Amino acid analysis is one of the most important techniques in life science research. Amino acids are the basic building blocks of human proteins. Except for a few aromatic amino acids, their UV absorption is weak, and direct detection using a UV detector suffers from low sensitivity and high interference. In recent years, in the study of peptide drugs, Amino Acid Composition Analysis (AACA) has become an indispensable core step. For example, amino acid sequence verification: the biological activity of peptide drugs is highly dependent on their amino acid sequence and composition. By analyzing the amino acid composition, it is possible to verify whether the synthesized peptide is consistent with the target sequence, avoiding functional failure due to synthesis errors (such as amino acid deletion, substitution, or unexpected modification). Amino acid structure characterization: combined with mass spectrometry (MS) and chromatography (such as HPLC-CAD), amino acid composition analysis can assist in elucidating the molecular structure of complex peptides (such as those containing unnatural amino acids or post-translational modifications) to ensure they meet design requirements.
Using a Charged Aerosol Detector (CAD) coupled with high-performance liquid chromatography (HPLC) for direct non-derivatization detection of 17 amino acids demonstrates significant technical advantages. Compared to traditional methods, this technique eliminates the cumbersome derivatization steps, avoiding sensitivity fluctuations and quantitative deviations caused by unstable derivatization reagents, side reactions, or product diversity. The universal detection principle of the CAD detector provides high sensitivity response to non-volatile and weakly UV-absorbing compounds (such as amino acids) without relying on specific functional group modifications for accurate detection. This method simplifies the pretreatment process, shortens analysis time, and reduces the use of toxic reagents, aligning with green chemistry principles. Additionally, its wide dynamic range and good linearity support simultaneous quantitative analysis of multiple amino acids in complex matrices (such as biological fluids and food samples), making it especially suitable for rapid screening and quality control in high-throughput laboratories. Studies have confirmed that this method exhibits excellent performance in retention time stability, repeatability, and recovery rate, providing an efficient and reliable analytical solution for life sciences, clinical diagnostics, and the food industry.
This article uses reversed-phase HPLC combined with Instrumax's Charged Aerosol Detector (CAD) for direct determination of 17 amino acids. The method is fast, simple, accurate, highly sensitive, with good repeatability and excellent linearity, providing strong technical support for amino acid detection and peptide drug research. Click to view full article