The concentrations of tartrazine (Yellow #5), Red #40, and Blue #1 were successfully determined for seven flavors of Mountain Dew using the method of constant volume standard addition. These data were used to determine the extent of possible health risks involved with drinking Mountain Dew by comparison to the acceptable daily intake (ADI) values and other research. The range of concentrations for the six varieties of Mountain Dew containing Yellow #5 ranged from 1.3 to 32 ppm. Of the four varieties containing Red #40, the concentrations ranged from 2.2 to 39 ppm. For two varieties containing Blue #1, the concentrations were both below 2.5 ppm. The experimental procedure was developed to teach students the method of standard addition and to illustrate an example of the matrix effect. After doing this experiment, students should also have a better appreciation of the concentrations and the potential health dangers of artificial dyes found in their diets.
Hofstein et al. (Fri,) studied this question.