Colorimetric Paper-Based Analytical Devices (PADs) Backed by Chemometrics for Pd(II) Detection

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Accurate determination of palladium(II) is crucial in various industrial and environmental applications.
• Existing methods for palladium(II) detection can be expensive, time-consuming, or lack selectivity.
• Development of rapid, selective, and cost-effective analytical tools is highly desirable.

Purpose of the Study:

• To develop and validate inexpensive Paper-based Analytical Devices (PADs) for the selective determination of palladium(II) (Pd(II)).
• To assess the selectivity and sensitivity of the developed PADs in highly acidic aqueous solutions.
• To establish a multivariate approach for quantifying Pd(II) in the presence of interfering metal ions.

Main Methods:

• Impregnation of filter paper with azoic ligand (2-(tetrazolylazo)-1,8 dihydroxy naphthalene-3,6,-disulphonic acid, TazoC).
• Colorimetric detection of Pd(II) complex formation on TazoC-PADs at low pH.
• UV-vis spectroscopy (300-800 nm) and Partial Least Square (PLS) regression for quantitative analysis.
• Validation using spiked tap water samples.

Main Results:

• TazoC-PADs exhibited high selectivity for Pd(II) in acidic media (pH < 2), forming a distinct purple-blue complex.
• The dye also formed complexes with Cu(II) and Ni(II) at higher pH, but Pd(II) could be quantified using a multivariate approach.
• PLS models accurately predicted Pd(II) concentrations in both single-analyte and multi-analyte solutions, including real-world samples.

Conclusions:

• Developed TazoC-PADs offer a cheap, selective, and rapid method for Pd(II) determination.
• The combination of PADs with UV-vis spectroscopy and PLS regression enables robust quantification of Pd(II) even in complex matrices.
• This approach shows significant promise for on-site and economical sensing of palladium(II).