Automatized flow-batch method for fluorescent determination of free glycerol in biodiesel samples using on-line extraction

► An automatized flow-batch method was proposed to determine free glycerol in biodiesel. ► The flow-batch method allowed the on-line extraction of the analyte to obtain a fluorescent product. ► The obtained results by the proposed flow-batch system have been better than those from bibliography. ► The proposed method's advantages of automation are many; such us the decrease in consumption reagent, waste volume (environmentally friendly).