Infrared Spectroscopy for Water Analysis

Water is undoubtedly one our most precious resources and monitoring water quality is critical for a sustainable future. A wide range of natural and human activities pose threats to the quality of drinkable water around the globe.

Heavy pollution is creating new challenges for wastewater treatment facilities and a demand for new methods to accurately identify and quantitate pollutants. Regulatory bodies such as the United States EPA as well as the World Health Organization (WHO) and agencies within the European Union publish guidelines on maximum allowable contaminant concentrations in drinking water1. However, current methods for assessing water quality require multiple manual sample preparation steps that make real-time water analysis impractical.  

Can Infrared (IR) Spectroscopy be used for water analysis?

Until recently, mid-infrared was not considered an effective method for water analysis. This is largely due to strong absorption of water at 3314 cm-1 and 1638 cm-1 [2]. These water absorption peaks make Mid-IR light nearly impossible to pass through the sample.

Spectroscopy instruments, such as Fourier Transfer Infrared (FT-IR) and Raman, lack the spectral brightness and reliability to make direct measurements of aqueous samples.

Real-time, high sensitivity measurements can now be achieved with the use of high-spectral brightness quantum cascade lasers (QCLs). The high-power of the QCL source coupled with broad tuning enables high sensitivity through long path lengths with large dynamic range. The Culpeo® liquid analyzer is a robust analytical platform that can be used for quantitative analysis levels of organic and inorganic pollutants.

1 EPA. (2021, January 5). National Primary Drinking Water Regulations. US EPA.

2 De Bruyne, S. S. (2018). Applications of mid-infrared spectroscopy in the clinical laboratory setting . Critical reviews in clinical laboratory sciences, 55(1), 1-20. doi:

Culpeo® Liquid Analyzer

The Culpeo® Analyzer is a compact, intelligent spectrometer that uses the power of quantum cascade lasers to analyze and identify chemicals. It combines the latest high-speed, broadly tunable QCL technology with advanced, uncooled detection capability.

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