Hobbies And Interests
Ion Exchange
Ion exchange chromatography takes advantage of the electrical charge of chemical molecules and separates the molecules by positive and negative charge. Molecules that have a negative charge are called anions. Positive charged molecules are called cations. The electrical charge can be used by scientists and researchers to determine the pH level and type of chemical in the sample. The sample containing the chemicals to be identified is exposed to a negatively charged resin to attract the positively charged ions and then to a positively charged resin to attract the negatively charged ions.
Gas Chromatography
Gas chromatography is used to identify molecules by vaporizing a portion of the sample material to be identified. The sample is exposed to an inert gas, such as nitrogen or helium. The exposure to the gas is called the mobile of gas chromatography. The next step is the stationary stage, in which the gas mixed with the chemical compounds from the sample is exposed to a thin layer of polymer or liquid in a glass tube. The different molecules in the sample will be absorbed and retained by the polymer or liquid at different rates, which allows the researcher to identify the chemical composition of the sample.
Thin Layer Chromatography
A thin sheet of plastic, aluminum or glass coated with absorbent silica or cellulose is used to perform thin layer chromatography. The sample is applied to the test sheet and then a solvent is added. The solvent facilitates the movement of the chemicals in the sample through the absorbent thin layer by capillary action. Chemicals are absorbed at different rates. Scientists can identify the chemical compounds based on the rate of absorption as the chemicals ascend the plate.
Paper Chromatography
Paper chromatography is similar to thin layer chromatography, except a single strip of absorbent, porous paper is used to absorb the chemicals in the sample. The test sample is placed on the paper and then the paper with the sample is dipped into a solvent. The chemicals contained in the sample are absorbed at different rates as the solvent spreads across the paper. After the chemicals are completely dissolved and the chemicals are spread throughout the paper, it is dried and sprayed with a chemical reagent that causes the chemicals compounds in the paper to change color. The chemicals in the sample are identified by the colors on the paper.