Subcritical Water Chromatography with Electrochemical Detection

Area of Science:

• Analytical Chemistry
• Green Chemistry

Background:

• Reverse phase liquid chromatography (RPLC) consumes large volumes of hazardous organic solvents globally.
• Disposal of these solvents presents significant environmental and cost concerns.
• Water alone is often too polar to elute organic analytes in conventional RPLC.

Purpose of the Study:

• To evaluate the feasibility of using water as a mobile phase in chromatography.
• To assess the effectiveness of electrochemical detection with a water mobile phase.
• To explore subcritical water chromatography as a sustainable analytical technique.

Main Methods:

• Utilized subcritical water chromatography with an electrochemical detector.
• Separated neurotransmitters/metabolites, nucleic acids/heterocyclic bases, and capsaicinoids.
• Employed both isothermal and temperature-programmed separations from 25 to 100 °C.

Main Results:

• Increasing separation temperature decreased retention times and analysis duration.
• Higher temperatures resulted in narrower chromatographic peaks.
• Effective separation was achieved for all tested analyte classes using water as the mobile phase.
• The limit of detection for neurotransmitters/metabolites ranged from 0.112 to 0.224 ppm.

Conclusions:

• Subcritical water chromatography is a viable and greener alternative to traditional RPLC methods.
• Temperature manipulation of water effectively alters its solvent properties for chromatographic separations.
• This technique offers reduced analysis times and improved peak shapes, with potential for broad applicability.