Analysis of Tapwater Contaminants by FTIR and EDX Spectroscopy

Analysis of Tap Water Contaminants by FTIR and EDX Spectroscopy

Importance of the Topic

Contamination of tap water systems by fragments of plumbing materials and rubber seals can compromise water quality and pose health risks. Rapid identification of such contaminants is essential for timely corrective actions in both residential and industrial water supply systems.

Objectives and Study Overview

This study demonstrates a combined approach using Fourier-transform infrared (FTIR) spectroscopy and energy-dispersive X-ray (EDX) analysis to identify and trace the origin of two common tap water contaminants labeled A and B. Samples were collected from a shower head filter and a tap outlet during routine maintenance.

Methodology and Instrumentation

Samples were analyzed by attenuated total reflection FTIR (ATR-FTIR) for polymer identification and by EDX spectroscopy for elemental composition. A custom tap water contaminants library containing infrared spectra and EDX profiles was used for rapid spectral matching.

• FTIR Instrument: IRAffinity-1S with MIRacle10 Ge ATR prism; resolution 4 cm^–1; 40 scans; Happ–Genzel apodization; DLATGS detector.
• EDX Instrument: EDX-8000 with Rh target; 15 kV for light elements (C–Sc, S); 50 kV for heavy elements (Ti–U); vacuum mode; beam diameter 1 mm (A) / 3 mm (B); 100 s/ch integration; polypropylene support film.

Key Results and Discussion

Contaminant A: A black 1 mm fragment observed inside a shower head was identified by ATR-FTIR as ethylene-propylene diene rubber (EPDM) containing talc and kaolin additives. EDX analysis confirmed a polymer matrix (C₅H₁₀, ~97.6%) with minor Cl, Si, Al, Ca and trace metals (Cu, Fe, Zn, Mn, Br). Comparative FTIR of a rubber gasket part established the fragment’s origin as a degraded gasket.

Contaminant B: A white ~2 mm particle trapped at a tap outlet matched vinyl chloride-vinyl acetate copolymer in the ATR-FTIR library. EDX quantification showed a balance of vinyl acetate (C₄H₆O₂, ~39.4%) and vinyl chloride (C₂H₃Cl, ~56.4%), with minor metals (Si, Ni, Al, Zn, Fe, Cu, Ca, Cr, Pb). It was attributed to flaking of a seal material at a pipe connection.

Benefits and Practical Applications

The combined FTIR-EDX workflow enables rapid, non-destructive identification of polymeric and inorganic constituents in waterborne debris. This approach supports quality control in plumbing maintenance, helps pinpoint failure points in water fittings, and informs material selection to reduce future contamination.

Future Trends and Potential Applications

• Integration of automated spectral-search algorithms and expanded contaminant libraries for faster on-site diagnostics.
• Coupling with microscopy for morphological correlation and particle distribution mapping.
• Development of in-line sensors using miniaturized ATR probes for continuous monitoring of polymeric particulates in water systems.

Conclusion

The study highlights the effectiveness of ATR-FTIR combined with EDX for comprehensive analysis of tap water contaminants. By identifying material composition and tracing sources, this methodology facilitates swift countermeasures and enhances water supply safety.

References

1. Shimadzu Application News No. X255