Abstract: In a method for introducing a sample into a graphite tube in flameless atomic absorption spectroscopy a lamella- or crucible-like sample carrier is introduced into the graphite tube from the end face in axial direction. Drying and ashing of the sample is effected outside the graphite tube. The sample carrier may be heated indirectly by radiation or directly by electric current being passed therethrough.
Type:
Grant
Filed:
September 24, 1982
Date of Patent:
October 22, 1985
Assignee:
Bodenseewerk Perkin-Elmer & Co., GmbH
Inventors:
Bernhard Huber, Rolf G. A. Tamm, Toma Tomoff, Winfried Gonner
Abstract: A lamella-shaped sample carrier is attached to a tubular carriage and is movable into a graphite tube of a graphite tube cuvette from the end fact below the measuring light beam of an atomic absorption spectrophotometer. The carriage with the sample carrier is movable between an inner position, a dosing position and an outer position. The sample carrier is electrically heated in any position by means of busses. Drying and ashing of the sample take place outside the graphite tube. The graphite tube is then heated to atomizing temperature, while the sample carrier is in its outer position. Subsequently, the sample carrier is advanced into the inner position and heated itself. Thus, rapid atomization of the sample is achieved.
Abstract: In a photometer for measuring atomic fluorescence, a partial light beam is branched off the exciting light beam by means of a mirror having a hole. The partial light beam falls on a scattering disc, from which a reference light beam impinges upon the detector through opposite windows of the measuring cell. A chopper alternately transmits the exciting light beam and the partial light beam. The signal thus obtained at the detector permits compensation of the influence of variations of the light source brightness and of contamination of the windows.
Abstract: Apparatus for use in conducting both static and dynamic thermomechanical analysis includes a load member, one end of which is supported by the sample located in a sample receptacle, eventually in a selected gas atmosphere, in heat equilibrium and the other end of which is loaded statically by a weight or dynamically by the armature of an electromagnet.
Abstract: A needle assembly for feeding a carrier gas into a sample vessel during the head-space analysis of a sample includes a lateral outlet passage for conveying the gas.
Abstract: A plurality of samples subject to the same thermostatting time periods are directed one by one to the inlet section of a gas chromatograph for analysis in accordance with the head space method. To this end, a first heatable sample store adapted to be stepwise advanced is provided, in which thermostatting of the samples is accomplished. A second sample store also adapted to be stepwise advanced is provided, from which sample vessels are transferred one by one into the first sample store.
Abstract: According to the head space method, samples are supplied from sealed sample vessels by means of a needle. A change-over valve, an optionally higher or reduced carrier gas pressure is applied to a carrier gas conduit comprising a shut-off valve and terminating between the needle and entrance of the separating column. This enables a defined sample feeding and analysis by an optimum carrier gas pressure even with volatile samples.
Abstract: A needle, for use in withdrawing a liquid sample from sample vessels closed by self-sealing diaphragms, includes a capillary tube 12 turned inwardly at its end. The end thereof is tapered conically at the inside as well as at the outside.
Abstract: A pre-monochromator having a grating monochromator includes an unsymmetrically ruled concave diffraction grating, by means of which a light source is directly imaged upon an exit slit. The diffraction grating is unsymmetrical with respect to the distribution of the grating constants such that the image distance remains substantially constant during the rotation of the diffraction grating.
Abstract: In gas chromatography, the column ends of two capillary columns are inserted into a straight capillary from both sides forming annular gaps. The capillary is located in a tee out of which the capillary columns are sealingly guided, and to which carrier gas is supplied by means of a flushing flow conduit. A "straight-forward operation" having capillary columns connected in series and a "flush-back operation" are possible. The dead volume between the capillary columns can be kept small.
Abstract: An apparatus useful for flameless atomic absorption spectroscopy includes a sample carrier adapted for receiving non-gaseous sample material and means for radiantly heating the sample carrier to effect the uniform thermal decomposition thereof.
Abstract: An apparatus for enriching a sought element from a solution for flameless atomic absorption spectroscopy includes a constant voltage current source. The solution is enriched by electrodepositing the sought element therefrom and integrating the current with respect to time.
Abstract: A mechanism for automatically supplying sample fluids to a chromatographic column is provided. The mechanism obviates the need for sealed sample containers as well as the need for pressurized gas commonly employed to force sample fluid from the sealed containers.
Type:
Grant
Filed:
July 9, 1981
Date of Patent:
November 8, 1983
Assignee:
Bodenseewerk Perkin-Elmer & Co., GmbH
Inventors:
Toma Tomoff, Hans G. Mohr, Volker Kempf
Abstract: A chamber useful with an atomic absorption spectrometer includes at least two atomization means installed therein. The means can be serially aligned with the measuring beam or arranged parallel to the axis thereof.
Type:
Grant
Filed:
December 11, 1980
Date of Patent:
September 27, 1983
Assignees:
The Perkin-Elmer Corp., Bodenseewerk Perkin-Elmer & Co., GmbH
Inventors:
Toma Tomoff, Rolf Tamm, Bernhard Huber, Alan Walsh
Abstract: An apparatus useful in the flameless atomic absorption spectroscopy analysis of a sample includes an electrically conductive sample carrier adapted to be heated whereby drying and ashing steps can be performed by passing an electric current therethrough. By use of such an apparatus, the temperature at which the ashing process occurs can be controlled.
Abstract: A dissociation chamber and measuring cell combination which is useful for making atomic fluorescence measurements includes a heated dissociation chamber and a measuring cell separate therefrom. The combination is particularly useful for use with elements which form hydrides of the sought element.
Abstract: A double monochromator having a principal stage and a pre-monochromator or first stage that includes a coarse reflecting plane diffraction grating and a concave mirror for converging the object beam on the grating and for imaging the selected band of diffracted light from the grating on the entrance slit of the principal or second stage. The first stage spectral bandwidth is much larger than the second stage, thus permitting use of a grating having a groove spacing approximately ten times that of the second stage grating, and the use of linear wavelength adjusting means. The imaging mirror results in a shorter image and object distance and therefore a smaller convenient instrument.
Abstract: Graphite capsules are supported in a flame in an atomic furnace between electrical current heating electrodes that are mounted in the faces of a pair of water-cooled housings, one of which may be pivoted by a pneumatic piston to facilitate removal and insertion of the capsules and which provides a constant and firm contact pressure against the capsule ends independently of capsule length or diameter variations.
Abstract: A method for coating a graphite tube for use in atomic absorption spectroscopy includes forming a layer of an adhesive volatile material on the tube. An inert material, in the form of a powder, is applied to the layer and heated to pyrolyze the inert material. Thereafter, the graphite tube is coated with pyrolytic graphite.
Abstract: Disclosed is apparatus for automatically transporting liquid samples from sample vessels to the burner of a flame atomic absorption spectrometer or a flame photometer. A sample feed tube pivots between a first position with its end disposed in a sample feeding vessel for discharging, in sequence, sample liquid and a flushing liquid into the feeding vessel and a second position with its end in communication with a sample vessel. The sample feeding vessel has an upper opening, a bottom outlet, and a cavity between the outlet and opening having an annular convex interior surface to ensure accurate and repeated insertion of the sample feed tube into the sample feeding vessel when the sample feed tube is moved into its first position and full and complete discharge of the sample liquid into the sample feeding vessel. A control mechanism is provided to prevent discharge of the sample liquid from the sample feed tube unless and until the sample feed tube obtains its first position.