A urine sample of a man suspected of suffering from chromium poisoning was analysed by atomic emission spectroscopy. Chromium standards were prepared at concentrations of 5, 10, 15 and 20 ppm. To 100 cm³ of each standard and to 100 cm³ of the urine sample was added 0.1 cm³ of a 500 ppm yttrium solution. Emission from chromium and yttrium in each solution was then measured with the following results.
Solution | Chromium Emission (arbitrary units) | Yttrium Emission (arbitrary units)
---|---|---
5.0 ppm standard | 13.0 | 6.0
10.0 ppm standard | 28.6 | 6.6
15.0 ppm standard | 31.2 | 4.8
20.0 ppm standard | 46.8 | 5.4
Urine | 31.1 | 5.2
Determine the concentration of chromium in the urine sample in ppm.