Flow Injection Analysis with Direct UV Detection Following Electric Field Driven Membrane Extraction

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Separation Science

Background:

• Selective quantification of analytes in complex matrices like urine is challenging.
• Traditional methods often require extensive sample preparation.
• Flow-injection analysis (FIA) offers rapid analysis but can lack selectivity.

Purpose of the Study:

• To develop an on-line matrix elimination technique for selective analyte quantification.
• To enable the determination of ultraviolet absorbing compounds using flow-injection analysis.
• To demonstrate the method's efficacy for naproxen determination in human urine.

Main Methods:

• Utilized electric field-driven extraction across a polymer inclusion membrane (PIM) for selective analyte transport.
• Employed a PIM composed of cellulose triacetate, *o*-nitrophenyl octyl ether, and Aliquat 336.
• Integrated flow-injection analysis with electrokinetic extraction and UV detection.

Main Results:

• Achieved selective extraction and enrichment of naproxen from spiked human urine.
• Demonstrated a linear quantification range from 5 to 200 µM with R² = 0.9978.
• Reported a reproducibility of 7% (n=8) and a detection limit of 2 µM for naproxen.

Conclusions:

• The developed on-line matrix elimination method provides selective quantification of UV-absorbing analytes.
• Electric field-driven extraction across PIMs is an effective strategy for sample cleanup and analyte enrichment in FIA.
• This approach offers a promising tool for the rapid and selective analysis of pharmaceuticals in biological samples.