Figure 7 shows results for the extraction of Danshen using a solvent of 80% methanol and 20% water (by volume) for temperatures from 50°C to 70°C, where the upper limit is defined by the solvent's boiling point. 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, an extraction time of 5.00 min, and a microwave power of 600 W.
Consider the data in Figure 7 and explain any trends you see in the relative extraction efficiencies as a function of temperature. What is the optimum temperature for extracting samples of Danshen? Are your results consistent with your expectations? Why or why not?