(a) Interpretation: The type of substance to which gas-liquid chromatography is most applicable is to be stated. Concept introduction: The type of substance for chromatography depends on the physical and chemical properties of the substance. The separation of a substance depends on the time taken by the substance move with gas as opposed to attached to the liquid phase. There are two phases in gas-liquid chromatography, first is the stationary phase and the second is the mobile phase. The carrier gas acts as the mobile phase and high boiling point liquid acts as a stationary phase.

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Principles of Instrumental Analysis

7th Edition
Douglas A. Skoog + 2 others
Publisher: Cengage Learning
ISBN: 9781305577213
BuyFind

Principles of Instrumental Analysis

7th Edition
Douglas A. Skoog + 2 others
Publisher: Cengage Learning
ISBN: 9781305577213

Solutions

Chapter 28, Problem 28.1QAP
Interpretation Introduction

(a)

Interpretation:

The type of substance to which gas-liquid chromatography is most applicable is to be stated.

Concept introduction:

The type of substance for chromatography depends on the physical and chemical properties of the substance. The separation of a substance depends on the time taken by the substance move with gas as opposed to attached to the liquid phase. There are two phases in gas-liquid chromatography, first is the stationary phase and the second is the mobile phase. The carrier gas acts as the mobile phase and high boiling point liquid acts as a stationary phase.

Expert Solution

Answer to Problem 28.1QAP

The volatile and thermally stable substances are used for gas-liquid chromatography.

Explanation of Solution

The gas-liquid chromatography is used, when the substance is in the mixed form of gas and liquid. The substances that are volatile and thermally stable is used in gas liquid chromatography.

Interpretation Introduction

(b)

Interpretation:

The type of substance for liquid adsorption chromatography is to be stated.

Concept introduction:

The type of substance for chromatography depends on the physical and chemical properties of the substance. The liquid adsorption chromatography depends on the retention of solute molecules on the liquid surface. The solute is the adsorbate which acts as the mobile phase and the solvent is the adsorbent which acts as a mobile phase.

Expert Solution

Answer to Problem 28.1QAP

The nonpolar polymers and isomeric compounds of low molecular weight are used in liquid adsorption chromatography.

Explanation of Solution

The substances that absorbed the other substance are called adsorbent substance. The liquid adsorption chromatography uses the quantity absorbed by the adsorbent. The different layer of absorbed substance is contained in the liquid adsorption chromatography. The nonpolar polymers and isomeric compounds of low molecular weight are used in liquid adsorption chromatography.

Interpretation Introduction

(c)

Interpretation:

The type of substance for liquid-liquid partition chromatography is to be stated.

Concept introduction:

The liquid substances that are immiscible can be separated by inserting a different liquid in the mobile phase. The separation of substance is based on the partition between the liquid stationary phase and the liquid mobile phase. The substance to be separated is passed through a column of the stationary phase. The adsorption process is used to separate the substance.

Expert Solution

Answer to Problem 28.1QAP

The amino acids, glycosides and carbohydrates are used in liquid-liquid partition chromatography.

Explanation of Solution

The non-volatile and thermally unstable substances like amino acids, glycosides and carbohydrates are used in liquid-liquid partition chromatography.

Interpretation Introduction

(d)

Interpretation:

The type of substance for reversed-phase chromatography is to be stated.

Concept introduction:

The organic compound of covalently bonded creates a hydrophobic stationary phase. This hydrophobic stationary phase reverses the polarity of the mobile phase and stationary because it has a strong affinity towards less polar compounds. The inert polar substances like silica act as a stationary phase and organic solvents act as the mobile phase for reversed-phase chromatography.

Expert Solution

Answer to Problem 28.1QAP

The thermally unstable and non-volatile organic substances are used in reversed-phase chromatography.

Explanation of Solution

The molecules of the mobile phase absorb the molecules of the hydrophobic stationary phase, and hydrophilic molecules pass from the mobile phase. The thermally unstable and non-volatile organic substances are used in reversed-phase chromatography.

Interpretation Introduction

(e)

Interpretation:

The type of substance for ion exchange chromatography is to be stated.

Concept introduction:

The ions exchange takes place when two insoluble and high molecular mass ionic compounds come in contact. The molecules of the substance are separated on the ionic strength of the solvent. This method is used for the analytical purposes as well as for the preparation of new substances. The anions and cations act as a stationary phase and mobile phase.

Expert Solution

Answer to Problem 28.1QAP

The ionic compounds are used in ion-exchange chromatography.

Explanation of Solution

The affinity of ion exchange is more so ionic compounds of high molecular mass are used in ion-exchange chromatography.

Interpretation Introduction

(f)

Interpretation:

The type of substance for gel permeation chromatography is to be stated.

Concept introduction:

The molecular size of the analyte is different for different materials. This type of chromatography separates the molecules of substances on the basis of their size. The molecule of smaller size remains for more time in pores of separating medium. This method is used to obtain the relative molecular weights of polymers. This method of separation is less time-consuming.

Expert Solution

Answer to Problem 28.1QAP

The gel permeation chromatography is used substances of high molecular weight and soluble in nonpolar solvent.

Explanation of Solution

The larger size molecule remains for less time in pores of gel so they get separated very easily. The material of high molecular weight and soluble in nonpolar solvent are used in gel permeation chromatography.

Interpretation Introduction

(g)

Interpretation:

The type of substance for gas-solid chromatography is to be stated.

Concept introduction:

The separation of substance occurs in gas-solid chromatography due to the physical adsorption of the analyte. The analyte is separated between the gaseous mobile phase and the solid stationary phase. The inert gas is used for the mobile phase. The substance to be separated is treated with a carrier gas and the detected in the detector.

Expert Solution

Answer to Problem 28.1QAP

The substances of non-volatile and low molecular mass gas are used in gas-solid chromatography.

Explanation of Solution

The molecules of the gaseous substance whose size is smaller than the pore size of solid surface easily passed from the pores. The molecules of size greater than the pore size of solid surface separated from the solid surface. The substances of non-volatile and low molecular mass gas are used in gas-solid chromatography.

Interpretation Introduction

(h)

Interpretation:

The type of substance for gel filtration chromatography is to be stated.

Concept introduction:

The gel in this type of chromatography separates the molecules of size smaller than the size of pores is separated. The gel filtration chromatography is a type of sieve chromatography. The substance to be separated is dissolved in the solvent and then passed through the porous matrix column. This type is mainly used for separating biochemicals.

Expert Solution

Answer to Problem 28.1QAP

The molecules of high molecular mass and hydrophilic nature are used in gel filtration chromatography.

Explanation of Solution

The porous matrix of gel acts as a stationary phase and the substance to be separated acts as a mobile phase. When molecules of a smaller size than porous matrix passes, they get easily passed and molecules of size greater than porous matrix get separated.

Interpretation Introduction

(i)

Interpretation:

The ionic compounds used in ion-pair chromatography is to be stated.

Concept introduction:

The substance in ion-pair separates on their affinity towards the ion and polar molecules. The ion-pair chromatography is a modified form of reverse phase chromatography. The organic salt is used to produce ions in the mobile phase. The ion pairs are separated in the nonpolar stationary phase. The ionic and non-ionic compounds present in the sample are separated by this type of chromatography.

Expert Solution

Answer to Problem 28.1QAP

The small ionic organic and inorganic substances are used in ion-pair chromatography.

Explanation of Solution

The substance in ion-pair chromatography separated in anions and cations on the basis of their polarity. Two different mechanisms can be used to separate the ions in the substance. In the first mechanism, unchanged ion pair with solute ion pair in the mobile phase is portioned into a nonpolar stationary phase. In the second mechanism, separation takes place between the neutral stationary phase and the charged mobile phase.

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