Development and validation of an LC-HRMS method for the determination of monomers of wine fining PVPP and PVI-PVP polymers

A HPLC-HRMS method was developed and validated to analyze the polyvinylimidazole/polyvinylpyrrolidone (PVI/PVP) monomers (N-vinylimidazole, N-vinyl-2-pyrrolidone, imidazole, and 2-pyrrolidone) in wines. The use of a C30 column and HRMS allowed to obtain high selectivity, excluding several interferents. The lower limit of quantification was 10 ng/mL for the targeted molecules and the method was linear from 10 to 1000 ng/mL. Matrix effect (ME) was detected for all compounds, except for N-vinylimidazole and a correction function to overcame ME was suggested with the use of a calibration curve in hydroalcoholic solution. Migration tests demonstrated that imidazole reveals the oenological use of PVI-based products, whereas 2-pyrrolidone represents a very questionable marker for PVPP fining agents since all analyzed wines showed levels of this compound higher than the limit defined by OIV. Further investigations are necessary to test commercial products using both model and real wines in order to find new markers of PVPP treatment.