Pfleger-Maurer-Weber library

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. 

The interpretation of spectra is considerably facilitated by modem data processing. In commercial libraries, e.g. the NIST 75.000 or the Pfleger-Maurer-Weber library for drugs and pesticides, reference spectra are available that can be compared with the measured spectra, the degree to which the measured spectrum matches the entry in the library being known as the similarity . The library search can be fully automated (Fig. 4-6), which represents a considerable saving in time. 

The tg values give the retention times ofthe standards and the substance corrected for the dead time = Ir - (q). As the dead time is constant in the cases considered, uncorrected retention times are mostly used. The determination of the Kovats indices (Figure 3.24) can be carried out very precisely and on comparison is reproducible within 10 RI units between various different laboratories. In libraries of mass spectra, the RIs are also given (see NIST, the terpene library by Adams, the toxicology library by Pfleger/Maurer/Weber). 

K. Pfleger, H.H. Maurer, and A. Weber, Mass Spectral Library of Drugs, Poisons, Pesticides, Pollutants and their Metabolites, 3rd ed., 2000, Hewlett Packard, Palo Alto, CA. 

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