Abstract: The atomic constituents of volatile organic compounds are determined by a burner design having improved stability and, consequently, increased detection sensitivity. An optical window is included at one end of a burner tube to stabilize a hydrogen-air flame to avoid blow out. Since air and combined air and helium are introduced immediately in front of the window and the flow rate of the gases and a sample are particularly oriented, burning is complete for increased detection sensitivity by an interconnected atomic absorption spectrophotometer.

Abstract: For nebulizing sample liquid for spectroscopical purposes a liquid to be nebulized is pressurized to a minimum pressure of 30 bar through a high-pressure pump formed as a separate unit, and is nebulized through a nozzle having a smallest flow aperture of less than 5.multidot.10.sup.-9 m.sup.2. The high-pressure pump and the nozzle are interconnected through conduits. In one embodiment the pump takes in pure solvent. The sample is taken in on the high-pressure side through a loop, which is arranged to be connected between pump and nozzle.

Abstract: Disclosed is apparatus comprising a means for injecting a controlled stream of hydrocarbon liquid into a concurrently flowing stream of gas in a Venturi forming droplets. Droplets are subsequently combusted in a gas stream. The level of radient emissions is measured photoelectrically. Results obtained are useful in predicting service life of combustor walls in jet engines and the like.

Abstract: A sample transport, sample introduction, and flame excitation system for spectrometric analysis of high temperature gas streams which eliminates degradation of the sample stream by condensation losses.

Abstract: A spectroscope apparatus includes means for separating light from an object to be measured into spectral components, means for mixing that part of the spectral components which exists in a desired wavelength range, and means for forming an image of the to-be-measured body of mixed light. The image thus obtained is very useful for observing the state of a combustion flame, the progress of photochemical reaction, the progress of biochemical reaction, a desired tissue in a cell, and the state of a flame for analyzing a solution which contains a metal ion, by flame spectrophotometery, that is, provides accurate information and makes possible a precise control operation.

Abstract: A transport detector system comprises(a) a liquid delivery tube,(b) a plurality of moveable spokes, the spokes being positioned to pass in sequence under the delivery tube, the spokes being constructed from a refractory inorganic material of low thermal conductivity,(c) one or more evaporators, positioned so that the spokes pass sequentially through it or them after liquid has been deposited on the spokes,(d) a detector positioned so that the spokes pass sequentially through it after passage through the evaporator(s),(e) one or more coolers, positioned so that the spokes pass through it or them after passage through the detector,(f) a stepper motor adapted to move the spokes in a series of discrete steps, and(g) a control system for the stepper motor, evaporators and coolers.The system is particularly suitable for use in HPLC analysis and may be interfaced with a plasma spectrometer.

Abstract: A burner for a flame photometric detector includes a stainless steel housing having a passage therethrough; a stainless steel burner tube extending through the passage and having a flame holder at one end; and at least one stainless steel inlet tube extending through the housing for admitting a support gas to the burner. The burner tube and inlet tube are brazed to the housing to form a unitary device having no sealing rings which can degrade and leak. A transfer line is connected to one end of the burner to conduct the material to be tested to the burner. The transfer line includes a fused silica tube surrounded by a stainless steel outer tube.

Abstract: A process which extends the measurement range of Zeeman atomic absorption spectroscopy by linearization of the calibration curve in the region of relatively high sample concentration. The intensities of the Zeeman components I.pi.o, I.sigma.o, I.pi. and I.sigma.

Abstract: An atomic spectrometer in combination with an atomizer apparatus for atomizing a test sample into an atomic state for analysis in the atomic spectrometer. The atomizer apparatus includes a heater for heating a sample to free individual atoms of the sample for atomic spectroscopy, a tube member containing a packing of an adsorbent, a reagent adsorbed on the adsorbent which reacts with a metal constituent in a sample to form a metal complex which adsorbs to the adsorbent at a first temperature and is volatile at a second higher temperature for desorption from the adsorbent, and a heater for heating the tube member.

Abstract: A method for determining parameters, especially pressure, temperature, concentration, number of particles and particle size distribution, of gaseous substances present in combustion processes and other high temperature processes, comprises transmitting spectrally broad-band light through an object (2) of measurement, spectrally dividing the light transmitted through said object, and recording the spectral distribution of the light in the studied wavelength range a large number of times. Each recording occurs sequentially in that the spectrally divided light is swept relative to a one-channel detector and for such a short time that the total light intensity of the entire wavelength range is constant during each recording.

Abstract: 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.

Abstract: A burner assembly for an atomic absorption spectrometer having carrier (20) fixed to the burner head (14) and mounting a flame sensor (96) and an ignition device (16) so as to permit a single alignment of the flame sensor (18) and the ignition device (16) relative to the burner head (14) and subsequent movement or adjustment of the burner relative to the housing without changing the mutual positions of the ignition device (16) and the flame sensor (18) and while the flame is burning.

Abstract: 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.

Abstract: Oxygen or a mixed gas containing oxygen, or a chemical flame produced by a mixture of a combustion gas and a combustion-assisting gas containing oxygen, is blown against the surface of molten iron to cause radiation emission. The radiations are divided into components of different wavelengths, and the resulting emission spectra are measured to determine the composition of the molten iron.

Abstract: The optical measurement signals in a flame atomic absorption spectrophotometer are first amplified in a substantially linear variable gain amplifier. The gain of the variable gain amplifier is adjusted to provide a predetermined magnitude of output signal during a calibration phase of the spectrophotometer. The resultant output signals from the variable gain amplifier are then converted to a logarithmic function in a logarithmic amplifier during optical absorption measurements.

Abstract: There is provided an atomic absorption spectrophotometer wherein a magnetic field having a suitable value is applied to a light source radiating the emission spectral light of the atom to be analyzed in the advance direction of the radiated light in order to cause the Zeeman effect so that the wavenumber of a component which is included in the spectra shifted in wavenumber and which is varied to have a smaller wavenumber may coincide with or approach the wavenumber whereat the absorption spectrum is maximized, thereby the sensitivity of the atomic absorption being raised, the linear region of the working curve being improved, and the emission spectral light being stabilized.

Abstract: A spectrometer includign a flame atomiser (7) is provided with a sample diluter comprising a mixing vessel (1) having a diluent supply channel (20) and a sample supply tube (10). The mixing vessel (1) has a converging lower portion (2) to which a outlet tube (5) is connected, the outlet tube feeding a mixture of sample and diluent to a nebuliser (47). The sample supply tube (10) is aligned with and spaced from the outlet tube (5). Sample liquid from the sample supply tube (10) passes into the outlet tube (5) as a central core (29) entrained in a sheath of diluent. The sample and diluent flow through the tube (5) with a laminar flow due to the profile of the mixing vessel (1) thus preventing the sample liquid from coming into contact with the wall of the outlet tube (5). Consequently memory effects are reduced.

Abstract: The present invention is directed to a lamp assembly for use in atomic absorption spectrometers in which an atomic element hollow cathode lamp assembly has a lamp formed by a hollow cathode electrode and an anode electrode within a sealed envelope. A base structure is attached to the envelope, and located within the base structure is a resistor network consisting of four resistors connected to a common lead and having four plug terminals protruding from the base structure. Two further plug terminals also protruding from the base structure are connected respectively to the cathode and anode electrodes to provide a connecting structure for connecting these electrodes to a lamp power supply. The five plug terminals protruding from the base structure and connected respectively to the resistors and the common lead provide a further connecting structure of the resistor network to a measurement circuit in an atomic absorption spectrophotometer.

Abstract: A furnace system connected to a burner including a furnace for burning a fuel and air ejected from the burner into the furnace to produce a flame therein, and a combustion condition determining device for determining the conditions of combustion of the fuel in a zone of the flame extending along different strata thereof by collecting light in the flame at one point in the flame by moving such point. Signals outputted by the combustion condition determining device are utilized for monitoring or controlling the flame and controlling exhaust emission control devices for controlling exhaust emissions produced by the combustion of the fuel. Control of the conditions of combustion of the flame can be effected quickly with a high degree of precision by monitoring the flame.

Abstract: The interlock assures that the end of a drain trap entrance pipe is covered with liquid. The system includes a control circuit with a circuit element which changes impedance with temperature changes. The circuit element is arranged to be thermally coupled with the drain trap liquid when the discharge end of the drain trap entrance pipe is immersed in the liquid. The circuit applies a current to the circuit element to thereby apply energy thereto. The circuit element achieves a lower steady-state temperature when thermally coupled with the liquid. The control circuit is operable to detect the difference in resistance when the circuit element is at the lower temperature. The control circuit is connected to a valve device for controlling combustion gas for the spectrophotometer and is operable to enable the valve device to enable the spectrophotometer when the circuit element is at the lower temperature and to disable the spectrophotometer at a higher temperature.

Abstract: An improved source lamp assembly for use in atomic absorption spectrophotometers is described having encoded structures for identifying the atomic element of the source lamp assembly, as well as to represent lamp operating current. The encoding structures are formed by way of mechanical, optical, or magnetic means. In particular, a mechanical arrangement involves a plurality of projections and recesses, either formed relative to a base structure of the lamp assembly or relative to an attached card-like structure. A card reading device is used to read this card-like structure. These alternative arrangements can be also used relative to optical encoding or magnetic encoding.

Abstract: A method of analyzing using an atomic absorption spectrophotometer including a flame atomizer is disclosed. The method comprises the steps of (a) setting the parameters of the spectrophotometer to a set of preset values dependent on the substance to be detected, (b) setting the gas flow rate to the burner to a preset value dependent on the substance to be detected, (c) aspirating an optimization standard into the flame, (d) measuring the absorbance of the optimization standard and storing the result, (e) modifying the gas flow rate in incremental steps and at each incremental step of flow rate repeating steps (c) and (d), and comparing the new absorbance value with the stored value until a maximum absorbance measurement is found, (f) using the maximum absorbance measurement value to select one of a plurality of sets of parameters for the spectrophotometer, and (g) subsequently aspirating and measuring the absorbance of a sample using the selected set of parameters.

Abstract: The invention concerns a device for guiding the sample flow in an analyzer, especially in an atomic absorption spectrophotometer, in order to accomplish an essentially even flow front. Consistent with the invention, the burner (11) has been equipped with a flow divider (12) that due to its advantageously chosen construction and manufacturing material also works as a drop eliminator that removes the harmful drops, which are present in the sample spray.

Abstract: A precision current meter of wide dynamic range and sensitivity to low currents is disclosed. The precision current meter is particularly useful as a component for spectrochemical computations in spectrometers for the simultaneous multielement analysis of unknown samples in solution. The precision current meter comprises a source of input current, preferably a photomultiplier tube, an integrator having an integrating capacity for detecting the input current from the source, a source of reference currents including an offset current, a switch with a drain current coupled to the integrator. A clock is provided for generating clock signals for the current meter, including a series of pulses to actuate the switch and thereby to admit drain current segments to the integrator.

Abstract: The flame in a flame atomic absorption spectrophotometer is shut down while using nitrous oxide as the oxidant, without shifting to a different oxidant such as air, by flooding the burner with a substantial excess of nitrous oxide to blow out the flame.

Abstract: An atomic spectroscopy surface burner, includes a housing having at least one channel for carrying fuel and at least one separate channel for carrying oxidant formed therein, the housing having an upper surface with two elongated slots formed therein, each of the slots being in communication with a respective one of the channels for delivering fuel and oxidant separately to the surface, and means for delivering a nebulized sample to the surface through one of the channels.

Abstract: A flame atomic absorption spectrophotometer burner apparatus for burning a fuel such as acetylene as one essential gas in the oxidant such as nitrous oxide as another essential gas includes a system for safely changing oxidants between air and nitrous oxide during start up. The system has a pressure sensor for sensing the pressure of at least one of the essential gasses, and a valve selectively operable in response to the pressure sensor for effecting the supplying of air as the oxidant and continuing to supply air as the oxidant when the pressure of the essential gas is low and for selectively switching to nitrous oxide as the oxidant only when the pressure of the essential gas is high.

Abstract: An automatic gas flow safety device or system is provided for use with an atomic absorption spectrophotometer burner. Generally speaking, a dual function pneumatic and electrical safety device is described which provides for a cut-off of the (acetylene) gas to the burner, upon monitoring an unacceptable air flow or electrical condition, to avert possible flash-backs at the burner. The invention basically comprises a pneumatic and electrical actuated means to control the on/off flow of gas to the burner determinative on the status of the air pressure and electrical power to the system.

Abstract: A chopperless spectroanalytical system of the double beam type in which radiation from a common source is split into reference and analysis beams. The two beams are directed along similar paths such that the analysis beam passes through an analysis region and the reference beam bypasses that analysis region. A monochromator has two spaced aperture regions such that one aperture region provides an entrance aperture for the analysis beam and an exit aperture for a dispersed portion of the reference beam; and the other aperture region provides an entrance aperture for the reference beam and an exit aperture for a dispersed portion of the analysis beam. The beams exiting from the two exit apertures are simultaneously monitored and compared to compensate for errors due to source fluctuations and the like.

Abstract: In atomic absorption spectrophotometer, a reference path may be provided for radiation which excludes the flame. This radiation provides a signal from a detector which varies only with the instrumental drift produced by variations in the radiation source brightness and by variations in detector gain. The signal can be used to compensate for drift in other signals received through a sample path including the flame. In the present invention, radiation passes through the sample path continuously during measurement, and only through the reference path between sample measurements. Movable mirrors shift the radiation between the paths upon externally applied commands. Conveniently, the reference path measurement is made while the flame is stabilized during the change between samples. The reference path measurements are stored and used to correct for drift.

Abstract: A dosing device for emitting liquid samples to an automatic absorption spectrophotometer having a liquid atomizer for the samples, utilizes at least one three-way distributor, one of the ports of which communicates with the atomizer, another port of which communicates with the spectrophotometer, and a third part of which communicates with a vessel containing the liquid sample. An electromagnetic valve is provided for the port communicating with the atmosphere. In the preferred embodiment, two such distributors are provided in series and the second distributor is connected to a source of pure solvent and is interposed between the first distributor and the spectrophotometer.

Abstract: An electrolyte in a sample is stably measured by using an automatic biochemical analyzing apparatus wherein a flame photometer is assembled, which comprises a sample pipetting and delivering member, a reagent liquid delivering member, reaction cups charging the sample delivered through the sample pipetting and delivering member and the reagent liquid delivered through the reagent delivering member and a flame photometer for measuring an electrolyte, the method being characterized in that with respect to a sample cup to which the measurement of electrolyte is ordered, the sample pipetting and delivering member and the reagent delivering member are operated to deliver the sample and the reagent liquid to a reaction cup and an electrolyte of the diluted sample in the reaction cup is measured by the flame photometer and with respect to a sample cup to which the measurement of electrolyte is not ordered, the sample pipetting and delivering member is not operated and into a reaction cup corresponding to said sample

Abstract: A flame coloring device makes a flame, such as a flame from a propane burner, visible even when the burner is used outdoors or in a bright environment. The device includes a carrier adapted for placement on the burner barrel and a solid colorant emitter such as sodium chloride supported by the carrier. When the carrier and colorant emitter are heated by the burner flame, the emitter emits a material that provides visible light, thereby defining the flame.

Abstract: A flame detector analyzer of the type wherein a sample gas is introduced into a flame formed by burning a fuel gas in presence of a combustion supporting gas, comprises a background providing device for supplying a background component gas capable of emitting a characteristic spectrum having the same wave length as that of the characteristic spectrum of a measuring object component contained in the sample gas, the light spectrums emitted from the measuring object component and the background component gas being received and treated to be detected, thereby increasing the measuring accuracy for the measuring object component and improving the resolving power at a low concentration detection region.

Abstract: A Zeeman atomic absorption spectrophotometer which monitors atomic absorption signals after a sample is introduced into the chemical flame atomizing portion. A signal peak value is measured in the portion of atomic absorption signals rising after the sample is introduced, or in the portion of atomic absorption signals breaking after the introduction of the sample is discontinued. A relation between the peak value and the sample concentration establishes a monovalent function. According to the conventional method, a relation between an average value of atomic absorption signals within a predetermined period of time and the concentration of specimen establishes a divalent function, and it is difficult to measure the samples, particularly in high-concentration regions. According to the present invention, however, it is possible to measure the samples of even high concentrations without having to dilute the samples.

Abstract: A research type burner is provided which permits ready optical access for study of precombustion and primary reaction zones of adiabatic flames of premixed gases. The burner includes a channel for relatively laminar gas flow having an outlet with a pair of essentially parallel closely spaced knife edges for providing an essentially stable and adiabatic flame. The knife edges project sufficiently above the burner housing to allow the passage of a laser beam between the knife edges through the zone to be studied.

Abstract: This invention relates to a spectrophotometer which includes a burner adapted for burning a gaseous fuel and for atomizing a sample to be analyzed in a burner compartment, mechanical elements or electrical circuitry serving to periodically pass a beam of light through the burner compartment, a detector, electrical circuitry for energizing the detector during the period of absence of the beam of light through the burner compartment, said detector being adapted when energized to produce an electronic signal representative of the presence of a flame in the burner compartment; and control elements responsive to the electronic signal for controlling the feeding of fuel to the burner.

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: The disclosure relates to an optogalvanic intracavity detector and method for its use. Measurement is made of the amount of light absorbed by atoms, small molecules and ions in a laser cavity utilizing laser-produced changes in plasmas containing the same atoms, molecules, or ions.

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 spectroanalytical instrument includes burner structure and a nebulizer for furnishing sample in fog form for flow through a premix chamber to the burner structure. Flow structure extending from a chamber port to a drain port provides a condensate flow path from the chamber to a drain. Trap structure is disposed in series in the flow path between the chamber port and the drain port, and drain line closure apparatus is switched between a first condition in which the drain line is closed and a second condition in which the drain line is opened by a control responsive to liquid in the trap structure such that the drain line is initially closed and is opened automatically in response to accumulation of condensate liquid in the trap structure to enable maintenance of positive pressure in the premix chamber.

Abstract: A method and apparatus for carrying out atomic spectroscopy, and particularly atomic absorption and atomic fluorescence spectroscopy. The method involves passing the emission spectrum of a light source through an atomized sample, changing the relationship between a selected emission line of the emission spectrum and a corresponding absorption line of the atoms of interest and measuring the absorption of that emission line by the sample before and after the aforementioned change in relationship. The change in emission and absorption line relationship can be effected by application of the Zeeman Effect, Stark Effect, or Doppler Effect. The apparatus, in one form, includes an electro-magnet operative to apply a magnetic field to the atomized sample and thereby cause splitting and shifting of the aforementioned absorption line, and the magnet is modulated to effect periodic variation of the spectral line relationship.

Abstract: A method of controlling spectroscopic analysis in which a sample in liquid concentrate form and containing an element of interest, is nebulized and carried into an analysis zone by pressurized support gas. The invention comprises regulating the flow rate of the support gas to control the density of atoms of the element present in the analysis zone so as to be within a measurable range. The flow of support gas controls sample uptake at the nebulizer, and that uptake is reduced by dividing the gas flow before the nebulizer so that one part by-passes the nebulizer but is nevertheless directed into the analysis zone so that the total gas flow to the analysis zone remains constant.

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: An inductively coupled plasma atomic fluorescence spectrometer (ICP-AFS) for multielement analysis of unknown samples. The ICP-AFS spectrometer comprises a plasma stream atomizing a dispersed sample and directed along a central axis, a plurality of optical stations surrounding the central axis, each including an energizing illuminator and a fluorescence detector focused at the same region of the plasma stream, and a readout system for identifying the unknown samples. Preferably, the plasma stream is controlled by inductive coupling, the energizing illuminator is a modified hollow cathode lamp, the fluorescence detector includes an interference filter, and the readout system incorporates multiplexing and intermittent modulation of the energizing illuminators.

Abstract: A grinding wheel is used to pulverize solid test samples and propel particles thereof into a flame for analysis by an instrument such as a mass spectrometer. The sample is attached to one end of a pivoted lever arm. The other end of the lever arm is connected to a solenoid. Activation of the solenoid brings the sample into contact with the rotating grinding wheel. The solid particles produced by the wheel are propelled into the flame through a slot in an intermediate draft shield. The sampling cone of a conventional mass spectrometer or similar instrument may be placed in the flame to analyze the nature of the test materials. The device may also be used to inject test particles into the air or gas feed stream ahead of the flame if desired.

Abstract: An oxidant flow conduit having a restriction and branching downstream of the restriction to provide a primary flow conduit for supplying oxidant to a nebulizer and an auxiliary flow conduit having an adjustable valve for supplying oxidant to a mixing chamber is provided. A differential pressure transducer measures the pressure drop across the restriction to provide an output signal. A primary fuel conduit is provided having a pair of restrictions with an adjustable valve for supplying fuel to the mixing chamber. A boost conduit having a restriction is connected to the primary fuel conduit and between the restrictions providing for supplementing the fuel to the mixing chamber when a different fuel mixture is used. A differential pressure transducer measures the pressure drop across the pair of restrictions to provide an output signal. A square root linearization operation is performed on each signal in a microprocessor and modified output signals drive respective fuel and oxidant digital displays.

Abstract: The invention contemplates apparatus for simultaneous photometric observation of a plurality of elements in a liquid sample, wherein a dilute solution of the sample is atomized and fed to an elongate steady flame and wherein light from a hollow-cathode lamp, and containing at least one narrow-band emission line of one of the elements to be determined, is directed through the flame; plural photoelectric receivers, each with an associated filter unique to a line characteristic of a different specific element to be determined, are disposed to respond to light passing through the flame or to light emitted by the flame, as the case may be. The detected outputs of the receivers are fed to a computer for evaluation, the outputs of emission receivers being first electronically processed for the effective removal of "dust flashes" in the flame.

Abstract: There is described a programmable gas flow control apparatus for use in atomic absorption spectroscopy. Essentially, an all pneumatic system is described which provides for a predetermined flow of fuel and oxidant to the burner. The invention compensates for the variation in oxidant flow due to nebulizer adjustments by adjusting the oxidant flow to the auxiliary inlet of the burner. The invention utilizes a pneumatic computing relay which senses the oxidant flow to the nebulizer and simultaneously adjusts the flow to the auxiliary inlet so that the total flow of oxidant satisfies the predetermined optimum rate. The constant monitoring of the nebulizer line by the computing relay allows for continual adjustment of the oxidant flow to offset subsequent adjustments.

Abstract: A method and apparatus for carrying out atomic spectroscopy, and particularly atomic absorption and atomic fluorescence spectroscopy. The method involves passing the emission spectrum of a light source through an atomized sample, changing the relationship between a selected emission line of the emission spectrum and a corresponding absorption line of the atoms of interest and measuring the absorption of that emission line by the sample before and after the aforementioned change in relationship. The change in emission and absorption line relationship can be effected by application of the Zeeman Effect, Stark Effect, or Doppler Effect. The apparatus, in one form, includes an electro-magnet operative to apply a magnetic field to the atomized sample and thereby cause splitting and shifting of the aforementioned absorption line, and the magnet is modulated to effect periodic variation of the spectral line relationship.