This is an advanced version of the NIST EI GC/MS Search. With the V4.0 (2026) release, NIST has further enhanced its EI library search program with integrated GC/MS chromatogram analysis and improved deconvolution workflows. This represents a significant advance, strengthening the already central role of EI libraries in GC/MS and further improving confidence in compound identification. In addition, a novel approach is included to support accurate mass EI data deconvolution and library searching.
NIST26 is the current release of the NIST Mass Spectral Search Program and represents the most capable version available, including integrated AMDIS processing, support for accurate-mass EI GC-MS, expanded libraries, and numerous workflow improvements. Together, these enhanced GC/MS analysis capabilities and the continued expansion of the NIST/EPA/NIH EI-MS Library create a powerful combination for compound identification. The library now includes 382,180 compounds and 431k EI spectra, with ~35k newly measured compounds, along with extensive retention index (RI) data (527k values) to support identification.
However, many laboratories continue to use NIST20 and NIST23, and the fundamental principles of EI library searching, deconvolution, spectral interpretation, and unknown identification remain the same across all versions. After completing the NIST26 content, information in Part 0-Part VII is still viable and will be useful in using NIST26.
This collection of tutorials is organized by software version so that users can quickly find material matching their installation. Whether you are using NIST20, NIST23, or the latest NIST26 release, the concepts presented here will help you identify unknown compounds more efficiently and make better use of the NIST software and libraries. The material is intended for a broad range of scientists working in medical, environmental, industrial, forensic, and biological applications.
| If you are using... | Recommended starting point |
|---|---|
| NIST26 | Start here (recommended for all new users) |
| NIST23 | Many tutorials useful, start V3.0 Part 0 |
| NIST20 | Introduction to the core workflow, start V2.4 Part I |
| Older versions | Most concepts still apply, although some interfaces differ |
• V4.0 (2026): start with NIST26
• V3.0 (2023): start with Part 0
• V2.4 (2020): start with Part I
Videos and Videos Zipped:
NIST26(opens in new tab)
Part 0: Changes in EI NIST23 Program (V3.0)(opens in new tab)
Part I: Spectral Searches with NIST MS Search(opens in new tab)
Part II: Structure Searches with MS Search and Using MS Interpreter(opens in new tab)
Part III: AMDIS (NIST) for Processing EI Mass Spectral Data Files(opens in new tab)
Part IV: Advanced NIST Hybrid Search of EI and MS/MS Spectra(opens in new tab)
Part V: Creating and Sharing User EI Libraries(opens in new tab)
Part VI: Creating and Using Retention Indices in NIST Software(opens in new tab)
Part VII: Tracking Complex Coelution with AMDIS and NIST Search(opens in new tab)
Parts 0-VI Zipped(opens in new tab)
Detailed Handouts:
Part 0: Changes in EI NIST23 Program (V3.0)(opens in new tab)
Part I: Spectral Searches with NIST MS Search(opens in new tab)
Part II: Structure Searches with NIST Search and MS Interpreter(opens in new tab)
Part III: AMDIS (NIST) for Processing EI Mass Spectral Data Files(opens in new tab)
Part IV: Advanced NIST Hybrid Search of EI Spectra(opens in new tab)
Part V: Creating and Sharing User EI Libraries(opens in new tab)
Part VI: Creating and Using Retention Indices in NIST Software(opens in new tab)
Part VII: Tracking Complex Coelution with AMDIS and NIST Search(opens in new tab)
Other Webinar Resources:
Other Courses for EI GC-MS and LC-MS(opens in new tab)
Fully functional NIST Search NIST Link(opens in new tab)
Purchasing and Product Brochures(opens in new tab)
NIST Mass Spectrometry Website(opens in new tab)
Importance of NIST Retention Indices (RI's) in Identifications(opens in new tab)
NIST Retention Indices (RI's) versus Artificial Intelligence Retention Indices (AIRI's)(opens in new tab)
Library Settings NIST23 MS Search V3.0 (EI mode)(opens in new tab)
Test Files Used In Part VII for Tracking Coelution in Complex Mixtures with AMDIS and NIST(opens in new tab)
NIST23 ASMS Presentation Houston, TX(opens in new tab)
NIST 23 Separation Science Article by David Sparkman(opens in new tab)
NIST and AMDIS User Manuals(opens in new tab)
NIST Approach for Creating 2023 Commercial Libraries(opens in new tab)
ACD Free Software(opens in new tab) (structure drawing program personal/academic use)
Mass Spec Calculator Professional(opens in new tab) (free structure drawing program)
Details on Using Hybrid Search with Delta Mass Tables(opens in new tab)
Hybrid Search/ChemSpider/SciFinder for Illicit Drug Identifications(opens in new tab)
MS_Interpreter Correlating Structure to Spectrum(opens in new tab)
NIST Tutorials and Settings for AMDIS(opens in new tab)
Example Files for Part III AMDIS Webinar(opens in new tab)
Example Spectra/Structures in Library Format Parts I-V(opens in new tab)
Wiley Library User Manual with Spectral Source Codes(opens in new tab)
(opens in new tab)Using with Manufacturers Data Processing Software(opens in new tab)
FREE Library Spectra in NIST Format(opens in new tab)