Paraffin - Mineral Oil

Mineral Oil

Liquid paraffin, or mineral oil, is a mixture of heavier alkanes, and has a number of names, including nujol, adepsine oil, alboline, glymol, medicinal paraffin, or saxol. It has a density of around 0.8 g/cm3. Medicinal liquid paraffin is used to aid bowel movement in persons suffering chronic constipation; it passes through the gastrointestinal tract without itself being taken into the body, but it limits the amount of water removed from the stool. In the food industry, where it may be called "wax", it can be used as a lubricant in mechanical mixing, applied to baking tins to ensure that loaves are easily released when cooked and as a coating for fruit or other items requiring a "shiny" appearance for sale.

It is often used in infrared spectroscopy, as it has a relatively uncomplicated IR spectrum. When the sample to be tested is made into a mull (a very thick paste), liquid paraffin is added so it can be spread on the transparent (to infrared) mounting plates to be tested. Mineral oil has also seen widespread use in biotechnology for preventing the evaporation of small volumes of liquid during heating. Polymerase chain reaction samples may need to be overlaid with a layer of mineral oil to prevent evaporation during the high heat (95 °C) required to denature DNA.