Multicommuted Flow Analysis Procedure for Total Polyphenols Determination in Wines Employing Chemiluminescence Detection

A flow procedure based on a multicommuted flow analysis process for the determination of polyphenolic compounds in wine employing chemiluminescence as detection technique is described. The method was based on the reaction of hypochlorite with gallic acid, the remaining hypochlorite reacted with luminol in an alkaline medium generating electromagnetic radiation with maximum emission at 425 nm. The luminescence intensity presented an inverse relationship to the concentration of polyphenol compounds, which was monitored employing a homemade luminometer. The flow system manifold was designed to use solenoid mini-pumps for propelling fluids in order to obtain a setup of downsized dimension. After setting the variables control of the flow system and the concentrations of the reagent, the following features were achieved: a linear response ranging from 10 to 100 mg L−1 gallic acid (R2 = 0.997), a relative standard deviation of 3.4 (n = 11) for a 50 mg L−1 gallic acid solution, a detection limit of 6.6 mg L−1, a sampling throughput of 180 determination h−1, and a waste generation of 1.1 mL per determination.