Question

You wish to measure the concentration of methyl benzoate in a plant stream by gas chromatography. You prepare a sample of butyl benzoate to use as an internal standard. A preliminary run, shown at the right involved a solution containing 1.97 mg/mL of methyl benzoate (peak A) and 2.17 mg/mL of butyl benzoate (peak B). The area of peak A was determined to be 3.30 × 102 and of peak B to be 395 (measured in arbitrary units by the computer). To measure the sample, 1.00 mL of a standard sample of butyl benzoate containing 2.21 mg/mL was mixed with 1.00 mL of the plant stream material, and analysis of the mixture gave a peak area of 499 for peak A and 399 for peak B. What is the concentration of the methyl benzoate in the plant stream?

Answer 1

peak A = 1.97 mg.mL

peak B = 2.17 mg/mL

Area of peak A = 3.30 x 10²

Area of peak B = 395 arbitrary units

Methyl benzoate is a crystalline solid or a solid dissolved in a liquid. Denser than water.