As recently shown for positive ions (Rapid Commun. Mass Spectrom. 10, 871 (1996)), small to moderate-sized analyte ions (`20 000 Da) can fully suppress all matrix signals in matrix-assisted laser desorption/ionization (MALDI) mass spectra at appropriate matrix:analyte mixing ratios. The technique is useful for removing matrix interferences and led to a model for primary ion formation mechanisms. We here extend the method to negative ions, and investigate the effects of analyte type and size on the matrix suppression concentration range. For a given matrix/analyte pair, suppression was observed in either positive-or negative-ion mode, but not both. Some matrices do not show the effect at all, which is attributed to unfavourable thermodynamics. The analyte concentration where suppression appears is correlated with the analyte molecular weight and supports the proximity requirement of the model. The dependence of matrix signals on analyte concentration is very similar in both modes, and may have implications for the role of plume reactions at low analyte concentrations. Delayed extraction was found to extend matrix suppression to lower analyte concentrations. Lack of homogenous matrix/analyte co-crystallization at low analyte concentrations is shown to prevent the appearance of matrix suppression or to modify the shape of the concentration curves in some cases. Evidence is presented for the activity of electronic excitations in IR as well as in UV MALDI.

A series of new rhodium complexes with chiral ferrocenyl chelating ligands containing a tertiary phosphine and a pyrazole moiety have been obtained in good yields from the reaction of the corresponding P,N ligand (1a − p) with [Rh(1,5-COD)2]BF4, [Rh(CO)2Cl]2, and [Rh(COE)2Cl]2. The electronic influence of the P,N ligands has been evaluated by the measurement of the carbonyl stretching vibration in the compounds 5a − p. Qualitative trend correlations between ν(CO) values for such complexes and the enantioselectivities obtained in the Rh-catalyzed hydroboration of styrene utilizing the corresponding ligands have been found. Thus, both electron-donating groups on the pyrazole and electron-withdrawing substituents on the phosphine lead to both higher enantioselectivities and higher CO stretching frequencies. The compounds [{1-{(S)-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethyl}-3,5-dimethyl-1H-pyrazole}Rh(1,5-COD)]BF4 (3a), [{1-{(S)-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethyl}-3,5-bis(trifluoromethyl)-1H-pyrazole}Rh(1,5-COD)]BF4 (3h), [{1-{(S)-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethyl}-3,5-dimethyl-1H-pyrazole}Rh(CO)Cl] (5k), and [{1-{(S)-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethyl}-3,5-dimethyl-1H-pyrazole}Rh(CO)Cl] (5n) have been characterized by X-ray diffraction and were found to display very similar conformational features.

Due to the imminent demographic surge of older people, many suffering from multiple chronic diseases and age-related health problems, the demand for professional nursing care will increase massively over the coming decades. However, the demand for qualified nursing personnel in long-term healthcare is already outpacing the supply. Without a change of course, this can only lead to a crisis of quality. Experiences, e.g. from the U.S., have shown that masters-prepared Advanced Practice Nurses (APN) facilitate quality improvement in the long-term care of elderly people. With their focus on interdisciplinary collaboration and clinical results, they support the development of the institutions they work with and of gerontological nursing in general. This article describes the development of Advanced Nursing Practice in three gerontological long-term care facilities in Switzerland's German speaking region on the basis of practice development projects advancing the assessment and management of pain. APNs' defined competencies serve as a framework to evaluate the implementation of their roles: working in clinical leadership projects, they support interdisciplinary collaboration, focusing on direct clinical practice, the development of evidence-based nursing care, and the expert guidance of nurses. The role of APN in stationary long-term care in Switzerland has considerable potential for development.

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