Copper and iron interactions with angiotensin-converting enzyme inhibitors. A study by fast-atom bombardment tandem mass spectrometry

Fast atom bombardment, combined with high-energy collision-induced tandem mass spectrometry, has been used to investigate gas-phase metal-ion interactions with captopril, enalaprilat and lisinopril, all angiotensin-converting enzyme inhibitors.Suggestions for the location of metal-binding sites are presented. For captopril, metal binding occurs most likely at both the sulphur and the nitrogen atom. For enalaprilat and lisinopril, binding preferably occurs at the amine nitrogen. Copyright 1999 John Wiley & Sons, Ltd.     

Characterisation of biological RMs for potential use in human brain analysis

Summary In order to investigate the precision and accuracy obtainable with instrumental neutron activation analysis (INAA) and inductively coupled plasma atomic emission spectrometry (ICP-AES), five different biological reference materials were analyzed. Four of them originated from the US National Institute of Standards and Technology (NIST) (Bovine Liver (SRM 1577; 1577/a; 185/A), Orchard Leaves (SRM 1571)) and one of them came from the International Atomic Energy Agency (IAEA) (Animal muscle (H-4)). The decomposition efficiency of microwave acid digestion was examined in comparison to digestions carried out in a Parrbomb. Five to ten subsamples of each material were subjected to the two digestion procedures and the solutions were analyzed by ICP-AES. The dried samples were analyzed by INAA. Up to 16 elements (Al, B, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Zn) were determined in various materials.     

Nachweis und Bestimmung von Nitraten in der Milch

Ohne Zusammenfassung     

Determination of loads applied perpendicularly to the outer boundary of a ring using coefficients of influence

A procedure is explained to determined the amount of several pairs of diametrical loads applied to the outside boundary of a ring when stresses at selected points of the inside or outside boundaries are known. Coefficients of influence are used, following an approach similar to the one presented in a previous paper. Examples of application are given and the possible increase in precision is shown when the number of points of measurements is larger than the number of loads to be determined.