The CIQTEK EPR200-Plus is a floor-standing EPR spectrometer with enhanced sensitivity for robust continuous wave (CW) EPR measurements. The model can be customized with three different sizes of electromagnets.
An upgraded version, CIQTEK EPR300, is another floor-standing CW EPR spectroscopy with higher sensitivity and optional Q-band extension.
>> EPR200-Plus Accessories: Dual Mode Resonator, High-temperature System, Liquid Nitrogen Variable Temperature With Cryostat, Liquid helium Variable Temperature, Liquid Helium-free Dry Cryogenic System, Time-resolved EPR System, Goniometers, Irradiation system, Flat cell.
Electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is a powerful analytical method to study the structure, dynamics, and spatial distribution of unpaired electronics in paramagnetic substances. It can provide in-situ and non-destructive information on electron spins, orbitals, and nuclei at the microscopic scale. EPR spectroscopy is particularly useful for studying metal complexes or free radicals so it has important applications in the fields of chemistry, materials, physics, environment, etc.
The ultra-low noise microwave generation technology combined with weak signal detection technology guarantees the high sensitivity of the EPR (ESR) spectrometer.
The probes can be equipped with optional continuous wave high Q probes, high-temperature probes, dual mode cavities, etc. Meanwhile, the probe can be customized to meet the needs of different scenarios.
The maximum magnetic field strength can reach 1.5 T. The precise magnetic field scanning control technology makes the magnetic field uniformity better than 10 ppm and the long-time stability of the magnetic field better than 10 mG/h, guaranteeing high-quality spectra.
Experienced technical application engineers provide professional EPR (ESR) services to help beginners master the analysis and attribution of EPR spectra.
The combination of time-resolved techniques with EPR (ESR) spectroscopy can be used to study transients such as free radicals or excited triplet states during fast reactions.
High temperature up to 650 K to meet the demand of high-temperature reactions in the petrochemical field and realize in-situ high-temperature EPR detection. Low temperature to liquid nitrogen temperature or even liquid helium temperature, to achieve in-situ detection of weak signals at low temperatures, to help research exploration in the field of chemistry and materials. Fast heat-up and cool-down speeds to meet the needs of variable-temperature testing.
EPR Application Cases
EPR Detection of Free Radicals
Free radicals are atoms or groups with unpaired electrons that are formed when a compound molecule is subjected to external conditions such as light or heat and the covalent bonds are split. For more stable free radicals, EPR can detect them directly and quickly. For short-lived free radicals, they can be detected by spin trapping. For example, hydroxyl radicals, superoxide radicals, single-linear oxygen light radicals, and other radicals produced by photocatalytic processes.
Paramagnetic Metal lons
For transition metal ions (including iron, palladium, and platinum group ions with unfilled 3d, 4d, and 5d shell respectively) and rare earth metal ions (with unfilled 4f shell), these paramagnetic metal ions can be detected by EPR spectrometer due to the presence of the single electrons in their atomic orbitals, thus obtaining the valence and structure information. In the case of transition metal ions, there are usually multiple valence states and spin states with high and low spins. Parallel modes in a two-mode cavity allow detection of the integer spin regime.
Conduction Electrons in Metal
The EPR line shape that conducts electrons is related to the size of the conductor, which is of great significance in the field of lithium-ion batteries. EPR can non-invasively probe the interior of the battery to study the deposition process of lithium in a close-to-real situation, from which the microscopic size of metallic lithium deposits can be inferred.
Material Doping And Defects
Metallofullerenes, as new nanomagnetic materials, have significant application value in magnetic resonance imaging, single-molecule magnets, spin quantum information, and other fields. Through EPR technology, the electron spin distribution in metallofullerenes can be obtained, providing an in-depth understanding of the ultrafine interaction between spin and the magnetic nucleus of metals. It can detect changes in spin and magnetism of metallofullerenes in different environments. (Nanoscale 2018, 10, 3291)
Photocatalysis
Semiconductor photocatalytic materials have become a hot research topic due to their potential applications in environmental, energy, selective organic transformation, medical, and other fields. EPR technology can detect active species generated on the surface of photocatalysts, such as e-, h+, •OH, O2, 1O2, SO3, etc. It can detect and quantify vacancies or defects in photocatalytic materials, assist in studying active sites and reaction mechanisms of photocatalytic materials, optimize parameters for subsequent photocatalytic application processes, detect active species and their proportions during photocatalysis, and provide direct evidence for system reaction mechanisms. The figure shows the EPR spectra of 0.3-NCCN and CN, indicating that 0.3-NCCN contains more unpaired electrons, higher crystallinity, and an extended p-conjugated system, resulting in better photocatalytic performance. (International Journal of Hydrogen Energy, 2022, 47: 11841-11852)
Parallel magnetic field signal of a diamond |
Signal of TEMPOL after deaeration |
Various free radical signals |
Cu valence |