The volumes of a solution containing 1.10ppm Zn+2 shown in the table below were pipetted into separatory funnels, each containing 5.00mL of an unknown zinc solution. Each was extracted with three 5-mL aliquots of CCl4 containing an excess of 8-hydroxyquinoline. The extracts were diluted to 25 mL and their fluorescence was measured. What is the concentration of the zinc in the unknown solution?
Volume of Zn standard(mL) Florescence Reading
0 6.12
4 11.16
8 15.68
12 20.64
20 30.76