Figure 8 shows results for the extraction of Danshen using a solvent of 80% methanol and 20% water (by volume), a temperature of 70°C, and a range of microwave powers from 400 W to 1000 W. Each extraction maintains the remaining conditions used for the data in Figures 3–5: a solvent-to-solid ratio of 60.0 mL of solvent and 3.00 g of Danshen, and an extraction time of 5.00 min.
Investigation 18. Consider the data in Figure 8 and explain any trends you see in the relative extraction efficiencies as a function of the microwave's power. What is the optimum power for extracting samples of Danshen using a solvent that is 80% methanol and 20% water by volume and an extraction temperature of 70°C?