MS library

[ito_miura]

Hi All,

Does anyone use MS library except NIST that give quickly for identification every peak?

Thank's for the info ...

Ito

[Peter Apps]

As far as I know it is the MS software,not the library, that determines whether you can just run through a chromatogram and generate a list of best fit identities for all the detected peaks.

Peter

[Consumer Products Guy]

We have NIST library, but also have generated our own library of consumer products ingredients and fragrance components.

[West Chemist]

We also use Wiley's library. Wiley is great as well. There are certain compounds that Wiley will find for us that Nist won't. But for the most part they agree well with one another and are pretty comparable to each other. But at times it can be nice to see the little details that are different between Nist and Wiley so as to compare to the spectra from my instrument when making judgement calls.

In addition we have built our own library which since it was built on our own runs of standards, of compounds we expect to potentially see, we usually will get quite nice matches there.

Depending on the library your software has (could have all but five compounds in the library) or something like NIST with tens of thousands of compounds you will certainly stand to see more spectra matching to the one you produce with the larger library. But sure the software needs the capability. And I know from the types of compounds we test for, there often are still compounds that go unknown.

[Don_Hilton]

The phrase "identification for every peak" stands out to me. Let me repeat one thing that Peter pointed out: best fit identifies.

Some people expect mass spectral libraries to provide correct compund identificaiton to every peak in a chromatogram. While this may happen, it often does not. There are several places on the site where the reasons for this are disucssed.

[lmh]

yes, that phrase scares me. A library as big as NIST will identify every peak in the sense that every peak will provide a hit of some sort, but depending on your sample, it is highly likely that many peaks are wrongly identified.

This isn't the software's fault, or NIST's. It's simply that there are more chemicals in the world than can possibly be put in one library (at the moment) and the software is only supposed to find the best fit, not check whether it's definitely right. Some things, in any case, are extremely difficult to distinguish by mass spec alone.

[MSCHemist]

I have NIST, WIley, Flavors, and custom additions and still frequently get peaks with no match.

[ito_miura]

Thanks All for clearing our misconceptions on peak identification

As Peter said, it is the MS software,not the library that determines whether onecan just run through a chromatogram and generate a list of best fit identities for all the detected peaks. We have Perkin Elmer, Clarus 600 T with TurboMass software. Must we use this software or can we use other software with our MS? Because it is very time consuming to identify major peaks one by one.

[Peter Apps]

I would be surprised if you could run your MS using other software, and even more surprised if the software that you have cannot do automated library searches if you set them up in the data processing part of a method.

Peter

[Jetjamnong]

In the turbomass SW, you can change searching parameter to obtain more faster result within 2-3 second or you can open up with NIST/AMDIS and do library search. An another way to do library search using turbomass is by selecting a communique' report in the sample sequence table at the qulitative analysis column and setup this, its can provide you all matching results within a minute depend on your criteria.