The following data are for a liquid chromatographic column: Length of Packing 24.7 cm Flow rate 0.313 mL/min Vm 1.37 ml Vs 0.164 ml A chromatogram of a mixture of species A, B, C, and D provided the following data: Width of Peak Base Retention Time, min (W), min Nonretained 3.1 A 5.4 0.41 13.3 1.07 C 14.1 1.16 D 21.6 1.72 Calculate the plate height for the column.

The following data are for a liquid chromatographic column: Length of Packing 24.7 cm Flow rate 0.313 mL/min Vm 1.37 ml Vs 0.164 ml A chromatogram of a mixture of species A, B, C, and D provided the following data: Width of Peak Base Retention Time, min (W), min Nonretained 3.1 A 5.4 0.41 13.3 1.07 C 14.1 1.16 D 21.6 1.72 Calculate the plate height for the column.

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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Substances A, B, C and D were found to have retention times of 8.3 min (A), 10.6 min (B), 12.4 min (C) and 13.5 min (D), respectively on an 15.0 cm long column. There was also an unretained species which appeared at 1.5 min. The widths of the peak bases were 0.90 min (A), 1.1 min (B), 1.3 min (C) and 0.80 min (D). Given this information listed above, please choose the most appropriate answer for the six questions listed below for the list of possible answers. Part A Calculate the capacity factor (k') for peak B and peak D. Part B. Calculate the resolution (R) between peaks B and D. Part C. What do the capacity factor and resolution tell you about the separation of peaks B and D on this column? Part D What are the theoretical plate number (N) for peaks Band D? Part E. What is the average plate height (H), based on the information in Part D and the column length listed above? Part F What would be the required length of a column to achieve a Rs of 2.07
You perform a concentration of a single component using displacement chromatography, and the following data applies: Concentration of binding sites: 4*10^(-4) M Kd for displacer: 2.0*10^(-5) M Kd for component A: 4*10^(-5) M Kd for component B: 1.5*10^(-4) M The concentration of the injected displacer is 2.0*10^(-4) M Determine and justify whether the components are part of a displacement system, and if so, provide their free and bound concentrations. Assume that the number of binding sites is the same for all components.
Select wether the following statements are True or False: Two compounds that are separated on a 10 cm column have a resolution equal to 1.5. If all conditions remain identical, if the length of the column is doubled, the resolution will increase. An example of a stationary phase support used in strong anion exchange would be a quarternary ammonium-functionalized polymer. In normal phase chromatography, a more polar compound will have a higher partition coefficient than a compound that is less polar. In gas chromatography, compound with higher boiling points generally (but not necessarily) elute later than compounds with lower boiling points. In a chromatographic separation, a compound with a capacity factor equal to 1 must spend an equal amount of time in the mobile phase as it does in the stationary phase.
The write-up says “A C18-silica column is used in this experiment, a 0.46 x 15 cm column with 5-µm particles. Equilibrate the column with 20 empty column volumes of 0.010 M phosphate buffer (pH 7.2) at a flow rate of 1.2 mL/min before beginning chromatography.” Show the calculation for how much mobile phase you would use (volume) and how long it will take to equilibrate the column.
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Substances A and B have retention times of 16.40 and 17.63 min, respectively,on a 30.0-cm column. An unretained species passes through the column in 1.30 min. The peakwidths (at base) for A and B are 1.11 and 1.21 min, respectively. Calculate(a) the column resolution,(b) the average number of plates in the column,(c) the plate height,(d) the length of column required to achieve a resolution of 1.5.
Next, 2.00 mL of 9.63 mM S was added to 10.00 mL of a solution of unknown concentration of X, and the mixture was diluted to 25.0mL. Chromatographic analysis of this solution produced peak areas of 4822 for X and 4099 for S. What was the concentration of 5 (in mM) of the 25.0mL solution?
The following data are for a GLC column: L= 35.5 cm, flow rate = 0.303 mL/min A chromatogram of a mixture of the following compounds provide the following data: (min) (min) Air 0.9 | Benzene 5.0 0.71 Toluene 7.9 0.82 Xylene 8.4 1.16 Calculate: a. The number of plates from each peak. b. The mean for N. C. The plate height H. From the data above, calculate the resolution for d. Benzene and toluene. e. Toluene and xylene. F. Benzene and xylene. g. The length of column required to achieve an average resolution of 4.50.
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The data in the following table were extracted from a gas chromatographic analysis of a two- component mixture. Air nonane decane Retention time (s) 5 26 32 Peak width, baseline (s) 5 4 (i) Calculate the capacity factor, k, for the two compounds. (ii) Calculate the selectivity factor, a, for the two compounds.
A mixture of three components is separated using paper chromatography, and each component is analyzed using absorption. With standards containing 100 ppm of each component run simultaneously, the following data were obtained: cmpd A, 0.72 absorbance; B, 0.55; C, 0.80. For the unknown mixture, the data obtined when run under identical conditions were as follows: cmpd A, .0.15 absorbance, B, 0.84; C, 0.75. a) Calculate the relative percentage composition of the unknown mixture. b) The distances traveled by the three components were 8.5, 6.3, and 5.5 cm, respectively. Sketch the appearance of the paper chromatogram. Label each spot. c) Calculate the Rf values if the solvent front is 18 cm.
Consider the following chromatographic data for the separation of methylparaben from ethylparaben in a sunscreen sample. Compound Methylparaben Retention time, tr (min). Width at base of peak, Wb (min) 3.2 4.2 0.55 0.60 Ethylparaben A compound not retained by the column in this analysis had a tm of 0.75 minutes. The column used was a C18 column with a mobile phase mixture of 75% methanol and 25% water. Calculate the number of theoretical plates for ethylparaben.