Measurement of Purine Content in Foods Using HPLC

Importance of the Topic

Purine compounds in food contribute significantly to uric acid levels in the human body. Imbalance between uric acid production and excretion can lead to hyperuricemia and gout. Additionally, recent research links low serum uric acid to mental health disorders. Accurate quantification of dietary purines is essential for nutritional management and disease prevention.

Objectives and Study Overview

This study demonstrates an HPLC method using the Shimadzu Prominence-i system to measure five purine bases (adenine, guanine, hypoxanthine, uric acid, xanthine) in food matrices. Analysis includes comparison of samples with and without enzymatic treatment to distinguish purine peaks from impurities, using tuna and broccoli as representative samples.

Instrumentation

• HPLC system: Shimadzu Prominence-i 3D
• Analytical column: Shodex Asahipak GS-320HQ (300 mm × 7.5 mm I.D., 6 μm)
• Detector: Photodiode array (PDA) at 260 nm
• Mobile phase: 150 mmol/L sodium phosphate buffer (pH 2.6)
• Enzymatic reagent: Xanthine oxidase for selective oxidation of purine bases

Methodology

Calibration curves for each purine base (0.1–20 mg/L) exhibited excellent linearity (R2 ≥ 0.9999). Samples were homogenized, freeze-dried, and hydrolyzed with 70% perchloric acid, then neutralized. Two pretreatment protocols were applied: A without enzyme followed by centrifugal filtration, and B with xanthine oxidase treatment followed by ultrafiltration. Chromatographic conditions: 0.6 mL/min flow, 35 °C column temperature, 10 μL injection volume.

Main Results and Discussion

All calibration curves showed strong linearity. Tuna contained 17.0 mg adenine, 12.4 mg guanine, and 175.6 mg hypoxanthine per 100 g (total 205.0 mg purines; uric acid equivalent 251.9 mg). Broccoli contained 25.9 mg adenine, 32.0 mg guanine, and 0.4 mg hypoxanthine per 100 g (total 58.3 mg; equivalent 68.3 mg). Enzymatic oxidation shifted peak positions, enabling clear identification of purine peaks by comparing treated and untreated chromatograms. PDA spectra confirmed purine identities and highlighted potential impurities.

Benefits and Practical Applications

This HPLC-PDA approach offers sensitive and accurate quantification of dietary purines in diverse food samples. It supports dietary management for hyperuricemia patients and quality control in food analysis laboratories.

Future Trends and Applications

Potential expansions include coupling with mass spectrometry for broader compound profiling, automation of sample pretreatment for high-throughput screening, and extension to additional food products. Real-time monitoring of purine content during food processing may also be explored.

Conclusion

The presented HPLC method with enzymatic differentiation and PDA detection provides reliable quantification of key purine bases in food matrices, demonstrating excellent sensitivity, linearity, and practical applicability for nutritional and clinical research.

References

• Kaneko K, Yamanobe T and Fujimori S, Biomed Chromatogr, 23, 858-864 (2009)