Therefore, two matrix modifiers were tested during the construction of the analytical curve in order to eliminate possible matrix effect due to interference derived from high alcohol content and improve poor precision and accuracy: ethanol (in range of 3–15%
(v/v)) and ascorbic acid in range of 5–250 lg L1 for final volume of 50 mL. In lower values than 8.0% (v/v) alcohol and 150 lg L1 ascorbic acid, it was observed that the modifiers didn’t cause a significant change in the slope and intercept of calibration graph.