On-line solid phase extraction system using PTFE packed column for the flame atomic absorption spectrometric...

Area of Science:

• Analytical Chemistry
• Environmental Chemistry

Background:

• Accurate determination of trace copper in water is crucial for environmental monitoring.
• Existing preconcentration methods for flame atomic absorption spectrometry (FAAS) can be limited by sorbent material lifetime and system flexibility.

Purpose of the Study:

• To develop a new flow injection on-line adsorption preconcentration system for sensitive copper determination using FAAS.
• To utilize a novel sorbent material for improved system performance and longevity.

Main Methods:

• A flow injection system was designed using a mini-column packed with polytetrafluoroethylene (PTFE) turnings as the sorbent.
• Copper was complexed with ammonium pyrrolidine dithiocarbamate (APDC) and adsorbed onto the PTFE.
• The adsorbed copper complex was eluted on-line with isobutyl methyl ketone (IBMK) directly into the flame of the FAAS.

Main Results:

• The developed system achieved a detection limit of 0.05 µg L⁻¹ and a precision of 1.5% at 2.0 µg L⁻¹ Cu.
• An enhancement factor of 340 was obtained with a 1-minute preconcentration time and a sample frequency of 40 h⁻¹.
• The PTFE-based system demonstrated a practically unlimited lifetime, improved flow rates, and greater flexibility compared to other methods.

Conclusions:

• The new flow injection on-line adsorption preconcentration system is effective for sensitive and accurate copper determination in various water types.
• The use of PTFE turnings offers significant advantages in terms of system performance, durability, and operational flexibility.
• The method is suitable for routine analysis of trace copper in environmental water samples without significant interferences.