How Spectrophotometers Can Ensure the Purity of Aspirin


Aspirin was discovered in Germany in 1899. Aspirin whose chemical name is acetylsalicylic acid was derived from a compound called salicylic acid. The medicinal pain killing values of acetylsalicylic were already known at the time, but so was its most common side effect which was stomach upset.

The first person to buffer this side effect was a French Chemist named Charles Frederick Gerhardt who added sodium and acetyl chloride to it in 1853. Mr. Gerhardt did not pursue marketing his buffered product and thus it remained fairly unknown for years. In 1899, however, a German Chemist named Felix Hoffman used the formula to relieve his own father s arthritic problems. Mr. Hoffman, who worked for Bayer, informed the company of the results and the rest as they say is history.

Because today’s aspirin is mass produced in tablet form, Spectrophotometers are a reliable and economical way to keep the purity of Aspirin consistent throughout the manufacturing process. The purity and amount of acetylsalicylic acid in aspirin can be measured using a Visual Spectrophotometer. Here’s why: when iron is added to aspirin, it produces violet tetraaquosalicylatroiron complex. To put it simply there is a visible violet color reaction.

Because violet is the color with the shortest wavelength (400-420 nm) it can easily be measured by a Visual Spectrophotometer. The intensity of the color is related to the purity and concentration of aspirin in a tablet. Using a series of different aspirin concentrations a spectrophotometer can measure each solution and a calibration curve can be constructed as a baseline for the amount of aspirin in a given aspirin product. This use of spectrophotometers allows manufacturers to keep their products consistent across the board. It also saves money as many visual spectrophotometers are portable and can be set up for use in any lab or field operation. Keeping aspirin pure and potent is just another way spectrophotometers are improving manufacturing processes around the world.

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