Figure 5

Applications of paper strip and optimized spectrum based on BCS-Cu+ color reaction in fruits and vegetables. 0.1 g samples of several common fruits and vegetables (grape, peach, apple, spinach, cabbage) were collected and digested in 10% nitric acid for BCS assays. (A) Solutions of the indicated fruits and vegetables were visualized in glass test tubes to demonstrate the color development in solution. Cu contents of indicated fruits and vegetables were determined by paper strips (B), optimized spectrum method (C) or ICP-MS (D).