FR2547053A1 - ATOMIC ABSORPTION SPECTROPHOTOMETER - Google Patents

Abstract

AN ATOMIC ABSORPTION SPECTROPHOTOMETER USES HCL1-HCL4 HOLLOW CATHODE LAMP ASSEMBLIES THAT ARE MAGNETICALLY CODED. THE MAGNETIC CODE IS READ BY CORRESPONDING MAGNETIC CODE READERS MCR1-MCR4 WHOSE OUTPUTS ARE APPLIED TO AN MCP COMPUTER WHICH INCLUDES AN MP MICROPROCESSOR, ROM DEAD MEMORY AND RAM RAM. THE ROM DEAD MEMORY CONTAINS SETS OF INFORMATION BY MEANS OF WHICH THE MICROPROCESSOR CAUSES THE APPLICATION OF THE CORRECT OPERATING CURRENT TO THE LAMPS BY THE LPS LAMP CURRENT SUPPLY DEVICE AND CAUSES THE MONOCHROMATOR MN TO BE SUPPLIED OVER THE LENGTH OF THE LAMPS. APPROPRIATE WAVE BY MWC MONOCHROMATOR WAVELENGTH ADJUSTMENT DEVICE. THE MAGNETIC CODE MAY MAKE ANY APPROPRIATE SHAPE AND MAY BE PRESENT ON A LABEL ATTACHED DIRECTLY TO THE LAMP HOUSING OR ON A SEPARATE CARD ATTACHED TO THE LAMP, THE CARD BEING INSERTED IN A MAGNETIC CARD READER.

Description

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  The present invention relates to an atomic absorption spectrophotometer comprising a source lamp for producing a radiation of the resonance line characteristic of one or more atomic elements, a monochromator for passing the radiation of the atomic absorption. a chosen wavelength characteristic of one or more atomic elements, a wavelength adjustment device responsive to wavelength information applied thereto for adjusting the monochromator to the wavelength chosen, a microprocessor, a memory retaining wavelength information in a location which is each time associated with the atomic element or the respective atomic elements of several of these lamps, and a device for rendering the microprocessor able to identify the atomic element (s) of the source lamp, in which the microprocessor is designed for application to the wavelength adjustment device, the wavelength information derived from the memory for a

  atomic element that is identified as well.

  A spectrophotometer as specified in the preceding paragraph is described in British Patent Application No. 8133968 (PHB 32832). The spectrophotometer described in this patent application uses a source lamp which comprises an electrical network of resistors housed in the base of the lamp and comprises a measuring circuit designed to identify, from the value of the resistors, the particular wavelengths that the lamp will emit, that is to say the particular atomic elements for which

  the radiation line is characteristic.

  The object of the invention is to provide an atomic absorption spectrophotometer comprising another device for identifying the atomic elements of

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the lamp.

  The invention provides an atomic absorption spectrophotometer as specified in the first paragraph, characterized in that the source lamp is magnetically encoded, the code being representative of the at least one atomic element, and the spectrophotometer further comprises a reader magnetic code and a device for applying one or more output signals from the magnetic code reader to the microprocessor to render the microprocessor able to identify the at least one atomic element. In a first construction, a magnetic code card may be attached to the source lamp, the magnetic code reader

  It is provided with a slot in which the card is inserted to allow reading of the code. Alternatively, the source lamp may be provided with a label on its outer surface, the tag 20 bearing the magnetic code.

  The spectrophotometer may comprise, in

  furthermore, a lamp turret carrying a plurality of source lamps and a magnetic code reader may be provided for each lamp location on the turret.

  The invention further provides a spectrophotometer in which the magnetic code is further representative of the operating current of the lamp, the spectrophotometer comprising a lamp power supply device and the memory retaining the current information of the lamp. lamp, the microprocessor being arranged to adjust the lamp power supply device using, together with the lamp current information of the memory, further lamp current information derived from the

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  magnetic code via the magnetic code reader. An analysis which involves the use of the spectrophotometer to analyze one or more samples with respect to an atomic element of such a lamp assembly can be controlled by the fact that the microprocessor is designed to use a set of information stored continuously in a random access memory for at least the duration of this analysis, the information set comprising information

  which relates to the atomic element, in particular the wavelength information, which can be derived from the read-only memory for this atomic element, as well as information relating to the sample which may come from elsewhere. for one or more samples.

  The spectrophotometer may include a support device for holding more than one source lamp at a time, magnetic code readers being provided for each lamp thus held, the outputs of the magnetic code readers being connected to the microprocessor and a device arrangement for positioning a lamp at a time for lamp assemblies thus maintained in the optical path of the monochromator, it being understood that an analysis sequence consisting of the implementation of the spectrophotometer for analyzing the sample or samples in turn for each of the atomic elements of a set of such elements, the source lamp for each atomic element of the set forming part of such a lamp assembly, is governed by the fact that the microprocessor is designed to control the support devices and positioning for positioning a lamp emitting radiation characteristic of each atomic element of the set of elements in turn in the path

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  optical monochromator and in that the microprocessor is provided to use each of these various sets of information successively, a set of information being provided for each atomic element of the set of elements, the various sets of information being stored continuously in the RAM

  for at least the duration of the analysis sequence.

  An embodiment of the invention will be described hereinafter, by way of example, with reference to the accompanying drawings, in which: FIG. 1 schematically illustrates a first embodiment of a line-forming lamps resonator having the form of a hollow cathode lamp for a single element carrying a magnetic code on its outer surface; Fig 2 is a perspective view of a hollow cathode lamp to which is attached a card carrying a magnetic code; Fig. 3 illustrates a lamp turret carrying four lamps as shown in Fig. 2 and four magnetic code readers; Fig. 4 is a block diagram of an atomic absorption spectrophotometer using four lamp assemblies as shown in Fig. 2, and

  Fig. 5 is a flowchart of an operation of the spectrophotometer shown in Fig. 4.

  As shown in Fig. 1, a resonance line source lamp having the form of a hollow cathode lamp assembly for a single HCL element comprises a CA electrode which is a hollow cathode and an AN electrode which is an anode in a tightly sealed envelope S Eo A cap BA is attached to the envelope SE and carries two connection pins P1 and

  P 2 to which the anode AN and the cathode CA are onP 2 to which the anode AN and the cathode CA are con-

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  These connecting pins are used to connect an LPS lamp power supply device (see FIG. 4) to the anode AN and to the cathode C Ao A label LA carrying a magnetic tape MCS is attached to the envelope SE of the HC Lo hollow cathode lamp The MCS magnetic tape is encoded to represent the atomic element of the lamp and may also represent the current that the HCL lamp 10 requires from the power supply device of lamp current

  LPS An MCR magnetic code reader is provided for reading the code from the LA tag and producing a code dependent output electric signal, which output is applied to a microprocessor / u P in the spectrophotometer (see Fig. 4). ).

  Fig. 2 illustrates a lamp mounting variant comprising a hollow cathode lamp HCL to which a card CC is attached by a string ST which passes through a hole pierced in an ear LU of the base BA of the lamp HICL. gang

  MCS magnet which is encoded to represent the atomic element of the lamp and which can further represent the operating current of the lamp.

  The card CC could be replaced by a body of different shape, for example a bar or rod bearing the magnetic code. The rod or the bar can be made of a magnetic material comprising

  north and south poles that alternate in the longitudinal direction to form the magnetic code.

  The magnetic code can be relatively

  dense and in this case a relative displacement must be provided between the read head and the magnetic tape.

  For this purpose it is possible to move the head above the band, either by hand, or automatically or move the band opposite a stationary head, for example in a strip opposite a fixed head, for example in

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  By introducing a card into a slot, the head being placed close to the slot With a less dense code, it is possible to read the code while the magnetic tape and the reading device are both stationary, for example using of Hall effect devices.

  FIG. 3 illustrates a turret TU in the form of a turntable which carries four HCL source lamps 1 to HCL 4 and four MCR code readers 1 to MCR 4 The HCL 1 to HCL 4 lamps are of the type shown in FIG. Fig 2 and the code readers MCR 1 to MCR 4 each have a slot CC Sl to CC 54 in which the coded cards CC 1 to CC 4 are introduced. This arrangement has the advantage that the presence of a card can be monitored. in a continuous manner and that the type of lamp put into use can also be monitored continuously if the magnetic code is in a suitable form Even without the continuous monitoring of the magnetic code, it is possible to easily detect the moment or a lamp is removed from its socket by monitoring the current of the LPS power supply because, when the lamp is removed, the current supplied to this socket

falls to zero.

  Although the lamp assemblies described with reference to FIGS. 1 and 2 are hollow cathode lamps each corresponding to a single atomic element, other lamps intended to produce resonance line radiation characteristic of one or more elements. Atomic could also be used These lamps include hollow cathode lamps for several elements and discharge lamps

without electrode.

  FIG. 4 illustrates an atomic absorption spectrophotometer comprising four montages of

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  hollow cathode lamps for a single atomic element HCL 1 to HCL 4, each of these assemblies being in accordance with the HCL lamp assembly described above with reference to FIG. 2 and being connected to a magnetic code reader MCR 1 to MCR 4 The four fixtures of lamps HC L1 through HCL 4 are held in a turret TU actuated by a TUC turret controller to position a lamp assembly selected from the four HCLI fixtures. HCL 4 at a given moment in the optical path of the spectrophotometer Fig. 4 illustrates the lamp arrangement HC L1 in the optical path The radiation emitted by the HCL lamp assembly 1 passes from the corresponding C A1 cathode through an AT atomizer The samples to be analyzed by the spectrophotometer are introduced into the AT atomizer by a sampler device which can be of conventional flame type or electrothermal furnace type. Automatically AS actuated by a controller of automatic sample changer ASC and the atomizer is actuated by the control device AT Co After passing through the atomizer AT, the radiation passes through a monochromator MN The wavelength of the radiation which Through the MN monochromator is selected by the PCM wavelength setting device and the bandwidth, i.e., the width of the slot, of the MN monochromator is selected by the slot adjusting device MSC A photomultiplier tube detector DET provides a voltage signal whose ampliude is proportional to the intensity of the radiation coming out of the monochromator MN, and a logarithmic converter LG provides an amplified voltage signal proportional to the logarithm of the output of the detector DET The concentration of the atomic element for which the samples presented to the AT atomizer are

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  analyzed, is essentially proportional to the signal

  output of the logarithmic converter LG.

  The two electrodes of each of the montages of

  HCL lamps 1 to HCL 4 are connected to the LPS lamp power supply device 5, only the hollow cathodes C A1 being schematically represented in the drawing with a single connection in each case.

  During the operation of the spectrophotometer, the magnetic code readers MCR 1 to MCR 4 read the magnetic code on the cards C C1 to CC 4 attached to the HCL lamps 1 to HCL 4 as soon as the cards are inserted into the slots. This measurement is then This is repeated as a basic verification program that is interrupted when an analog signal produced by the spectrophotometer, for example the output of the log converter LG, is to be applied to the microprocessor via the ADC analog-to-digital converter. For example, basic verification can be used to produce an error signal if a lamp is not present in

a required position.

  An MCP microcomputer comprises the microprocessor / u P, a volatile RAM RAM for temporarily holding the data to be processed by the microprocessor / u P and a ROM retaining the program information for conditioning the operation of the microprocessor / Advantageously, the ROM memory is a read-only memory. The bus BS connects the microprocessor / u P to the random access memory RAM, to the read-only memory ROM, to the digital analog converter ADC, to the locking circuit device LH, to the power supply device. of the LPS lamp current, the TUC turret controller, the ASC autosampler controller, the ATC atomizer controller, the

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  MSC Slot Adjuster and MW Co Wavelength Adjuster In addition to retaining program information, the ROM also retains information pertaining to the atomic element, particularly the wavelength information, in a location associated therewith, the respective atomic element of each of the single atomic element hollow cathode lamp assemblies with which the spectrophotometer can be used More than 60 of these lamp mounts However, at any given moment, a single lamp assembly or some of them, for example the four HEICL 1 A HCL 4 arrays, are placed in the spectrophotometer. with their cards inserted in the MCR code readers The microprocessor / u P is conditioned to identify atomic element of the few or some fixtures of lamps In the case of four montages of 20 HCL 1 to HCL 4 shown in Fig 4, this identification is sensitive to the output of magnetic code readers MCR 1 to MCR 4 which are interrogated in turn by the microprocessor via the LH latch circuit device. The microprocessor / u P is further conditioned to apply to the wavelength adjustment device MWC, the wavelength information derived from the read-only memory ROM for the lamp assembly among the few fixtures of lamps of which the atomic elements are identified and whose lamp is also present in

  The optical path of the monochromator The turret TU and the turret control device TUC comprise means which enable the microprocessor / uP to identify the lamp present in the optical path 35 of the monochromator.

  Read 2547053 The ROM also retains the lamp current information The microprocessor / u P is conditioned to adjust the LPS lamp power supply device with the aid of this lamp current information for the one or several lamp assemblies whose atomic elements are identified via MCR magnetic code readers It is advantageous for the microprocessor / u P to use the maximum lamp current information derived from the magnetic code via the magnetic code readers MCR as well as 1 lamp current information derived from the ROM to set the LPS lamp power supply device If the magnetic code did not contain representative elements of the maximum lamp operating current of the lamp assemblies respective lamps, the lamp current information in ROM could be retained at locations associated respective atomic elements of each of the various lamp assemblies & hollow cathodes with which the spectrophotometer can be used and could fully define the operating current for the

respective lamps.

  For analysis involving the use of the spectrophotometer to analyze one or more samples with respect to the single atomic element of one of the various hollow cathode lamp assemblies for which information is stored in read-only memory The information on the atomic element and the information relating to the sample are both necessary. The automatic operation of the spectrophotometer is facilitated by the fact that the two types of information are put together to form a game. of information that is continuously stored for 35

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  at least the duration of this analysis in NVM nonvolatile random access memory The microprocessor / u P is connected by the bus BS to the NVM memory and is conditioned to use this set of information in order to conduct this analysis. The information relating to the atomic element for each set of information in the NVM may be derived from the ROM and transferred to it by the microprocessor / u P when identifying the atomic element of the memory. This information relating to the atomic element comprises the aforementioned wavelength information, together with the slot width information to be applied to the MSC slot adjusting device. the atomizer AT is of the flame type, the information relating to the atomic element, which can be derived from the read-only memory ROM, includes the information identifying the type of fuel and the flow rate of the fuel to be applied to the device ATC atomizer control and can also

  The time during which the output signal of the detector DET, received via the log converter LG and the analog-to-digital converter ADC, is used on average by the microprocessor / u P for.

  reducing the noise of this signal is determined by the measurement time In the case where the atomizer AT is of the electrothermal furnace type, the information relating to the atomic element again comprises the wavelength information. and the slit width information, but it further comprises the furnace heating cycle information to be applied to the ATC atomizer controller and may include the appropriate measurement time information to determine the 35 results of peak height and ridge area

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  from the output signal of the DET detector.

  The sample-related information for each set of information in the NVM can be entered into an appropriate location in this memory by the user of the spectrophotometer via a KPD digital keyboard connected by the bus. This information pertaining to the sample comprises the number of standard concentration samples to be retained in the AS autosampler and the information identifying the concentration of these standard samples. The background correction feature, which is well known and therefore not otherwise mentioned in this specification, is normally intended for use in the spectrophotometer and the information relating to the sample in this case also indicates whether or not a background correction is to be used in the spectrophotometer. A particular analysis The information relating to the atomic element may also include an instrumental Bumping effect intended to cut the background correction for atomic elements for which the radiation wavelength that the monochromator can pass is greater than

some value.

  The results of an analysis of one or more samples for a single atomic element are stored temporarily in the volatile RAM RAM of the microcomputer MCP and are finally transferred to a suitable recorder, for example a PRI printer shown connected by the bus BS to the microprocessor / u P, and possibly to a display device (not shown) It should be mentioned here that the automatic sampling device AS is of a type which can, in a specific way, be used either with

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  A flame type AT atomizer, either with an electrothermal furnace type AT atomizer, as the case may be. Further, the autosampler controller ASC is normally partly specific to the particular autosampler device AS and placed in the autosampler type atomizer AS. It is well known that atomic absorption spectrophotometers are mainly provided with a type of atomizer and can be For example, it is known to use an atomic absorption spectrophotometer which is primarily intended for use in the flame mode, but which can be used with the other type of atomizer as an accessory. adapted to the electrothermal mode, and in this case, the atomizer controller ATC for the electrothermal oven is normally provided as a Instead of being placed in the main body of the instrument and being permanently associated with the microprocessor, suitable detectors (not shown) are provided, so that the type of atomizer AT and in the case mentioned above, in which the ATC atomizer controller is provided as an accessory of the spectrophotometer, its random access memory is identified for the microprocessor / uP for the appropriate operation. The clean volatile can contain several sets of information relating to the thermal cycle of the furnace and this information which, as mentioned above, can be derived from the read-only memory RM 0, can instead remain in the non-volatile random access memory of the device. Atotherm electrothermal oven atomizer control, which can then be considered part of the RAM

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  nonvolatile NVM containing all the information set

necessary for an analysis.

  The nonvolatile random access memory NVM is able to store several sets of information as described above. An analysis sequence consisting in the use of the spectrophotometer to analyze one or more samples retained in the AS autosampler device for each turn. each element of a set of atomic elements is therefore governed by the fact that the microprocessor / u P is designed to use each of the various sets of information successively, one set of information for each atomic element of the set of elements The various sets of information are continuously stored in the NVM for at least the duration of the analysis sequence. For example, the NVM memory is able to store at least four sets of information, one for each of the four single atomic element HCL 1 to HCl 4 hollow cathode assemblies shown in FIG. In this way, information relating to the atomic element in each set of information may be derived from the ROM ROM. The spectrophotometer may further be able to use lamps other than the lamp assemblies described with reference. Figs. 1 and 2 which are coded to identify the corresponding atomic element. For example, a conventional single atomic element hollow cathode lamp may be received in each of the four lamp locations of the turret In this case, the user of the spectrophotometer can simply provide, via the keypad KPD, information microprocessor / u P identifying the atomic element of each lamp and, in response to this information, the microprocessor / u P can derive all the necessary information concerning the atomic element of the read-only memory ROM and transfer it, for use, in the non-volatile memory NVM As another example In this case again, the user provides, via the KPD keypad, the information identifying the corresponding atomic element of the lamp and, furthermore, the user must provide the necessary information for an auxiliary power supply to operate electrodeless discharge lamps. As another example, cathode lamps may be used These lamps may be conventional, in which case the user provides, via the KPD keypad, the information identifying the lamp as a lamp for several elements, the information identifying the atomic elements of the lamp. The lamp and the lamp current information. One possible variant is that the cathode lamp is hollow for a number of cells. Atomic sources may be provided with a magnetically encoded card for reading by the magnetic code reader MCR, by which it provides information about the current of the lamp and information identifying it as a lamp for Several elements The user then provides via the KPD keypad information that identifies the atomic elements of the lamp and the microprocessor / u P is conditioned to derive information relating to the atomic element. ROM and transfer it to a separate set of information in the RAM

  volatile NVM for each of these atomic elements.

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  The spectrophotometer can be provided with a manual bumping device such that the user is able to introduce, via the keyboard KPD, into a set of information in the NVM nonvolatile random access memory. relating to the atomic element which is different from the information

  which would otherwise be derived from the ROM.

  An external computer (not shown) can be connected via an appropriate interface circuit to the bus BS. An external computer can, for example, facilitate the automatic operation of the spectrophotometer by increasing the function of the non-volatile random access memory. For example, as soon as a set of information including the information pertaining to the atomic element and the information relating to the sample, as described above, has been introduced into the nonvolatile memory. NVM for a particular analysis, this set of information can be transferred to the external computer for later recall to be used in the repetition of the same analysis despite the fact that the capacity of the non-volatile memory NVM may have been fully used in

  meanwhile for different analyzes.

  It will be understood that in the foregoing description of an atomic absorption spectrophotometer

  given with reference to FIG. 4, only the features of such a spectrophotometer which are important for the invention have been mentioned and there are other features which are usually present or may be present. The current from the lamp is normally modulated and the signal from the detector DET is correspondingly demodulated before being processed by the logarithmic converter L GB. In addition, the detector DET is subjected to a gain adjustment which can be

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  In addition, a dual beam operation, ie the establishment of a reference optical path that derives the atomizer and the use of the derived signal through this reference path to provide a baseline correction that counteracts instrumental drift, particularly the output of the hollow cathode lamp and the detector output, is a well-known eventuality of the atomic absorption spectrophotometers in the case of the spectrophotometer

  As described above with reference to FIG. 4 which is able to operate automatically for a long time, a dual beam operation is particularly advantageous and most likely incorporated. Fig. 5 is a flowchart of a spectrophotometer operation shown in Fig. 4.

  In operation 1 "power up", the user puts into service the power supplies feeding the spectrophotometer In operation 2 "initialize", the user ensures that the four assemblies of hollow cathode lamps HCL 1 to HCL 4 for a single atomic element, are loaded while being installed in the TU turret and electrically connected, and that four corresponding sets of information are placed in the nonvolatile RAM VM 4 There is only one loading position for the lamps, which coincides with the position in which a lamp is located on the optical axis of the spectrophotometer, i.e. the position of the HCL lamp mount 1 shown in Fig 4 as

  each lamp assembly is in turn charged, the microprocessor / u P can transfer the information concerning the atomic element in question to the corresponding information set of the read-only memory ROM in an appropriate location of the non-volatile memory.

  tile NVM in response to the identification of the respective code among the lamp mount codes by the microprocessor from the code read by the magnetic code readers MCR 1 to MCR 4 At the moment each lamp is in the loading position , the user can enter relevant sample information for the corresponding information set into the NVM memory via the KPD keyboard and the microprocessor / u P It is possible that the operation of the spectrophotometer a repetition, for a new set of samples in the autosampler device AS, of an immediately preceding analysis sequence for a different set of samples for the atomic elements 15 of the same HCL 1 to HCL 4 S lamp assemblies This is so, the lamp assemblies are already loaded and the corresponding information sets are present in the NVM nonvolatile memory before the "power up" and operation 2 "initialize" shall not be performed by the user In operation 3 "current supplied to the lamps", the user turns on the LPS lamp power supply device for each lamp successively and, in response to this action for each lamp successively, the appropriate lamp current information is derived from the non-volatile memory NVM by the microprocessor / u P and applied to the LPS lamp power supply device. AT atomizer is of the flame type, an operation (not shown) performed either after operation 2 or after operation 3 and which involves a user intervention is necessary to ignite the flame of AT atomizer AT During operation 4 "start of the automatic sampler", the user initiates the operation of the autosampler AS and, in response to this operation, appropriate information is introduced to the autosampler. from the autosampler control device ASC in RAM RAM, after which the operation of the spectrophotometer can be fully automatic under the control of the microprocessor / u P, without further

user intervention.

  In response to step 4, the microprocessor / u P executes the operation 5 "set to 1 of N" N 10 represents a turret count; The turret count N determines which of the four assemblies of HCL lamps 1 to HCL 4 must be in the optical path during the duration of an operation of the automatic sampler AS, that is to say of an analysis of the 15 samples contained therein for an atomic element, and it also determines the information set in the non-volatile memory NVM to be used by the microprocessor / u P during this analysis The turret count N is held in the memory RAM fast for the duration of each scan In response to operation 5, the microprocessor / u P executes the operation 6 "setting the turret lamp to N". During this operation, the turret TU is brought into position N (at this stage N = 1, for example corresponding to the HCL lamp assembly 1) 25 by the turret control device TUC In response to the operation 6, the microprocessor / u P controls the operation 7 '"adjustment of the slots "in which the width of the slot of the The monochromator MN is set by the slot adjusting device MSC by means of slit width information from the set of information present in the NVM non-volatile memory, and then the microprocessor / u P controls the operation 8 "setting of the wavelength "in which the wavelength of the monochromator MN is set by the MWC wavelength adjuster With wavelength information from the set of information present in the In a conventional manner, the gain of the detector DET is automatically adjusted together with the adjustment of the wavelength of the monochromator. In addition, in response to the operation 6, the microprocessor / u P transfers the detector. information concerning the measurement time of the non-volatile memory NVM to the volatile random access memory RAM for use by the micropro

  c / u P during subsequent measurements of the samples for said atomic element.

  After the operation 8, the microprocessor / u P controls the operation 9 "blank measurement" During this operation, under the control of the autosampler control device ASC, the autosampler AS supplies a sample to the atomizer AT which contains a nominally zero concentration of the atomic element for which the set of samples is to be analyzed. This sample is atomized by the atomizer AT under the control of the ATC atomizer controller and the signal of The output of the DET detector is passed through the logarithmic converter LG and the analog-to-digital converter ADC to the microprocessor / u P, the result being stored in RAM as a base measurement representing a zero concentration. of the atomic element during the duration of the analysis of the set of samples for this atomic element In the case where the atomizer AT is of the flame type, the microprocessor r / u P applies fuel and fuel flow information from the NVM nonvolatile memory to the ATC atomizer controller for atomizing this sample and all subsequent samples during the analysis of the fuel. this element

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  In the case where the atomizer AT is of the electrothermal furnace type, the microprocessor / UP applies furnace heating cycle information from the nonvolatile memory NVM to the ATC atomizer controller for the atomization of this and all subsequent samples during the analysis of this particular atomic element.

  After the operation 9, the microprocessor / u P controls the operation 10 "standard sample measurements". During this operation, from standard samples,

  that is, samples of known concentration, which are present in a predetermined number in the corresponding set of information in the non-volatile memory NVM, are supplied in turn by the automatic sampler device AS to the AT atomizer.

  In each case, the output signal of the detector DET is applied via the analog-to-digital converter ADC to the microprocessor / u P and an absorbance result is calculated by comparison with the basic measurement in RAM RAM and is then stored in this random access memory RAM After the operation 10, the microprocessor / u P executes the operation 11 "calibration" During this operation, the microprocessor / u P derives the known concentration values from the standard samples of the game relevant information in the non-volatile memory NVM and uses these concentration values as well as the absorbance results for the standard samples that were stored in the RAM RAM 30 and in the operation 10 to compute a set of coefficients of calibration which are then stored in the RAM RAM during the duration of the analysis on the said atomic element These calibration coefficients allow to apply the functions known usually as scalar expansion and

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  curvature correction to subsequent sampling measurements. After the operation 11, the microprocessor / u P controls the operation 12 "measure sample, calculate 5 and store the concentration" During this operation, a sample of the set of samples to be analyzed for the said atomic element is supplied by the autosampler AS to the atomizer AT The absorbance result for the sample, derived from the output signal of the detector DET, is applied to the random access memory RAM, the calibration coefficients in the random access memory RAM are applied to the absorbance result to produce a concentration result and the concentration result is stored in RAM RAM. After the operation 12, the microprocessor / u P controls the operation 13 "end of the operation of the autosampler?" During this operation, the autosampler controller ASC detects whether or not the autosampler AS has reached the end of its operation and should not measure

  another sample If the answer is "no", operation 12 is repeated for the next sample.

  When the operation 12 has been executed for all the samples and their respective concentration results are stored in the random access memory RAM,

  the next operation 13 produces the answer "yes" and the microprocessor / u P goes to the operation 14 "N = limit?".

  In this operation, the turret count N is checked to determine whether or not it corresponds to the number of turret positions, for example four positions as shown in Fig. 4. During the first analysis, N = 1, is established by the operation 5, and in this way the operation 14 produces the answer "no" as a result of which the microprocessor / u P executes the operation 15 "N = N + 1" in which it increments the

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  turret count value N In response to operation 15, the microprocessor / u P performs the operation 6 in which the turret TU is driven to the next position to bring the next HCL lamp assembly 2 into the path The spectrophotometer optics and operations 7 through 13 are repeated to provide another set of concentration results in RAM RAM for the same set of samples in AS autosampler with respect to the only atomic element of the assembly. When finally the operation 14 produces the answer "yes", the microprocessor / u P performs the operation 16 "print the edited results and stop" During this operation, the results of concentration of all the Samples from the sample set in the AS autosampler for the atomic elements of all HCL 1 to HCL 4 lamp assemblies for a single atomic element in the tower they are extracted from the RAM RAM in edited form and printed by the PRI printer, then the

  The spectrophotometer is stopped, that is, most of the power supplies are shut down and a dormant state is established. An analysis sequence for a new set of samples then requires the user to start the entire process. sequence of operations from operation 1.

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Claims (8)

R E V E N D I C A T IONS   __________________________1. An atomic absorption spectrophotometer comprising a source lamp for producing a radiation of the resonance line characteristic of one or more atomic elements, a monochromator for passing radiation of a selected wavelength characteristic of one or more a plurality of atomic elements, a wavelength adjustment device responsive to wavelength information applied thereto for setting the monochromator to the selected wavelength, a microprocessor, a memory retaining length information wave at a location therein each time associated with the atomic element or the respective atomic elements of several of these lamps, and a device for making the microprocessor able to identify the atomic element or elements of the lamp forming source, in which the microprocessor is adapted to apply to the wavelength setting device, wavelength information. e derived from the memory for an atomic element which is thus identified, characterized in that the source lamp is magnetically encoded, the code being representative of the at least one atomic element, and in that the Dm Letr spectmphco further comprises a magnetic code reader and a device for applying one or more output signals from the magnetic code reader to the microprocessor to make the microprocessor able to identify the one or more atomic elements.   An atomic absorption spectrophotometer according to claim 1, wherein a magnetic code card is attached to the lamp and the magnetic code reader has a slot into which the card is inserted to allow the 2547053 reading the code.   An atomic absorption spectrophotometer according to claim 11, wherein the source lamp is provided with a label on its outer surface, the label bearing the magnetic code. 4. Spectrophotometer according to any one   of the preceding claims comprising a lamp turret carrying a plurality of source lamps, wherein a magnetic code reader is provided   for each lamp position on the turret, 5. Spectrophotometer according to any one   of the preceding claims, wherein the magnetic code is further representative of the operating current of the lamp, the spectrophotometer   comprising a lamp power supply device and the memory retaining lamp current information, the microprocessor being arranged to adjust the lamp power supply device 20 using, together with the information of lamp current from the memory, further lamp current information derived from the magnetic code via the magnetic code reader. 6 o Spectrophotometer according to any one   of the preceding claims, wherein the memory is a ROM.   A spectrophotometer according to claim 6 as claimed in claim 1, wherein an analysis consisting of the use of the spectrophotometer for analyzing one or more samples with respect to an atomic element of such a lamp assembly is governed by the that the microprocessor is designed to use a set of information stored continuously in a random access memory for at least 26 2547053   the duration of this analysis, and wherein the set of information includes information relating to the atomic element, including the wavelength information derivable from the dead memory for that atomic element, as well as information pertaining to the sample that may come from   besides for this or these samples.   A spectrophotometer according to claim 7 which includes a support device for holding more than one source lamp at a time, magnetic code readers being provided for each lamp thus held, the outputs of the magnetic code readers being connected to the microprocessor and a positioning device for positioning a lamp at a time for lamp assemblies thus held in the optical path of the monochromator, it being understood that an analysis sequence consisting of the use of the spectrophotometer for analyzing the the samples in turn for each of the atomic elements of a set of such elements, the source lamp for each atomic element of the set forming part of a lamp assembly, is governed by the fact that the microprocessor is designed to control support and positioning devices for positioning a lamp emitting a characteristic radiation for each the atomic element of the set of elements in turn in the optical path of the monochromator and in that the microprocessor is provided to use each of these information sets in succession, a set of information being provided for each atomic element of the game of elements, the various sets of information being stored continuously in the RAM memory   for at least the duration of the analysis sequence.