Wednesday, March 29, 2017

Thin Layer Chromatography Vs Column Chromatography

Thin-Layer Chromatography- An Introduction

There are many different types of chromatography in use to separate components of various mixtures. One of the most commonly used is Thin Layer Chromatography or TLC, as it is popularly known as. Thin Layer Chromatography is mainly employed to separate non-volatile mixtures. This form of chromatography works by coating a glass sheet, plastic or aluminium foil with adsorbent material like Silica Gel, Aluminium Oxide and Cellulose and then passing the mixture through it. This mixture is generally known as the mobile phase. Depending on their polarity, different components in the mixture, which is to be separated will be absorbed at different levels. This is how the Thin Layer Chromatography process works.

Now, Column Chromatography

Another form of chromatography, which is equally popular is column chromatography. It is known as column chromatography because the separation process takes place in a vertical glass column. In this process, the mixture is moved down the glass column and the different components are easily absorbed by the stationary phase. The rate at which the components are separated depends on their affinity to the stationary adsorbent.

Difference between Column Chromatography and Thin-Layer Chromatography

Now that we have looked at two types of chromatography, let us try to understand the basic differences between the two. These differences will help us know why one form of chromatography is preferred over the other.

1) Thin-layer chromatography requires higher samples and lower analysis time. This is because the number of samples separated via TLC is much more than that done in the column chromatography process.

2) In Thin-layer chromatography, one makes use of strong reagents to identify the different components of the mixture. This works out well in comparison to column chromatography because the TLC plate can withstand strong solvents and colour creating agents.

3) The plates used in the thin-layer chromatography process are designed in such a manner that they can be heated to very high temperatures without undergoing any damage. This may not work out for Column chromatography plates.

4) Thin-layer chromatography is said to be more sensitive as there is less spreading of substance zones in this process in comparison to the column chromatography process.

Monday, January 16, 2017

Silica Gel 70-230 Mesh

The principal elements of Silica Gel are that should be an excellent adsorbent as well as has a very huge surface area. These kinds of attributes benefit it in adsorbing little impurities and allow only the desired molecules to pass through.
In many these types of chromatography, the solid or stationary phase (Silica Gel) essentially adsorbs the several elements at many levels to achieve higher levels of filtration.

Grade Laboratory Grade
Particle Size: 70-230 Mesh (210-63μm)
Boiling Point: 2230 0C
Melting Point: >1600 0C
Bulk Density KG/LIT 500-650
Ph 10% aq solution 7 ± 0.5
Fe (Iron) <75 ppm
Chloride(NaCl) Max 300ppm
Pore Diameter –A 40-60A
Surface Area m2/gm 350-550

Friday, December 9, 2016

Which Adsorbents Are Superior in Chromatography?

Chromatography and Its Different Types

Chromatography is a commonly used method for the separation and purification of different mixtures. It basically involves two steps- the mobile phase and the stationary phase. The chromatography process is explained as follows- at first the mixture, which has to be separated is dissolved in the liquid mobile phase and then placed on top of a vertical glass column. Then it is passed down the vertical column containing the solid stationary phase. As the mixture makes its journey downwards, different components will get separated at different levels. This is because different components move at different speeds and this is the reason behind their separation. The latter is also dependent on the differential partitioning between the mobile and stationary phases.

Chromatography is broadly divided into preparative and analytical. While preparative chromatography is used to isolate the components of any given mixture for further use, analytical chromatography uses smaller amounts of material. This form of chromatography is mainly used for measuring the relative proportions of analyses in a mixture. Based on other parameters, chromatography is also categorized into thin-layer chromatography and column chromatography. Both these methods are helpful in separating different components of mixtures.

Adsorbents Used in Chromatography

The stationary phase of the chromatography process makes use of a thin layer of adsorbent like Silica Gel, Alumina and Cellulose on a flat inert substrate. Companies make use of high-quality adsorbents because it will take in all the different components at different levels. Adsorbents are clearly preferred over simple paper as it can absorb faster and thus ensure better separations.

Which Adsorbent is Superior?

Each adsorbent has its own advantages and disadvantages when being used in the chromatography process. While Silica Gel is readily available in beaded, granular and ball form, there are some benefits of using Alumina adsorbent. Silica Gel as an adsorbent has a larger sample load and thus can absorb more effectively. However, Activated Alumina showcases amphoteric properties and is known to act as a weak ion exchanger.

Silica Gel Adsorbents hydrolyzes at temperatures more than 40 degrees Celsius and that too in the presence of phosphates and carbonate ions. Another advantage of using Silica Gel adsorbent is that it dissolves in aqueous/organic media and slightly alkaline media at high temperatures.

Even though Silica Gel has the above mentioned advantages as an adsorbent, Activated Alumina is considered superior because the latter has excellent pH stability over Silica Gel. Activated Alumina is also best suited for reverse phase chromatography and for the preparation of chemically bonded C18 phases and other ligands.

Monday, January 25, 2016

Flash Chromatography Works Better With Silica Gel

What is Flash Chromatography?

In the traditional chromatography method, the sample, which is placed on top of the vertical column, moves at a very slow rate. This results in a lot of time being consumed in separating the different components of the original mixture. As the sample's downward movements are prolonged, one will have to wait a long time before securing the final segregated components.

It is to solve this problem of time consumption that flash chromatography is now being considered as an alternative. Flash chromatography is the best solution to the time consumption problem one faces while working with the traditional column chromatography method.  

Flash chromatography works by the means of air pressure being applied on the solvent to make it move faster through the vertical column. As the pressure is applied, the solvent speeds up its movement through the stationary phase and mobile phase. The separation of the components also, therefore, happens faster than before. With the help of flash chromatography, the complete procedure is done in less than 15 minutes. That is a lot of time and money saved.

Flash chromatography is important for pharmaceutical and healthcare industries where it is used in research about existing and new drugs, cleaning up samples and separating products.

Silica Gel in Flash Chromatography

Silica Gel is the most preferred adsorbent while conducting the Flash Chromatography method. For flash chromatography to yield successful results, it is important the correct adsorbent is used. This is why companies always choose Silica Gel. Other adsorbents that are also used include Florosil, Alumina and reverse phase Silica.

The main reason why Silica Gel is most preferred for Flash chromatography is because it has a high absorption area and even-sized pores. The same-sized pores do not allow the impurities to pass through and only the mixture moves forward. The adsorbent particle size of Silica Gel also plays an important role as this decides the movement of the solvent through the glass column.

The particle size is another point of difference between column chromatography and flash chromatography. While column chromatography makes use of Silica Gel with large particle size, those with small particle size are preferred in flash chromatography.

Friday, October 30, 2015

Know Your Chromatography Adsorbents Better

We all know an adsorbent as a highly porous material with a large surface area, which is capable of adsorbing substances by using inter molecular forces. Adsorbents find extensive use in thin-layer and column chromatography because of the fact that by using them, solutes are evenly distributed between the adsorbent surface and a mobile phase. Adsorbents find extensive use in gas-solid and liquid-soild chromatography. They are also utilized to extract traces of organic materials from large amounts of water. The most commonly used adsorbents in both gas-soild and liquid-solid chromatography include silica gel, alumina, carbon and different types of bonded phases. 

Where are Adsorbents Mostly Used?

Supplier of Chromatography Adsorbents
The type of adsorbent to be used in chromatography, be it thin-layer, flash or column, depends on the nature of the mixture that has to be split apart. One also needs to factor in the purpose for which the chromatography is being carried out. Chromatography adsorbents are mainly used in research laboratories across the world as here many compounds are joined together and then separated to produce expensive drugs and other products. These adsorbents also find use in pharmaceutical and chemical companies, where chromatography is carried out on a regular basis to make pure products. 

Common Chromatography Adsorbents

1) Silica Gel: Silica Gel is one of the most commonly used chromatography adsorbents. These are very popular because of their high capacity for linear as well as non-linear iso-thermal separations. Silica gel adsorbents also display inertness for labile compounds, thus qualifying as the first choice for all forms of chromatography.  

Mainly a polar absorbent, silica gel is slightly acidic and therefore graviates towards adsorption of highly basic substances when compared to adsorption on a neutral or basic adsorbent. Silica gel mostly finds use in the separation of steroids, lipids, amino acids, dyes, alkaloids, phenolic compound and pharmaceutical intermediates. Most chemical companies are adsorbent suppliers for chromatography purposes as they offer adsorbents in various grades and pore sizes at highly affordable prices. 

2) Aluminium Oxide: After silica gel, aluminium oxide is the most preferred chromatography adsorbent. An all-purpose adsorbent, aluminium oxide is a typical polar adsorbent and separates matter almost in the same manner as silica gel. As alumina offers preferential adsorption of acidic substances, it is extensively used in the seperation of weak acids. Aluminium oxide is further helped by basic solvents. Aluminium oxide finds use mainly in separating dyes, dye intermediates, steroids, lipids, amino acids, hormones, alkaloids, aliphatic and aromatic hydrocarbons and other pharmaceutical products. Aluminium oxide is usually available in the powdered form in air-tight, humidity free packets. 

Other chromatography adsorbents like carbon, magnesium oxide and carbonates also find use in different types of chromatography. 

Monday, August 10, 2015

Benefits of Silica Gel Chromatography

Chromatography is a more popular method which is used in several laboratories and industries for separating several components of a mixture or solution. It is precisely used for separating complex components that have more or less similar chemical and physical properties. Silica gel chromatography is a process which is increasingly popular due to the benefits it gives. Silica gel is a good quality desiccant that is used extensively in chromatography for separation of chemical due to its exceptional water adsorption properties. 

Even though there are many other famous desiccants such as activated alumina and molecular sieves silica gel is the usually used one because it has the high absorbing capacity. They are also very reasonable as compared to other famous desiccants. Further, its high adsorption nature and its cost silica gel are also extremely quick in its performance because as it absorbs moisture very quickly inside the packaging unit. It is unnecessary to say that silica gel chromatography for chemical separation is easier and simpler process for extrication components inside a given mixture.

Advantages of Silica Gels for Chromatography 

Benefits of Silica Gel Chromatography
Silica gel is known as an adsorbent that is used in various mesh sizes and is chosen on the basis of the water content which is there in the complexity and solution of the mixture. The size of the adsorbent involves the solvent’s flow all through the column chromatography procedure. The colored estranged compounds that are available in these desiccants are preordained to indicate the failure or success of the chromatography process. As soon as this procedure comes to a conclusion, the silica gel beads tend to change their color to know whether the moisture substance is dried up or it is not dried up. 

Few of the More Benefits Include:

•Best choosing of particle size for optimizing the competence
•Large surface area.
•Bulk quantities available and No scale-up limitations for large scale applications.
•Exceptional quality due to our closely restricted manufacturing process.
•Reproducible properties (physical, chemical, and structural).
•No scale-up limitation.
•There is less trace metal content.
•Controlled content for water level.
•High surface area and Neutral pH.
•No increased back-pressure or No clogging. 
•No particles going through contaminating final product and the filter.
•More stable, regular and reproducible chromatography.
•Quicker and more flow rate for good separation.
•There will be only improvement without any extra cost for you.
•Consistent and Reproducible retention for permitting straight scale up from industries  and laboratories through diverse process applications.

Applications Used For Silica Gel Chromatography:

• Steroids
• Organic compounds
• Dyes
• Amino acids
• Phenolic compounds
• Alkaloids
• Pharmaceutical intermediates

Monday, June 22, 2015

Silica Gel for Thin Layer Chromatography

TLC or Thin Layer Chromatography would generally refer to the process or a technique used to separate combined mixtures. Here, the Silica Gel TLC would refer to the phase of the TLC that contains Silica Gel plate under which the mixed samples are kept to get separated. This phase is meant to be the Stationary phase. In Silica Gel TLC, the silica gels or silica Acid would be used to separate the combined mixture. Here, Silica Gel acts as an adsorbent and this is the only method that is most commonly used in the partition chromatography. In this thin layer chromatography materials like alumina is used normally with Silica Gel and both of these adsorbents would act to make partitions and adsorption methods. In this chromatography, the solid layers would get formed by applying the slurry of suitable solvents on the clean glass plate. This method of separating the mixture within the stationary phase of TLC would refer to commercial spreading. This is to control the thickness of the layers that are formed.

Described Steps of TLC

In Silica Gel TLC, a small amount of the solvent is added into a developing jar with a filter paper. This filter paper would be soaked in the solvent. The jar will be closed and hereby the jar is ensured for the presence of moisture free atmosphere with filter paper and Silica Gel plate that is saturated with solvent. Now, the process of chromatography will start. Here, the solvent would eventually rise to a particular centimeter within the jar below the top of the TLC Silica Gel plate. Now, the plate is dried using a UV light on the TLC plate. Here, Silica gel spots would get turned into fluorescent green. By comparing the spots to the solvent using the RF value, the mixture of combined molecules could be found and separated. One could buy silica gel supplier for thin layer chromatography to separate the mixtures in normal partition as per the procedure in a very easy manner. The sample with multiple compounds will start to react with more polar and from hydrogen bonding. Finally, polar compounds get separated and become less resistant to the solvent. This whole process of Silica gel in Thin Layer Chromatography is also called as the Adsorption.