Electron Paramagnetic Resonance (ESR/EPR) Spectroscopy Analytical Service

Overview

Electron Paramagnetic Resonance (EPR), also known as Electron Spin Resonance (ESR), is a magnetic resonance technique that detects unpaired electrons' magnetic moments. It is widely used to study the states of unpaired electrons in compounds or minerals and explore their surrounding structural environment. The application of this technique include the following areas:

1. Biology: Revealing molecular structures, conformations, and interactions through labeling unpaired electrons in biomolecules.
2. Chemistry: Investigating unpaired electrons in catalysts to identify active sites and reaction mechanisms.
3. Materials Science: Analyzing impurities, defects, and doping in semiconductors for device optimization.
4. Environmental Science: Detecting free radicals, heavy metal ions, and pollutants to understand their sources and guide environmental protection.

Similar to NMR but focused on unpaired electrons. Under a magnetic field, unpaired electrons exhibit energy level splitting. When exposed to microwave radiation, electrons transition between energy levels, allowing the detection of their resonance frequency, number, structure, and environmental interactions

Testing Procedure (Only for Reference)

1. Sample Preparation: Select a sample containing unpaired electrons. These unpaired electrons may be a natural component of the substance or introduced by adding suitable materials.
2. Set Up Experimental Apparatus: Place the sample in a sealed chamber with stable temperature and atmosphere control. A microwave pulse system is typically used to enable the sample to absorb microwave radiation at specific frequencies.
3. Apply Magnetic Field: Apply a constant and strong magnetic field around the chamber. The strength of the magnetic field is proportional to the frequency of the microwave radiation and is usually determined by the instrument used.
4. Signal Detection: Microwave radiation at specific frequencies interacts with the unpaired electrons in the sample, causing resonance. Under resonance conditions, energy transfer occurs, and the microwaves are absorbed or emitted.
5. Analyze Measurement Results: By adjusting the magnetic field strength and frequency, the position of the absorption peaks observed provides information about the unpaired electrons.

Sample Requirements

Powder Samples:

• Typically require 10–20 mg; minimum amount is 1–2 mg, but smaller quantities may affect signal quality. Please assess the risk independently.

Liquid Samples:

• Generally require at least 2 mL; for precious or limited samples, a minimum of 300 µL is acceptable.

Bulk/Film Samples:

• For testing persistent free radicals: the width should be less than 4 mm.
• For vacancy testing: two dimensions should be within 3 mm, and the third dimension within 1 cm.
• For free radical samples pre-processed externally before testing, there are no size requirements.

Other Special Requirements

• Magnetic Samples: Please indicate if the sample is magnetic, as this may affect testing feasibility (strongly magnetic samples can damage the instrument—contact us in advance to confirm). If instrument damage occurs due to failure to disclose this information, repair costs will be charged.
• Reagent Mixing: If reagents need to be added and mixed in the laboratory, please provide the reagents yourself.

Instrument Models: Bruker EMXplus, Bruker EMXmicro, Bruker A300, etc.

Note: The listed price is for reference only. Please request a quote for the final pricing.

Analytical Service Minimum order requirement: $250 per order. A $200 handling fee will be applied if order is below $250.

Please contact sales@msesupplies.com for additional information and instructions on our Analytical Services program. Confirmation of the sample(s) requirements, SDS sheets and additional information is needed prior to processing the Analytical Service order. 

***Please do not ship any samples without authorization from MSE Supplies***