Which chemical is commonly used for sample preservation when testing for oils and greases?

The commonly used chemical for sample preservation when testing for oils and greases is hydrochloric acid. This acid is effective in preventing the degradation of oil samples and helps to maintain their integrity during the analysis. Hydrochloric acid works by adjusting the pH of the sample, which can reduce the potential for microbial growth and chemical changes that could otherwise alter the sample's characteristics.

In oil and grease testing, maintaining the stability of the sample is crucial for accurate results, and hydrochloric acid has been found to be particularly effective in preventing the hydrolysis of fats and oils, thereby allowing for more reliable analysis.