Which statement best describes the effect of increasing the number of theoretical plates on chromatographic peaks?

Which statement best describes the effect of increasing the number of theoretical plates on chromatographic peaks?

• A. Sharper peaks and higher resolution.
• B. Longer retention times.
• C. Greater baseline drift.
• D. Lower detector sensitivity.

Answer: (A)

Increasing the number of theoretical plates boosts column efficiency, which makes chromatographic peaks narrower and easier to separate. A higher N means the solute undergoes more discrete equilibrium steps along the column, reducing peak broadening. Because peak width is tied to dispersion and is roughly inversely related to N, the peak becomes sharper as N grows. This sharpening directly improves resolution between neighboring peaks, since two nearby peaks overlap less when each is narrower. The retention time is dictated mainly by the solute’s interactions with the stationary phase and the mobile phase setup, so it doesn’t inherently increase with more plates. Baseline drift and detector sensitivity are not direct effects of increasing theoretical plates, so they aren’t the expected outcome here.

Increasing the number of theoretical plates boosts column efficiency, which makes chromatographic peaks narrower and easier to separate. A higher N means the solute undergoes more discrete equilibrium steps along the column, reducing peak broadening. Because peak width is tied to dispersion and is roughly inversely related to N, the peak becomes sharper as N grows. This sharpening directly improves resolution between neighboring peaks, since two nearby peaks overlap less when each is narrower. The retention time is dictated mainly by the solute’s interactions with the stationary phase and the mobile phase setup, so it doesn’t inherently increase with more plates. Baseline drift and detector sensitivity are not direct effects of increasing theoretical plates, so they aren’t the expected outcome here.