Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electrolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: Polybetaine-stabilized, palladium-containing nanoparticles, a process for preparing them and also catalysts prepared from them for producing vinyl acetate. The invention relates to soluble nanoparticles which comprise palladium alone or palladium together with metals of the groups 8-11 of the periodic table and which are embedded in protective colloids, wherein the protective colloids comprise at least one polymer having betaine groups, and to a process for preparing them. The soluble nanoparticles are suitable for the preparation of catalysts.

Abstract: A miniaturized detector cell (4) having a measuring chamber volume of 25 fl-1 .mu.l is described. In spite of its miniaturized construction, the detector cell has an optical path length of about 0.1-100 mm. The incident measuring light (R) is repeatedly reflected at the inner walls (23, 25, 26) of the interaction region (21 ) before it leaves the detector cell (4) again. In a preferred manner, the detector cell (4) is manufactured from silicon or quartz by photolithographic means.

Abstract: A device for the electrophoretic separation of complex fluid substance mixtures comprises a channel system (21, 2, 22) for a carrier medium (C), an injection device (3) for the injection into the carrier medium (C) of a substance mixture (S) to be separated, and a separating path (2) for the separation of the substance mixture (S) in an electric field applied along the separating path (2). Downstream of the injection device (3) for the substance mixture (S) to be separated and at a distance therefrom there is provided a second separating path (4) for the further separation of the substance mixture (S) in an electric field applied along the second separating path (4). The second separating path (4) is inclined at an angle (.alpha.) with respect to the first separating path (2). The region of intersection of the first (2) and second (4) separating paths forms a second injection device (5) for injecting the partially separated substance mixture (S) into a second carrier medium (E).

Abstract: A device for the separation of fluid substances, especially a capillary chromatographic separating device, is provided, which comprises a separating path in which a stationary phase is arranged and through which flows a mobile phase containing a sample to be separated into its components. The device also comprises means for transporting the mobile phase, and a detection device for detecting the separated components. The separating path is constructed in the form of an annular channel into which lead the inflow and outflow channels for the mobile phase and the fluid substance to be separated. In a very especially preferred variant of the invention the means for transporting the mobile phase are arranged inside the annular channel. In the described method of separating fluid substances the mobile phase together with the sample to be separated is circulated cyclically in a separating path constructed in the form of an annular channel.

Abstract: In an electrophoretic separating device, a channel defining a separating path is constructed in the form of a closed loop. A sample to be separated is introduced via a feed opening into an electrolytic carrier medium that is moved with the aid of an electric field through the channel, which is provided in the region of its ends with inlet and outlet openings for the carrier medium, and is separated into individual components by the electric field. The electric field is generated in the channel by connecting electrodes in the region of the inlet and outlet openings to different potentials of a voltage source. The procedure for carrying out the method according to the invention is distinguished especially by the fact that the carrier medium and the sample are moved along the substantially closed separating path formed by the channel which is constructed in the form of a closed loop.

Abstract: An apparatus (1) for processing or preparing liquid samples for a preferably quantitative chemical analysis, especially for flow-injection analysis, is, for the purpose of miniaturisation and reducing the necessary sample volume while at the same time reducing the analysis time, assembled from a set of plate-like components (8). Each of the components (8) includes channels to form pipe pieces (9) and/or branches (13) with orifices and/or values, for example non-return valves, and/or pumps (6,7) in order to be able to feed the carrier liquid and sample to a detector (3) in the desired manner. Depending on the purpose of the analysis, the components (8) with the pipes and functional parts contained in them may be stacked in varying number and/or sequence and/or angular orientation relative to one another and can be connected in a sealing manner in the operative position.

Abstract: An apparatus (1) is used for the preparation or extraction of samples, especially for analytical purposes, from a liquid or using a carrier liquid, where only very little liquid and substrate is available or is to be used and where the sample separation is to be carried out very quickly. For this, the apparatus (1) comprises, etched or machined into a plate-shaped body (8), an essentially planar flow bed (10) which has inlets and outlets arranged at opposing ends in the direction of flow, and is covered and sealed on the processing side of the plate-shaped body (8) by a further plate, so that the flow bed (10), which has an approximately groove-shaped flat cross-section, is sealed on all sides. There extend parallel to the flow bed (10), but also machined or etched into the plate-shaped body (8), electrode chambers (13), which are connected by way of electrodes (13b) to a current source (13a) in order to generate an electric field in the flow bed (10) transversely to the direction of flow.

Abstract: A liquid chromatograph comprises an analyzing chip in which a capillary is formed in a substrate and a detector section is disposed downstream of the capillary. The capillary is covered so that an inlet opening end and an outlet opening end of said capillary flow path is opened. A frame member has a sample introduction path, a carrier liquid introduction path and a liquid discharge path. The analyzing chip is movably disposed in the frame member so that the inlet opening end and the outlet opening end of the capillary are selectively in communication with and/or under interruption against said sample introduction path, the carrier liquid introduction path and the liquid discharge path. The liquid chromatograph is very small in size but is easy to handle. Incidentally, there is disclosed also a sample introduction apparatus and method for the chromatograph, and an FET type detector suitable for the chromatograph.