The analysis of lead, Pb, in urine was carried out using atomic absorption spectroscopy as follows.
All of the Pb in a 500.00 mL sample of urine was extracted into 5.00 mL of toluene containing a lead complexing agent. When this toluene solution was injected into an air/acetylene flame in an atomic absorption spectrometer it gave an absorbance of 0.0520 at 283.3 nm. 500.00 mL samples of standard solutions containing 0.0100 and 0.0200 ppm by weight Pb in water were extracted and examined in exactly the same way, and these gave absorbances of 0.0410 and 0.0820 respectively.
Calculate the concentration of Pb in the urine sample as:
i) ppm, ii) µg L-1, iii) and molarity (molar mass of Pb = 207.2 g mol-1).
[For the purpose of calculation you may consider urine to be a dilute aqueous solution.]