In gradient LC, peak capacity is estimated from gradient time and which parameter?

In gradient LC, peak capacity is estimated from gradient time and which parameter?

• A. Gradient time and average peak width
• B. Column length and particle size
• C. Detector sensitivity and injection volume
• D. Mobile phase pH and temperature

Answer: (A)

In gradient LC, peak capacity is a way to estimate how many separate peaks you can resolve in the time the gradient runs. The two factors that set that time window are the gradient time, which is the total time over which the mobile phase composition changes, and the average width of the peaks as they elute. If the gradient time is t_G and the average baseline-to-baseline peak width is w, you can roughly fit t_G divided by w peaks in the same run (n_c ≈ t_G / w). So longer gradients allow more peaks to be separated, while broader peaks reduce how many you can resolve. The other options don’t define the time window for separation: column length and particle size affect column efficiency (and thus peak shapes to some extent), but the standard estimate of peak capacity in gradient elution relies on gradient time and peak width; detector sensitivity and injection volume, or mobile phase pH and temperature, don’t set this basic capacity metric.

In gradient LC, peak capacity is a way to estimate how many separate peaks you can resolve in the time the gradient runs. The two factors that set that time window are the gradient time, which is the total time over which the mobile phase composition changes, and the average width of the peaks as they elute. If the gradient time is t_G and the average baseline-to-baseline peak width is w, you can roughly fit t_G divided by w peaks in the same run (n_c ≈ t_G / w). So longer gradients allow more peaks to be separated, while broader peaks reduce how many you can resolve.

The other options don’t define the time window for separation: column length and particle size affect column efficiency (and thus peak shapes to some extent), but the standard estimate of peak capacity in gradient elution relies on gradient time and peak width; detector sensitivity and injection volume, or mobile phase pH and temperature, don’t set this basic capacity metric.