Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
  • G01N31/002—Determining nitrogen by transformation into ammonia, e.g. KJELDAHL method
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N35/00—Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
  • G01N35/00584—Control arrangements for automatic analysers
  • G01N35/00594—Quality control, including calibration or testing of components of the analyser
  • G01N35/00693—Calibration
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N35/00—Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
  • G01N35/00584—Control arrangements for automatic analysers
  • G01N35/00722—Communications; Identification
  • G01N35/00871—Communications between instruments or with remote terminals

Definitions

• Measurement system for determining analyte information of a test sample
• the present invention relates to a measurement system and in particular to a measurement system for determining analyte information of a test sample of unknown composition.
• spectral measuring instruments of the same type may be standardized against a single instrument of that same type (so called 'master' instrument) so that a measurement made on any satellite instrument will be the same as if made on the master instrument.
• a portable device for use in the standardization of each satellite measurement instrument.
• the portable device comprises a reference sample holder collocated with an information unit which may be read by a satellite instrument when the holder is introduced into the satellite instrument.
• Information typically including a spectrum, regarding measurements made on the reference sample by the master measuring instrument is held in the information unit and transferred automatically to a satellite instrument.
• This information is employed to generate a standardization model for the satellite instrument.
• the standardization model may then be employed in a mathematical transformation of subsequent measurements made by the satellite instrument on unknown samples to ones that would have been made on the master instrument.
• One such type of instrument is a chemical assay measurement instrument. This type of instrument is often used to make routine chemical assays of an unknown test sample such as a food or a feed sample or a pharmaceutical sample.
• One such instrument operates according to the Kjeldahl method and is employed to provide, for example, information on the amount of nitrogen, and optionally from this an amount of protein, in a test sample.
• Other such instruments are known which operate according to well established measurement methodologies in order to measure, for example, a fat or fiber content of a sample.
• stoichiometric reference sample the composition of which known directly.
• This reference sample may, for example, be provided to a user of the measurement system pre-weighed, in an ampoule or a user may be required to manually weigh the stoichiometric material in order to create the reference sample.
• the results of measurements on this reference sample by a particular chemical assay measurement instrument are then correlated by the measurement system with information that indicates an expected measurement results for that sample.
• This information is typically in the form of a data sheet or other printed material that is separate from the reference sample and that identifies the chemical composition of the sample and possibly its weight. This information is then manually entered by a user into the measurement system that may then be configured to automatically compute an expected amount of one or more analyte.
• a measurement system as described in and characterized by the present Claim 1.
• information about the reference sample such as composition and weight or an expected amount of analyte, that was obtained using a second, different, preferably direct, measurement methodology may be quickly, accurately and automatically transferred into the system where it may be employed in a comparison of expected analyte information with analyte information obtained using the system in order to, for example, verify the correct operation of the measurement system.
• Fig. 1 shows schematically a first embodiment of a measurement system according to the present invention
• FIG. 2 shows schematically a digestion tube for a reference sample usable in the measurement system of Fig. 1;
• Fig. 3 shows schematically a second embodiment of a measurement system according to the present invention.
• Fig. 4 shows schematically a portable holder according to the present invention usable with the system of Fig. 3.
• Kjeldahl type is illustrated schematically.
• the system 2 is here shown to comprise three functional units 4,6,8 which may be separate as in the present embodiment or may, for example, be contained in a single housing. Whatever the arrangement of units 4,6,8 these together form a Kjeldahl measurement instrument 10 that is operably connectable to a data processor 12.
• This data processor 12 may also be contained within the same housing as the other functional units 4,6,8 and may be provided in permanent connection with the instrument 10.
• the first unit 4 is a pre-treatment unit and typically comprises a heating block 14 having a number, such as twenty, receptacles that are here illustrated as cylindrical bores 14a, each for holding a digestion tube, at least one of which will be of the type that is to be described in relation to Fig. 2.
• a nitrogen containing test or reference sample of known weight may be transformed into ammonium ions within this unit 4.
• the unit 4 operates by so called ⁇ digestion' whereby the sample is contained within the digestion tube in the presence of an acidic reagent and a catalyst and is then heated by the heating block 14, normally to temperatures of 300-600 0 C for periods of up to say two hours.
• the second unit 6 is a distillation unit in which the digested sample undergoes dilution, alkali addition and distillation, such as steam distillation.
• the third unit 8 is a determination unit in which test or reference measurement data on the distillate is generated by a one of a number of known measurement methodologies, such as gravimetrically, volumetrically, chromatographically or, as in the present example, titrimetrically using so called acid-base titration.
• the data processor 12 of the present embodiment comprises a calculations unit 12a, a screen 12b and a user input 12c, such as a keypad and is an integral unit of the measurement system 2.
• the data processor 12 may be realized in a number of known and uninventive ways, such as by means of a suitably programmed personal computer configured with interfaces for data communication with the system 2.
• the calculations unit 12a is, in the present embodiment, provided with a working access to a mathematical algorithm for the calculation of the nitrogen content (%N) , as analyte information, using the test- or reference measurement data resulting from the titration.
• the system 2 as is so far described is well known in the art and is commercially available, such as the KjelTec TM product range that is available from FOSS Analytical AB, H ⁇ ganas,
• a further functional unit that is configured as a reader 16 shown in Fig. 1 for reading information from an information unit of a portable holder shown in Fig. 2.
• the reader 16 is, in the present example, collocated with the distillation unit 6 and is operably connected to the data processor 12 to permit data transfer there between.
• a portable holder 18 is here illustrated as comprising a digestion tube 20 and an information unit 22 attached to a side wall of the tube 20.
• the tube 20 is provided with a removable lid 24 for sealing a predetermined amount of a known reference sample 26 into the tube 20 until use. This facilitates the storage of the reference sample 26 and helps assure the integrity of the reference sample 26.
• the information unit 22 comprises a remotely addressable memory 28 for holding analyte information data, such as weight, composition or expected amounts of analyte, regarding the reference sample 26 that was obtained by a second, different measurement methodology. Coupled to this memory 28 is an antenna 30 by which the data may by wirelessly transmitted to and from the memory 28, such as by radio frequency (RF) transmissions.
• RF radio frequency
• the information unit 22 is energized upon receipt of an appropriate wireless transmission from the reader 16 of the measurement system 2 and returns data to the reader 16 in the form of an appropriate wireless transmission.
• the reader 16 then operates to convert this transmission to a data signal usable by the data processing means 12.
• the reference sample 26 comprises a stoichiometric compound of known weight.
• data indicating the identity of the compound and the weight of the reference sample is transmitted to the information unit 22 and stored in its memory 28 together with an allowable measurement tolerance for the measurement instrument 10.
• the digestion tube 20 is then sealed by means of the lid 24 and shipped to an end user having a measurement system 2 in need of calibration.
• the digestion tube 20 is unsealed and placed in the measurement system 2.
• the reference sample may be an amino acid if the whole analysis procedure, including digestion is to be verified or it may be an ammonium salt if only the distillation and subsequent quantification is to be verified.
• the calibration procedure may be initiated on the measurement system 2 via the user input 12c, or may be initiated automatically by data elements returned to the reader 16 from the information unit 22.
• the determination unit 8 of the measurement system 2 is then operated to perform an analysis, here by titration.
• the reference measurement data from the determination unit 8 is passed to the calculations unit 12a which operates as it would for a test sample to process the measurement data and determine thereby constituent information of the reference sample 24 as an amount of nitrogen present in the reference sample 24.
• the calculations unit 12a also operates during this calibration procedure to receive information from the reader 16 that in the present embodiment indicates the chemical formula and the weight of the reference sample 26 and to process this information to generate corresponding expected analyte information, being here an expected amount of nitrogen present in the reference sample 26. It will be appreciated that the expected amount of nitrogen, determined essentially as it would have been determined by the calculations unit 12a, may be stored directly in the information unit 22 as expected analyte information and accessed by the calculations unit 12a. This would serve to reduce the processing burden on the unit 12a.
• the unit 12a is programmed to then perform a comparison of the determined amount of nitrogen with the expected amount in order obtain an indication of the numerical difference there between.
• a signal indicative of the same is subsequently originated.
• this signal is then compared with a signal from the reader 16 indicating the allowable measurement tolerance and a further signal is originated within the system 2.
• This further signal is, in the present embodiment, used to inhibit the future operation of the measurement system 2 to measure test and/or reference samples when the comparison shows the difference to lie outside the allowable tolerance.
• the further signal may, for example, be employed within the data processor 12 in order to generate a warning message on the screen 12c and to lock the operation of the calculations unit 12a to prevent a determination of an amount of nitrogen in a test sample.
• the calculations unit 12a may be temporarily unlocked automatically in response to the user or the information unit 22 input indicating a calibration procedure so as to enable an amount of nitrogen in a reference sample 26 to be determined.
• the operation of the measurement system 2 to measure test samples may be reinstated when the results of a subsequent calibration procedure indicates the operation of the instrument 10 to be within the allowable tolerance.
• the calculations unit 12a may ⁇ be configured to store reference analyte information for further processing.
• This information may, for example, be automatically transformed into a calibration function which relates expected reference analyte information to corresponding actual reference analyte information as determined by the system 2 for a number of reference samples having different amounts of the analyte present.
• This function (or data that may be employed in an automatic calculation of the function) may then be stored in an addressable memory included in the data processor 12, for use in the subsequent operation of the system 2.
• Such use may, for example, include the operation of the calculations unit
• a functional block diagram is depicted of a measurement system 32 including a measurement instrument in the form of a flow cytometer type cell counter 34.
• This measurement instrument 34 may be considered to comprise three functional units, 40,42,44 that in the present embodiment are shown as being contained within a single housing of the instrument 34.
• the first unit 40 is a sample preparation unit comprising a sample intake 36, such as a pipette, and transport system 38.
• the sample intake 36 is operable to remove an amount of a liquid from a sample holder 48, such as a vial, test tube or other liquid container, into the instrument 34.
• the transport system 38 may be considered to operate to mix the amount of liquid with a fluorescent marker dye for highlighting the specific cells or bacteria to be counted to produce a test sample.
• the system then provides a heated test sample to an optical unit 42.
• the optical unit 42 basically comprises a light source for exciting fluorescence and a cooperating detector (neither shown) for detecting the amplitude of the so excited fluorescence to generate test measurement data.
• An analysis and control unit 44 includes a data processor 46 that is configured to receive the test measurement data from the detector and to process this to determine constituent information of the test sample, being here the number of cells or bacteria of interest present in the test sample.
• This first measurement methodology provides a so-called indirect determination of the number of particles of interest since the amount of total luminescence is measured which is then related to the number of particles.
• Such a measurement instrument 34 as so far described is well known in the art, and is, for example, commercially available from FOSS A/S Hiller ⁇ d, Denmark, where it is marketed as FOSSOMATIC TM.
• the reader 50 is operably connected to the analysis and control unit 44 to permit data transfer there between, said data being usable within the data processor 46.
• an exemplary embodiment of a portable holder 52 is shown as comprising a container 54 for a reference liquid 64.
• the container 54 of the present embodiment being removably located within a housing 56 so as to provide, in use, an externally accessible region 58 by which liquid 64 may be removed from the container 54.
• the housing 56 is devised to provide physical protection for the liquid container 54.
• the housing 56 is provided with a recess 60 in which a remotely readable information unit 62, similar in function to that unit 22 of Fig. 2, may be located either fixedly or removably.
• the information unit 62 is configured to retain data indicating an expected number of cells or bacteria of interest within the reference liquid 64 as determined according to a measurement methodology different to that employed in the measurement instrument 34 of the system 32 of Fig. 3.
• this different measurement methodology directly determines the number of particles and comprises the counting of individual cells or bacteria, such as by eye with the aid of a microscope or by the computer- aided analysis of a digitised image that records the individual cells or bacteria.
• the portable holder 52 is placed proximal the pipette 36 of the measurement instrument 34 so that an amount of the reference liquid 64 may be taken into the measurement instrument 34.
• it is mixed with a suitable fluorescent marker to produce a reference sample for measurement in the optical unit 42 according to the measurement methodology employed on the test sample as described above and to thereby originate reference measurement data.
• the data processor 46 is adapted to process this reference measurement data to determine reference analyte information as indicating an amount of the cells or bacteria of interest in the reference liquid 64.
• the data processor 46 then operates to compare this with the data provided from the information unit 62 indicative of corresponding expected analyte information of the reference sample, here being the expected number of cells or bacteria, so as to determine whether or not the measurement instrument 34 is operating in an acceptable manner.
• the subsequent operation of the measurement instrument 34 may then be varied in a manner dependent on this determination, similar to the control and/or calibration of the measurement instrument 10 of Fig. 1 described above.
• the samples comprise biological material.
• Such material typically has a limited useful lifetime, after which the cell or bacteria content becomes unreliable. It may be useful then to include in the data held in the information unit 62 temporal data that may, for example, provide an indication of the useful lifetime of the reference sample material. This may be in the form of date information indicating, for example, the last date on which the reference sample should be used (so-called 'expiry date') .
• the data processor 46 may then be programmed to determine whether or not to perform a calibration procedure or to use the results of such a procedure in dependence of this date information.
• temporal data may be provided to and employed in a similar manner within the measurement system 2 of Fig. 1.
• the portable holders 18;52 may take any form that is suitable for use with a particular measurement instrument of interest and are not confined to the forms illustrated in the present embodiments . It will also be appreciated that other data may be held in the information units 22; 62 to be used by the system, for example in automating the operation of the measurement instrument 10;34. Such automation may involve an automatic selection of on or more of an appropriate sample handling protocol, a measurement protocol, and a data processing (control or calibration for example) protocol, all based on data identifying the sample type or class.

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• 2004
  • 2004-08-18 SE SE0402047A patent/SE0402047D0/sv unknown
• 2005
  • 2005-07-29 EP EP05762905A patent/EP1825252A4/en not_active Withdrawn
  • 2005-07-29 WO PCT/SE2005/001191 patent/WO2006019349A1/en active Application Filing
  • 2005-07-29 AU AU2005273070A patent/AU2005273070B2/en not_active Ceased
  • 2005-07-29 NZ NZ552349A patent/NZ552349A/en not_active IP Right Cessation
  • 2005-07-29 JP JP2007527141A patent/JP2008510162A/ja active Pending

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