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Hyphenation of liquid chromatography (LC) techniques with electrospray ionization (ESI) orthogonal acceleration time-of-flight (oa-TOF) mass spectrometry (MS) provides both MS-based structural information and LC-based quantitative data in polymer analysis. In one experimental setup, three different LC modes are interfaced with MS: size-exclusion chromatography (SEC/MS), gradient polymer elution chromatography (GPEC/MS), and liquid chromatography at the critical point of adsorption (LCCC/MS). In SEC/MS, both absolute mass calibration of the SEC column based on the polymer itself and determination of monomers and end groups from the mass spectra are achieved. GPEC/MS shows detailed chemical heterogeneity of the polymer and the chemical composition distribution within oligomer groups. In LCCC/MS, the retention behavior is primarily governed by chemical heterogeneities, such as different end group functionalities, and quantitative end group calculations can be easily made. The potential of these methods and the benefit of time-of-flight analyzers in polymer analysis are discussed using SEC/MS of a polydisperse poly(methyl methacrylate) sample, GPEC/MS of dipropoxylated bisphenol A/adipic acid polyester resin, LCCC/MS of alkylated poly(ethylene glycol), and LCCC/MS of terephthalic acid/neopentyl glycol polyester resin.

Polydisperse synthetic polymers cannot be characterized reliably by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI MS) alone. Coupling of size-exclusion chromatography (SEC) with MALDI MS provides both absolute mass calibration of the SEC column based on the polymer itself and determination of monomers and end groups from the mass spectra. Now a micro-scale SEC (μSEC) system has been developed in which the MALDI matrix solution is coaxially added to the column effluent and directly spotted onto the MALDI targets in a robotic interface. Each spot corresponds with a 10-s elution window from the μSEC column, thus yielding a narrow polymer distribution which is amenable to characterization by MALDI MS. This μSEC/MALDI MS system is less laborious and time-consuming and features very low solvent consumption and reduced solvent emission during the evaporation step as compared to the conventional-sized SEC/fraction collector systems applied in the past. The performance is demo...

Capillary zone electrophoresis (CZE) was successfully applied to the chiral separation of basic drugs after addition of a suitable cyclodextrin chiral selector to the electrophoresis buffer. Commercially avaliable cyclodextrins (α- β-, and γ-cyclodextrin and heptakis(2,6-dl-O-methyl)-β-cyclodextrin) were evaluated for their enantioselectrivity toward 10 compounds having rather complex molecular structures. In contrast to liquid chromatographic attempts, the enantiomers of all racemates investigated could be resolved with a resolution of more than 1.4, except for one (R S 1.1), and showed theoretical plate numbers up to 265,000 with good peak shapes

Small precolumns packed with C18, PRP/sub 1/, and cation-exchange materials have been used for the on-line group separation and trace enrichment of industrial waste water samples. The sample is divided into three main groups: a fraction containing nonpolar compounds, a second fraction containing medium polarity compounds and certain polar substituted aromatics, and a third fraction containing polar anilines and other polar bases. Each precolumn fraction is subsequently chromatographed on a C18 analytical column with a methanol gradient and detected by a diode-array UV-Vis detector. Multisignal plots and three-dimensional spectrochromatograms are used to get information about the identity of the pollutants present. The completely automated system is optimized for 29 selected organic pollutants of particular interest. Some of these compounds were found in the waste water samples tested and were quantitated. 14 references, 7 figures, 3 tables.