A chiral crown ether Is successfully used as a pseudo stationary phase In capillary zone electrophoresis to separate optically active amines. On the basis of the results obtained from the separation of more than 20 amines, two recognition mechanisms are proposed: (I) the four crown ether substituents act as chiral barriers for the guest molecules and (II) lateral electrostatic Interactions occur between host and guest. These results are confirmed by thermodynamic studies on the hostguest complexes. Best resolutions are achieved If the chiral center Is adjacent to the amine functionality. However, even racemates with a chiral center In the ^-position to the amine could be resolved excellently. For the separation of aliphatic amino acids a method has been developed allowing detection by an Indirect detection mode.

No abstract

Capillary zone electrophoresis using optically active 18-crown-6 tetracarboxylic acid (18C6H4) as chiral selector was studied for the enantiomeric separation of primary amines. From the separation of a variety of pharmaceutical drug substances, amino alcohols and amino acids, conclusions could be made concerning the influence of the chemical structure of the analytes on the separation. In addition, the effects of experimental parameters such as pH, proportion of organic modifier and buffer composition on the separation are discussed. A synergistic effect obtained by the joint application of 18C6H4 and a cyclodextrin was exploited to resolve analytes which were separated neither by the crown ether nor by the cyclodextrin.

A skin sample from the Iceman (Otzi, Similaun Man, Man from Hauslabjoch) was studied by means of IR spectroscopy and histology, and the results were compared to those obtained from nine other more recent human tissue samples with known case reports. Attenuated total reflection IR spectroscopy was used for studying the fate of proteins and lipids in these rare skin tissues. This technique provided a simple yet powerful means for semiquantitative determination of the main compound classes found in skin samples, namely, triacylglycerols, their main breakdown products (fatty acids), and proteins. When combined with histology, I R spectroscopy provided reliable information about the main conditions uader which mummification of the samples had taken place. In the case of the 5300-year-old Iceman, preserved collagen contributed to the conservation of morphological structures of the skin, although no Keywords adipocere * IR spectroscopy -lipidsmummification * skin cellular structures such as nuclei survived. In addition, post-mortal alterations such as hydrolysis of triacylglycerols and phospholipids into fatty acids were unequivocally demonstrated. The solidified fatty acids provided a certain degree of preservation to the tissue characteristic of adipocere. Based on this observation, taken together with the concomitant loss of epidermis, we suggest that Iceman's body was submerged in water for a period of at least several months prior to desiccation. Results from other research disciplines support our conclusions.

Interaction of cis-[Pt(NH3)2Cl2] (cisplatin) with 5'-guanosine monophosphate (5'-GMP) has been investigated for the first time by on-line coupling of high performance ion chromatography (HPIC) to inductively coupled plasma sector field mass spectrometry (ICP-SFMS). The time-dependent reaction course of the cisplatin-5'-GMP system was followed after incubation under simulated physiological conditions by monitoring the decrease in the concentration of 5'-GMP and the increase in the concentration of formed adducts, on the basis of speciation analysis. Because of the two-step mechanism an intermediate mono adduct was observed together with the major product, the bis adduct cis-[Pt(NH3)2(GMP)2]2-. The data obtained correlated well with those from earlier studies employing orthogonal techniques such as capillary electrophoresis (CE). Furthermore, HPIC-ICP-SFMS provided unambiguous stoichiometric information about the major GMP-adduct. For this purpose the platinum-to-phosphorus ratio was determined by simultaneously measuring 31P and 195Pt. To separate significant interferences from 15N16O+, 14N16O1H+, 12C18O1H+, and 13C17O1H+ on 31P, high-mass resolution (m/deltam = 4,500) proved to be mandatory. The P/Pt signal ratio of 2/1 obtained corresponds to the molar ratio in the bis adduct cis-[Pt(NH3)2(GMP)2]2-.