Detection of contaminants in fluids with single-photon technique

The present invention refers to the realisation and use of a device for spectroscopic analysis in the ultraviolet and visible range.

How does it work?

The invention covered by the patent provides for using single-photon-sensitive photosensors with sub-nanosecond time resolution; in addition, a sphere is adopted instead of the typical cuvette as a sample holder for the spectrophotometer.

This new technique provides for using a pulsed source with a very small pulse width and for measuring the times the photons exit the sphere. The time a photon exits the sphere is directly proportional to the path travelled within the sphere itself, which depends on the number of reflections that have occurred within it. The path travelled by the light within the sphere is greater than the path travelled by the photons in the cuvettes, and this consequently increases detection sensitivity.

With this technique, it is possible to detect the presence of non-miscible substances (liquid/gas) in solution (liquid/gas), which are not otherwise detectable by current commercial spectrophotometers using quartz cuvettes. Finally, this technology also allows the non-distorted measurement of contaminants in turbid solutions.

Applications

• real-time or off-line verification of mains water for the presence of contaminants;
• monitoring of substances suspended in liquids and gaseous mixtures for industrial purposes;
• real-time or off-line analysis of air quality for health and civil purposes;
• in fundamental research it can provide a measure of the absorption length of different materials.

Advantages

• also substances floating or settling in the solution can be detected;
• use of technology for turbid solutions;
• increased sensitivity and decreased detectability threshold compared to commercial products.