Scavenger (chemistry)

A scavenger in chemistry is a chemical substance added to a mixture in order to remove or inactivate impurities or unwanted reaction products. Their use is wide-ranged:

• In atmospheric chemistry, the most common scavenger is the hydroxyl radical, a short-lived radical produced photolytically in the atmosphere. It is the most important oxidant for carbon dioxide, methane and other hydrocarbons, sulfur dioxide, hydrogen sulfide, and most of other contaminants, removing them from the atmosphere.
• In molecular laser isotope separation, methane is used as a scavenger gas for fluorine atoms.
• Hydrazine and ascorbic acid are used as oxygen scavenger corrosion inhibitors.
• Tocopherol and naringenin are bioactive free radical scavengers and synthetic catalytic scavengers their synthetic counterparts
• Organotin compounds are used in polymer manufacture as hydrochloric acid scavengers.
• Oxygen scavengers are small sachets or self adhesive labels that are placed inside modified atmosphere packs to help extend product life ( notably cooked meats ) and help improve product appearance. They work by absorbing any oxygen left in the pack by oxidation of the iron powder contained in the sachet / label.