Cobalt was used as an internal standard to analyze a sample of titanium with atomic absorption spectroscopy. A mixture was prepared by combining a 4.00 mL Ti solution of unknown concentration with 3.00 mL of a 11.7 micrograms/mL solution of Co. The atomic absorbances were measured as 0.128 and 0.218 for Ti and Co, respectively.
As a reference, a standard mixture containing 1.58 micrograms Co/mL and 2.31 micrograms Ti/mL was prepared and measured to have a signal-to-signal ratio of 2.65 Ti: 1.00 Co.
Determine the concentration (moles/L) of titanium in the original unknown solution.