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.

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.

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.

Abstract: A graphite tube assembly for use in the atomic absorption spectroscopic measurement of samples, particularly liquid samples, during the passage of a beam of radiation through a graphite tube is disclosed. The graphite tube assembly includes a graphite tube and a sample holding platform which are cooperatively adapted to allow the platform to be removed and reinserted, or exchanged with another platform, while maintaining a preselected orientation of the platform with respect to an inlet port extending through the wall of the graphite tube.

Abstract: Stray light produced in a monochromator by the diffuse reflection of the incoming light beam specularly reflected from the surface of the diffraction grating is practically eliminated by interposing a black glass "absorbent-reflector" in the path of the specularly reflected beam. The small percentage of radiation that is not absorbed by the absorbing glass is reflected to an opposite blackened wall which diffuse reflects an extremely small percentage of the beam back to the absorbent-reflector where a very negligible part is returned to the grating surface and eventually to the monochromator exit slit.

Abstract: Disclosed are methods and apparatus for concentrating a looked-for element from a solution for flameless atomic absorption spectroscopy. The tip of an electrode is dipped into a sample vessel containing the solution and an electric current is passed through the electrode and solution to electrodeposit the components of the solution on the electrode. The electrode with the electrodeposition is removed from the sample vessel and inserted into the graphite tube. The tube is then heated and the sample components electrodeposited on the electrode are atomized for analysis by the measuring beam of the atomic absorption spectrometer.

Abstract: Apparatus for injecting a selected one of a plurality of samples into a graphite tube atomizer of a flameless atomic absorption spectrometer. A sample dilutant or blank solution, a standard solution for calibrating the spectrometer, and each of a plurality of unknown sample solutions are continuously fed into separate overflow vessels mounted in a turntable driven by a servomotor and monitored by a suitable analog-to-digital encoder. Each of the vessels overflow into a common drain channel and the vessels are positioned by a control system so that a small sample from selected vessels that may contain an unknown sample, dilutant, or calibrating standard, is drawn by a pump into an intake tube. A servomechanism then repositions the tube into the graphite tube atomizer and the pump reverses to inject the solution into the atomizer.

Abstract: A sample feeding device includes a turntable driven by a servomotor and mounted on a carrier driven by a separate servomotor. The turntable servomotor and the carrier servomotor, as well as a movable intake tube, are controlled by a control device.

Abstract: Method and apparatus for generating a gaseous test sample from a liquid sample and for transferring this test sample into a measuring cuvette of an atomic absorption spectrometer, in which an inert gas flow is directed through a sample vessel and into a measuring cuvette and, after the air has been displaced from the sample vessel, a reagent is added for generating a gaseous test sample, the test sample being carried into the measuring cuvette by the inert gas flow, wherein prior to the adding of the reagent, the flow rate of the inert gas flow is changed-over from a higher value to a lower value.