Data supplements
Supplemental Data
Supplemental Figure 1 Color change in Gastec 5M tubes. A: Tube prior to use. B: Tube after two assays on blank solutions, then 15 min rest. C: Tube after two assays on blank solutions with no rest. Discoloration from purple to orange is due to CO2 gas. D: Tube after two runs: one blank model wine and one model wine with 35 mg/L free SO2. E: Tube after a single run of a model wine with 35 mg/L free SO2. The distance between the white arrows indicates the discoloration length, where Free SO2 (mg/L) = 1.84 * Length (mm).
Supplemental Figure 2 Calibration plot of SO2 tube color change (mm) vs. free SO2 by A-O (mg/L) for SO2 standards in model wine. Error bars represent standard deviations (n = 2). The best fit line equation was y = 0.543x + 0.0033 (r2 = 0.99, 1/x weighting). The y-intercept was ignored because it was negligible, resulting in the relationship: Free SO2 (mg/L) = 1.84 * Length (mm).Files in this Data Supplement: