The distribution constant for chemical species X in a gas chromatography experiment can be described by the following equation: K=[Xs]/[Xm], where "s" and "m" refer to stationary and mobile phases. A large value of K implies:a. greater affinity for mobile phase and shorter retention time. b. greater affinity for stationary phase and shorter retention time. c. greater affinity for mobile phase and longer retention time. d. greater affinity for the stationary phase and longer retention time.

Question

Journey Hunt

Chemistry

2 December, 08:55

The distribution constant for chemical species X in a gas chromatography experiment can be described by the following equation: K=[Xs]/[Xm], where "s" and "m" refer to stationary and mobile phases. A large value of K implies:a. greater affinity for mobile phase and shorter retention time. b. greater affinity for stationary phase and shorter retention time. c. greater affinity for mobile phase and longer retention time. d. greater affinity for the stationary phase and longer retention time.

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Abbey Howard · Answer 1

D

Explanation:

The distribution coefficient increases as [Xs] increases, that is, the analyte has greater affinity for the stationary phase. Also from

KA=tR-tM/tM, we see that increase in retention time tR leads to increase in the retention factor. It should be noted that longer retention time and greater affinity for the stationary phase ensures better separation in chromatography. tM is void time, that means, the time it takes the unretained solute to pass through the column.