Abstract: A NMR method to verify the presence of organic molecular compounds consisting of repetitive occurring individual structures is presented. The method comprises the steps of assigning structure codes to the selected compounds, in accordance with the respective starting compounds used, measuring multi-dimensional NMR spectra from at least some of the compounds, uniquely assigning signal groups of NMR spectra to the individual structures, checking the NMR spectra of the compounds for the presence of all assigned signal groups, and characterizing a particular compound as being TRUE if the check of its particular combination of structures yields the result that the signal groups of structures contained in its total code had been observed. The method permits rapid and accurate verification of the presence of compounds having repetitive structures such as those produced in combinatorial chemistry.

Abstract: A device for trapping at least one chromatography peak of a chromatography flow comprises at least one trapping column, an inlet capillary for leading the chromatography flow into the trapping column and an outlet capillary departing from the trapping column. A plurality of trapping columns are provided on a column carrier wherein the trapping columns are separately and selectively connectable to and/or removable from the inlet and outlet capillary.

Abstract: A probehead for nuclear magnetic resonance measurements has a network. The network comprises in series an NMR coil for receiving a sample, a line resonator as well as a probehead terminal. The line resonator is configured as a delay line.

Abstract: The magnetic field in the working volume of an apparatus for measuring the magnetic resonance, in particular nuclear magnetic resonance, is homogenized in that shim plates are disposed at predetermined positions about the working volume and, in sum, do not generate a field in the center of the working volume. The summed effect of the shims is preferably inductively decoupled from the coil generating the magnetic field.

Abstract: A device and a method for characterizing and identifying an object, e.g. a container, with a surface visible from outside the object, onto which is disposed an optically readable one-dimensional bar code consisting of bars and spaces, are characterized in that the bar code is disposed in an annular range (2) of the surface, that the bars and spaces extend in a star-like manner from a center of the annular area (2) to the outside and that the bar code is read in the circumferential direction of the annular area (2). This device and method enable automatic detection, recognition and identification of objects, like e.g. sample bottles for spectroscopic analysis in a simple technically undemanding and cheap manner, wherein automatic identification of hollow, in particular hollow cylindrical objects can also be easily realized.

Abstract: A method and an apparatus for investigating the imperishability of n liquid foodstuffs using electron spin resonance (ESR) exposes samples of the foodstuffs to an elevated temperature for an extended time-period. At predetermined intervals during the period, the intensity of an ESR signal of each sample is measured and plotted vs. time in a diagram for that sample. The time of a superproportional increase in intensity is detected for each foodstuff. The number n of different foodstuffs is determined by dividing the predetermined interval by the measurement time. The n samples are investigated simultaneously by sequentially cycling the n samples through a common sample vessel. Each time, the intensity of the ESR signal of the sample is measured and then plotted in a diagram unique to that foodstuff. The sequence of foodstuffs are cycled through the sample vessel until a predetermined number m of measuring points per foodstuff has been attained.

Abstract: A spin resonance spectrometer comprises a radio frequency transmitter operating at a predetermined basic frequency and a probehead supplied by the radio frequency transmitter. At least one load is interposed between the radio frequency transmitter and the probehead. The load is tuned to a multiple of the basic frequency.

Abstract: A device for feeding a chromatography flow coming from a flow source, in particular from a liquid chromatography (LC) separating unit or a peak sampling or trapping unit, in part to at least a first decision detector unit and/or at least a first destination detector unit, and in part to at least a second destination detector unit is disclosed, including a first capillary line coming from the flow source, a second capillary line leading to the first decision detector unit, and/or to the first destination detector unit, and a third capillary line leading to the second destination detector unit, the first, second and third capillary line being connected with one another by means of a flow splitter splitting the flow coming from the first capillary line into two parts, a first part being fed into the second capillary line and the second part being fed into the third capillary line.

Abstract: A cryostat arrangement for keeping liquid helium comprising an outer shell (2), a helium container (6) installed therein and a neck pipe (4) extending from the helium container to the outer shell whose upper warm end is connected to the outer shell and whose lower cold end is connected to the helium container, wherein the outer shell, the helium container and the neck pipe define an evacuated space (13) containing a radiation shield (15) surrounding the helium container and being connected at a coupling to the neck pipe in a heat-conducting fashion, wherein a refrigerator is installed in the neck pipe having a cold finger (5a) which consists of at least one pipe and projects into the neck pipe, is characterized in that at least one pipe of the cold finger is surrounded by at least one separating body (3a) which divides the neck pipe into two partial volumes (8a and 9a) which are connected to one another through a lower opening (10a) and an upper opening (7a).

Abstract: An iterative method of homogenizing the magnetic field in the working volume (8) of the main field magnet (1) of a magnetic resonance apparatus uses ferromagnetic homogenizing elements (6) which are mounted at predetermined positions (9) on one or more support bodies (5), wherein in a first measuring step, the profile of the magnetic field is determined through measurements and in a first calculation step, occupation by homogenizing elements (6) at the predetermined positions (9;29) is calculated such that the calculated overall field, i.e.

Abstract: A cryostat arrangement for keeping liquid helium comprising an outer shell (2), a helium container (6) installed therein and a neck pipe (4) extending from the helium container to the outer shell whose upper warm end is connected to the outer shell and whose lower cold end is connected to the helium container, wherein the outer shell, the helium container and the neck pipe define an evacuated space (13) containing a radiation shield (15) surrounding the helium container and being connected at a coupling to the neck pipe in a heat-conducting fashion, wherein a refrigerator is installed in the neck pipe having a cold finger (5a) which consists of at least one pipe and projects into the neck pipe, is characterized in that at least one pipe of the cold finger is surrounded by at least one separating body (3a) which divides the neck pipe into two partial volumes (8a and 9a) which are connected to one another through a lower opening (10a) and an upper opening (7a).

Abstract: A NMR method to verify the presence of organic molecular compounds consisting of repetitive occurring substructures is presented. The method comprises the steps of assigning sub-structure codes to the selected compounds, in accordance with the respective starting compounds used, measuring multi-dimensional NMR spectra from at least some of the compounds, uniquely assigning signal groups of NMR spectra to the individual sub-structures, checking the NMR spectra of the compounds for the presence of all assigned signal groups, and characterizing a particular compound as being TRUE if the check of its particular combination of substructures yields the result that the signal groups of substructures contained in its total code had been observed. The method permits rapid and accurate verification of the presence of compounds having repetitive substructures.

Abstract: The magnetic field in the working volume of an apparatus for the measurement of magnetic resonance, in particular nuclear magnetic resonance, is homogenized in that shim platelets are arranged in stacks in pre-calculated positions around the working volume and for a fine adjustment in the mounted state they are continuously displaced from these positions, preferably by means of piezo translators.

Abstract: A probehead for nuclear magnetic resonance measurements is disclosed. At least a first and a second distinct kind nuclei are excited in a magnetic field. The probehead comprises a measuring coil cooperating with a sample. The coil is connected to a first terminal for feeding a signal of a first frequency for exciting the first kind of nuclei and/or for receiving a resonance signal emitted by nuclei of the first kind of nuclei, and to a second terminal for feeding a signal of a second frequency for exciting the second kind of nuclei and/or for receiving a resonance signal emitted by nuclei of the second kind of nuclei. A radio frequency transmission line of predetermined length is connected to the measuring coil. The transmission line is bridged at about half of its length by a resonance element.

Abstract: A probe head is used for nuclear resonance measurements during which two different kinds of nuclei are excited by means of radio frequency irradiation in a constant magnetic field. The probe head is provided with a pick-up coil receiving a sample under investigation. The pick-up coil is connected to a first input for feeding a signal of higher frequency for exciting a first kind of nuclei and/or for receiving a resonance signal emitted by the first kind of nuclei. The pick-up coil, further, is connected to a second input for feeding a signal of a lower frequency for exciting a second kind of nuclei and/or for receiving a resonance signal emitted by the second kind of nuclei. The pick-up coil, moreover, is connected to a radio frequency line the electrical length of which corresponds to an integer multiple of a quarter of the wave length of the higher frequency. A series capacitor is interconnected between the radio frequency line and the pick-up coil.

Abstract: A new two-dimensional NMR carbon-proton chemical shift correlation experiment, the MAS-J-HMQC experiment, is proposed for rotating solids. The magnetization transfer used to obtain the correlations is based on scalar heteronuclear J couplings. The 2D map provides through-bond chemical shift correlations between directly bonded proton carbon pairs in a similar way to corresponding high-resolution liquid state experiments. The transfer through J coupling is shown to be efficient and more selective that those based on heteronuclear dipolar couplings. The experiment, which works at high MAS spinning rates, yields the unambiguous assignment of the proton resonances. The experiment is demonstrated on several organic compounds.

Abstract: Magnetic shielding for a superconducting magnet coil, arranged in the inside of a cryostat and having a vertical z-axis for generating a static magnetic field of a homogeneity of <10−7 in the measuring volume of an NMR spectrometer, wherein the shielding comprises spatial shielding at a distance from the cryostat in the form of a ferromagnetic shielding plate arranged above the cryostat, is characterized in that the shielding plate comprises either areas outside of the z-axis having a final curvature in the downward direction or plane surfaces which are inclined with respect to the horizontal line at an angle 10°<theta<60°, truncated conical or truncated pyramid shaped surfaces. In this manner, the magnetic flux in a room located above the spectrometer is minimized and the expenditure for material and assembly for the shielding elements is considerably reduced.

Abstract: An arrangement for the investigation of hydrophilic macromolecules (1) in an aqueous solution having a solid carrier surface (5) onto which a lipid film (24) is disposed, wherein the molecules (1) to be investigated are bound, by means of a molecular coupling system (20), to the lipid film (24) and thus are immobilized, is characterized in that the molecular coupling system (20) comprises at least two, preferably three molecular or nuclear components (21, 22, 23), which can be coupled to each other, of which a first component (21) is bound to the lipid film (24) and a second component (22) is bound to a hydrophilic macromolecule (1) to be investigated. In this way, it is rendered possible to immobilize and investigate any hydrophilic macromolecules, wherein the coating of the solid carrier surface should be able to be carried out in an as easy as possible and reversible manner.

Abstract: A device for infrared (IR) spectroscopic investigation of internal surfaces of a body, for example of blood vessels, comprising an endoscope (10) with light guide means to illuminate the surfaces is characterized in that at the distal end of the light guide means there is arranged a detector (12) for detecting IR light scattered from the illuminated surface and transforming it into electric signals. For otherwise identical conditions, compared to comparable known devices, the device according to the invention offers a higher signal strength and thereby the possibility to shorten the measuring time for equal signal quality.

Abstract: A gradient coil (1) to generate switched magnetic field gradients in an nuclear spin resonance (NMR) device consisting of one or several current paths (a, b) following windings and being arranged on the surface of a geometric body is characterized in that at least two electrical current paths (a, b) are provided for, running geometrically essentially parallel to each other and being electrically connected in parallel, which current paths cross n times per winding, wherein n is an integer with n.ltoreq.8, preferably n=1 or n=2. In this way, eddy current generation by current re-distributions on the gradient coil conductor strips and thereby a time-dependent distortion of the generated magnetic field gradient inside the volume of interest of the NMR apparatus is considerably reduced.