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As the quantification of peptides and proteins extends from comparative analyses to the determination of actual amounts, methodologies for absolute protein quantification are desirable. Metal-coded affinity tags (MeCAT) are chemical labels for peptides and proteins with a lanthanide-bearing chelator as a core. This modification of analytes with non-naturally occurring heteroelements adds the analytical possibilities of inductively coupled plasma mass spectrometry (ICPMS) to quantitative proteomics. We here present the absolute quantification of recombinantly expressed aprotinin out of its host cell protein background using two independent MeCAT methodologies. A bottom-up strategy employs labeling of primary amino groups on peptide level. Synthetic peptides with a MeCAT label which are externally quantified by flow injection analysis (FIA)-ICPMS serve as internal standard in nanoHPLC-ESI-MS/MS. In the top-down approach, protein is labeled on cysteine residues and separated by two-dimensional gel electrophoresis. Flow injection analysis of dissolved gel spots by ICPMS yields the individual protein amount via its lanthanide label content. The enzymatic determination of the fusion protein via its β-galactosidase activity found 8.3 and 9.8 ng/μg (nanogram fusion protein per microgram sample) for batches 1 and 2, respectively. Using MeCAT values of 4.0 and 5.4 ng/μg are obtained for top-down analysis, while 14.5 and 15.9 ng/μg were found in the bottom-up analysis.

Three hundred and twenty‐seven atoms with a combined molecular weight of 9250.9 Da make up the title compound, from which, as a cluster of the mesoscopic range, one can expect unusual material properties. A central O33 polyhedron (shown on the right) defines the unusual cavity of this giant cluster and points to interesting host‐guest chemistry. The cluster has been characterized by numerous analytical and spectroscopic methods.

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The deposition of thin iron oxide films on Si͑100͒ by metallorganic chemical vapor deposition at 55 mbar was systematically studied as a function of temperature between 673 and 1023 K. Ferrocene and oxygen were used as precursors. The growth rate was measured as a function of temperature and the films were characterized by X-ray diffraction ͑XRD͒, Auger electron spectroscopy, energy dispersive X-ray analysis, and scanning electron microscopy. The change from the kinetically controlled regime to the transport controlled regime occurs near 750 K. At similar temperatures, a phase change of the deposited material was observed. Films prepared at temperatures higher than 823 K show the structure of ␣-Fe 2 O 3 , whereas deposition at lower temperature leads to the growth of ␣-Fe 2 O 3 and other oxide phases. The XRD pattern of these films can be explained by the coexistence of different iron oxide phases, namely ␣-Fe 2 O 3 , ␥-Fe 2 O 3 , and/or ␤-Fe 2 O 3 .