The chromatograms in the picture below show the separation of a two-component mixture. The Liquid
Chromatography column is 25 cm long. The flow rate was 0.40 ml/min. Using the chromatograph to
answer the following questions.
Source: Test Bank Hage/Carr Analytical Chemistry & Quantitative Analysis C. McLaughlin
1. Determine the dead time of the chromatographic analysis
2. Determine the retention time of compounds A and B
3. Calculated the adjusted retention time of the compound A and B
4. Calculated the capacity factor (k’) for compounds A and B
5. Calculate the selectivity factor between peaks A and B
6. Discuss the influence of reducing the flowrate on selectivity factor
7. Discuss the separation between compound A and B as shown on the chromatograph
8. Calculate the number of theoretical plates involved in the separation of A and B
1- Most people I encounter refer to this as the column dead time peak, abbreviated t0. We'll see that t0 can be a useful diagnostic tool to identify potential . Although there are more-exact measurement techniques for t0
2-Retention time (tR) is the time elapsed between sample introduction .The HRT is the average length of time that a soluble compound remains in the .related to the diameter of the packing material (dp); B is diffusion coefficient of the .mean residence time of the wastewater within a biological reactor, thus determining the
3-The term (tr - to) is called the adjusted retention time and is often expressed as t'r, so k'x can ... is very small, there is so little retention of the compound that separation is not possible. ... b) Calculate the average number of plates for the column.
4-Capacity factor is an indication of how long a compound can be retained by the stationary phase. It is calculated as, k = (Tr - To)/To, where Tr is
5- It is generally calculated by k' = (tR - tM)/tM = tR'/tM. g) The selectivity factor (α) of a column for two analytes (A eluting before B) is given by α = KB/KA = k'(B)/k'(A) = tR'(B)/tR'(A).
6-flow-rate. For example, a change in flow-rate of 1–2 mL/min reduces N by ... describe retention in isocratic separation. Retention factor is ... This change is caused by the influence of flow-rate ... factor is defined as where tG is
7-Chromatography is a separation technique that every organic chemist and ... carried out chromatographic separations of a variety of mixture of compounds in the lab. ... As shown above, the three components A, B and C of the reaction mixture
8-N, the number of theoretical plates, is one index used to determine the ... Furthermore, it cannot calculate the width unless the peak is completely separated. ・・・4) a0.1: Width of first half of peak at 10 % height b0.1: Width of second half o