Determination of 3-mercaptopropionic acid by HPLC: A sensitive method for environmental applications

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Biogeochemistry

Background:

• 3-mercaptopropionic acid (3-MPA) is a key thiol intermediate in organic sulfur metabolism.
• Its high reactivity complicates detection and quantification in natural environments.
• Understanding 3-MPA pathways is vital for tracking sulfur cycling and its impact on climate.

Purpose of the Study:

• To develop a sensitive and reliable method for determining 3-MPA concentrations.
• To overcome challenges associated with the compound's extreme reactivity and unstable derivatives.
• To enable accurate measurement of 3-MPA in complex environmental matrices like estuarine sediments.

Main Methods:

• Developed a method using pre-column derivatization of 3-MPA with monobromobimane.
• Analyzed derivatives using high-performance liquid chromatography (HPLC) with fluorescence detection.
• Optimized reaction conditions using Tris-HCl buffer for improved peak shape and separation.

Main Results:

• Achieved a low detection limit of 4.3 nmol L(-1) with high recovery rates (97-105%) in estuarine waters.
• Demonstrated excellent linearity (r>0.99) and precision (intra-day %CV 2.68-7.01%, inter-day %CV 4.86-12.5%).
• Showcased high stability of derivatized samples, with <5% loss after over a year of storage at 4°C.

Conclusions:

• The developed HPLC method provides a sensitive, reliable, and stable approach for 3-MPA quantification.
• This methodology enables accurate measurement of 3-MPA concentrations and production rates in estuarine sediments.
• The method facilitates a better understanding of the role of 3-MPA in organic sulfur cycling in natural environments.