In this video ZP used a model pharmaceutical molecule to show how the SIA potentiostat can be used to screen conditions (potential, solvents etc) and then be used to perform a micro-electrolysis on a 50 uL scale.

SIA potentiostat

carbon electrodes

gold electrodes

platinum electrodes

Exploring Green Electroorganic Chemistry with Microscale Electrochemistry

Introduction

Welcome to this blog post, where we dive into an exciting application of electrochemistry—green electroorganic synthesis! While much of our focus at Zimmer Pot revolves around biosensor development and manufacturing, today we’re taking a different approach by exploring how microscale electrochemistry can be leveraged for organic synthesis and metabolite studies.

Why Microscale Electrochemistry?

Traditionally, organic synthesis and electrolysis experiments require large volumes of solvents and reagents. However, by using screen-printed electrodes (SPEs) and microliter-scale volumes, we can:

Reduce solvent waste – Minimizing environmental impact.
Lower costs – Using smaller quantities of reagents.
Increase efficiency – Faster experiments with high surface-area-to-volume ratios.
Enable rapid screening – Quickly identifying optimal reaction conditions.

In this demonstration, we’ll be performing the electrooxidation of acetaminophen (paracetamol) to produce benzoquinone imine—a reaction that showcases the power of green electrochemistry.

Experimental Setup

Materials & Equipment

Screen-printed electrode (SPE) – A 4 mm working electrode designed for high efficiency.
Potentiostat – Controlled via smartphone for real-time data acquisition.
Acetaminophen solution – 10 mg dissolved in 1 mL of acidic aqueous buffer.
Pipette & vortex – For precise microliter-scale handling and dissolution.

Methodology

1. Cyclic Voltammetry (CV) for Screening

First, we need to determine the optimal voltage for oxidizing acetaminophen.

Step 1: Run a background scan (solvent only) to establish a baseline.
- Conditions:
  - Start potential: -200 mV
  - End potential: +1000 mV
  - Scan rate: 900 mV/s
  - Current range: 1000 µA
  - Scans: 3
Step 2: Run the acetaminophen solution under the same conditions.

Results:

The solvent CV shows a flat baseline (as expected).
The acetaminophen CV reveals a distinct oxidation peak around 600–800 mV, indicating where the reaction occurs.

By overlaying the two scans, we clearly see the difference—confirming that ~800 mV is the ideal potential for electrolysis.

2. Bulk Electrolysis (Amperometry)

Now that we’ve identified the optimal voltage, we’ll perform electrolysis to convert acetaminophen into benzoquinone imine.

Conditions:
- Applied potential: +800 mV
- Duration: 1000 seconds (~16 minutes)
- Sample volume: 50 µL
- Data collection: 1 point per second

Why This Works:

The small volume (50 µL) ensures efficient conversion due to the high electrode surface area.
The reaction can be monitored in real time, and post-electrolysis samples can be analyzed via HPLC or mass spectrometry.

Key Advantages of This Approach

Minimal Waste – Uses microliter volumes instead of milliliters.
Fast Screening – CV quickly identifies reaction conditions.
Scalable Insights – Results can guide larger-scale syntheses.
Versatility – Applicable to metabolite studies, organic synthesis, and more.

Final Thoughts

This experiment demonstrates how microscale electrochemistry can revolutionize green electroorganic synthesis. By reducing reagent use, accelerating screening, and enabling precise control, this method offers a sustainable and efficient alternative to traditional approaches.