Comparison of the Identification Hierarchy with Identification Categories per USP <1663>
| Level | Identification Hierarchy | Description per USP <1663> | Title in USP <1663> | |
|---|---|---|---|---|
| Information Content | Information Type | |||
| 1 | Insufficient information to propose a structure or identity (Unidentified) | Chromatographic and/or spectroscopic data that provide little or no insight into the possible structure or identity | Not used in USP <1663> but inferred to be a compound whose identity cannot even be proposed based on the available data. | Unknown |
| 2 | Sufficient information to propose a structure but insufficient information to propose a specific identity (Partial) | Chromatographic and/or spectroscopic data that are sufficient to infer a general structure but not sufficient to propose a specific identity | Data have been collected that are consistent with a class of molecule only. Examples of such data include mass spectrometric fragmentation behavior/expert mass spectrum interpretation and mass spectrum matches automated library or literature spectrum | Tentative |
| 3 | Sufficient information to propose a specific identity (Tentative) | Chromatographic and/or spectroscopic data that are sufficient to infer a specific identity; however, inference is not supported by additional data. | Not used in USP | NA |
| 4 | Sufficient information to support a proposed specific identity (Confident) | Chromatographic and/or spectroscopic data that are sufficient to infer a specific identity; inference is supported by additional data. | A tentative identification that has been bolstered by additional and sufficient confirmatory information to preclude all but the most closely related structures. Such confirmatory information could include confirmation of molecular weight, confirmation of elemental composition (via accurate mass), and supporting spectral information from an orthogonal method (e.g., NMR) | Confident |
| 5 | Sufficient information to confirm a specific identity (Confirmed) | Chromatographic and/or spectroscopic data that are sufficient to infer a specific identity; inference is supported either by comparison to an authentic reference standard of the inferred substance or via a preponderance ofcollaborating data. | A preponderance of evidence confirms the entity in question can only be the identification provided. Although it is possible that a highly confident identification may meet the standard implied by the preponderance of evidence, the only means of providing a confirmed identification is via mass spectral and retention time match with an authentic reference compound. | Confirmed |