[yungsushi]

I have a homework problem asking me to calculate the peak widths of a two-component mixture on a 20-cm packed liquid chromatography column. I know the flow rate (0.30 mL/min), the dead time (5 min), and the retention times of both components (35 min and 60 min). I know that the retention time and peak width are related by the equation [tex]N = 16(\frac{t_{r}}{W})^2[/tex] where N is the number of plates a column has, t_r is the retention time, and W is the peak width. I also know that [tex]N = \frac{L}{H}[/tex] where L is the packing length and H is the plate height. Since both equations equal N, I can set them equal to each other, but that leaves me with 2 unknowns: H and W. Am I missing another equation that I could use to solve for H and leave me with just W as an unknown, or is there not enough information given to me to solve this?

[Hunter2]

H is the packaging height. This information should gives your column. Probably the 20 cm.

[MOTOBALL]

As stated by the OP, H is the plate height, NOT the "packaging" height, whatever that may be.

L/H = (4 Tr/W)sqd

So, W = (4 Tr) / sq rt (L/H) ; NOTE you may need to correct Tr to Tr - T0, where T0 is the dead time, i.e. NO retention; N = usually around 5,000 - 10,000 plates, for HPLC column.

You have not been given  H = HETP = height equivalent to a theoretical plate, so cannot give a numerical answer.

Regards,

Motoball