Bodenseewerk Perkin-elmer Co.

The Perkin-elmer Corporation

Bodenseewerk Perkin-elmer Gmbh

Other

Bodenseekwerk Perkin Elmer Gmbh

Bernhard W Huber

Rolf G Tamm

Toma Tomoff

Winfried K Gonner

Klaus Joachim Braun

Gunther Rodel

Wolfgang Chlosta

Gunther Dencks

Alan Walsh

Erich Stengele

Franz Eier

In a device for analyzing samples for mercury and/or hydride-forming elements by means of atomic absorption spectroscopy, a first arrangement for determining the mercury according to the amalgam method comprising passage throttling means in the form of a washing bottle and a tube connected downstream to a reaction vessel, the other end of which tube is connected to the measuring cell. The tube contains a gold net adapted to be heated and recooled according to the amalgam method. The second arrangement by which hydrides of the sample are directly connected to the measuring cell employs a conduit which leads directly to the measuring cell, bypassing the gold net by branching off from between the reaction vessel and washing bottle. The tube is connectable to a carrier gas source between the washing bottle and position of the gold net in the tube through a first shut-off valve. A second shut-off valve is arranged in the conduit directly leading to the measuring cell. The first and the second shut-off valves are interconnected so that opening the first shut-off valve causes the second shut-off valve to close.

Device for analyzing samples for mercury and/or hydride-forming elements

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. When the liquid level drops due to aspiration of liquid into the aspirator tube, the lower end of the latter follows just this drop of the liquid level so that the aspirator tube continuously remains immersed into the liquid but only with the short length at its lower end.

Control apparatus for controlling an aspirator tube in an automatic

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.

Apparatus for analysis of volatile samples by atomic spectroscopy

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. Subsequently, the heating of the solid substance takes place with the closure being destroyed, and then the generated mercury vapor being passed by the carrier gas flow over the amalgam-generating body.

Method and device for analyzing solid substances on mercury

An apparatus and method for analyzing mercury by the atomic absorption spectrometry technique consisting of a quartz collecting tube containing a metallic net for collecting an amalgam of mercury sample, a heater for heating the collecting tube sufficiently to convert the mercury sample to an atomic state for appropriate analysis at another location, and a fluid cooling device for quickly cooling the collecting tube and metallic net to thereby prepare for the next sample analysis. The collecting tube is positioned and arranged such that in a first position it is inside of the heater and quickly after conversion of the mercury sample the tube is moved to a second position outside of the heater and adjacent to the cooling device.

Method and device for mercury analysis

A device for electrothermal atomization of a sample for spectroscopic purposes comprises a furnace (10) which is held between two contacts (54, 56). The contacts (54, 56) surround the furnace (10 ) and form a cavity (58) with an insulating gap (88) being formed between the contacts (54, 56). This gap (88) is closed by a seal (142) made of ceramic felt so that inert gas passed into the cavity (58) emerges only through a bore (14) of the furnace (10) and sample inlet ports (116, 120). Thereby, the inert gas consumption is reduced well-defined flow conditions also result for the inert gas in the cavity (58) which expands when the furnace (10) is heated.

Electrothermal atomization of a sample for spectroscopic purposes

In an atomic absorption spectrometer, a burner 16 for atomizing a sample is movable between a first and a second position. In the first position, the 'cloud of atoms' is formed in the area of the housing-fixed measuring light beam 14. In the second position, it is formed outside the measuring light beam. The measurement is made in the first position whereby the utilization of the energy of the measuring light beam is optimal. A drift compensation is made in the second position to take care of variations of the lamp intensity and of the detector sensitivity.

Atomic absorption spectrometer

The present application is directed to new and improved apparatus for use in analytical instruments which includes an elongated dosing tube having a tip at one end which is constructed and arranged to move between a sample vessel, a rinsing vessel and an analytical instrument; the other end of the dosing tube being connected in fluid flow communication to a rinsing liquid supply vessel through a sample pump assembly and a rinsing liquid pump assembly; the liquid pump assembly including a pump cylinder having an inlet and an outlet; a pump piston arranged for reciprocal movement in the pump cylinder between a first end position in the discharge direction and an opposite second end position in the intake direction; a first check valve mounted on the inlet of the pump cylinder and a second check valve mounted on the outlet of the pump cylinder; a seal mounted adjacent the outlet which cooperates with the pump piston to sealingly close the outlet when the pump piston is positioned in its first end position in the discharged direction.

Rinsing liquid apparatus for analytical instruments

In a device for supplying liquid to an atomization device operating with a nebulizer (22) in a spectrometer, the liquid is fed to the nebulizer (22) by a peristaltic pump (10) through a supply conduit (12). A valve (18) responding to liquid pressure is arranged closely in front of the nebulizer (22) and controls a connection between the supply conduit (12) and an outlet (30) through which excess liquid can flow off. A sensor (44) responding to the opening of the valve (18) is adapted to control the speed of the peristaltic pump (10), such that the quantity fed by the peristaltic pump (10) is slightly larger than the feeding capacity of the nebulizer (22).

Device for supplying liquid to a nebulizer in a spectrometer

In a flow injection analysis apparatus, the flow of reagent to a measuring apparatus is generated by means of a peristaltic pump. A sample liquid which is contained in a loop of tubing is introduced into the flow of reagent by a change-over valve with the loop being connected in a conduit of a carrier liquid. The measuring apparatus measures the reaction between sample liquid and reagent. The peristaltic pumps are driven by stepper motors. The stepper motors are controlled by control electronics such that nonuniformities of the delivery of the peristaltic pumps caused by geometry are compensated by inverse nonuniformities of the angular rates. For that purpose the frequencies of the switching pulses are varied depending on position sensors.

Flow injection apparatus for carrying out chemical analyses

A gas conducting tube (12) with a flat end (14) cut off at an angle is pivotal above the burner head 10 for lighting the flame of an atomic absorption spectrometer. Gas emerging from the burner is passed through the tube from the first end 14 to a second end 16 where a glow filament 24 is arranged. The diverted gas is lit and flashes back to the burner, whereby the flame thereof is lit. After the flame has been lit, the tube 12 is rotated out of the area of the burner head 10.

DEvice and technique for lighting a flame in an atomic absorption

An apparatus and method for determining the zero line in atomic absorption spectrometers having an atomizer and a burner for atomizing the sample wherein the flow of oxidizing agent supplied to the atomizer is interrupted by means of a switching valve and an additional flow of oxidizing agent is supplied to the burner through a by-pass conduit by-passing the atomizer with the additional flow being equal to the flow of oxidizing agent to the atomizer during operation of the atomizer and the absorption of the measuring light beam defining the zero line.

Method and apparatus for determining the zero line in atomic absorption

Inert gas is supplied to a closed reagent reservoir for reagent dosing in producing gaseous measuring samples according to the 'hydride method'. Thereby, reagent is pressed into a sample vessel through a reagent dosing conduit. A manometric switch is provided at the inert gas connecting conduit to produce a defined reagent flow, by means of which manometric switch a valve located in the connecting conduit is driven into its closed position, if a preset pressure has been reached.

Device for producing a gaseous measuring sample for atomic absorption

The present invention is directed to a gas control device for controlling the fuel gas and the oxidizing agent supplied to a burner in an atomic absorption spectrometer. The device includes a pressure controller and a downstream flowmeter, connected to the aforesaid pressure controller in each of the device's supply conduits to an atomizer, oxidizing agent port and full gas port of the burner. Each flowmeter employed in the preferred embodiment of the invention is comprised of a turbine wheel which is exposed to the gas flowing through the flowmeter. By the rotation of the turbine wheel output, signals are generated depending on the angular rate thereof and thus as a function of the gas flow rate. These output signals are input into a control unit and a set of servomotors, each associated with one of said pressure controllers, are reproducibly adjusted under the control of said control unit, even under unstable pressure conditions, to selected gas flow rates.

Gas control device for controlling the fuel gas and oxidizing agent

The present invention is directed to a gas control device for controlling the fuel gas and the oxidizing agent supplied to a burner in an atomic absorption spectrometer, which includes a first restrictor and a first pressure regulator for the fuel gas line, and a second restrictor and a second pressure regulator of the oxidizing agent line, the regulators being connected upstream of the restrictors, respectively, and servomotors for reproducibly adjusting the pressure settings of the pressure regulators, respectively.

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Uberlingen, Germany

Bernhard W Huber