Question

Map A researcher was attemping to quantify the amount of DDT (dichlorodiphenyltrichloroethane) in spinach with gas chromotography using a chloroform internal standard. To begin, the researcher examined a sample containing 8.59 mg/L DDT standard and 1.60 mg/L chloroform as the internal standard, producing peak areas of 5101 and 10087, respectively. ns hhomed ts Then, the researcher collected 13.08 g of spinach, homogenized the sample, and extracted the DDT using an established method (assume 100% extraction), producing a 3.48 mL volume of unknown sample. The researcher then prepared a sample that contained 0.750 mL of the unknown sample and 1.00 mL of 10.15 mg/L chloroform, which was diluted to a final volume of 25.00 mL. The sample was analzed using GCMS, producing peak areas of 6189 and 14127 for the unknown and chloroform, respectively Calculate the DDT concentration in the spinach sample. Express the final answer as milligrams DDT per gram of spinach. Number mg DDT/g spinach

Answer 1

F =[ 5101 / 8.59 ] x [ 1.60 / 10087 ]

= 593.83 x 0.0001586 = 0.09419