Synthetic peptides are a growing class of biological therapeutic drugs. Glucagon like peptide-1 (GLP-1) agonists are a class of synthetic peptides that mimic natural GLP-1 hormones and play an important role in metabolic regulation. They can promote insulin secretion and help with weight loss. Due to the susceptibility of GLP-1 molecules to multiple degradation pathways, evaluating the quality and stability of GLP-1 type therapeutic drugs is crucial to ensure their effectiveness.

At present, ultraviolet spectroscopy is commonly used to detect changes in peptide absorption spectra and monitor their stability [2]. This non-destructive testing technology brings significant advantages to the workflow: for example, precious samples remain intact after analysis and can continue to be used for complementary techniques such as liquid chromatography-mass spectrometry. In addition, UV visible spectroscopy detection is fast, easy to operate, and convenient for users with various skill levels and professional backgrounds to use.

However, when monitoring small changes in biomolecules caused by environmental factors such as oxidative stress (such as slight shifts in absorption peak positions or slight changes in intensity), traditional UV visible absorption spectroscopy data is often difficult to parse. In addition, when the spectrum of biomolecules contains multiple overlapping components, the difficulty in distinguishing spectral peaks is also a major challenge for analysis. Derivative spectroscopy technology can effectively distinguish overlapping peaks that are difficult to distinguish in traditional absorption spectra by enhancing the characteristics of fine light spectra, thus overcoming these limitations.

The Agilent 3500 multi cell UV visible spectrophotometer is equipped with a multi cell module, combined with second derivative measurement function, providing a powerful tool for biomolecule analysis. This instrument can measure multiple samples simultaneously under the same conditions, including standards, samples, and controls. The Agilent Cary UV Workstation software, which is used to control the Cary 3500 multi cell UV visible spectrophotometer, has built-in equation calculation function. After completing absorbance measurement, it can automatically generate second derivative spectra to minimize calculation errors and achieve efficient data processing.

This application brief demonstrates how to use the advanced features of the Cary 3500 multi cell UV visible spectrophotometer, combined with UV visible second derivative spectroscopy technology, to effectively improve the resolution of overlapping absorption peaks of peptides and aromatic amino acids.