2. Separation of Amino Acids by lon-Exchange Chromatography Mixtures of amino acids can beanalyzed by first separating the mixture into its components through ion-exchange chromatography. Amino acids placed on a cation-exchange resin (see Fig. 3-17a) containing sulfonate (OSO3_) groups slow down the column at different rates because of two factors that influence their movement: (1) ionic attraction between the sulfonate residues on the column and positively charged functional groups on the amino acids, and (2) hydrophobic interactions between amino acid side chains and the strongly hydrophobic backbone of the polystyrene resin. For each pair of amino acids listed, determine which will be eluted first from an ion-exchange column by a pH 7.0 buffer. (a) Asp and Lys (b) Arg and Met (c) Glu and Val (d) Gly and Leu (e) Ser and Ala

2. Separation of Amino Acids by lon-Exchange Chromatography Mixtures of amino acids can beanalyzed by first separating the mixture into its components through ion-exchange chromatography. Amino acids placed on a cation-exchange resin (see Fig. 3-17a) containing sulfonate (OSO3_) groups slow down the column at different rates because of two factors that influence their movement: (1) ionic attraction between the sulfonate residues on the column and positively charged functional groups on the amino acids, and (2) hydrophobic interactions between amino acid side chains and the strongly hydrophobic backbone of the polystyrene resin. For each pair of amino acids listed, determine which will be eluted first from an ion-exchange column by a pH 7.0 buffer. (a) Asp and Lys (b) Arg and Met (c) Glu and Val (d) Gly and Leu (e) Ser and Ala

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter33: Automated Methods Of Analysis

Section: Chapter Questions

Problem 33.8QAP

See similar textbooks

Similar questions

hree components in a mixture have varying distribution constants between the mobile phase and the stationary phass One of the components has a very low distribution constant, Would this component likely elute first or last and how would you design an experiment or modify the components of the separation to make it perform in the opposite manner?
In ion-exclusion chromatography, ions are separated from nonelectrolytes (uncharged molecules) by an ion-exchange column. Nonelectrolytes penetrate the stationary phase, whereas ions with charge of the same sign as that of the stationary phase are repelled by the stationary phase. Because electrolytes have access to less of the column volume, they are eluted before nonelectrolytes. A mixture of trichloroacetic acid (TCA, pKa 5 20.5), dichloroacetic acid (DCA, pKa 5 1.1), and monochloroacetic acid (MCA, pKa 5 2.86) was separated by passage through a cation-exchange resin eluted with 0.01 M HCl. The order of elution was TCA , DCA , MCA. Explain why the three acids are separated and the order of elution.
A scientist wishes to measure the concentration of methyl benzoate in a plant stream by gas chromatography. He prepares a sample of butyl benzoate to use as an internal standard. The results of a preliminary run, which used a solution known to contain 1.37 mg/mL of methyl benzoate (peak A) and 1.51 mg/mL of butyl benzoate (peak B), are shown. The area of peak A is determined to be 3.40×102 and the area of peak B is determined to be 398 measured in arbitrary units by the computer. To measure the sample, 1.00 mL of a standard sample of butyl benzoate containing 2.49 mg/mL is mixed with 1.00 mL of the plant stream material. Analysis of the mixture gave a peak area of 437 for peak A and 415 for peak B. What is the concentration of methyl benzoate in the plant stream?
The required mobile phase for the analysis caffeine in soft drinks in liquid chromatography are methanol and water. What class of methanol and water must be used? Kindly explain the answer.
in HPLC, what does it mean to equilibrate the system. Let us assume that the system is currently running 100%B. You have told them to run the first standard of caffeine using Reverse Phase chromatography with a C18 column, 30% A (Water/0.1%TFA) and 70% B (MeOH/0.1%TFA).What should I equilibrate the system to and for how long?
1. Calculate the capacity factor, k' for methyl paraben and propyl paraben. 2. Calculate the selectivity factor, a for the two-component mixture.
In a separatory funnel, if "The layer separating the two solvents (organic & aqueous) is not visible" Describe two methods by which you can solve this problem and locate the separation between the 2 layers.
In chromatography, the compound that is least soluble in the mobile phase a) Travels the furthest away from the line of origin b) Stays closest to the line of origin
Algal oil from Spirogyra sp. was extracted using a combined technology of partitioning between phase extraction as shown in Figure Q.1. (a) Suitable extraction technique to extract the oil from the algal suspension as shown in the first step. (b) Suitable extraction techniques to separate the aqueous layer, algal protein suspension particle and the organic layer on the third step. Please explain in detail each of the steps. (c) Suitable evaporation technique for separate algal oil from the organic layer in the fourth step.
Help me.... Explain the principles of gel permeation chromatography in Polymer, what is the application in Polymer analytics
Calculate the vapor pressure of propanol (b.p. 97.0 ∘C97.0 ∘C) at the gas chromatography column temperature of 95.0 ∘C95.0 ∘C using the form of the Clausius–Clapeyron equation shown ln(?1?2)=−(Δ?vap?)(1?1−1?2)ln(P1P2)=−(ΔHvapR)(1T1−1T2) where ?R is the ideal gas constant, Δ?vapΔHvap is the enthalpy of vaporization, ?1T1 and ?2T2 are two different temperatures, and ?1P1 and ?2P2 are the vapor pressures at the respective temperatures. The enthalpy of vaporization can be estimated using Trouton's rule, Δ?∘vap=(88 J·mol−1⋅K−1)×?bp.ΔHvap∘=(88 J·mol−1⋅K−1)×Tbp. ?=P= TorrTorr Calculate the vapor pressure of pentane (b.p. 36.0 ∘C36.0 ∘C) at the same column temperature. ?=P= TorrTorr For compounds of the same chemical class, what is the relationship between vapor pressure of a compound and retention in gas chromatography? As the vapor pressure decreases, retention time decreases. As the vapor pressure increases, retention time increases. As…
Which statements are true for molecular exclusion chromatography?I Molecular exclusion chromatography separates on the basis of size.II Small molecules can fit in the pores of the stationary phase and effectively pass through a larger volume, and elute last.III The pores in the stationary phase are too small for large molecules to pass through, so large molecules elute first.IV Molecular exclusion chromatography with a hydrophilic stationary phase and an aqueous solvent is called gel permeation chromatography. A. I, II, III B. III and IV C. II only D. I and II only E. I, III, and IV