Huestis et al (2007) measured the amount of cocaine and its metabolites in urine (of a healthy adult male) within four hours of a controlled dose. Some of their results are reproduced in Fig. 1.4

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a. From the data in Fig 1.4 estimate the maximal urinary concentration of cocaine after a dose of 40 ng. Do the same for a dose of 20 mg. Convert these concentrations to ppm and ppb.

b. The legal limit for benzoylecgonine (BZE) is 50 µg/L.

From the data in Fig.1.4 estimate the maximal amount of BZE in the urine four hours after a 40 ng dose. How far over the legal limit is this? Since a typical dose taken through the nose (i.e., snorted) is around 100 ng, about how far over the legal limit would you expect to be after taking a typical dose?