Kinetic methods for the determination of cadmium(II) based on a flow-through bulk optode

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• Accurate determination of heavy metals like cadmium is crucial for environmental monitoring and industrial processes.
• Existing methods for cadmium detection may have limitations in sensitivity, speed, or sample compatibility.

Purpose of the Study:

• To develop and validate kinetic methods for the determination of cadmium(II) (Cd(II)).
• To evaluate the performance of a flow-through bulk optode membrane incorporating 1-(2-pyridylazo)-2-naphtol (PAN) for Cd(II) sensing.
• To select the most suitable method for practical applications in sample analysis.

Main Methods:

• Three kinetic methods were employed: flow injection, flow, and stopped-flow injection.
• A flow-through bulk optode membrane with PAN in a plasticized poly(vinyl) chloride matrix on a cellulose support was utilized.
• Calibration curves were generated by plotting reflectance at 560 nm against Cd(II) concentration or its square root.

Main Results:

• Linear calibration graphs were obtained up to 56.2 mg l(-1) for all methods.
• Detection limits were as low as 0.01 mg l(-1) for the flow injection method.
• The flow injection method demonstrated excellent sensor response stability (±0.31% to ±0.65%) and regenerability with a pH 4 buffer.

Conclusions:

• The flow injection (FI) method using the PAN-based optode is a highly effective technique for Cd(II) determination.
• The developed sensor is robust, reproducible, and suitable for analyzing cadmium in real-world samples like alloys and water.
• This method offers a sensitive and practical approach for environmental and industrial cadmium monitoring.