A miniature and efficient colorimetric system assisted by the microplasma jet array for Cr (VI) detection

Area of Science:

• Analytical Chemistry
• Plasma Science
• Environmental Monitoring

Background:

• Microplasma jets (MPJs) are utilized for contaminant detection in miniaturized systems.
• Limited radical generation restricts the efficiency of conventional MPJs.

Purpose of the Study:

• To develop a novel 4-channel microplasma jet array (MPJA) for rapid oxidation of 3,3,5,5-tetramethylbenzidine (TMB).
• To create a colorimetric detection system for hexavalent chromium (Cr(VI)) using the MPJA.

Main Methods:

• Fabrication of a 4-channel microplasma jet array from a ceramic tube for direct sample contact.
• Development of a colorimetric system integrating the MPJA for Cr(VI) detection.
• Optimization of operating conditions for enhanced sensitivity and linear response.

Main Results:

• The MPJA facilitated rapid TMB oxidation without external reagents or catalysts.
• The developed system demonstrated significantly improved effectiveness and sensitivity compared to single MPJs.
• A linear response for Cr(VI) detection was observed in the range of 0.3-1.2 μmol L⁻¹, with a detection limit of 0.11 μmol L⁻¹.
• Practicality was validated using real-world samples, with a compact design and low power consumption (0.052 W).

Conclusions:

• The MPJA-based colorimetric system offers a sensitive and effective method for hexavalent chromium detection.
• The system's portability and low power consumption make it suitable for on-site and emergency sample determination.
• This technology presents a promising advancement in rapid analytical techniques for environmental monitoring.