Derivative (finance) In finance, a derivative is a contract that derives its value from the performance of an underlying entity. This underlying entity can be an asset, index, or interest rate, and is often simply called the underlying.
Examples. Preservatives are either natural or chemical. Examples of chemical preservatives include nitrates, sulfites, sodium benzoate, potassium sorbate, and propyl gallate. Common natural preservatives include salt, lemon juice (citric acid), vinegar (acetic acid), sugar, and certain spices.unction. Preservatives work in one of three ways. They can prevent growth of microorganisms by creating an environment hostile to them. They can block the process of oxidation that causes foods to turn rancid.
1 Eyedrops with preservatives. 2  These artificial tears often come in multidose bottles and contain chemicals (preservatives) that discourage growth of bacteria once the bottle has been opened. 3  The preservatives may irritate your eyes, especially if you have moderate or severe dry eyes. 4  Preservative-free eyedrops.hese additives may promote healing of the surface of the eyes. Artificial tears may also contain thickening agents, which keep the solution on the surface of your eyes longer. There are two categories of artificial tears: 1  Eyedrops with preservatives.