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 293,000 citations (GC conditions, literature citations with titles, and RI values) for over 42,000 compounds on both non-polar and polar columns.