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The following questions apply to separation of a solution containing pentanol (F

ID: 991495 • Letter: T

Question

The following questions apply to separation of a solution containing pentanol (FM 88.15) and 2,3 butanol (FM 102.17). Pentanol is the internal standard. Separation of a standard solution containing 205 mg of pentanol and 269 mg of 2,3-dimethy1-2-butanol in 10.0 mL of solution ted to a pentanol:2,3-dimemyl-2-butanol relative peak area ratio of 0.890:1.00. Calculate the response factor. Calculate the areas for pentanol and 2,3-dimethy1-2-butanol gas chromatogram peaks in an unknown For pentanol. the peak height was 61.1 mm and the width at half-height was 1.6 mm. For 2.3-dimethyl-2- butanol, the peak height was 34.3 mm and the width at half height was 3.8 mm. Assume each peak to be a Gaussian.

Explanation / Answer

(a) Response factor for 2,3-dimethyl-2-butanol

= (1/0.890)(205 x 102.175/269 x 88.148)

= 0.992

(b) Area = height x width at half height

Pentanol = 61.1 mm x 1.6 mm = 97.76 mm^2

2,3-dimethyl-2-butanol = 34.3 mm x 3.8 mm = 130.34 mm^2

(c) If the concentration of pentanol = 36.7 mM

Concentration of 2,3-dimethyl-2-butanol = (1 x 36.7/0.890 x 0.992)

= 41.57mM