The derivatization of thiamin vitamers to their respective thiochrome by ferricyanide to facilitate fluorescence
detection following separation by HPLC provides a powerful analytical tool. However the polyphenolic
compounds in red wine readily interact with ferricyanide, reducing the effectiveness of ferricyanide
oxidation in the derivatization of thiamin. We describe a method to facilitate the removal of polyphenolic
compounds that interfere with the ferricyanide derivatization of thiamin. Polyvinylpolypyrrolidone afforded
the total removal of phenolic compounds from red wines and allowed a spike recovery of thiamin
vitamers (101% for thiamin; 104% for TMP; and 100% for TDP) in a wide range of red wines. This research
found that Merlot styles of red wine contained the highest concentration of total thiamin (29.01 ng/mL)
while Pinot Noir wines contained the lowest total concentration (8.27 ng/mL).