The use of novel polysiloxanes as stationary phase carrying chiral groups enables the separation of most amino acid enantiomers in a much shorter time than ever reported previously. Phases of this type exhibit very low volatility and high thermal stability and may be used in routine analysis with open tubular columns ant temperatures of at least 175 degrees C. Most protein amino acids are separated in a temperature program between 90 and 175 degrees C, thus obviating the need for multiple injections. Resolution factors are somewhat lower than those of other diamide phases containing the L-valine t-butyl-amide group, but are sufficient for resolution of almost all protein amino acid enantiomers.

The partly halogenated C2-hydro(chloro)fluorocarbons (HFC, HCFC) 1,1,1-trifluoro-2,2-dichloroethane (HCFC-123), 1,1,1,2-tetrafluoro-2-chloroethane (HCFC-124), and 1,1,1,2-tetrafluoroethane (HFC-134a) are CFC substitutes found at increasing levels in the atmosphere. Trifluoroacetate (TFA) is an atmospheric degradation product of these compounds and due to its perstistence its potential accumulation in some aquatic ecosystems is a matter of environmental concern. The present study was undertaken to determine the present-days base level of environmental TFA and whether model calculations are in line with the actual data. Average levels of about 120 ng L-1 as predicted for the year 2010 are found in rain in Germany already now, slightly higher than in rain collected in Switzerland or Nevada. In the major rivers in Germany, TFA is present at average concentrations of 140 ng L-1. In air, levels of 45−60 pg m-3 have been found in Central Europe. Between March 1995 and September 1996, a period of substantial increase in atmospheric HFC-134a mixing ratio, the TFA concentrations in air and precipitation did not significantly increase. TFA is absent in old groundwater samples, and in river water from remote locations, concentrations are low. These data suggest that the total TFA in both compartments exceeds the formation potential of currently known sources, that TFA in atmosphere and rain is regionally associated with industrial or population density, and that other unresolved sources must contribute to the present concentrations.

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Haloacetic acids are atmospheric oxidation products of airborne C2-halocarbons which are important solvents and propellants. Levels of trichloroacetate (TCA) in conifer needles from mountain ranges in Germany (Black Forest, Erzgebirge) and from two sites in Finland are compared; TCA is present in conifer needles at concentrations up to 0.7 μmol/kg, MCA up to 0.2 μmol/kg. At the Finnish sites, TCA-concentrations and branch degeneration symptoms of Scots pine are correlated. Monochloroacetate (MCA) has been determined in needle samples from Southern Germany in concentrations exceeding its phytotoxicity threshold towards photoautotrophic organisms. Data on atmospheric chloroacetate levels in Germany are also given; ambient air levels of chloroacetic acids range from about 2 pmol/m(3) (TCA) to 390 pmol/m(3) (MCA). TCA and dichloroacetic acid (DCA) arise from atmospheric oxidation of airborne C2-chlorocarbons, while the source of MCA is not yet known; several tentative pathways are suggested.

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Haloacetates in various environmental compartments can be determined by gas chromatography-negative-ion chemical-ionization mass spectrometry after derivatization with 1-pentafluorophenyl diazoethane. Detection limits in absolute amounts per injection are between 0.01 fg (chlorodifluoroacetate) and 80 fg (monofluoroacetate). Sampling of haloacetates in urban air was performed by means of cylindrical denuders coated with alkalized glycerol. The haloacetates detected are trifluoro-, monochloro-, dichloro-, trichloro-, monobromo-, and dibromoacetate. The concentrations in ambient air fluctuate strongly, e.g. between 20 and 3000 pg/m3 for TFA. Haloacetates are also found in river waters and tree foliage. A major problem is interference from contamination with trifluoro-and trichloroacetate.

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