Multivariate Analysis of pH-Dependent Carbon Dots Sensitivity for Fe³⁺ Ions Detection Using UV-VIS Spectroscopy.

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Fluorescent carbon dots (CDs) are versatile nanomaterials for heavy metal ion detection.
• Ferric ions (Fe3+) pose significant environmental and health risks.
• Developing sensitive and specific detection methods for Fe3+ is crucial.

Purpose of the Study:

• To synthesize blue-emitting carbon dots (CDs) from lemon juice.
• To investigate the pH-dependent sensitivity of CDs for ferric ion (Fe3+) detection.
• To apply multivariate analysis for understanding sensing mechanisms and optimizing performance.

Main Methods:

• Hydrothermal synthesis of carbon dots from lemon juice.
• UV-Vis absorbance spectroscopy to measure Fe3+ ion concentrations (0-400 µM) across a pH range (3-13).
• Multivariate analysis including Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA), and Partial Least Squares Regression (PLSR).

Main Results:

• CDs exhibited pH-dependent fluorescence quenching in the presence of Fe3+ ions.
• Absorbance enhancement varied significantly with pH, indicating complex interactions.
• Multivariate analysis revealed correlations between pH, electronic transitions, and Fe3+ sensing.
• PLSR identified pH 7 as optimal for Fe3+ detection, balancing ion solubility and CD sensitivity.

Conclusions:

• Lemon juice-derived CDs are effective for Fe3+ sensing.
• pH plays a critical role in the performance of CDs for Fe3+ detection.
• Multivariate analysis enhances understanding and optimization of CD-based sensors.
• The study highlights the potential of CDs for real-world environmental and biochemical monitoring at physiological pH.