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    Chemical Separations Problem

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    The H (height equivalent of a theoretical plate) value for an HPLC column at mobile phase flow rates of 1ml/min, 3ml/min and 4ml/min are 4.1mm, 4.7mm and 5.675mm. Calculate:
    1. The van Deemter parameters A, B and C
    2. The flow rate at which H is a minimum and the value of H at this flow rate
    3. The efficiency N if the length of the column is 18cm

    © BrainMass Inc. brainmass.com October 9, 2019, 3:55 pm ad1c9bdddf
    https://brainmass.com/chemistry/experimental-design-and-methods-in-chemistry/chemical-separations-problem-17410

    Solution Preview

    You have three unknowns and three simultaneous equations.
    H = A + B/u + C(u)
    where H is the plate heights, u is the flow rates and A, B, C are unknown.

    The equations become:
    4.1 = A + B/1 + C(1) or multiply out 1 4.1 = A + B + C

    the next equation is:
    4.7 = A + B/3 + C(3) multiply sides by 3 14.1 = 3A ...

    Solution Summary

    You have three unknowns and three simultaneous equations H = A + B/u + C(u) where H is the plate heights, u is the flow rates and A, B, C are unknown.

    $2.19