To access the most up-to-date version go to https://data.nist.gov/od/id/mds2-2387 and download the file called 'PFAS Suspect List.xlsx'
The list is intended to be used to enable screening high-resolution mass spectrometry data for possible known per- and polyfluoroalkyl substances (PFAS). This list meant to supplement current non-targeted analysis and suspect screening analysis workflows, it does not have a function alone.
For each compound listed, the following properties are provided:
| Property | Description |
|---|---|
| NAME | User input name of the compound, there is no formal rules for nomenclature |
| INCHI | IUPAC International Chemical Identifier (InChI) notation for the chemical structure |
| SOURCE | Citation for the source of the compound structural information |
| SOURCE_TYPE | Type of citation used for the source of the compound structural information |
| ADDITIONAL | An aggregation of all additional columns provided by the input user |
| SMILES | Simplified molecular-input line-entry system (SMILES) structural notation |
| INCHIKEY | Hashed form of the InChI structure |
| FIXEDHINCHI | InChI Key notation with fixed hydrogen layer (non-standard) |
| LOCAL_POS | Number of atoms with a fixed positive charge state |
| LOCAL_NEG | Number of atoms with a fixed negative charge state |
| FORMULA | Elemental formula of the structure |
| FIXEDMASS | Exact mass of the fixed elemental formula, including charge state |
| NETCHARGE | Formal charge of the structure |
| DTXSID | EPA DSS Tox Substance Identifier |
| DTXCID | EPA DSS Tox Compound Identifier |
| CASRN | Chemical Abstracts Service registry number |
| PUBCHEMID | PubChem ID for the InChI Key structure, multiple IDs are separated by semi-colons (;) |
| INSPECTEDBY | The initials of the user that manually evaluated the structure and the associated data, NA indicates that the structure has not been manually evaluated |
Input files must be Microsoft Excel (.xlsx) format with the minimum headers in the first row (case sensitive): NAME, INCHI, SOURCE, SOURCE_TYPE
A blank input form is available as pfas_inputform.xlsx, additional columns can be added if needed. Examples of complete input forms are in the example directory.
These headers are defined as:
NAME - Name of the compound
INCHI - InChI structural notation of the compound
SOURCE - Specific citation for the compound, DOI or website is preferred (do not use "Author et al."-type citations). More than one can be separated by a semi-colon (;)
SOURCE_TYPE - type of citation listed above, see Additional Information for more
Blank values for any additional headers are accepted, empty cells for NAME, INCHI, SOURCE, SOURCE_TYPE will lead to an error.
An example file for providing new compounds is included in this directory as a file named "example_input.xlsx"
Currently, input files can be emailed to pfas at nist.gov. You will receive a verification email once the data is loaded onto the suspect list, you may be requested to provide review of flagged entries.
Source Types:
| Value | Type | Definition |
|---|---|---|
| C | Curated | Compound structure, name, and other properties have been evaluated through a documented process for a database or library. |
| E | Empirical | Structure has been measured and derived empirically through a peer-reviewed process. |
| I | Inferred | Structure that is a homolog (differing in CF2 chain lengths) of an empirically-derived structure, but has not been observed empirically. |
| S | In Silico | Structure has been predicted through documented in silico processes, but has not been observed empirically. |
| D | Documented | Structure has been reported in documentation (e.g., patent, safety data sheet), but has not been observed empirically. |
| L | Limited | Limited information to support structure, only a formula exists |
In addition, there are R scripts available for further processing of the NIST List of Possible PFAS in the fn directory. For the use of these scripts, there is a User Guide available.
The data provided in the PFAS Suspect List has been aggregated from public sources and users, including peer-reviewed literature, patent literature, and public websites. Therefore, the quality and accuracy of the compound names, structures, and other properties has not been validated. The National Institute of Standards & Technology does not endorse or provide any assessment of confidence with the information provided.
Certain commercial equipment, instruments, software, or materials are identified in this documentation in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose.
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