Preparation of a versatile fluorescence sensor for co-detecting ions in aqueous solution

Area of Science:

• Analytical Chemistry
• Environmental Science
• Materials Science

Background:

• Water quality monitoring is crucial for public health and environmental protection.
• Developing sensitive and selective sensors for multiple ions is essential for comprehensive water analysis.
• Fluorescence-based sensors offer advantages in sensitivity and real-time detection.

Purpose of the Study:

• To develop a multifunctional fluorescence sensor (PCBH-FS) for detecting multiple ions in aqueous solutions.
• To investigate the sensing mechanism and performance of the PCBH-FS for Fe3+, Al3+, F-, and AcO-.
• To establish a sequential detection strategy for these ions using the developed sensor.

Main Methods:

• Synthesis and characterization of a new compound PCBH.
• Construction of the PCBH-based fluorescence sensor (PCBH-FS) in THF-H2O.
• Spectroscopic analysis to study the fluorescence response to various ions (Fe3+, Al3+, H+, F-, AcO-) across different pH ranges.
• Investigation of binding ratios and sensing mechanisms.
• Determination of the limit of detection (LOD) for each ion.

Main Results:

• PCBH-FS demonstrated a distinct red-shifted emission and a "turn-on" fluorescence response to Fe3+ and Al3+ (pH 5-9).
• PCBH-FS showed a good fluorescence response to H+ (pH 1-5).
• The Al3+-PCBH system enabled F- detection, and both Al3+-PCBH and Fe3+-PCBH systems allowed sequential AcO- detection.
• The sensor achieved low LODs for Fe3+ (0.44 µM), Al3+ (0.36 µM), F- (2.02 µM), and AcO- (1.45 µM).

Conclusions:

• PCBH-FS is a versatile fluorescence sensor for detecting multiple metal ions and anions.
• The sensor employs a combined "on-off" and fluorescent-shift strategy for sequential ion detection.
• This sensor offers a promising tool for real-time, on-site water quality monitoring.