An analyst attempted to quantify the amount of dichlorodiphenyltrichloroethane (DDT) in spinach with gas chromatography. The analyst began with preparing the standard sample containing 6.64 mg/L DDT standard and 1.20 mg/L chloroform as the internal standard, producing peak areas of 2885 and 11189, respectively. 2.30 mL spinach extract was treated with 1.00 mL of 12.25 mg/L chloroform and the mixture was diluted to a final volume of 25.00 mL. Gas chromatography gave peak areas of 7785 for the DDT in the spinach extract and 12093 for the chloroform.
(a) What is the concentration of DDT in 2.30 mL of original extract volume?
(b) A column with 12,000 plates was used for this GC analysis. An unretained compound had a retention time of 45 s and the peaks for DDT and chloroform had retention times of 3.53 min and 3.70 min, respectively. Using the Purnell equation, calculate the resolution between DDT and chloroform. Are these peaks baseline resolved? Justify your answer.
