QA/QC of tea using the Agilent Cary 630 ATR-FTIR analyzer

Importance of the topic

Tea ranks as the second most consumed beverage worldwide after water. Ensuring the authenticity, safety and consistent quality of tea products is critical for manufacturers, regulators and consumers. Rapid, non-destructive analytical techniques that require minimal sample preparation can streamline quality control (QC) and quality assurance (QA) workflows, reduce operational costs and enable on-site testing across the supply chain.

Objectives and Study Overview

This application note demonstrates the use of the Agilent Cary 630 ATR-FTIR analyzer for QA/QC of various commercial tea varieties. The study aims to establish a reliable spectral fingerprint database for white, green, oolong, black and blended teas, and to evaluate the performance of the instrument and software in rapidly identifying tea samples and ensuring batch consistency.

Methodology and Instrumentation

• Sample preparation: Commercial tea leaves were ground to a uniform powder.
• Instrumentation: Agilent Cary 630 ATR-FTIR analyzer equipped with a diamond ATR crystal and pressure clamp (slip clutch prevents overtightening).
• Spectral acquisition: 64 scans per sample at 4 cm⁻¹ resolution in under 30 seconds using Agilent MicroLab FTIR software.
• Data management: Spectra automatically stored in a reference database; software performs percentage similarity and pass/fail comparisons.

Main Results and Discussion

Spectra spanning 3800–2600 cm⁻¹ and 2000–600 cm⁻¹ contain characteristic absorption bands of key tea constituents: polyphenols (including catechins), caffeine, amino acids, lipids, carbohydrates, proteins and moisture. Duplicate analyses on different days yielded highly reproducible spectra. New samples were automatically matched to stored references by the MicroLab FTIR software, achieving accurate identification within seconds and enabling validity checks against preset similarity thresholds.

Benefits and Practical Applications

• Rapid, solvent-free analysis requires no sample extraction, delivering results in under a minute.
• Portability (~3 kg) allows deployment at receiving docks, production lines, QC laboratories or field sites.
• User-friendly software minimizes training needs while providing real-time pass/fail decisions or similarity scores.
• Versatile approach supports authentication of incoming tea batches, verification of stored inventory and final product consistency after blending.

Future Trends and Potential Applications

Combining ATR-FTIR data with multivariate chemometric models and machine learning algorithms could enhance classification and quantitation of tea constituents. Expansion into monitoring other food matrices, in-line process control and traceability systems may further strengthen QA/QC in the food and beverage industry. Miniaturized, handheld FTIR devices and cloud-based spectral libraries will support decentralized, real-time analytics.

Conclusion

The Agilent Cary 630 ATR-FTIR analyzer provides a rapid, robust and portable solution for comprehensive QA/QC of tea products. By generating distinct molecular fingerprints without solvents or complex preparation, it streamlines supply chain authentication, improves batch consistency and reduces analytical costs. The integrated MicroLab FTIR software facilitates easy database management and automated sample identification.

Reference

• Rodriguez-Saona LE, Allendorf ME. Use of FTIR for rapid authentication and detection of adulteration of food. Annual Review of Food Science and Technology. 2011;2:467–483.
• Budínová G, Vláčil D, Mestek O, Volka K. Application of infrared spectroscopy to the assessment of authenticity of tea. Talanta. 1998;47:255–260.