The LEDIF Technology

Ecosen Solutions licenses a proprietary technology, dubbed ‘LEDIF’ (for LED-Induced Fluorescence) [二极管] developed by Ng et al. (2011) at the Singapore-MIT Alliance for Research and Technology Centre (新加坡麻省理工学院科研中心). The development was started in 2009 and has been successfully test-bedded for observing both spatial pattern and temporal trend of water quality in the field. 

The LEDIF pioneers the theme of ‘bringing lab to water’ with an automated standalone tri-optical sensing technology utilizing both multi-excitation and broadband sources to enable ‘lab-like’ water quality (chemistry, biological pigments, and physical) assessment to be performed in-situ to monitor water resources in real-time. 

The LEDIF technology uses a combined optical technology to identify and quantify contaminants and natural substances in water. This combined optical technology includes:

(a) Fluorescence – Emission of light by a substance that has absorbed light or other electromagnetic radiation

(b) Absorbance – Quantitative measure expressed as a logarithmic ratio between the radiation falling upon a material and the radiation transmitted through a material

(c) Scattering – Irregular dispersal of waves or particles

The LEDIF runs on a custom software that allows the operator to modify the sensor function or write operation script for a specific mission in the field. 

A Holistic Solutions

The LEDIF is compatible with multiple platforms (e.g. mobile platform, fixed platform, and portable mode of sensing) to achieve both 3-D water quality mapping and long-term continuous monitoring. With dimensions of 20(L)x15(W)x20(H) cm, it can be packaged inside a compact enclosure and mounted at a fixed location or platform (such as buoy) or placed submerged underwater for long-term monitoring, having 3G/4G real-time data communication capability, and allowing users to automate defined tasks based on operation needs and literally empowering them with an automated optical laboratory in the water. Like a “lab-on-a-chip”, when put on an Autonomous Underwater Vehicle (AUV), the LEDIF is a powerful “lab-on-AUV” that would go a long way in reinforcing efforts in safeguarding water resources while potentially improving the efficiency and accuracy of monitoring water quality. These coverage are important in helping to ensure that waters resources are clean from industrial pollution, oil spills and harmful algae growth. 

Most high precision organic matter detection procedures involve laboratory analysis of water samples, which would probably be time-consuming and costly. Grab water samples at specific spots may also fail to adequately capture the spatiotemporal variability, which may hold the key to understanding the biogeochemical processes in water bodies. In recent years, in-situ water quality instruments installed on water bodies have helped to provide continuous, real-time data, but are typically limited in spatial coverage due to their fixed locations. Commercially available in-situ sensing probes are usually limited to physical water properties or target a specific chemical. 

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