The use of filter paper strips as a specimen support allows (self-)collection of stool samples by untrained persons. Diarrheal stool samples from remote areas can be stored and transported to a central diagnostic laboratory without the need for freezers or special shipping conditions.

That’s called adhesion. The water also sticks to itself. That’s called cohesion. Both of these sticky forces – adhesion and cohesion – cause the water to travel up the paper towel, moving against gravity.

The water is being absorbed, or soaked up, by the paper towel material through a process called capillary action. Capillary action, also known as capillarity, is the rising or absorption of liquids through small gaps and holes certain materials.

As the water travels up the paper strip (similar to capillary action in plants), it dissolves the ink and pulls it up the paper too.

To perform ink chromatography, you put a small dot of ink to be separated at one end of a strip of filter paper. This end of the paper strip is placed in a solvent. The solvent moves up the paper strip and, as it travels upward, it dissolves the mixture of chemicals and pulls them up the paper.

Paper chromatography, in analytical chemistry, technique for separating dissolved chemical substances by taking advantage of their different rates of migration across sheets of paper. It is an inexpensive but powerful analytical tool that requires very small quantities of material.

Chromatography is also used to help catch criminals. In line with programmes like CSI, gas chromatography is used to analyse blood and cloth samples, helping to identify criminals and bring them to justice. It’s clear to see that chromatography is an unsung hero when it comes to keeping you healthy and safe everyday.

But in fact, the process is one which affects our daily lives in a variety of ways. Used to separate out a compound into its various components, chromatography plays a part in the realms of forensics, food regulation, athlete testing and even quality control in our favourite alcoholic drinks.

Chromatography is an important biophysical technique that enables the separation, identification, and purification of the components of a mixture for qualitative and quantitative analysis.

Advantages and disadvantages of chromatography

• -More efficient technique than the other.
• -Chromatographic technique can separate the mixture contain more than one component.
• -It requires the small amount of sample for the analysis.
• -Most widely used method in pharmaceutical industry.

Liquid chromatography is a useful analytical tool for establishing the components of a drug’s formulation, enabling researchers to quantify the formulation and discover whether there are any impurities in a product.

Chromatography has various applications. It is used for the separation of different colors of ink. It is also used to identify and separate the preservatives and additives added in the food items. It is also used in DNA fingerprinting and bioinformatics.

Paper chromatography uses paper as the stationary phase. The exact type of paper used is important. Filter paper is one of the best types, although paper towels and even newspaper can also be used.

Usually ascending type or radial paper chromatography is used as they are easy to perform. Also, it is easy to handle, the chromatogram obtained is faster and the process is less time-consuming. Selecting a suitable filter paper: Selection of filter paper is done based on the size of the pores and the sample quality.

Readily Available Solvents for Paper Chromatography

The stationary phase of paper chromatography is cellulose paper which polar and water are also quite polar, therefore there is no distinction by which to separate the molecules. The water is not used in the paper chromatography, due to the water the paper swells up and ultimately dissolves.

Different solvents will dissolve different substances. A non-polar solvent will dissolve non-polar substances. Not in the video, but if you want to do chromatography with ink from a permanent marker you would need to use a different solvent (an alcohol could work).

Temperature can affect retention, selectivity and peak shape, as well as column pressure and other less important variables. In gas chromatography separations, temperature is a primary variable used to control the separation, and it acts in a similar capacity as mobile-phase strength in LC.

The temperature is a very important parameter to influence separation. As a rule of thumb, for every 15 °C higher or lower, the retention of a column decreases or increases by a factor of 2. That means if the last peak elutes at 100 °C after 10 minutes, it will elute at 5 minutes at 115 °C and at 20 minutes at 85 °C.