Determination of lidocaine injection by solid carbon paste electrode potential method

A carbon paste electrode for the determination of lidocaine was prepared by using the association complex of iodine with lidocaine as an electroactive substance.The electrode showed Nernst response for lidocaine in the range 5.0×10-2～4.0×10-5 mol·L-1 with a slope of 30mV/pC.The detection limit is 3.0×10-5 mol·L-1.The electrode has fast response and good repeatability.The electrode has been used for the determination of lidocaine in injection by the standard curve method.The procedures of this method are simple and the results obtained agree with those of pharmacopoeia method.