Measurement uncertainty of shikimic acid in red wines produced in Chile

High-performance liquid chromatography (HPLC) to determine shikimic acid is used as a complementary tool to differentiate wine varieties. In order to correctly classify, measurement uncertainty of shikimic acid by HPLC in red wine was estimated considering the following components: uncertainty associated with the preparation of shikimic acid stock solution, uncertainty associated with quantification using a calibration curve, and uncertainty associated with precision. The most important contribution to total uncertainty was the method precision. The expanded uncertainty (U) for different wine varieties was between 2.6 and 8.5%. The method was applied to determine the concentration of shikimic acid in different emerging wine varieties cultivated in Chile, such as CarmenSre, Shiraz, and Pinot Noir, comparing them with classical varieties, such as Cabernet Sauvignon and Merlot. Shiraz wines presented lower shikimic acid concentrations (between 27 and 86 mg L-1 with U ((k=2)) = 2.6%) than Cabernet Sauvignon wines (between 41 and 142 mg L-1 with U ((k=2)) = 8.1%), but their concentrations were higher than found in Merlot (from 9 to 41 mg L-1 with U ((k=2)) = 4.3%) and CarmenSre wines (between 7 and 49 mg L-1 with U ((k=2)) = 5.8%). Pinot Noir was the variety with the lowest concentration of this acid (7-14 mg L-1 with U ((k=2)) = 8.5%).