Digestion procedure: The digestion procedure was carried out according to Voegborlo and Akagi
(2007). An approximately of 1 g of red chili pepper was accurately weighed into 250 mL Erlenmeyer
flask and added with 8 mL of nitric acid (HNO3) and 4 mL of perchloric acid (HClO4). The mixture
was then heated at a temperature between 150-250°C until the solution was clear. The sample
solution was then cooled and diluted to 25 mL with distilled water