[Nat (OP)]

Hi there, I am having major problems answering this question:

A suspect in a shooting incident had his hands swabbed with 5% nitric acid. The swabs were then extracted into 20 cm3 of nitric acid. A portion of the sample solution was analysed by atomic emission spectroscopy and a response of 120 mV obtained. Next a 0.010 cm3 of a standard solution containing 40 µg of lead per cm3 was added to 5 cm 3 of the sample solution and the analysis repeated. A response of 141.0 mV was obtained from the "spiked" sample. Calculate the amount of lead recovered by the swabs in µg. Please do not type in the units.

If anyone could point me in the right the right direction/explain/answer it, I would be very greatful!

Nat

[Bored chemist]

Have you heard of the method of standard additions?