Jerome F. Eastham

Optical Fiber Fluoroprobes for Biological Measurements

An optical fiber fluoroprobe has been designed to make in vivo fluorescence measurements in minute volumes of body fluids. The fluoroprobe is evaluated for conventional laser excited, two-photon excited, and sequentially excited modes of fluorescence detection. Limits of detection, approximately 5 × 10−7 M, were determined for test compounds measured in various solvents including cerebral spinal fluid and whole blood, and are comparable for the three fluorescence techniques. Linear dynamic ranges are shown to be solvent dependent and superior for the nonlinear excited fluorescence techniques. The ultimate detectability and selectivity of this technique are also discussed.

The influence of benzene on disproportionation of a tertiary amine complex of ethylaluminum dichloride

Abstract The tendency toward disproportionation of ethylaluminum dichloride complexes of tertiary amines in the presence of excess ethylaluminum dichloride EtAlCl 2 ·NR 3 + (EtAlCl 2 ) 2 AlCl 3 ·NR 3 + Al 2 Et 3 Cl 3 dimer has been studied in cyclohexane and benzene. With dimethylcyclohexylamine (DMCHA) the concentrations of the various possible complexes could be directly obtained via integration of the methylamino-PMR signals. The DMCHA methyl resonance exhibited a characteristic chemical shift when complexed with a specific alkyl aluminum chloride or AlCl 3 .