Lidocaine, also known as xylocaine and lignocaine, is an anesthetic and cardiac depressant used as an antiarrhythmic agent. It numbs tissue in a specific area by blocking nerve signals in the body. The medication is used to reduce pain caused by skin irritations. An overdose of numbing medicine can cause fatal side effects Primesep 200, a reverse phase column, contains embedded acidic ionizable groups and can retain Lidocaine. The method is UV compatible and can be used as a general approach for analyzing similar compounds.