HPLC columns

Hplc columns are the heart of HPLC systems as the basic principle of separation of complex compounds occurs within the columns. There are various columns available in the market. Some of the more common columns used for separation of compounds are C8,C18,Silica and Cyano columns.
C8 and C18 columns contain nonpolar stationary phases and hence are to be used only with polar mobile phases. Silica as the name suggests consists of silica as stationary phase and is to be used only with nonpolar mobile phases like benzene, hexane,etc.
Separation inside the columns is based on differential adsorption between the liquid mobile phase and the solid stationary phase. When a mixture of compounds is injected into the mobile phase in solution form, interaction takes place between the compounds and the stationary C18 carbon chain compound. The compounds get retained on the stationary phase based on the affinity between them and the stationary phase. Different compounds have different rates of absorption. Compounds with high rate of absorption gets elutes last from the column.
Selection of the column plays a very important role in deciding a method for seperation. C18 columns contain more number of carbon atoms than C8 columns and hence give more separation. Separation also depends on the chemistry used in preparation of C18 coating substance like end-capping, pore size, particle size, surface area,etc.
Some of the well known brands of columns are given below,

1. Inertsil columns
2. Hypersil columns
3. Waters columns
4. MN columns
5. SG columns

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Influence of computers

Computers,computers everywhere. Wherever I see there are computers. Computers to surf the net. Computers to check eyes. Computers to generate bills. Computers to run machines. Computers for calculations. Computers to earn money on the internet. Computers have become an integral part of our lives. Nowadays executives don’t carry folder’s or files to meetings, they carry laptops filled with all the data. Some even carry chargers with them lest it ran out of energy in the middle of an important conference.
No need to go to the bank for a transaction, one can do it right at home on the Computer(Provided it has an internet connection and a net banking account). Computers can open house doors, pull the curtains, operate lifts, lock doors and do almost anything the human mind could imagine. Maybe someday computers may start treating patients for cough and cold and prescribe appropriate pills.
The influence of computers on human lives has become so great , chances are there would be a computer designed to run human lives. The thought scares me. What if a computer or programme was so designed so as to control all aspects of human life from birth to death? Something like the Truman Show. Consider the scenario:
1) A child is born and a computerized horoscope is prepared.
2) The computer calculates all the luck needed to make the child a successful human being.
3) The child is put through all the motions as given by the computer.
4) The child follows a specified way of life dictated by the computer throughout life.
5) Even the smallest of things like walking on the road or sitting for dinner is predetermined and the person has to follow it .
6) Even the time of expiry would be known beforehand.

If the above were to happen, humans would lead a life of Robots, all their life being told what to do and what not . Freedom would be lost. Everything would be monotonous and boring. There would be no unexpected events. The thrill of the unknown would be no more. No more surprises or shocks.

Would I really like such a life where everything is perfect. Never, I would prefer that the computer be controlled by me rather than me being controlled by the computer.

HPLC

Old HPLC systems had manual injectors between pump and detector for injecting samples. Modern systems have automated samplers and injectors which are programmed to inject samples and run the chromatograms for specified period of time. These systems are also equipped with mobile phase degassers as well as temperature controls for sample solutions and HPLC columns.

The fuction of the pump is to deliver the mobile phase through the system at a constant flow. The function of the injector is to deliver a specified amount of the sample solution into the mobile phase. The mobile phase then carries the sample into the HPLC column where the components of the sample are separated based on their affinity to interact with the stationary phase of the column. The separated components then pass out of the column at different time intervals into the detector which quantifies the components on the basis of their ability to absorb or reflect specified wavelength of light.

Mobile phases are of two types – Normal Phase and Reverse Phase

Normal mobile phase consists of organic liquid reagents which are non-polar and does not have any aqueous solutions like water. Reverse mobile phases are made up of mainly water based solutions (polar) of solid reagent buffers generally mixed with less polar liquid reagents. Normal mobile phases are used for separation of non-polar compounds and require pure silica columns. Reverse mobile phases are for separation of polar compounds and require silica based columns coated with a substance containing carbon chain atoms.

Some of the popular HPLC systems are as below,

1. Shimadzu
2. Waters
3. Agilent
4. Dionex
   

Internet and money

Hello there,
So what am I doing here? The same thing that most of the people in the world are doing-BLOGGING. Blogging about the internet and money. Is it easy to become wealthy just by being on the internet for a few minutes? I have been online for hours and have yet to accumulate a decent amount. And that too after joining most of the legitimate PTC/PTR sites. Some of them have lowered their payout per click. Some have shut shop. The recession is really taking toll on the internet too.However I have not lost hope. Might as well keep accumulating the credits. The recession will end soon and by that time I probably will be rich.