A flow injection procedure using Layered Double Hydroxide for on line pre-concentration of fluoride

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• Fluoride determination in water is crucial for environmental and health monitoring.
• Traditional methods may lack sensitivity or require complex sample preparation.

Purpose of the Study:

• To develop and optimize a flow system for preconcentration of fluoride ions.
• To utilize Layered Double Hydroxides (LDH) as an adsorbent for efficient fluoride capture.

Main Methods:

• A flow system with solenoid valves was designed for automated sample handling.
• Fluoride was preconcentrated in an LDH-coated mini-column.
• Elution was performed using sodium hydroxide, followed by spectrophotometric determination.
• System parameters including adsorbent mass, eluent, flow rate, and pH were optimized.

Main Results:

• Optimized conditions yielded a detection limit of 15 µgL⁻¹, coefficient of variation of 0.8%, and a linear range of 50-500 µgL⁻¹.
• A preconcentration factor of 10 was achieved.
• Method accuracy was validated using certified reference material (ALPHA APS 1076).
• The method successfully determined fluoride in water samples, with levels below regulatory limits.

Conclusions:

• The developed flow system offers a sensitive and accurate method for fluoride preconcentration and determination.
• The use of LDH as an adsorbent proved effective for fluoride capture.
• The method is suitable for routine analysis of fluoride in various water samples and meets regulatory requirements.