An exploiting of cost-effective direct current conductivity detector in gas diffusion flow injection system

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• Flow analysis systems require sensitive and cost-effective detection methods.
• Dissolved inorganic carbon (DIC) is a key parameter in water quality assessment.

Purpose of the Study:

• To develop and validate a homemade, cost-effective direct current (DC) conductivity detector for flow analysis.
• To apply the developed detector for the determination of dissolved inorganic carbon (DIC) in water samples.

Main Methods:

• Fabrication of a homemade DC conductivity detector.
• Coupling the detector with a gas diffusion flow injection system.
• Conversion of DIC to CO2, followed by membrane diffusion and conductivity measurement.

Main Results:

• The DC conductivity detector showed negligible electrolysis under flow conditions.
• A linear calibration range for DIC was established from 1.0 to 10 mmol L⁻¹.
• The method achieved a limit of detection of 70 µmol L⁻¹, <3% RSD repeatability, and 15 injections h⁻¹ sample throughput.

Conclusions:

• The developed homemade DC conductivity detector is a viable, cost-effective alternative for flow analysis.
• The coupled system provides a reliable method for determining DIC in natural water samples.