Mass Spectral Index

In this Volume 5 of the second edition of IDDA, we have included a special section of analytical data especially designed for toxicologists. This text contains mass spectra of over 280 derivatives of drug compounds, a retention time index, a mass spectral index, and a page index of diese derivatized drugs. 

List possible structures or partial structures consistent with the mass spectral data. If probable molecular formulae are tabulated and the structure is still unknown, possible structures can easily be obtained from such sources as Beilstein, Merck Index, Handbook of Chemistry, Handbook of Chemistry... 

McLafferty. F. W., and Stauffer, D. B. Important Peak Index of the Registry of Mass Spectral Data. New York Wiley-Interscience, 1991. 

Solvents and their impurities represent a wide class of compound types therefore, a discussion of common mass spectral features is meaningless. However, most of the mass spectra are listed in computer library search programs and The Eight Peak Index. ... 

Compilations of Reference Spectra There are several compilations of reference mass spectra available of which the oldest is the American Petroleum Institute (Ref 82) collection of spectra obtained mostiy on the older type instruments. Recent collections index spectra variously, eg, under reference number (Ref 19). molecular weight (Refs 12 19), molecular formula (Ref 19), fragment ion values (Ref 19), and base peak (Refs 12 19). A quarterly journal, Archives of Mass Spectral Data ... 

F.W. McLafferty, Mass Spectral Correlations Advances in Chemistry Series No 40, AmChemSoc, Washington, DC (1963) 12) Anon, Index of... 

Today, GC-MS (see Section 4.1.1) is a golden standard for detection and quantification of drugs and poisons volatile under GC conditions, whereas nonvolatile compounds require LC-MS (see Section 4.1.2). The GC-MS technique is much more popular for identification purposes than LC-MS, because of the easy availability of the reference mass spectra for many xenobiotics and their derivatives, either in printed or computer form. The most popular libraries are the NIST library, which contains the mass spectra of 130,000 compounds, the Wiley Registry of Mass Spectral Data, which contains 390,000 reference spectra, and the Pfleger-Maurer-Weber library, with 6,300 mass spectra and other data, such as chromatographic retention indexes. 

C. Wagner, M. Sefkow, and J. Kopka, Construction and application of a mass spectral and retention time index database generated from plant GC/EI TOF MS metabolite profiles. 

W. Jennings and T. ShSoaxnoto, Qualitative Analysis of Flavor andFragrance Volatiles by Glass Capillary Gas Chromatography, Academic Press, Inc., New York, 1980 also includes retention indexes and mass spectral data. 

ASTM (1963). Index of Mass Spectral Data, American Society for Testing and Materials. STP-356, 244 pp. 

When identifying an eluted compound by comparing its mass spectrum with a mass spectral library, false matches are frequent. If retention index is used as a second characteristic, false matches are reduced. 

The assumption for Eq. (1) is that the ELSD peak area is directly proportional to mass. For compounds of widely varying structures, charges, or vapor pressure, or for varying mobile phase compositions (e.g., gradient HPLC), the ELSD response can vary markedly (16-22). Thus, Eq. (1) is limited in its applicability. Similarly, mass spectral (MS) detectors are universal, but the response per unit weight depends greatly on the ionization type (e.g., electrospray, fast-atom bombardment, etc.) and on the ionization efficiency of the analyte. Refractive index is another universal detector, but it too suffers from variability in response depending on the mobile phase... 

GC retention index and mass spectral software/ database AMDIS (Automated Mass Spectrometry Deconvolution and Identification System). The AMDIS is distributed with the OCAD for free to SPs. 

The Eight-Peak Index of Mass Spectra published by the Mass Spectrometry Data Centre of the Royal Society of Chemistry is a popular printed index of mass spectral data that now contains some 81000 spectra of over 65000 different compounds [4], These spectra are published in the shape of lists of the eight main peaks. The complete data are sorted in three different ways to allow easy identification of unknown compounds by (i) molecular weight subindexed on molecular formula, (ii) molecular weight subindexed on m/z value and (iii) m/z value of the two most intense ions. 

MASS SPECTRAL DATA Many of the monographs in Part 2 contain mass spectral data in the form of the eight most intense ions, in descending order of intoisity. These values have also been used to compile an 8-peak index in Part 3 for rapid se[Pg.262]

In this system, amphetamine, 3,4-methylenedioxyamphetamine (MDA) and the A-methyl and A-ethyl analogues of the drugs were derivatized, with 4-chloroamphetamine being used as the internal standard. For powders, solutions were prepared at concentrations of 1 mgml in methanol and a 100 til aliquot blown dry under nitrogen. To the residue was added 50 p.1 of 0.5 M KOH and 500 p,l of toluene. The mixture was then shaken for 30 s and centrifuged, after which the toluene layer was recovered and HFBA (5 til) added. The excess reagent was neutralized with 500 p,l of 10% NaHCOs and an aliquot (1 ttl) analysed by GC-MS. Each of the amphetamines and the A-alkylated derivatives could be separated and identified on the basis of retention index and mass spectral data. 

A typical chromatographic separation is presented in Figure 5.1. The compounds are identified in GC-MS analysis on the basis of two pieces of information, namely the retention time (or relative retention index) and mass spectral data. 

The assignment of each alcohol residue, however, was checked by synthesis starting from the lactone of 2-hydroxyglutaric acid with a two step esterification. Table 1 shows a collection of our results concerning GC-0 evaluation together with retention index and mass spectral data. The sensory properties of compoimd 1 are described as weak, fatty, lactone-like. 

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