Serum taken from a patient being treated with lithium for manic-depressive illness was analyzed for lithium concentration. A reading of 412 units was obtained for the intensity of the 671 nm red emission line. After that 1.00mL of a 10.9mM Lithium standard was added to 9.00mL of serum as well as this spiked serum gave an intensity reading of 893 units. Explain what is the original concentration of Li in the serum?