Welcome to AEL/LEA New Caledonia


What is THOË?

THOË is an autosampler that uses “passive samplers” type DGT ™ for the analysis of a range of analytes including metals and / or organic compounds dissolved in water. This device, designed by AEL / LEA and manufactured by TECHNICAP, allows the acquisition of time series data over preprogrammed time periods.

Aimed at revolutionizing the way that data is collected, THOË can be deployed for months and, at a time, provides a very cost-effective solution for continuous data collection (sets of serial data).


DGT: How does it work?

The DGT device once immersed accumulates the analytes passively on a resin gel. A number of factors control the amount of analyte accumulated, including temperature, the gel surface area exposed to the water, the analyte being accumulated, the total time that the device is immersed. This information allows users to accurately determine a “time averaged concentration” for each analyte. The analyzable parameters are those guaranteed by DGT Research, the manufacturer of passive samplers. These include:

  • LSNM-NP: 30 metals including Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn;
  • LSNP-NP: Phosphorus and oxyanions including As, Mo, Sb, Se, U, V, W;
  • LSNX-NP: Phosphates and more than 40 metals including Al, As, Cd, Co, Cu, Fe, Mn, Ni, Pb, Sb, Se, U, V, W, Zn;
  • LSNB-AP: Mercury and As (III);
  • LSNE-NP: Chrome-VI;
  • LSNC-AP: Polar organic compounds including antibiotics;
  • LSND-AG: Polar organic compounds including pesticides and certain pharmaceutical products.

Possible application areas


There are many potenisal uses for THOË, including:

  • Baseline surveys, impact studies, risk assessment of aquatic environments;
  • Regulatory environmental monitoring, including the marine environment, ports, estuaries, rivers and lakes or reservoirs;
  • Scientific programs invloving water chemical transfer studies.

The main characteristics of THOË

THOË is an autonomous automaton capable of continuously monitoring the concentrations of analytes in water up to a maximum immersion depth of 1000m, in its current version.

This configuration allows the sequential exposure of 12 DGT ™ whose individual sampling duration can be programmed to between a few hours and several weeks, depending on the environment to be monitored.

The sequences are programmed using a simple USB connection. A sensor continuously records the temperature required for concentration calculations.

The autonomy of THOË is at least 1 year.

All the components of THOË are made of inert materials: PEEK, PETP, PTFE and silicone for supports and parts in contact with DGT ™ and titanium for the axis of rotation and screws.

THOË is relatively small and lightweight, enabling it’s deployment from small vessels.