Saturday, June 27, 2020

Advantages of capsules over tablets

Capsules are most commonly prescribed as an oral solid dosage form, which is made of special film-forming material, used to enclose drugs and excipients to a relatively stable shell from which they can be taken orally. There are two major types of capsules are soft-shell capsules and hard-shelled capsules. Tablets are the most commonly used oral solid dosage forms in which the powdered drug that has been mixed with excipients and then compressed them to get the shape. Tablets can be coated to protect from taste and odor, generally, it comes with uncoated.
Advantages of capsules over tablets

The most commonly used forms for the medication in the finished product are tablets and capsules. Some drugs can be used in liquid oral dosage forms, but tablets and capsules are the most common. Both are working for a specific purpose of delivering a drug or supplement through your digestive tract. Both tablets and capsules offer numerous advantages. Capsules are convenient for consumers for a few different reasons; let's look at some advantages of capsules over tablets.
  • The major advantage of the capsule over the tablet is that within the capsule the most numerous drugs and excipients or ingredients are mixed, making it easier for a patient to swallow the capsule without having to deal with an unpleasant taste or odor.
  • Compared to tablets, it is less likely to cause gastrointestinal irritation.
  • The capsule is quite convenient for the patient as it is easier to swallow than a tablet.
  • The capsule is tamper-resistant- it is not easy to split it in half or crush it like pills, so it may be more likely to be taken as needed.
  • It can be attractive to children as it is available in a wide range of colors.
  • The gelatin shell can provide protect the drug from moisture, light, and air.
  • The capsules have higher bio-availability compared to tablets, which means more drugs are likely to enter your bloodstream.
  • It can dissolve rapidly, reach the bloodstream quickly.
  • Compared to tablets, less excipients is required to prepare the capsule.

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Friday, June 26, 2020

Advantages of tablets over capsules

The medicine or drug can be administered in a variety of pharmaceutical dosage forms. It may be as intravenous or oral medication. Solid and liquid medicines are types of oral medication. Solid medication is either taken in tablet or capsule form. Both tablets and capsules are most commonly prescribed as an oral solid dosage form. However, both have some similarities like both are solid dosage form, work similarly, both have excipients, both are used for treatment. But they also have some major differences.
The advantages of a tablet over the capsule are as follows.
  • The major advantage of the tablet over the capsule is that the tablet can come in a fast release, delayed-release, sustained-release, or extended-release type, which is not available in the capsule.
  • The stability of the tablet is higher than the capsule, as it is less affected by moisture, air, and light, etc.
  • Special conditions are not required to store tablets.
  • Unlike capsules, tablets can be cut into two or more pieces if small doses are required.
  • The tablets are cost-effective compared to capsules, as the medicine and excipients of capsules need to be packed in hard or soft gelatin shells.
  • Tablets can be manufactured in custom sizes, shapes, and colors.
  • For those who have difficulty swallowing, especially for children, sick patients, several tablets are available as chewable or orally dissolving tablets.
  • The shelf-life of the tablets is longer and it comes in several forms.
  • The tablet accommodates a higher dose of the active ingredient than the capsule.
  • The manufacturing process of tablets in pharmaceutical industries is easier than that of capsules.
  • Tablets are available in a wide variety of sizes and shapes.
  • The tablet is very stable and retains drug potency compared to capsules.

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Thursday, June 25, 2020

Advantages and disadvantages of tablets

The tablet is the most commonly prescribed solid dosage forms. Generally, it is intended for oral routes of administration. It is prepared by compressing powdered active pharmaceutical ingredient (API) with different excipients. The table is a flat, rounded in shape and differs in shape, size, and weight depending on the drugs used to prepare. Tablets usually contain flavoring agents, coloring agents, lubricants, diluent, filler, disintegrants, binder, anti-adherent, and some other excipients. Tablets are the most broadly used solid dosage forms due to the increasing advantages and popularity day by day.

Tablets- solid dosage form

 Advantages of tablets:
  • The major advantages of tablets have dose accuracy, stable dose, high precision, and lowest variability.
  • Tablets are cheaper than other dosage forms and are economical for packaging, transport, and storage.
  • It is easy to swallow, and in some cases, it can easily dissolve in water for feeding for children.
  • It is providing protection of drugs (API) from atmospheric conditions such as moisture, air, and light, etc.
  • Sugarcoating the tablet masks the unpleasant taste and smell of the drugs, hence it can be simply administered.
  • Tablets have a low production cost and mass production is possible as compared to the other dosage forms (capsule, liquid), as it is easier to prepare.
  • Tablets can provide flexibility in dosage form by creating a special release product such as a delayed-release, sustained release, and a rapidly dissolving tablet.
  • Whenever a partial dose is required, it is easy to divide into parts, which is not possible in capsules.
  • Tablets are most stable in chemical, physical, and microbiological properties.
  • It does not harm the gastrointestinal tract, as it easily and quickly digested.
  • Administration of the minute dose of the medicine is possible because it provides the exact amount.
  •  Tablets can be attractive as they vary in color.
  • As compared to liquid dosage form, it does not require much space for storage, and the production, packing, and handling is cheaper.
Disadvantages of tablets:
  • The major disadvantage of a tablet is that it is difficult to swallow, especially for children, sick, and unconscious patients.
  • Low density and amorphous APIs are difficult to compress in the tablet punching machine.
  • Drugs that are hygroscopic in nature are not suitable for compressed tablets.
  • Certain types of pills can cause problems in bio-availability.
  • Oxygen-sensitive drugs require special coating.
  • Drugs that have poor or low solubility in water, slow dissolution rates, and high absorption in the gastrointestinal tract may make them difficult to formulate.
  • Production costs can increase due to the coating and encapsulation of the tablet.
  • Sometimes due to unpleasant taste and odor, patients experience discomfort and avoid swallowing.
  • The manufacturing of tablets in the pharmaceutical industry requires complex and expensive machines.
  • Some medicines cause gastric irritation while administered in tablet form.
  • There is an unlimited amount of a unique mix of ingredients that can only be placed in capsules, not tablets.

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Tuesday, June 2, 2020

What are the different types of columns used in HPLC

Different types of HPLC columns are used to separate the analytes according to nature, composition, and separation modes of HPLC.

The column is the basic component in the analysis of the high-performance liquid chromatography as it is responsible for the separation of compounds. The sample solution moves through the column along with the mobile phase and it comes out of the column as the separate into its components. In general, silica gel is filled in columns due to its porosity and size of particle which helps to separate the compounds, and it is also inert solid support which does not react with solvents. Thus the silica columns are used in the analysis of compounds. Liquid chromatography can be classified into several modes. If the classification of chromatography depends on the stationary phase and the nature of the separation method, then it may be adsorption chromatography, size exclusion chromatography, and ion-exchange chromatography. With respect to the first type, there are two separation modes are based on polarity which is reverse-phase chromatography and normal-phase chromatography, these modes cover about 90% of all chromatography applications. 


There are various types of HPLC columns are available for liquid chromatography depending on their composition and separation system, let’s check it.

Reversed-phase HPLC columns:

The reversed-phase chromatography has a non-polar stationary phase and a polar mobile phase. Bonded hydrocarbons such as C8 and C18 and other non-polar hydrocarbons are used in reverse phase columns as a stationary phase, while an aqueous organic solvent such as acid, buffer, methanol, acetonitrile, or a suitable mixture of it is used as a mobile phase. The isolation of molecules in reversed-phase columns often takes place based on the sample polarity, but this is unlike the normal phase HPLC column so this type of chromatography is known as reverse phase chromatography.
The commonly used columns in reversed-phase are:
  • C18 RP-HPLC columns
  • C8 RP-HPLC columns
  • Alkyl reversed-phase columns
  • Phenyl reversed-phase columns
  • C4 RP-HPLC columns
  • C1 RP-HPLC columns
  • C30 RP-HPLC columns

Normal phase HPLC columns:

Normal-phase chromatography is a type of liquid chromatography it is used for the isolation of positional isomers which are complex to separate in RP-HPLC. The normal-phase chromatography has a more-polar stationary phase and a non-polar mobile phase. The solid support of the column is more polar hence rather than the water hexane, methylene chloride chloroform, diethyl ether, or a mixture of these used as mobile phase. Separation in normal-phase chromatography is based on the polarity of the analytes; more polar analytes interact more with the stationary phase.
The commonly used columns in normal-phase are:
Silica normal phase columns: these are potent and efficient column for isolating non-polar and moderately polar isomeric molecules.
Amino normal phase columns: These types of columns are mainly useful for the isolation of carbohydrates.
Cyano normal phase columns:  These types of columns have an optional selectivity and are more rapidly equilibrated, providing better suitability for normal phase gradient isolation than unbonded silica columns

Ion-exchange HPLC columns:

Using these columns, the molecules which can quickly ionize are analyzed. In these columns, the stationary phase remains acidic or basic for a positive or negative charge, whereas a polar mobile phase used in the form of a salt solution in water. The isolation of components takes place between the components and the charged stationary phase based on the attractive ionic force. For stationary phase different mediums are used, the most generally used immobilized charged groups are trimethylaminoethyl, diethyl-2-hydroxypropylaminoethyl, triethylaminoethyl, diethylaminoethyl, aminoethyl, sulphomethyl, sulphopropyl, and sulpho. Successful column packing is a significant aspect of ion-exchange chromatography. Polystyrene is used for the separation of small molecules in amino acids as a medium. The cellulose medium can be used to isolate large solutes since they have large pores. 

Size-exclusion HPLC columns:

Size exclusion chromatography (SEC) is also known as gel filtration chromatography. The size exclusion chromatography columns are typically filled with porous polystyrene divinylbenzene or silica particles. These columns are generally used for the analysis of synthetic polymers in organic solvents, whereas to separate the biopolymers the silica-based columns are used. The porous stationary phase in these columns allows the analytes to be separated as per their size. Small sample components enter the pores of the stationary phase, whereas larger molecules partially penetrate the pores. Thus the bigger sample components are eluted rapidly than the small molecules. Generally, these columns are not used for the analysis of pharmaceuticals.

Different types of gels in HPLC columns: 

Silica gel: Silica gel is the most commonly used packing material. There are two types of silica gels are available such as spherical and irregular shape, out of these the spherical shaped gels are most commonly used. The silica gel used in liquid chromatography has a pore on the surface; it gives a bigger surface area than without holes. The 5μm is the most widely used size, although smaller sized 1.5 to 3μm gels is also used in HPLC columns.
Polymer gel:  Silica gels are commonly used in HPLC development, although, polymer-based columns are also well-liked. Polyethylene and polypropylene are commonly known polymers for column packing. Columns of polymer gel are available in very small particles, like the silica gel. 
Other gel: In addition to silica and polymer gels, the gels used include natural substances such as cellulose, chitosan, dextrin, and ceramics are used in liquid chromatography to isolate analyses but have very limited use.
The column is the most important part in the HPLC system, the actual isolation of molecules of the sample mixture happens in the column. A column is located after the injector where the mobile phase is in contact with the stationary phase, forming an interface with the enormous surface. In recent years, the development of most chromatography has contributed to the creation of several different methods for through this interfacial contact. Usually, RP-HPLC columns are available in lengths of 30 to 250 mm, the diameter of 01 to 05 mm, and pore size of 03, 05, and 10 μm. 

Commonly asked questions on chromatography are as follows.

How many types of HPLC are there?
Depending on the stationary phase in the process, there are 4 types of HPLC, such as normal Phase HPLC, reverse phase HPLC, size-exclusion HPLC, and ion-exchange HPLC.

What is the difference between C8 and C18 HPLC columns?
The main difference between the C8 and C18 columns is their carbon atoms. C8 has 8 carbon atoms, whereas C18 has 18 carbon atoms. C8 has a small carbon chain, whereas C18 has a longer carbon chain. C8 has a short, whereas C18 has longer retention time (RT).

Which type of HPLC detector is most widely used?
The UV/VIS and PDA detectors are the most commonly used detector in HPLC as they give superior sensitivity for light-absorbing compounds.

Which is better GC or HPLC?
The gas chromatography (GC) is better for the separation of volatile compounds, whereas the high-performance liquid chromatography (HPLC) is better for the separation of less volatile samples.

What is the basic principle of chromatography?
There are different types of chromatography, although they operate on the same principle. They have a stationary phase and a mobile phase. The mobile phase has a sample mixture moves on the stationary phase, some solutes have an affinity for the stationary phase will travel slowly, While solutes that do not interact with the stationary phase will move faster.
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What is the difference between ascending and descending paper chromatography?

Paper chromatography is a separation technique in analytical chemistry that is used to separate the sample mixtures into their individual components. By capillary action, the sample mixture is moved to the stationary phase using the mobile phase. They move at different speeds, since, their different affinity with the stationary phase, and thus, get separated. Generally, the cellulose filter paper is used as solid support. Five types of paper chromatography are used, depending on how the chromatogram is developed such as ascending chromatography, descending chromatography, ascending- descending mode, radial mode, and two-dimensional chromatography, etc.
Both ascending chromatography and descending chromatography are types of paper chromatography used to separate molecules. The major difference between ascending and descending paper chromatography is that, In ascending chromatography, the analytes are in the mobile phase and travels from bottom to top (by capillary action). Similarly, in descending chromatography, the solvent travels from top to bottom. This method gives rapid separation as the mobile phase moves with gravity. However, the principle of separation in both types remains the same; ascending chromatography is technically easy to execute.
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Ascending and descending paper chromatography

Paper chromatography is a type of chromatography used for the separation and identification of chemical substances. The stationary phase in paper chromatography is a sheet of cellulose paper of appropriate thickness and texture, which may often be impregnated with a solvent that is immiscible with the mobile phase. Chromatographic separation on paper is much slower than the plates typically used in thin-layer chromatography and is not as versatile as compared with TLC because the degree of variation of the stationary phase is very much limited. However, paper chromatography is still a valuable and very effective method for separations.

Principle of paper chromatography:

The solvent mixture rises by capillary action through the stationary phase. The concentrated sample applies at the bottom of the filter paper in the form of a minute spot. As the liquid mobile phase moves up onto the filter paper, the spotted sample mixture gradually travels along with the mobile phase. This ultimately results in the separation of the solutes. The solutes in the mixture of samples will be separated as per their ability to solubility. In other words, it is polarity like open column chromatography. The molecules have less polarity will travel faster, while more polar molecules are travel more slowly. Every separated spot has its own Rf value. The retention factor (Rf value) signifies the ratio amongst the migration distance of a solute and the migration distance of the solvent front.

Different types or modes of paper chromatography:

There are five types of paper chromatography available based on the development of chromatograms.
1. Ascending chromatography
2. Descending chromatography
3. Ascending- descending mode
4. Radial mode
5. Two-dimensional chromatography
In this article, we are discussing ascending paper chromatography and descending paper chromatography.

Ascending paper chromatography:

Ascending chromatography is a separation method of paper chromatography in that the solvent travels up the stationary phase against gravity. The development of the chromatogram is caused by the upward movement of the mobile phase on paper. The bottom of the paper immersed in the mobile phase, but the spots remain just above the mobile phase. The analytes are separated because each molecule has a different affinity for the stationary phase.

Principle of ascending chromatography:

In ascending paper chromatography, the mobile phase moves upwards by the capillary action, opposite to gravity, and compound are separated by using the principle of partition chromatography or adsorption chromatography.

Procedure of ascending paper chromatography:

Application of the Sample:
  • Using a pencil marked the starting point on the paper.
  • A spotter, like a thin capillary tube, is used to spot on paper; it can be a very small dot of the sample mixture. Dry the sample spot.
Development of chromatogram:
  • The paper is put in a closed container like a beaker or chamber that contains a small amount of the mobile phase. The end of the paper is below the solvent level, and the starting point shown on the paper is above the solvent.
  • The mixture of solvents will gradually rise by capillary action. Compounds will also rise-up, although the rate is slower than in the mobile phase.
  • Analytes that have high solubility in the mobile phase and low solubility in the stationary phase are quickly moving up.
  • After the solvent front has about reached the top of the stationary phase the solvent front is marked and the paper is placed aside to dry.
Detection:
  • We can observe the position of each analyte on the paper if they are different in colors. However, when the analyte is colorless, then the several techniques are used to detect each analyte. For example, reactions with color-producing reagents: by spraying amino acid with ninhydrin reagent can produce visible violet spots. Or. If the sample has fluorescence or absorbs ultraviolet light, it can be viewed under ultraviolet light by placing it in a UV cabinet.
Calculating the retardation factor (Rf value):
  • Calculate the distances traveled by the mobile phase and each analyte. The retention factor is useful to compare results with results from another.

Descending paper chromatography:

Descending chromatography is a type of paper chromatography in which the chromatogram is developed by a solvent that travels downstream of the paper. The mobile phase flows over the stationary phase and it moves by gravity. Descending chromatography is used in both thin layer chromatography and paper chromatography.

Principle of descending chromatography:

Partition chromatography or adsorption chromatography is the basic principle of descending chromatography. It works on the principle of adsorption chromatography for and chromatography for the partition.

Procedure of descending paper chromatography:

  • The system of descending chromatography is the contrast of ascending chromatography. This is a considerably more complex setup than ascending chromatography.
  • The tank of the mobile phase is positioned on top of the system. The chamber wants to saturate before separating the components.
  • The spotting of the sample in descending chromatography is similar to that in ascending chromatography. After spotting the compounds, adsorption paper is attached to the top of the chamber.
  • The mobile phase travels slowly from top to bottom in the stationary phase. The sample goes with the solvent and its components are separated.
  • The isolated sample mixture is observed on paper as spots after drying. Coloring reagents are sprayed on paper to visualize the spot or viewed under ultraviolet light.

Difference between ascending and descending paper chromatography:

In paper chromatography, there are two methods for separating compounds: ascending and descending paper chromatography. The principle of separation, however, is the same in both forms. However, the principle of separation is the same in both types.
The major difference between ascending and descending paper chromatography is that in ascending paper chromatography the mobile phase is rises by capillary action through the stationary phase which is against the gravity, while in descending paper chromatography the mobile phase flows over the stationary phase and it moves by gravity.

Commonly asked questions on paper chromatography are as follows.

What is ascending and descending chromatography?
Both ascending and descending chromatography is a technique used in paper chromatography. In ascending chromatography, for the separation of components, the solvent moves upward by capillary action on the stationary phase. In descending chromatography, the mobile phase travels along with the gravity by which the separation takes place.

What are the advantages of ascending paper chromatography?
The major advantages of ascending paper chromatography include, that organic as well as inorganic compounds can be identified, it requires less amount of sample, it is an economical method, in the short time it separates the compounds, etc.

What are the major disadvantages of ascending paper chromatography?
This method is not suitable for a compound with a higher Rf value, as it does not have a long stationary phase. Another is, it does not save data for long periods.

What are the 4 types of chromatography?
There are four main chromatographic forms. These are liquid chromatography, thin-layer chromatography, gas chromatography, and paper chromatography.


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Mechanism of separation in paper chromatography

The chromatographic method works on the basis of four different separation mechanisms, such as partition, adsorption, size exclusion, and ion exchange.

What is paper chromatography?

Paper chromatography is one of the oldest and easiest separation techniques that have evolved along with other modern variants such as high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC), gas chromatography (GC) and hyphenated techniques throughout the years. Paper chromatography is a planar chromatography in which the stationary phase is a cellulose filter paper, on which the compounds are isolated. The edge of the paper is immersed in a mobile phase or solvent, and it moves up the paper by capillary action so the compounds are isolated.

Mechanism of separation in paper chromatography:

The process consists of a sample apply as a spot close to a corner of a paper. The filter paper is initially saturated with some suitable solution to form the stationary liquid phase. An edge of the paper above the sample spot is then soaked in another solution, in that the analytes become soluble in different degrees. The solvent enters by capillary action in the stationary phase and, passing through the spot of the sample it carries different analytes of the sample.

The analytes travel with a solvent flowing in velocity that is dependent on their solubility in the stationary and mobile phase. The separation of analytes is achieved when their relative solubility varies between the two solvents. Both solvents are evaporated until the moving solvent reaches the farther edge of the stationary phase and the position of the separated analytes is recognized, generally, reagents are sprayed to appearance colored compounds with different substances. The isolated analytes show as spots on the path of the solvent and hence we can calculate the Rf value of the compound. If the mobile phase that flows in one direction and that cannot adequately separate all the molecules, then the paper can be turned 90° and the process can repeat with another mobile phase.

The principle of paper chromatography:

"partition" is the basic principle involved in paper chromatography, in which the solutes are partitioned or distributed among the liquid phases. In this method a special type of chromatography paper or a piece of filter paper used as a stationary-phase which is made with cellulose. The mixture of sample is applied to the paper and the edge of the paper is immersed in a mobile phase which is placed in the TLC chamber. The mobile phase or solvent runs on the paper under capillary action in paper pores. The capillary attraction of the solvent relies on the cohesive and adhesive forces allow the mobile phase to travel up the stationary phase because of created surface tension interaction from the forces.

The properties and structure of each molecule vary, so they have differences in the relative affinity for the stationary phase and the mobile phase. It is also in the form of adsorption chromatography between liquid and solid phases, in that the mobile phase is the liquid and a stationary phase is a solid surface. Though the most widely used paper chromatography operates on the partition chromatography theory.

Different types of paper chromatography:

There are 5 types of paper chromatography available, depending on how the chromatogram is developed.

Ascending chromatography:

As the name suggests, chromatograms are ascending in this type of paper chromatography. The chromatograms are developed due to the upward movement of the mobile phase on paper. The solvent is at the bottom of the TLC chamber. The paper tip below the sample spot immerses to the bottom and therefore the spots remain just above the mobile phase.

Descending chromatography:

In this form of paper chromatography, the paper is developed by the solvent travels downstream of the paper. The solvent is flowing from the top of the stationary phase and it moves by gravity.

Ascending- descending mode:

This is a hybrid type of paper chromatography, the mobile phase first flows-up over a stationary phase, which is folded onto the rod and starts traveling downwards after crossing the rod. This method allows longer-term development and gives higher resolution, particularly used for the complex sample mixtures.

Radial or horizontal mode:

The solvent travels from the center to the periphery of the circular filter paper. For the development of chromatograms, this is usually done in a covered petri dish instead of a TLC chamber. The wick at the center of the stationary phase is dipped in the solvent from which the mobile phase is drained on the stationary phase and moves the solutes radially as concentric rings to form the spot of the solute.

Two dimensional paper chromatography:

In this type of paper chromatography, stationary phase is first used with one mobile phase in one direction, and then another solvent is used in direction at right angles to the first, after the paper has been dried.


Commonly asked questions on chromatography are as follows.

What is the paper used in paper chromatography?
Paper is made of cellulose fiber, and cellulose is a polymer of simple sugar, glucose.

What are some examples of chromatography?
Column chromatography, thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), gas chromatography (GC), partition chromatography, ion-exchange chromatography, are some examples of chromatography.

What does paper chromatography separate?
Paper chromatography is used to isolate colored chemicals or compounds.

What factors affect paper chromatography?
Length of the paper, the composition of the mobile phase, quality of paper used, nature of solvents used, temperature, the thickness of the paper, the polarity of components, the pH of the solvent, and saturation of the solvent, etc. are the factors that affect paper chromatography.

What are the advantages of TLC?
TLC is a type of planar chromatography it has many advantages such as, it is very simple to use, it required less time to isolate the compounds, it requires less amount of sample, we can recover the sample by scratching the TLC plate, more sensitive than paper chromatography, and it can be upgraded to HPTLC.


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Partition chromatography mechanism of action

The chromatographic technique works based on four different separation mechanisms, such as partition, adsorption, size exclusion, and ion exchange.  

What is partition chromatography?

Partition chromatography is the basic method of distribution mechanism of liquid-liquid chromatography, specifically when the stationary phase and mobile phase both are liquids. Isolation by distribution depending on the relative solubility of the component in both phases. The basic principle of partition chromatography is used in several methods, such as high-performance liquid chromatography (HPLC), paper chromatography, high-performance thin-layer chromatography (HPTLC), and gas chromatography (GC). 

Separation mechanism of partition chromatography:

The stationary liquid phase of partition chromatography is coated on solid supports such as silica gel or cellulose powder. Assuming solid supports have not adsorption, the mobile and stationary phases move the compounds through the system at rates determined by the solubility of their components. Usually, the mobile and stationary phases do not need to be entirely immiscible; however, it is ideal to have a low degree of mutual solubility. Hydrophilic stationary phase solvents are commonly used in combination with hydrophobic mobile phases, or vice versa.

Principle of partition chromatography: 

Partition chromatography is the technique of separation in which the solute present in a sample mixture distributes more possibility in two liquid phases as the differences in partition coefficients. In this method, the analytes are isolated amongst two phases i.e. both the mobile phase and the stationary phase are in the identical phase. In this process of separation, on the stationary phase, the immiscible solid surface coated with the liquid surface is in the mobile phase. The liquid surface is immobilized by a stationary phase resulting in its being a stationary phase. The mobile phase travels over the stationary phase and the analytes are separated. Consequently, the analytes are preferably dispersed at any phase.  

Different types of partition chromatography:

Liquid-liquid chromatography: In this kind of partition chromatography both phases such as stationary phase and mobile phase are taken in liquid form. However, the liquid stationary phase is supported by coated by solid supports. Its sub-types are paper chromatography, column chromatography, and thin-layer chromatography 

Gas-liquid chromatography: In this form, gas is used as a mobile phase which is unreactive, and the stationary phase is a non-volatile liquid held on an inert solid support. 


Commonly asked questions on chromatography are as follows.

What are the types of partition chromatography?
Two types of partition chromatography are available, liquid-liquid chromatography and gas-liquid chromatography.

What is partition chromatography used for?
Partition chromatography is a process used for the isolation and identification of mixtures of closely related substances such as amino acids.

What are the two main types of chromatography?
Liquid chromatography (LC) and gas chromatography (GC) are the two major types of chromatography.

What is the basic principle of paper chromatography?
The basic principle involved in paper chromatography is partition chromatography in which the solutes are partitioned or distributed between liquid phases.

Why do we use a pencil in chromatography?
The starting line in paper chromatography is drawn using a pencil, as the pencil lead will not dissolve in the mobile phase, and does not affect the separation.


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