Colorimetric sensor for Pb²⁺ detection in water using thioglycolic acid-conjugated gold nanoparticles

Area of Science:

• Environmental Science
• Nanotechnology
• Analytical Chemistry

Background:

• Lead (Pb²⁺) pollution presents severe health risks, including neurotoxicity and kidney damage.
• Gold nanoparticles (AuNPs) are effective colorimetric sensors for heavy metal detection via surface plasmon resonance.
• Developing sensitive and specific sensors for lead detection is critical for public health and environmental safety.

Purpose of the Study:

• To develop a novel colorimetric sensor for the detection of lead ions (Pb²⁺).
• To utilize thioglycolic acid (TGA) conjugated gold nanoparticles (AuNPs) for enhanced stability and specificity.
• To establish a simple, fast, and cost-effective method for real-time lead detection in water samples.

Main Methods:

• Synthesis and characterization of TGA-conjugated AuNPs.
• Optimization of sensor parameters including AuNPs volume, TGA concentration, and pH.
• Evaluation using UV-visible spectrophotometry, High-Resolution Transmission Electron Microscopy (HRTEM), and Fourier Transform Infrared Spectroscopy (FTIR).

Main Results:

• Optimal detection conditions achieved with 700 μL AuNPs, 500 μM TGA, and pH 10.0 for 10 minutes.
• The TGA-AuNPs sensor detected Pb²⁺ with a limit of 9.5 μg mL^-1.
• The sensor showed high specificity for Pb²⁺ over other tested metal ions (Ba²⁺, Mn²⁺, Cu²⁺, Mg²⁺, Hg²⁺).

Conclusions:

• A simple, rapid, and cost-effective colorimetric sensor based on TGA-AuNPs was successfully developed for Pb²⁺ detection.
• The sensor demonstrated good sensitivity and specificity, suitable for environmental water analysis.
• Analysis of water samples from Universitas Indonesia showed Pb²⁺ levels below the detection limit, indicating effective water quality in the tested areas.