Amino Acid Analysis

Concise Separation Columns for Amino Acid Analysis

  • Robust polymeric resin stable across the full pH range of 0 to 14
  • High efficiency and strong resolution for complex amino acid mixtures
  • Excellent lot-to-lot and column-to-column reproducibility
  • Available in Li+ form for physiological samples and Na+ form for protein hydrolysates
  • Optimized for post-column derivatization detection workflows

Concise Separations amino acid columns are engineered specifically for ion-exchange chromatography (IEC), the gold-standard technique for amino acid analysis due to its unmatched reproducibility. IEC delivers stable retention times and accurate quantitation regardless of sample matrix, making it ideal for clinical diagnostics, nutritional research, protein hydrolysate analysis, and quality control applications.

Amino acids naturally exist as zwitterions. Under low-pH conditions, they carry a net positive charge and bind strongly to negatively charged ion-exchange sites on the polymeric resin, while most matrix components elute in the void volume. Selective elution is achieved by gradually increasing pH and salt concentration, causing amino acids to dissociate from the stationary phase in a highly predictable manner.

The elution order generally follows the amino acids’ isoelectric points—acidic species elute first, followed by neutral and basic. Because the separation and subsequent post-column derivatization occur free from interfering contaminants, ion-exchange methods using Concise Separations columns consistently produce highly reproducible chromatograms suitable for precise quantitative analysis.

PHASE CROSS-LINKAGE IONIC FORM PARTICLE SIZE (µm) KEY SAMPLES COMMENTS
AMINOsep AA-911 8 Sodium 9 Designed for complicated samples from protein hydrolysates. Increased polymer bed yields better resolving power Popular column – higher capacity than Beckman columns
AMINOsep AA-511 10 Sodium 5 Designed for faster analysis than the AA-911 while still providing high resolution Most popular amino acid column
Lithium Amino Acid
(6300 & 7300 systems)		 10 Lithium 6 Designed for use with Beckman Coulter® 6300 and 7300 Amino Acid Analyzers using Beckman or Pickering lithium buffer systems Ideal for physiological amino acid analysis
Sodium Amino Acid
(6300 & 7300 systems)		 10 Sodium 5 Designed for use with Beckman Coulter® 6300 and 7300 Amino Acid Analyzers using Beckman or Pickering sodium buffer systems Ideally suited for routine hydrolysate analysis. Extremely rugged polymer
Sodium Amino Acid
(for System Gold)		 10 Sodium 5 Designed for use with the Beckman Coulter® System Gold Amino Acid Analyzer Ideal for separation of hydrolysate amino acids
DESCRIPTION SIZE AMINOsep AA-911 AMINOsep AA-511 LITHIUM AMINO ACID
(6300/7300)		 SODIUM AMINO ACID
(6300/7300)		 SODIUM AMINO ACID
(SYSTEM GOLD)
Column 4.6 x 250 mm AAA-99-8553 – – – –
Column (Waters) 4.6 x 250 mm AAA-99-8553W – – – –
Column 4.6 x 150 mm – AAA-99-7554 – – –
Column 4.6 x 120 mm – AAA-99-6554 – – –
Column 4.0 x 200 mm – – – – AAA-99-6310
Column 4.0 x 100 mm – – AAA-99-6311 – –
Guard Kit (1 holder, 2/pk cartridges)   AAA-99-2353 AAA-99-2354 AAA-99-2311 AAA-99-2312 AAA-99-2312
Guard Cartridges (2/pk)   AAA-99-1353 AAA-99-1354 AAA-99-1311 AAA-99-1312 AAA-99-1312
Key Definitions â–¸
Ion-Exchange Chromatography (IEC)
A separation technique in which charged analytes interact with oppositely charged sites on a stationary phase. IEC is the gold standard for amino acid analysis due to its high reproducibility and matrix independence.
Zwitterion
A molecule with both positive and negative charges. Amino acids behave as zwitterions, carrying a net positive charge at low pH, allowing them to bind strongly to negatively charged ion-exchange sites.
Isoelectric Point (pI)
The pH at which an amino acid carries no net charge. During IEC, amino acids elute in an order generally correlated with their isoelectric points—acidic first, then neutral, then basic.
Post-Column Derivatization
A detection technique where amino acids react with a colorimetric or fluorometric reagent after elution, producing highly sensitive and quantifiable signals for accurate amino acid profiling.
Matrix Insensitivity
The ability of ion-exchange amino acid methods to deliver consistent retention and quantitation regardless of sample matrix, enabling reproducible comparisons across patients, batches, and hydrolysate preparations.
Frequently Asked Questions â–¸

Why is ion-exchange chromatography preferred for amino acid analysis?

IEC provides highly stable retention times and quantification, regardless of the sample matrix. This consistency is essential for clinical testing, nutritional studies, and protein hydrolysate analysis where reproducibility is critical.

What is the difference between the Li+ and Na+ column formats?

Li+ columns are ideal for physiological amino acid analysis, while Na+ columns are optimized for protein hydrolysate samples. Each ion form provides different selectivity to match the sample type.

How does post-column derivatization improve amino acid detection?

After separation, amino acids react with a sensitive chromogenic or fluorogenic reagent, producing highly detectable signals and ensuring accurate quantitation even at low concentrations.