number of theoretical plates for a chromatography system =
= 16 * (((retention time in seconds to peak height for a compound) / (width of peak at its base in seconds)) ^ 2)
where:
• The width of a compound's peak is idealized from a triangle drawn with lines through the upward and downward slopes, avoiding the peak tails.
Alternatively:
number of theoretical plates for a chromatography system =
= 5.54 * (((retention time in seconds to peak height for a compound) / (width of peak when halfway between the baseline and peak)) ^ 2)
According to Dolan, the plate number reported for a column by a manufacturer is determined under ideal conditions and is unlikely to be achieved under usual working conditions. The number of plates that can be expected can be estimated from the column length and the size of the packing particles.
number of plates to expect for a column =
= 3000 * (length of the column in cm) / (diameter of the packing particles in micrometers)
It is probably not worth trying to improve the column performance if the observed plate number is > 80% of this number.
