Two modes of liquid-phase microextraction (LPME) were developed for capillary gas chromatography. Both methodologies, i.e., static LPME and dynamic LPME, involve the use of very small amounts of organic solvent (<2 μL) in a conventional microsyringe. The performance of the two techniques is demonstrated in the determination of two chlorobenzenes extracted into a single drop of toluene by the use of a 10-μL syringe. Static LPME provided some enrichment (∼12-fold), good reproducibility (9.7%), and simplicity but suffered relatively long extraction time (15 min). Dynamic LPME provided higher (∼27-fold) enrichment within much shorter extraction time (∼3 min), and relatively poorer precision (12.8%), primarily due to repeated manual manipulation. Both methods allow the direct transfer of extracted analytes into a gas chromatograph.

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Heavy metal fluoride glass ZBLAN, with molar composition ZrF4(53)–BaF2(20)–LaF3(4)–AlF3(3)–NaF(20), was studied in vacuum at high temperatures up to 480°C by Raman spectroscopy. The vitreous glass was found to crystallize at 330°C, most probably to β‐BaZrF6 crystallites. High‐temperature experiments in air were also carried out and ZrO2 was formed at the surface of the sample. Doping by SiO2 increases the crystallization temperature by 25°C for experiments performed in air, while PbO2 dopants are found to react with the host. © 1997 John Wiley & Sons, Ltd.

SummaryThe isocratic high-performance liquid chromatography of 1,1'-bis(diphenylphosphino)ferrocene (dppf), 1,1'-bis(diphenylphosphino)ruthenocene (dppr), bis(diphenylphosphino)methane (dppm) and triphenylphosphine (PPh3)-substituted heterometallic Au-Mn or AuRe carbonyl complexes is reported. A column packed with PGC (porous graphitic carbon) was used after preliminary experiments had shown that silica-and bonded-phase (silica-based) stationary phases were unsatisfactory for separation. The PGC column exhibited unique selectivity for the complexes studied. The mobile phases used were water-acetonitrile, dichloromethanehexane and tetrahydrofuran-hexane. The retention behaviour of the compounds was governed by the polar character and size of molecules, and influenced by metal-metal bond polarity. Separation of isomorphous structures with different metallocenyl moieties was achieved.

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