Hewlett-packard Company

Bernd Glatz

Manfred Berndt

Bernhard Dehmer

A connecting capillary for analytical measuring-technology, in particular for high pressure liquid chromatography and for capillary electrophoresis, comprises a glass capillary, in particular a fused silica capillary, which is characterized in that the glass capillary is surrounded at least it its end regions by a sheath of polyetheretherketone (PEEK) or a PEEK-derivative.

Connecting capillary

In a method for the manufacture of plastic parts which are used in an analytical measuring device and there come into contact with liquids, plastic base material is mixed with a suspension liquid and then extruded in the form desired. Before it is mixed with the plastic base material, aromatic and olefinic substances are removed from the suspension liquid by means of a chemical reaction, for instance, so that the final plastic products are free from such substances. In that way, it is avoided that, when using the plastic parts in an analytical measuring device, it may come to interferences of the detection by extraction of such substances into the flow of liquids and transportation into the detector. A vacuum degasser is a particularly advantageous field of application for the plastic parts manufactured in accordance with the invention.

Method for the manufacture of plastic parts

Herein described is a process for the chromatographic determination of ions, particularly anions on a reversed-phase column, in which sample ions are introduced into a mobile phase containing a modifier and a counterion, the mobile phase with the modifier, counterion and sample ions is passed through the column and, after separation with the aid of a suitable detection method, preferably an indirect UV-detection method, the individual sample ions are determined quantitatively via the decrease the counterion concentration in the eluent. In this process the mobile phase is a mixture of water an an organic solvent and has a pH-value of more than 5. The modifier used is a quaternary ammonium hydroxide of formula ##STR1## in which at least one radical is a straight-chained or branched alkyl radical with at least 8 and up to 20, more particularly 12 to 18 C-atoms. Prior to the passage of the mobile phase containing the sample ions, the reversed-phase column is preferably brought into equilibrium with the modifier, particularly with the modifier and the counterior. Trimethyl hexadecyl ammonium hydroxide is preferable used as the quaternary ammonium hydroxide. Also described herein is the use of said quaternary ammonium hydroxides for the quantitative chromatographic determination of ions and in particular for the determination of inorganic anions, as well as a reversed-phase material chromatographic column obtained through the conditioning with the modifier.

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Leonberg, Germany

Bernd Glatz