sensitivity for all compounds at the tested concentrations.

Benefits and Practical Applications

Using the Shim-pack GIS CN column simplifies workflows by combining amino and organic acid analyses in one run. The method’s isocratic nature reduces equilibration time and solvent consumption. Laboratories in food science, clinical biochemistry, and environmental monitoring can adopt this approach for routine quantification and quality assurance.

Future Trends and Potential Applications

Advances may include coupling the GIS CN phase with mass spectrometric detection to extend sensitivity and selectivity for trace analytes. Miniaturized or high-throughput HPLC systems could leverage this chemistry for rapid screening. Integration with chemometric tools will enhance profiling of complex biological matrices.

Conclusion

The Shim-pack GIS CN column delivers reliable, high‐resolution separation of free amino acids and organic acids under straightforward isocratic conditions. Its compatibility with UV detection and ease of use make it a valuable tool for diverse analytical laboratories.