Abstract: A plunger homing mechanism for use in automated chromatography. A plunger cap holder holds the plunger cap of a syringe within a housing. The housing is biased with an isolation spring within a casing. The casing is raised and lowered to move the syringe plunger held within the housing. When the casing is lowered and the plunger hits bottom, the relative movement between the housing and the casing is detected by a sensor. The casing movement is then caused to stop. This permits the detection of a home or reference position for the accurate and precise withdrawal of a sample to be analyzed. Additionally, damage to the syringe from over driving the plunger rod is prevented.

Abstract: A precision bridge measurement circuit connected to a current source providing a linear output voltage versus resistance change of a variable resistance (resistance temperature transducer) including a voltage follower in one branch of the bridge so that the zero setting of the transducer resistance does not depend upon the current source or upon an excitation voltage. The zero setting depends only on the precision and stability of the three resistances. By connecting the output of an instrumentation amplifier to a feedback resistor and then to the output of the voltage follower, minor nonlinearities in the resistance-vs-temperature output of a resistance-temperature transducer, such as a platinum temperature sensor, may be corrected. Sensors which have nonlinearity opposite in polarity to platinum, such as nickel-iron sensors, may be linearized by inserting an inverting amplifier into the feedback loop.

Abstract: A double monochromator comprises an inlet slit 20, which is imaged in the plane of an intermediate slit 34 through a first grating monochromator 36. The intermediate slit 34 is imaged in the plane of the outlet slit 34 through a second grating monochromator 58 identical with the first grating monochromator 36. Deflecting mirrors 64 and 66 can be moved into the path of rays to enable such a double monochromator to be optionally used as a single monochromator with increased light flux. An additional slit is arranged between the deflecting mirrors 64 and 66. The arrangement is such so that essentially identical beam geometries result at the outlet in both of the operation modes.

Abstract: Method for analysis of samples by means of atomic absorption spectroscopy with electrothermal atomization of sample consists of the method steps: (a) introducing a liquid sample into a furnace, (b) heating the furnace up to a drying temperature for drying the sample, (c) subsequently heating the sample up to an atomizing temperature, in which a cloud of atoms develops in the furnace, in which cloud of atoms the components of the sample are present in atomic state, and (d) measurement of the atomic absorption of a measuring light beam with resonance spectral lines of an element looked for in the sample guided through the cloud of atoms. In this method (e), the vapors formed in the furnace during the heating of the furance up to the drying temperature are sucked off by a vacuum. Also, a device for carrying out this method is described.

Abstract: A photomultiplier (10) with an elongated rectangular, cathode (20) tilted with respect to the inlet opening (14) is alternately illuminated by a measuring light beam (36) and a reference light beam (40). The measuring light beam (36) and the reference light beam (40) extend in a plane parallel to the longitudinal sides of the cathode (20) and impinge upon the cothode (20), such that they illuminate the same areas of the cathode (20).

Abstract: A process is described for the formation of high temperature superconducting materials from perovskites by inductively coupled plasma assisted oxidation. An inductively coupled plasma reactor is used to oxidize oxygen deficient perovskites in less time and at lower temperatures than previously possible. High power densities are created within the plasma reactor. This is thought to contribute to the rapid and low temperature phase change during oxidation from tetragonal to orthorhombic crystal structure apparently required for superconductivity at temperatures greater than approximately 77.degree. K. The low temperature and rapid processing time permits the application of conventional lithographic semiconductor manufacturing techniques to be applied to the potentially high temperature superconducting perovskite materials.

Abstract: An atomic absorption spectrometer with electrothermal atomization of the sample and background compensation by use of Zeeman effect comprises a furnace (130) for the electrothermal atomization of the sample which furnace is heated transverse to the direction of propagation of the measuring light beam (18) of the atomic absorption spectrometer and a switchable solenoid (44) for generating a magnetic field at the location of the sample which magnetic field extends parallel to the direction of propagation of the measuring light beam (18) such that the longitudinal Zeeman effect is obtained with switching on the solenoid (44). The solenoid (44) has pole pieces (46,48) with aligned apertures (50,52) for the passage of the measuring light beam (18). A contact carrier (96) is arranged on the pole pieces (48,50) in which contact carrier contacts (128,176) are supported in order to hold the transversely heated furnace (130), the axes of said contacts being perpendicular to the axis of the measuring light beam (18).

Abstract: A method for determining concentration by means of atomic absorption spectroscopy, whereby the sample is supplied to a continuously operating atomizing device of an atomic absorption spectrometer by flow injection technique and generates a transient output signal of the atomic absorption spectrometer, comprises the method steps of supplying a calibration sample with a known concentration of the looked-for element to an atomic absorption spectrometer by flow injection technique, the concentration of the element looked-for in this sample being in a range of minimum standard deviation; storing the obtained transient calibration signal; supplying a sample which is to be analyzed and has an unknown concentration of the looked-for element to the atomic absorption spectrometer by flow injection technique and measuring a transient sample signal; forming signal ratios of the sample signal and the calibration signal at mutually corresponding predetermined moments of time; and determining the concentration of the looked

Abstract: A light absorption detector includes a light source substantially adjacent a window of a chromatogrpahic flow cell. The flow cell is defined by a housing member which also includes a photo-sensitive detector.

Abstract: A system for introducing a sample substance into a spectroscopical analytical instrument which includes a first pump which, when on, pumps a sample liquid and a buffer liquid, and a second pump which, when on, pumps an eluting liquid and rinsing liquid. The system includes an ion exchanger column for retaining the elements of the sample to be determined and which can be eluted by the eluting liquid. A dosing capillary serves to introduce the sample into the furnace of an atomic absorption spectrometer. A valve has a first position wherein the first end of the ion exchanger column communicates with the first pump and the second end communicates with a waste outlet port, and the dosing capillary communicates with a source of displacing fluid; and a second position wherein the second end of the ion exchanger column communicates with the second pump and the first end communicates with the dosing capillary.

Abstract: In an atomic absorption spectrophotometer for multielement analysis, the light from a plurality of light sources each of which emits the resonance lines of one associated looked-for element is superimposed into a single light beam by means of interconnected light guides. The light is directed onto a polychromator 64 via an optical coupler.

Abstract: A device for electrothermal atomization of samples for spectroscopic purposes with a furnace body made of graphite, designed such that electrical current can be passed through, and a pot-shaped sample receptacle which is separated from the furnace body and projects into a lateral aperture of the furnace body comprises a driving device by which the sample receptacle is movable into and out of thermal contact with the furnace body. The driving device together with the heating current of the furnace body is controlled by a controlling device such that the sample receptacle engages the furnace body during a drying and decomposing step and thereafter, is raised from the furnace body by the driving device. Thereafter, with raised sample receptacle, the furnace body is heated to atomization temperature until a temperature stabilization is achieved and, finally, the sample receptacle is again moved into contact with the furnace body.

Abstract: The control apparatus controls the lowering motion of an aspirator tube into a sample vessel in an automatic sample dispenser in a manner such that the smallest possible portion of an external surface of the aspirator tube is wetted by a liquid present in the sample vessel. A servo drive lowers the aspirator tube into the sample vessel. A sensor arrangement containing a single light guide, a light transmitter and a photoelectric receiver is associated with the aspirator tube and responds to light reflections at the liquid surface upon immersion of the lower aspirator tube end into the liquid. The light guide guides the propagating light beam and a returning reflected light beam. An electronic control controls the advancement of the aspirator tube via the servo drive into a position in which a predetermined short length in the region of the lower aspirator tube end dips into the liquid.

Abstract: The volatile sample is entrained by a carrier gas flow leading to a measuring arrangement of an atomic spectrometer through a carrier gas conduit. A tube section containing a gas permeable, inert filling is placed in the carrier gas conduit. A cooling jacket is associated with this tube section. The volatile sample is frozen out and/or adsorbed at the filling. Subsequently, the filling is heated by at least one infrared radiator through the cooling jacket whereby the deposited volatile sample is vaporized and supplied to the measuring arrangement in concentrated manner.

Abstract: An improved electro-optical ion detector comprising a channel electron multiplier assembly located at the angled focal plane of the magnetic sector of a scanning mass spectrometer with a twisted fiberoptic window with a means for precisely optically coupling the assembly to the twisted fiberoptic window. Means are provided for precisely spacing the entrance end of said twisted fiberoptic window in the form of a foil of a selected thickness. Also disclosed is a method for making an improved electro-optical ion detector.

Abstract: In a driving mechanism for driving an oscillating polarizer in a polarimeter, the polarizer is driven by a stepper motor which is controlled by a computer to make a reciprocating movement. A reference position sensor is connected to the oscillating polarizer, to provide a reference signal when the oscillating polarizer is in a determined position. A zero position of the reference position sensor is obtained by spacing the reference position sensor a predetermined number of steps of the stepper motor.

Abstract: An apparatus for the pre-concentration of a sample substance for spectroscopical reasons in the flow injection analysis having an ion-exchanger column of conical shape filled with a granular ion-exchanger. For pre-concentration of the sample, the sample liquid flows through the ion-exchanger column from the smaller first end. Then the pre-concentrated elements are eluted by an eluting liquid from the wider second end. Therewith, a very low dispersion of the eluted sample slug results. Thus, a considerable increase in the degree of sensitivity can be achieved with high analysis frequency.

Abstract: For analyzing solid substances on mercury by measuring the atomic absorption, the substance is heated in order to expel the mercury. The generated mercury vapor is conveyed with a carrier gas flow over a body having a large surface made of an amalgam-generating material, so that the mercury vapor bonds and is accumulated as amalgam on the surface of this body. Subsequently, the body is heated in order to set the mercury accumulated as amalgam free again, and is conveyed by a carrier gas flow into a measuring vessel of an atomic absorption spectrometer. The solid substance which is to be analyzed is enclosed within a vessel having a closure which is destroyed during the heating of the solid substance. For this purpose, a cover is sealingly placed onto the vessel above the destructable closure through which cover a carrier gas flow can be supplied and be carried off.

Abstract: A fluid conduit including a tube having a two-dimensional serpentine opening therethrough and exhibiting low peak dispersion is applicable as an extra-column connection.

Abstract: In a double-beam photometer comprising a light source providing a light beam, detector means, a sample area, optical means for guiding the light beam as a measuring light beam through the sample area onto the detector means, means for guiding the same light beam as a reference light beam onto the detector means while avoiding the sample area, and chopper means disposed in a splitting location for splitting the light beam into the measuring light beam, which are combined into one path of rays in a recombination location, after the measuring light beam has passed through the sample area, with the splitting location and the recombination location being spatially close to each other. The chopper means has a single chopper which simultaneously effects the splitting and the combination of the measuring and reference light beams.