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Findings of illegal hormone preparations such as syringes, bottles, cocktails, and so on, are an important information source for the nature of the current abuse of anabolic steroids and related compounds as growth-promoting agents in cattle. A new screening method for steroids in cocktails is presented based on liquid chromatography (LC) with diode-array UV-absorbance detection and electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS). Accurate mass measurements were performed at a mass resolution of 4000 using continuous introduction of a lock mass through a second (electro)sprayer. Similar experiments were carried out using dual-sprayer quadrupole time-of-flight mass spectrometry (ESI-QTOFMS/MS) at a mass resolution of 10 000 with data-dependent MS/MS acquisition; i.e. beyond an intensity threshold for the [M + H](+) ions, MS/MS spectra were automatically acquired at three different collision energies. Elemental compositions were calculated for precursor and product ions and it is shown that the combined information from LC retention behavior, UV spectra, elemental compositions, and accurate mass MS/MS spectra yield a fast impression of the steroids present in the complex mixture. Using a new software tool for structure elucidation of MS/MS spectra, an additional non-steroidal additive was identified as well.

Synthetic polymers having a polydispersity greater than 1.1 cannot be reliably characterized by matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry alone. This complication has been overcome by off-line coupling of size-exclusion chromatography (SEC) with MALDI. Data are presented for a wide variety of synthetic polymers having polydispersities from 1.7 up to 3.0. Polystyrene (15 kDa and 48 kDa), polybutylacrylate (62 kDa), polycarbonate (28 kDa), aromatic polyester resin (8 kDa) and a methyl methacrylate–methacrylic acid copolymer (34 kDa) were injected on a conventional SEC system with refractive index (RI) or UV absorbance detection and 40 fractions collected over the polymer distribution. Ten fractions were analyzed by a MALDI time-of-flight mass spectrometer operated in the continuous extraction linear mode. The m/z thus obtained were used as calibration points for the SEC-RI system and allowed accurate calculation of the molecular weight averages Mw, Mn, Mz and the polydispersity for all the polymers tested. The data for these entirely different polydisperse polymers were in good agreement with reference data from, for example, SEC with intrinsic viscosity detection. In addition, the choices of matrix and cation for individual types of polymers are commented on. The end groups of the polymers were determined from isotopically-resolved oligomer spectra recorded by MALDI time-of-flight in the delayed-extraction reflectron mode. End groups proposed are compared with reference data from, amongst others, NMR and MALDI Fourier transform ion cyclotron resonance-MS measurements. © 1997 John Wiley & Sons, Ltd.

Three complementary techniques were applied to the characterization of a complex (methoxymethyl)melamine mixture: gradient reversed-phase liquid chromatography/mass spectrometry (LC/MS), size-exclusion chromatography/mass spectrometry (SEC/MS) and capillary zone electrophoresis/mass spectrometry (CZE/MS). The LC/MS system was used with an atmospheric-pressure chemical ionization interface and the spectra obtained showed characteristic fragmentation patterns and detailed structural information of the monomeric components: up to 18 individual monomeric and 7 dimeric components could be identified. The SEC/MS system was used with a (pneumatically-assisted) electrospray interface, thus providing soft ionization and molecular information about the trimers, the dimers, and the monomers, indicating that the total number of components exceeds one hundred. In addition, the applicability of CZE/MS and H/D-exchange CZE/MS was demonstrated using a tricoaxial sheath-flow electrospray interface. The CZE separation turned out to be governed by the number of unreacted melamine positions only. Detailed structural information could be deduced simply by combining the CZE migration behaviour, the mass spectrometry data and the total number of exchangeable hydrogen atoms as calculated from the H/D exchange experiments

A method is described for the identification of monomers and end groups in low molecular weight synthetic polymers using electrospray ionization and an orthogonal accelerated time-of-flight mass spectrometer. Thanks to the high mass accuracy the elemental composition of the monomer and end group of an unknown alkylated poly(ethylene oxide) was determined with an error of 1 mDa. The present method compares well with literature data for polymer characterization by Fourier transform ion cyclotron resonance mass spectrometry and might be a simple alternative provided that the inherent lower resolution is not critical.