Flow method based on liquid-liquid extraction using, deep eutectic solvent for the spectrofluorimetric determination of procainamide in human saliva

In the current study, liquid-liquid extraction, using deep eutectic solvent (DES) as a green extraction solvent, was coupled with a stepwise injection system for the first time. The suggested approach was applied for the development of spectrofluorimetric method for procainamide determination. The method is based on aspiration of saliva sample and DES (choline chloride with glycerol at a 1:2 M ratio) solution into the mixing chamber of a flow system, followed by injection of acetonitrile into the mixed DES-sample solution. The extraction process and final phase separation were then promoted by air-bubbling. After phase separation, the DES phase, containing the extracted procainamide, was transported to a spectrofluorimetric detector. The excitation and emission wavelengths were set at 280 nm and 347 nm, respectively. The calibration plot was linear in the range of 5x10(-6) to 5x10(-5) mol L-1. The limit of detection, calculated as 3 sigma of a blank test (n=10), was found to be 1.5x10(-6) mol L-1. The developed method was successfully applied for the determination of procainamide in human saliva samples, and the analytical results agreed rather well with the results obtained by the reference HPLC-UV method.