text: The analytical determination of a functional additive has particular problems associated with it. The concentration of a functional additive may be low compared to other ingredients; therefore, it may be difficult to detect. Proprietary ingredients are especially difficult to correctly identify. The functional role of a key component may not be obvious upon inspection. A key ingredient may be undisclosed by the maker of the material, but rather kept as a trade secret. Careful study of trade literature and patent filings associated with the manufacturer may aid the analyst in the characterization.