Fluorescence spectroscopy as a tool for determining microbial quality in potable water applications

Area of Science:

• Environmental Science
• Analytical Chemistry
• Microbiology

Background:

• Previous studies utilized fluorescence spectroscopy for sewage detection in rivers.
• Bacterial contamination in water poses significant public health risks, especially in areas with inadequate sanitation.

Purpose of the Study:

• To evaluate a portable LED spectrophotometer for quantifying bacterial numbers in water samples.
• To establish correlations between fluorescence measurements and standard bacterial enumeration techniques.

Main Methods:

• A portable LED spectrophotometer was employed to measure fluorescence at specific excitation/emission wavelengths (280 nm/360 nm).
• Water samples (river water, sewage effluent) were analyzed using standard bacteria enumeration techniques with various diluents.
• Fluorescence data from uncultured samples were compared with bacterial counts from cultured samples.

Main Results:

• Strong correlations were observed between spectrophotometer readings and bacterial counts for total coliforms (R² = 0.78), E. coli (R² = 0.72), and heterotrophic bacteria (R² = 0.81).
• The fluorescence detection corresponded to tryptophan and indole fluorescence regions.

Conclusions:

• The portable LED spectrophotometer is a viable tool for rapidly establishing bacterial numbers in water.
• This technology can be applied for drinking water quality assessment in areas with poor sanitation and limited laboratory access.
• It offers a practical solution for monitoring faecal contamination in water supplies.