Map You wish to measure the concentration of methyl benzoate in a plant stream b
ID: 1084358 • Letter: M
Question
Map 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 1.23 mg/mL of methyl benzoate ak A) and 1.35 mg/mL of butyl benzoate (peak B). The area of peak was determined to be 338 and of peak B to be 403 (measured in arbitrary units by the computer). To measure the sample, 1.00 mL of a standard sample of butyl benzoate containing 2.69 mg/mL was mixed with 1.00 mL of the plant stream material, and analysis of the mixture gave a peak area of 437 for peak A and 407 for peak B. What is the concentration of the methyl benzoate in the plant stream? 10 15 5 Time (min Number conc methyl benzoate mg/mL O Previous & Give Up & View Solution O Check Answer Next Exit. HintExplanation / Answer
peak B = 403 / 1.35 = 298.5
peakA = 338/ 1.23 = 274.8
Response factor = Peak B/Peak A
= 298.5 / 274.8
= 1.09
unknown :
peak B = 407 / 2.69 = 151.3
peak A = 437 / X
F = peak B / peak A
1.09 = 151.3 / (437 / X)
X = 3.13
concentration methyl benzoate = 3.13 mg / mL