Mass Spectrometry Blog

FREE Master Class on LCMS Unknown Identification Using MSMS Libraries

MS/MS (Tandem) spectra can be used to identify unknowns employing library searches. This is accomplished in much the same approach as that employed for EI GC-MS with the NIST search software. The much improved NIST Search Version 2.4 is included with the 2020 library release. This free master class will introduce the user to the use of the NIST Version 2.4 search software employing NIST, Wiley, “crowd-sourced (MoNA)”, and user libraries for the identification of unknowns.

NIST has an ambitious program to extend their already comprehensive, high-quality MS/MS databases. See: NIST Pipeline for Extending MS/MS Libraries

This involves a very comprehensive process for selecting pertinent compounds for purchase and subsequent analyses. The problem with variability of the spectra is reduced by analyzing the samples on a variety of instruments at a variety of energy levels (20 steps). In addition, many different precursor ions and fragment ions are characterized (MSn). This has already led to a very large high quality library of accurate mass MS/MS spectra in the 2020 release version (31K compounds/1.3 M spectra) and the effort is ongoing.

The masterclass is useful to a wide variety of research and developments scientists involved in medical, environmental, industrial, forensic, and biological disciplines.

Detailed PDF handouts that support the presented content can be downloaded at the end of each class.

 

Part I: Overview (17 min)

 

Part II: NIST MS/MS Search (18 min)

 

Part III: Detailed Discussion Hybrid MS/MS Search (18 min)

 

Part IV: Importing MSMS Spectra (11 min)

 

Part V: NIST Structure Searches (12 min)

 

Part VI: MS Interpreter (12 min)

 

Part VII: Creating-Using MSMS Libraries (12 min)

 

Part VIII: “Spectraless Libraries” (12 min)

 

 

Presented by James Little, Mass Spectral Interpretation Services

James Little Master ClassJames has been a contract worker for the NIST since 2016 as well as a research fellow at Eastman Chemical Company in Kingsport, Tennessee, USA for over 40 years. Specialties include: Corporate mass spectral databases, GC-MS, LC-MS, chemical ionization, and sample derivatization. James also has extensive NMR experience, both quantitative and qualitative as well as drug analysis by LC-MS in plasma.

 

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