Naphthalenedlsulfon ate-acetonitrile as a mobHe phase alone with a crow United amine-fluorocarbon polymer suca column has shown to be an effective combination tor the separation of aliphatic anionic surfactants. Indirect conductivity and photometric detection modes are used to monitor these analytes. The retention of these surfactants Is found to depend on both the Ionic strength and the organic solvent content of the moMe phase. The mechanism of retention Is believed to be a combination of both reversed phase and Ion exchange processes. Selective separation of both C,-C12 alkanesulfonates and alkyl sulfates can be achieved In less than 9 min. Detection limits are as low as 5 ng for most analytes, with linear responses extending from at least 500 ppm to the sub-ppm level.

A triply charged eluent has been characterized for anion-exchange chromatography with Indirect photometric detection. Sodium naphthalenetrisulfonate has shown particular promise for the separation and detection of N02", Br, N03", S042~, I", and SCN". The analysis of a mixture containing these anions can be performed In less than 16 min with detection limits of 0.4-1 ng for all anions. The determination of the strongly retained sulfur oxides such as dithlonlte, tetrathlonate, and other polythlonates can be easily accomplished with this highly charged eluent In a short time with high sensitivity. The chromatographic performance of this eluent requires no pH adjustment of the mobile phase. In addition, chromatograms obtained with this eluent were free from any system peaks.

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Short Communications ~~ ~~ separations are performed between 60 and 140 "C, the temperature limitations of these connectors do not seem too restrictive.Deactivation of the quartz couplings was essential for obtaining reproducible performance: this applied not only from the standpoint of inertness, but also to their ability to withstand high pressures. Untreated couplings regularly burst upon introduction of carbon dioxide a t moderate pressures because of the formation of fissures along the inner wall which grew until failure occurred.The deactivation layer formed a stabilizing bridge which prevented the growth of fissures and enabled the use of the couplings at pressures a s high as 10,000 psi. Similar observations of the embrittlement of raw and deactivated fused silica tubing over a wide range of dimensions have also been made in our laboratory.The epoxy adhesive used to bind the quartz coupling assembly cures to form a very hard glassy solid. Its point of contact with the fused silica tubing of the column and restrictor produces high stress which can lead to spontaneous breakage. A short piece of thin walled polyimide tubing inserted over the column or restrictor tubing at the interface to the coupling provides strain relief and produces a more robust connection. Strain relief is especially important with thin walled fused silica tubing (wall thickness <75 pm) but is not necessary with thick walled tubing (wall thickness >75 pm).In addition to coupling columns and restrictors, these quartz unions can also be used for efficient coupling of two columns coated with similar or different stationary phases in order to furnish higher resolution, or for selectivity tuning, respectively.They also provide an excellent interface between columns and retention gaps Hundreds of connections with fused quartz couplings have been made with success in our laboratories and fewer than 10 % resulted in poor connections The latter were usually a result of leaks in the assembly or breakage of the coupling References [ l ] M. Novotny, HRC & CC 9 (1986) 137.

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