Overview
2,2,5,5-Tetramethyl-1-pyrroline-N-oxide (TMPO) is a nitroxide radical commonly used as a spin trap in electron paramagnetic resonance (EPR) spectroscopy. Its stability and reactivity make it an invaluable tool for detecting and studying short-lived free radicals in various chemical and biological systems. TMPO is widely utilized in research fields such as biochemistry, materials science, and pharmaceuticals. First synthesized in the mid-20th century, TMPO has become a standard reagent in EPR studies due to its ability to form stable adducts with reactive radicals. This property allows researchers to analyze radical intermediates that would otherwise be difficult to observe. The compound's reliability and ease of use have cemented its role in modern scientific investigations.
Physical and Chemical Properties
TMPO is a colorless to pale yellow crystalline solid with a molecular weight of 141.21 g/mol. It has a melting point of approximately 45-50°C and is soluble in water, ethanol, and various organic solvents. The compound's stability as a nitroxide radical is attributed to the steric hindrance provided by its four methyl groups, which protect the reactive nitrogen-oxygen bond. In solution, TMPO exhibits paramagnetic properties, making it ideal for EPR spectroscopy. Its ability to trap and stabilize free radicals allows for detailed analysis of radical reactions. The compound is also relatively stable under standard laboratory conditions, though it should be protected from prolonged exposure to light and strong oxidizing agents to prevent degradation.
Main Applications
TMPO is primarily used in EPR spectroscopy to detect and study free radicals in chemical and biological systems. It forms stable adducts with reactive oxygen species (ROS), enabling researchers to investigate oxidative stress mechanisms in cells and tissues. This application is particularly important in medical and pharmaceutical research, where understanding radical-mediated processes can lead to new therapies. Beyond biochemistry, TMPO is employed in materials science to study polymerization reactions and radical-initiated processes. Its ability to trap radicals provides insights into reaction mechanisms and material properties. Additionally, TMPO is used in environmental science to analyze radical species in atmospheric and aquatic systems, contributing to pollution studies and remediation strategies.
Safety and Storage
TMPO should be handled with care to avoid inhalation, ingestion, or skin contact. Although it is not highly toxic, prolonged exposure can cause irritation. Laboratory personnel should use appropriate personal protective equipment (PPE), including gloves and safety goggles, when working with this compound. Storage conditions are critical to maintaining TMPO's stability. The compound should be kept in a cool, dry place, away from light and oxidizing agents. Sealed containers under inert gas can further enhance shelf life. Proper disposal methods should be followed to minimize environmental impact, adhering to local regulations for chemical waste.
B2B Procurement Guide
When procuring TMPO for research or industrial use, purity is a key consideration. High-purity grades (>98%) are recommended for sensitive applications such as EPR spectroscopy. Buyers should verify the CAS number (2255-24-2) to ensure they are purchasing the correct compound. Suppliers should be evaluated for reliability, with preference given to those providing detailed certificates of analysis (CoA). Bulk purchases may offer cost savings, but storage capacity and shelf life should be considered. For reference, prices typically range from $50 to $200 per gram, depending on purity and supplier. Establishing long-term relationships with reputable vendors can ensure consistent quality and availability.