Rapid, Label-Free Protein & Peptide Quantification with A-TEEM™: Sub-ppm Limits of Quantification

Accurate protein and peptide quantification is essential for biopharmaceutical R&D and quality control, yet conventional methods can be affected by matrix effects, sample composition, and assay complexity. A-TEEM™ (Absorbance-Transmittance Excitation-Emission Matrix) spectroscopy provides a rapid, label-free alternative that combines UV-Vis absorbance and full fluorescence EEM data in a single measurement.

A-TEEM™ generates reliable quantitative results while simultaneously capturing rich molecular fingerprints that provide insight into sample composition and structure. By leveraging the full spectral signature rather than a single analytical signal, the technique offers greater confidence in protein and peptide analysis.

Scientists Are exploring A-TEEM™ for a number of reasons, including:

• Rapid, label-free protein and peptide quantification
• Enhanced sensitivity compared to UV-only approaches
• Reduced reliance on dye-based assays and complex workflows
• Simultaneous structural and compositional fingerprinting

To evaluate analytical performance, bovine serum albumin (BSA) was analyzed across a concentration range of 30 to 620 ppm using the Veloci™ Biopharma Analyzer. Results demonstrated excellent linearity, precision, and reproducibility. Fluorescence-based approaches achieved sub-ppm limits of quantification, with the multivariate A-TEEM model delivering the highest sensitivity and a reported LOQ of 0.70 ppm.

Unlike traditional UV absorbance methods, A-TEEM™ incorporates automatic inner filter effect correction through EzSpec software. This capability helps maintain fluorescence fingerprint integrity and minimizes the impact of absorbance interferences, supporting robust analysis even in complex sample matrices.

In recent published studies, A-TEEM has also been used for:

• Protein and peptide quantification across a wide concentration range
• Vaccine identity testing using fluorescence fingerprinting and chemometrics
• Co-formulated monoclonal antibody characterization and discrimination
• Simultaneous quantification and structural assessment from a single measurement

By combining quantification and molecular characterization in a single experiment, A-TEEM™ can reduce analytical burden, streamline workflows, and increase confidence in decision-making across research, development, and QC environments. Download the application note to learn how A-TEEM™ spectroscopy can simplify protein and peptide analysis while delivering deeper analytical insight.