Full set of Notes with Fill-Ins - San Jose State University

Chem 155 Unit 17 Chromatography Page 304 of 316Plate count depends on retention time:Why does the plate count go up for the more retainedpeaks?Because more retained peaks are expected to getbroader by longitudinal diffusion – but these donot.N:2⎛ 400 ⎞⎜ ⎟⎠ = 1024⎝ 12.52⎛ 1200 ⎞⎜ ⎟ = 9216 N⎝ 12.5 ⎠2⎛ μ ⎞⎜ ⎟⎝ σ ⎠2⎛ 800 ⎞⎜ ⎟⎠ = 4096⎝ 12.52⎛ 1600 ⎞⎜ ⎟ = 16384⎝ 12.5 ⎠Illustration of different plate counts0.030.0250.02signal0.0150.010.00500 200 400 600 800 1000 1200 1400 1600 1800 2000retention time or column lengthPage 304 of 316