The performance of a commercial inductively coupled plasma mass spectrometer has been investigated as a function of a number of parameters associated with sample introduction and plasma operation. The forward r.f. power to the plasma and the nebuliser argon pressure are the two that have the greatest effect. For a variety of elements, similar optimum settings for these two variables are found. Optimising the signal due to M+ generally minimises the signal due to M*+ or MO+. Substantial differences between the optima for these variables in ICP-MS compared with ICP-ES are found.

The Fast Atom Bombardment mass spectra of a number of xanthane dyes are reported. These dyes are insuf6cienUy volatile to give spectra by conventional electron impact ionization. Fragmentation pathways have been determined by metastable Linked scan techniques and accurate lllssses obtained by peak matching.The xanthane dyes may be readily identified from their FAB spectra by the presence of chcteristic ions.

Physico-Chemical Measurements Unit, Haiwell, Didcot, Oxfordshire 0x1 1 ORE, UK "he electron impad and chemical ionization mass spectra of a number of aliphatic and aromatic glycidyl eíhers are reported. For electron impact spectra, partid fragmentation pathways have been detennined by metastable línked scan teehniques.

No abstract

Kinetic studies of a redox-initiated polymerization have indicated activation energies of 9.7 kcal. per mole for the decomposition of the initiating system, approximately 6 kcal. per mole for the propagation reaction, and 9.0 kcal. per mole for the consumption of MTM-4 in the emulsion system. Lower polymerization temperatures raised the gel point without shortening the polymer chains, apparently by decreasing the proportion of cross-linking to propagation reactions. Two types of nonmercaptan termination have been found to occur to appreciable extents: mutual termination of free radicals and a termination process involving the emulsifier.