Development of a sample preparation approach for the analysis of fining agents in wines by liquid chromatography with tandem mass spectrometry

During winemaking a wide variety of processing aids such as albumin, caseinates and lysozyme are often used. These proteins are considered allergenic and could become a human health risk in susceptible individuals. In our knowledge, there are no methods published for the analysis of these three proteins simultaneously by liquid chromatography with tandem mass spectrometry, with electrospray ionization. Therefore, in this work, a sample preparation approach for the analysis of alpha-casein, beta-casein, albumin and lysozyme, in a single run, was performed and compared with published data. Through a pH adjustment, combining the use of cellulose ester membranes, a precipitation with organic solvents and a final concentration/clean-up, we achieved recovery values from 90.7 to 108.6%. The method was validated, showing determination coefficients R-2 >= 0.99. This method was able to quantify proteins even at lower levels (limits of quantification from 0.01 to 0.25 mg/L) than the current legal limits.

Automated summary

A sample preparation approach for analyzing alpha-casein, beta-casein, albumin, and lysozyme was developed and validated in this study. The method showed high recovery values and could quantify proteins even at lower levels than the current legal limits.