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NIST GC Retention Index (RI) Database

NIST GC Retention Index) Database Enables Gas Chromatographers to Quickly and Easily Search and Compare Compounds


The NIST GC Retention Index (GC-RI) Database is a library and search program for GC Method Development that is an essential tool for anyone performing gas chromatography (GC, GC/MS, GC/FTIR). The program's gas phase Retention Index (RI) database contains the Kovats Indices (KI) for more than 349,103 citations (GC conditions, literature citations with titles, and RI values) for over 71,169 compounds on both non-polar and polar columns.

Vendor-Independent Tool Expedites Method Development

Users can not only search for RI data by compound name, partial name, formula, nominal molecular weight, CAS number, or structure, but also narrow  searches by column type, stationary phase type, or temperature conditions. Searches can even be constrained search by "RI value range".

  • Identify Unknowns. Have you ever generated a chromatogram where an unknown peak mysteriously appears between two peaks of known identity? NIST RI Search's search by RI value range feature can save hours of stress, fatigue, and frustration. Simply search the NIST RI database for compounds that have a retention index in the range that corresponds to the unknown compound. Your list of candidates is narrowed significantly, or at least, you have proof of your "hunch"!
  • Save Time. Learn whether compounds may be separated on a particular GC column, without resorting to ordering standards or performing time-demanding gas chromatography.
  • Rapid Column Determination. Quickly determine the recommended column type, without any "vendor bias". Vendor-independent column information includes packed or capillary, polarity, and in many cases the carrier gas used, phase type and thickness, and column length
  • Trustworthy Data. Data is accurate and defendable. All retention indices are cited from literature, and complete bibliographical references are included
  • Easy Comparison. RI data from different sources has variances. NIST has carefully developed an estimated non-polar retention index (n-alkane scale), complete with confidence intervals
  • Comprehensive. Each compound is also indexed by its synonym. Did you know that Guaifenesin® has 127 synonyms, including the brand name Robitussin, where it is an active ingredient? NIST RI Search enables you to quickly zero in on the right compound.
  • Search Specific-Parameters. Narrow Your Search with parameters that include compound name or a fragment thereof, nominal molecular weight, structure, structure similarity, CAS number, column type (polar or non-polar) temperature conditions (ramp or isothermal) or even choice of resolution type (Kovats or Lee).

Comprehensive Method Development Search Capability

Many of the compounds are indexed by multiple names (Synonyms). All the compounds are indexed by elemental composition (Formula), nominal mass (MW), Chemical Abstracts Services registry number (CAS#), and a sequence number pertaining to their position in the NIST GC-RI Database (ID#). Estimated non-polar retention index (n-alkane series) values, based on structure, are also provided for each compound.

Data can be retrieved through an incremental name search, a CAS# search, a MW search, a formula search, or a structure search. In addition, the Database can be searched by multiple variables that can be used to constrain the above-mentioned searches. Searches can be:.

  • Performed over a molecular weight (nominal mass) range
  • Constrained to the elements present and/or the number of each element present
  • Constrained for name fragments present in the main database name and in the synonym list
  • Constrained by RI value range

Search results for individual hits can be constrained according to column type (packed or capillary), stationary-phase type (polar or non-polar), GC temperature conditions (isothermal or temperature programmed), and/or retention index type (Lee or Kovats).

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