FTIR Analysis of Kidney Stone Using IRSpirit-TX

Importance of the Topic

Kidney stones (nephrolithiasis) are a common and painful disorder affecting patient quality of life and healthcare resources. Understanding stone composition at the molecular level provides insights into metabolic disorders, dietary influences, and recurrence risk. FTIR spectroscopy offers a rapid, non-destructive approach requiring minimal sample volume, enabling complementary analyses on the same specimen.

Objectives and Study Overview

This study demonstrates a streamlined workflow for identifying kidney stone components using attenuated total reflection (ATR) FTIR on the IRSpirit-TX system. By comparing sample spectra to the NICODOM IR Kidney Stones Library, accurate classification of stone minerals is achieved with minimal preparation.

Methodology and Instrumentation

Sample preparation and analysis conditions were as follows:

• Sample pulverization: Kidney stone fragments were mechanically ground with an agate mortar and pestle.
• ATR accessory: Single-reflection QATR-S with a zinc selenide (ZnSe) prism.
• Instrument: Shimadzu IRSpirit-TX FTIR spectrophotometer.
• Spectral parameters: 4 cm⁻¹ resolution, 45 accumulations, 4000–500 cm⁻¹ range, SqrTriangle apodization, DLATGS detector.
• Data processing: ATR correction applied to match transmission-based library spectra.

Key Results and Discussion

Library searching against 1668 reference spectra identified the sample as a mixture of carbonate apatite and struvite. The ATR-corrected spectrum exhibited characteristic phosphate and carbonate bands, confirming mixed mineralogenesis. This rapid identification highlights ATR-FTIR’s sensitivity to compositional differences.

Benefits and Practical Applications

ATR-FTIR analysis of kidney stones offers:

• Minimal sample preparation and rapid turnaround.
• High spectral quality without KBr pellet moisture issues.
• Preservation of sample for further techniques (SEM-EDX, TGA, DSC).
• Automated library matching via LabSolutions IR software for routine clinical or research use.

Future Trends and Potential Applications

Ongoing developments may include expanding spectral libraries to cover rarer stone types, integrating machine learning for automated classification, and miniaturizing portable ATR-FTIR for point-of-care diagnostics. Coupling FTIR data with patient metadata could drive personalized prevention strategies.

Conclusion

The combination of IRSpirit-TX and QATR-S streamlines kidney stone characterization, delivering fast, reliable compositional analysis. This method enhances understanding of nephrolithiasis etiology and supports both clinical decision-making and research.

Reference

• Placzyńska M, Milart J, Lubas A, Samotyjek J, Jurkiewicz B, Kalicki B, Jobs K. Association between the metabolic profile of urolithiasis in children with idiopathic hypercalciuria and the composition of the stone assessed by infrared spectroscopy. Pediatr Pol. 2023;98(4):271-277.