Highly sensitive UviLux Tryptophan fluorometer for real time detection of Tryptophan-like fluorescence (TLF), an indicator of bacterial contamination.

• Sensitive beyond ppb level
• Ideal tool for detecting sewage contamination

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Highly sensitive UviLux sensor for the detection of Tryptophan-like fluorescence


UviLux Tryptophan

Building upon years of research into the measurement of water quality using UV fluorometers, the UviLux Tryptophan is a highly sensitive, robust sensor designed for detecting and monitoring tryptophan in natural and process waters, giving an indication of bacterial contamination and overall water quality. Sensitive beyond ppb level, the UviLux Tryptophan fluorometer is an ideal tool for detecting sewage contamination.

Features & Applications

Key features

  • In-situ, real time monitoring of Tryptophan
  • Highly sensitive readings to 0.03 ppb
  • Couple with FDOM sensor to remove environmental interference
  • Easy to integrate with monitoring platforms and systems, or combine with Hawk for on the spot readings and logging
  • Depth rated to 1000m
  • Excellent turbidity rejection and high ambient light rejection
  • Service and support from dedicated technical team


  • Real time monitoring of sewage contamination in rivers and lakes
  • Bacterial contamination monitoring in groundwater
  • Assessment of overall water quality in catchments and natural waters
  • In situ bacterial contamination monitoring for shellfish aquaculture
  • Detection of bacterial contamination in process waters



UviLux Tryptophan sensor technical specification

Parameters Tryptophan
Sensitivity (QSU) 0.01
Calibrated range (QSU) 600
Example compound:sensitivity range (ppb) Tryptophan: 0.02 – 1200
BOD: 0.001 – 50 mg/L



Size Ø 70 mm x 149 mm
Weight in air 800 g in air / 150 g in water
Pressure housing Acetal C
Operating temperature -2 °C to + 40 °C
Storage temperature -40 °C to + 70 °C
Depth rating 1000 m
Connector Impulse MCBH6MP


Input voltage 9 – 36 V
Power requirements < 1 Watt @ 12 V

The sensitivity and calibrated range of each UviLux Tryptophan sensor has been standardised by cross-correlating each calibration solution against a certified reference standard of quinine sulphate using a bench-top spectrofluorometer.  Fluorescence is reported in Quinine Sulphate Units (QSU), where 1 QSU is equivalent to the fluorescence intensity recorded from 1 ppb quinine sulphate at an excitation wavelength of 347.5 nm and an emission wavelength of 450 nm. Factors are provided for selected compounds to convert the fluorescence output from QSU to ppb of the compound of interest


What is tryptophan?

tryptoLaboratory studies have clearly identified that TLF is produced by all bacteria tested, both laboratory and environmental freshwater derived; tryptophan is an essential amino acid produced by all living things. While this work has demonstrated very strong significant correlations between single species enumeration and TLF intensity, the omnipresence of TLF prevents it from being applied as a species-specific enumerator, for example as an E. coli counter. This is particularly problematic in complex surface waters where the microbial communities are diverse and complex, further complicated by optical interferences such as absorbance and turbidity.

Recently, the scientific literature has been moving away from the comparison of TLF to current water quality monitoring parameters and has focussed on exploring the benefit of this phenomenon as an informative parameter in its own right. This has been aided by the understanding that correction for optical inferences, such as turbidity and absorbance, can improve the robustness of the data generated. Informed by the scientific research, Tryptophan fluorometry sensors have been developed by Chelsea Technologies, reporting semi-quantitative corrected data. This allows for the comparison of different water bodies and sensors, enhancing the usefulness and robusticity of the data obtained.

Do I need to measure FDOM too?

In practice, Chelsea recommends combining the UviLux Tryptophan with the UviLux FDOM, to allow differentiation between the Tryptophan signal and the FDOM signal. The Tryptophan and FDOM signals do overlap, and the use of multiple sensors will give more differentiated datapoints.

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UviLux tryptophan sensor
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