ANALYTICAL SYSTEM AND METHOD

Abstract

An analytical system comprising a mass spectrometer and an ionization source. The analytical system further comprises an analytical fluidic system connectable to the ionization source for infusing samples into the mass spectrometer via the ionization source, a downstream pump fluidically connectable to the ionization source via the downstream valve, where the downstream pump is fluidically connected to a plurality of fluid containers comprising respective fluids, the fluids comprising a concentrated composition for calibrating the mass spectrometer and at least one diluent for diluting the at least one concentrated composition. The analytical system further comprises a controller configured to control the downstream pump to obtain at least one diluted composition by automatically mixing a concentrated composition with a diluent with a predetermined dilution factor, to infuse the diluted composition into the ionization source, to obtain a mass spectrum of the diluted composition and to execute a calibration of the mass spectrometer. A respective automated analytical method.

Claims

1. An analytical system comprising a mass spectrometer and an ionization source coupled to the mass spectrometer, an analytical fluidic system connectable to the ionization source via a downstream valve for infusing samples into the mass spectrometer via the ionization source, wherein the downstream valve is located downstream with respect to the analytical fluidic system in a normal direction of flow through a fluidic stream towards the ionization source, a downstream pump fluidically connectable to the ionization source via the downstream valve, wherein the downstream pump is fluidically connected to a plurality of fluid containers comprising respective fluids, the fluids comprising at least one concentrated composition for calibrating the mass spectrometer and at least one diluent for diluting the at least one concentrated composition, a controller configured to control the downstream pump in order to obtain at least one diluted composition by automatically mixing at least one concentrated composition with at least one diluent with a predetermined dilution factor, to infuse the at least one diluted composition into the ionization source, to obtain a mass spectrum of the at least one diluted composition and to execute a calibration of the mass spectrometer based on an assessment of the mass spectrum.

2. The analytical system according to claim 1 wherein the calibration includes a mass axis check and/or a mass axis adjustment.

3. The analytical system according to claim 2 wherein in case of failure or anticipation of failure of the mass axis check and/or mass axis adjustment, based on the assessment of the mass spectrum of the at least one diluted composition, the controller may be further configured to execute any one or more actions selected from adapting the dilution factor of the at least one concentrated composition, adjusting one or more mass spec acquisition parameters, executing a maintenance procedure, before repeating the mass axis check and/or mass axis adjustment.

4. The analytical system according to claim 1 wherein the at least one concentrated composition comprises cesium iodide, optionally ethylamine and/or formic acid, a polar solvent, in an embodiment methanol and/or water and optionally cyclosporine A and/or 5-(4-hydroxyphenyl)-5-phenylhydantoin and/or ammonium formate, and wherein the at least one diluent is any of methanol, acetonitrile, ethanol, propanol, isopropanol or a combination of any ones thereof.

5. The analytical system according to claim 3 wherein in the at least one concentrated composition: (i) cesium iodide has a concentration from 0.1 ?g/mL to 100 mg/mL; (ii) ethylamine, if present, has a concentration from 0.01 ?g/mL to 1 mg/mL, and formic acid, if present, has a concentration from 0.001% (v/v) to 10% (v/v) (iii) cyclosporine A, if present, has a concentration from 0.01 ?g/mL to 1000 ?g/mL, 5-(4-hydroxyphenyl)-5-phenylhydantoin, if present, has a concentration from 0.01 ?g/mL to 1000 ?g/mL, ammonium formate, if present, has a concentration from 0.01 mM to 1 M; (iv) a polar solvent, in an embodiment methanol, water, or a mixture thereof is added to 100%.

6. The analytical system according to claim 1 wherein the at least one diluent is any of methanol, acetonitrile, ethanol, propanol, isopropanol or a combination of any ones thereof.

7. The analytical system according to claim 1 wherein the analytical fluidic system comprises a plurality of fluidic streams, wherein at least one fluid container comprises a wash liquid, and wherein the controller is further configured to control the downstream pump and the downstream valve to connect to the ionization source between two consecutive fluidic streams in order to wash liquid from a previous fluidic stream out of a conduit between the downstream valve and the ionization source with the wash liquid before liquid from a subsequent fluidic stream enters the conduit.

8. The analytical system according to claim 1 wherein the analytical fluidic system comprises at least one fluidic stream comprising an HPLC column, wherein at least one fluid container comprises a wash liquid, and wherein the controller is further configured to control the downstream pump and the downstream valve to connect to the at least one fluidic stream in order to backflush and thereby clean the at least one HPLC column with the wash liquid.

9. An automated analytical method including use of a mass spectrometer, the method comprising connecting a downstream pump to an ionization source coupled to the mass spectrometer via a downstream valve arranged downstream of an analytical fluidic system, wherein the downstream valve is located downstream with respect to the analytical fluidic system in a normal direction of flow through a fluidic stream towards the ionization source, wherein the downstream pump is fluidically connected to a plurality of fluid containers comprising respective fluids, the fluids comprising at least one concentrated composition for calibrating the mass spectrometer and at least one diluent for diluting the at least one concentrated composition, controlling the downstream pump in order to obtain at least one diluted composition by automatically mixing at least one concentrated composition with at least one diluent with a predetermined dilution factor, infusing the at least one diluted composition into the ionization source, obtaining a mass spectrum of the at least one diluted composition, executing a calibration of the mass spectrometer based on an assessment of the mass spectrum.

10. The automated method according to claim 9 wherein executing the calibration comprises checking a mass axis and/or adjusting a mass axis.

11. The automated method according to claim 10 wherein, in case of failure or anticipation of failure of the mass axis check and/or mass axis adjustment, based on the assessment of the mass spectrum of the at least one diluted composition, the method comprises executing any one or more actions selected from adapting the dilution factor of the at least one composition, adjusting one or more mass spec acquisition parameters, executing a maintenance procedure, before repeating the mass axis check and/or mass axis adjustment.

12. The automated method according to claim 9 wherein the at least one concentrated composition comprises cesium iodide, optionally ethylamine and/or formic acid, methanol and/or water and optionally cyclosporine A and/or 5-(4-hydroxyphenyl)-5-phenylhydantoin and/or ammonium formate, and wherein the at least one diluent is any of methanol, acetonitrile, ethanol, propanol, isopropanol or a combination of any ones thereof.

13. The automated method according to claim 11 wherein in the at least one concentrated composition: (i) cesium iodide has a concentration from 0.1 ?g/mL to 100 mg/mL; (ii) ethylamine, if present, has a concentration from 0.01 ?g/mL to 1 mg/mL, and formic acid, if present, has a concentration from 0.001% (v/v) to 10% (v/v) (iii) cyclosporine A, if present, has a concentration from 0.01 ?g/mL to 1000 ?g/mL, 5-(4-hydroxyphenyl)-5-phenylhydantoin, if present, has a concentration from 0.01 ?g/mL to 1000 ?g/mL, ammonium formate, if present, has a concentration from 0.01 mM to 1 M; (iv) methanol, water, or a mixture thereof is added to 100%.

14. The automated method according to claim 9 comprising controlling the downstream pump and the downstream valve to connect to the ionization source between two consecutive fluidic streams of the analytical fluidic system in order to wash liquid from a previous fluidic stream out of a conduit between the downstream valve and the ionization source with a wash liquid before liquid from a subsequent fluidic stream enters the conduit.

15. The automated method according to claim 9 comprising controlling the downstream pump and any one or more valves including the downstream valve to connect to at least one fluidic stream of the analytical fluidic system comprising an HPLC column in order to backflush and thereby clean the HPLC column with a wash liquid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0094] The following detailed description of the embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

[0095] FIG. 1 schematically shows an analytical system and an analytical method comprising using a downstream pump for calibrating a mass spectrometer.

[0096] FIG. 2 schematically shows further details of the method of FIG. 1 in case of failure or anticipation of failure of calibration according to an embodiment.

[0097] FIG. 3 schematically shows a further embodiment of the analytic system and analytical method of FIG. 1 with the downstream pump having a further function.

[0098] FIG. 4 schematically shows a yet further embodiment of the analytic system and analytical method of FIG. 1 with the downstream pump having yet a further function.

[0099] Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of the embodiments of the present disclosure.

DETAILED DESCRIPTION

[0100] FIG. 1 shows a schematic example of analytical system 100 comprising a mass spectrometer 60 and an ionization source 61 coupled to the mass spectrometer 60, an analytical fluidic system 10 connectable to the ionization source via a downstream valve 20 for infusing samples into the mass spectrometer 60 via the ionization source 61, a downstream pump 40 fluidically connectable to the ionization source 61 via the downstream valve 20, where the downstream pump 40 is fluidically connected to a plurality of fluid containers comprising respective fluids 41, 42, 43, 44, the fluids comprising at least one concentrated composition 44 for calibrating the mass spectrometer 60 and at least one diluent 42, 43 for diluting the at least one concentrated composition 44. The analytical system 100 further comprises a controller 90 configured to control the downstream pump 40 in order to obtain at least one diluted composition 45 by automatically mixing at least one concentrated composition 44 with at least one diluent 42, 43 with a predetermined dilution factor, to infuse the at least one diluted composition 45 into the ionization source 61, to obtain a mass spectrum 62 of the at least one diluted composition 45 and to execute a calibration 63 of the mass spectrometer 60 based on an assessment 64 of the mass spectrum 62.

[0101] In particular, the analytical fluidic system 10 comprises a plurality of fluidic streams 11, 12, 13, whereas the downstream valve 20 comprises in this case a fluidic-stream port 21, 22, 23 for each fluidic stream 11, 12, 13 respectively and a waste port 21, 22, 23 for each fluidic stream 11, 12, 13 respectively, leading to a waste 50. The downstream valve 20 comprises in addition a valve-to-ionization-source port 25, connected to a conduit 30 leading to the ionization source 61 and alternately connectable to each of the fluidic stream 11, 12, 13 via the fluidic-stream ports 21, 22, 23 respectively. In particular, the downstream valve 20 further comprises a downstream-pump-inlet port 24 also connectable to the conduit 30 via the valve-to-ionization-source port 25 and a downstream-pump-waste port 24 leading to the waste 50 when connected to the downstream-pump-inlet port 24. It is clear that this is only an example and the number of ports and connections may be adapted according to the need and according to the number of fluidic streams.

[0102] In this example, the downstream pump 40 is controlled by the controller 90 to infuse the diluted composition 45 into the ionization source 61 at a flow rate similar to the flow rate 15 of the fluidic streams 11, 12, 13, e.g. about 500 ?L/min or less, e.g. 440 ?L/min, e.g. about 100 ?L/min or less, e.g. 50 ?L/min or less, e.g. 30 ?L/min.

[0103] FIG. 1 also schematically shows an automated analytical method including use of a mass spectrometer 60, the method comprising connecting a downstream pump 40 to an ionization source 61 coupled to the mass spectrometer 60 via a downstream valve 20 arranged downstream of an analytical fluidic system 10, where the downstream pump 40 is fluidically connected to a plurality of fluid containers comprising respective fluids 41, 42, 43, 44, the fluids comprising at least one concentrated composition 44 for calibrating the mass spectrometer 60 and at least one diluent 42, 43 for diluting the at least one concentrated composition 44. The method further comprises controlling the downstream pump 40 in order to obtain at least one diluted composition 45 by automatically mixing at least one concentrated composition 44 with at least one diluent 42, 43 with a predetermined dilution factor, infusing the at least one diluted composition 45 into the ionization source 61, obtaining a mass spectrum 62 of the at least one diluted composition 45, executing a calibration 63 of the mass spectrometer 60 based on an assessment 64 of the mass spectrum 62.

[0104] In this example, calibration includes a mass axis check and/or a mass axis adjustment; the concentrated composition 44 comprises for example cesium iodide, ethylamine, formic acid, methanol, and water, at 10-fold the required concentration, and the diluted composition 45 is obtained by mixing the concentrated composition 44 with for example a combination of methanol and acetonitrile as diluents 42, 43 the respective ratio being for example 10 (concentrated composition):45 (methanol): 45 (acetonitrile) such as to obtain a dilution factor of 10:90, i.e. a 10-fold dilution.

[0105] FIG. 2 schematically shows further details of the analytical system 100 and method of FIG. 1 in case of failure or anticipation of failure of the mass axis check (MAC) and/or mass axis adjustment (MAA), based on the assessment 64 of the mass spectrum 62 of the diluted composition 45. In particular, with reference to FIG. 2, the controller 90 is further configured to execute any one or more actions selected from adapting the dilution factor of the concentrated composition, adjusting one or more mass spec (MS) acquisition parameters, executing a maintenance procedure, such as a bake-out and/or IS cleaning procedure, before repeating the mass axis check (MAC) and/or mass axis adjustment (MAA). In particular, the method may comprise assessing parameters of the mass spectrum such as signal intensity, peak shape, background and presence of interferences. For example, in case of signal intensity below a reference range, e.g. for at least one or more peaks, e.g. for the highest m/z clusters, e.g. cesium iodide clusters, which tend to have a lower signal intensity versus more abundant m/z clusters, the action may comprise decreasing the dilution factor, such as to obtain a less diluted calibration solution, or enhancing the MS acquisition parameters, such as to increase the detector sensitivity, for individual m/z values or ranges or for the entire spectrum. On the other hand, in case of a signal intensity above a reference range, e.g. in case of signal saturation, e.g. for the most abundant clusters, the action may comprise increasing the dilution factor, such as to obtain a more diluted calibration solution, or reducing the MS acquisition parameters, such as to decrease the detector sensitivity, for individual m/z values or ranges or for the entire spectrum. Analogously, in case of abnormal peak shapes the action may comprise changing the MS acquisition parameters, either enhancing or reducing, accordingly. In case of background signal above a reference range, the action may comprise a bake-out and/or IS cleaning procedure and/or decreasing the dilution factor, such as to obtain a higher signal to noise ratio. Similarly, in presence of interferences, the action may comprise a bake-out and/or IS cleaning procedure and/or decreasing the dilution factor, such as to enhance the relative signal of the calibration solution components versus the signal of the interferences.

[0106] FIG. 3 schematically shows a further embodiment of the analytic system 100 and analytical method of FIG. 1 with the downstream pump 40 having a further function besides the function of providing the at least one diluted composition described in connection to FIG. 1 (represented in dashed lines in FIG. 3). In particular, at least one fluid container comprises at least one wash liquid 41, and the controller 90 is further configured to control the downstream pump 40 and the downstream valve 20 to connect to the ionization source 61 between two consecutive fluidic streams 11,12; 12,13; 13,11 in order to wash liquid from a previous fluidic stream out of the conduit 30 between the downstream valve 20 and the ionization source 61 with the wash liquid 41 before liquid from a subsequent fluidic stream enters the conduit 30.

[0107] Thus, the method comprises alternately connecting a plurality of fluidic streams 11, 12, 13 to the conduit 30 via the downstream valve 20 and connecting the downstream pump 40 to the conduit 30 between two consecutive fluidic streams 11,12; 12,13; 13,11 via the downstream valve 20 in order to wash liquid from a previous fluidic stream out of the conduit 30 before liquid from a subsequent fluidic stream enters the conduit 30.

[0108] The at least one wash liquid 41 can be for example water, acetonitrile, methanol, tetrahydrofuran or isopropylic alcohol, which may be pumped individually or mixed with each other in any combination and ratio, depending, e.g., on the LC conditions, on the type of samples and/or analytes flowing in between and on the desired washing effect. According to an embodiment, the at least one diluent 42, 43 for diluting the at least one concentrated composition 44 can be used as wash liquid and/or mixed with another wash liquid 41.

[0109] In this case, the downstream pump 40 can be controlled by the controller 90 to pump the wash liquid through the conduit 30 at a flow rate higher than the flow rate 15 of the fluidic streams 11, 12, 13.

[0110] FIG. 4 schematically shows analytic system 100 that is yet another variant of the analytic system 100 and analytical method of FIG. 1 and FIG. 3 with the downstream pump 40 having yet a further function. In particular, the analytical fluidic system 10 comprises at least one fluidic stream 11, 12, 13 comprising an HPLC column, and at least one fluid container comprises a wash liquid 41, as in the embodiment of FIG. 3. The controller 90 is here further configured to control the downstream pump 40 and the downstream valve 20 to connect to the at least one fluidic stream 11, 12, 13 in order to backflush and thereby clean the at least one HPLC column with the wash liquid 41. More particularly, the downstream pump 40 is connected to the downstream valve 20 via a wash selection valve 70. The wash selection valve 70 is configured to alternately connect the downstream pump 40 to any one of the fluidic streams 11, 12, 13 and to the conduit 30 via the downstream valve 20. In particular, the wash selection valve 70 is connectable to the fluidic streams 11, 12, 13 via respective fluidic stream wash ports 71, 72, 73 leading to respective three-way valves 16, 17, 18 fluidically connected to the downstream valve 20, via downstream-pump-inlet ports 21, 22, 23 that are also the waste ports 21, 22, 23, the three-way valves 16, 17, 18 each comprising a wash-selection-valve inlet port, a downstream-valve outlet port and a waste outlet port leading to the waste 50. The wash selection valve 70 further comprises a valve-to-conduit-wash port 74 connected to the downstream valve 20 via the downstream-pump-inlet port 24 for connecting to the conduit 30. In the example shown in FIG. 4, the wash selection valve 70, the downstream valve 20 and the three-way valve 16 are switched such that the downstream pump 40 is connected via the fluidic stream wash port 71, the three-way valve 16, the downstream-pump-inlet port 21 and the fluidic-stream port 21 to the fluidic stream 11, in order to backflush and thereby clean the fluidic streams 11 with the at least one wash liquid 41. At the same time, the fluidic stream 12 is connected to the conduit 30 via fluidic-stream port 22 and valve-to-ionization-source port 25, whereas the fluidic stream 13 is directed to waste 50 via fluidic-stream port 23, waste port 23 and three-way valve 18 respectively. It is to be noticed that the direction of flow 15 for the fluidic stream 11 is inverted with respect to the regular direction of flow, as shown in FIG. 1 and FIG. 3. The analytical system 100 may comprise other valves (not shown), e.g. one or more upstream valves, upstream of the fluidic streams 11, 12, 13 enabling e.g. exit and waste of the wash fluid in backflush mode.

[0111] The controller 90 may be configured to automatically backflush the HPLC columns of the respective fluidic streams 11, 12, 13 at regular intervals and/or upon detection of a pressure rise above a predetermined threshold in the at least one fluidic stream and/or upon detection of performance reduction of the HPLC columns below a predetermined threshold.

[0112] The controller 90 may be configured to manage a fluidic-stream-to-mass-spectrometer connection time, that is the connection time between the at least one fluidic stream 11, 12, 13 and the ionization source 61, a downstream-pump-to-mass-spectrometer connection time, that is the connection time between the downstream pump 40 and the ionization source 61, and a downstream-pump-to-fluidic-stream connection time, that is the connection time between the at least one fluidic stream 11, 12, 13 and the downstream pump 40, by controlling switching of any one or more valves including the downstream valve 20, the wash selection valve 70 and the three-way valves 16, 17, 18.

[0113] In the preceding specification, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one having ordinary skill in the art, that the specific details need not be employed to practice the present teaching. In other instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present disclosure.

[0114] Particularly, modifications and variations of the disclosed embodiments are certainly possible in light of the above description. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically devised in the above examples.

[0115] Reference throughout the preceding specification to one embodiment, an embodiment, one example or an example, one aspect or an aspect means that a particular feature, structure or characteristic described in connection with the embodiment or example or aspect is included in at least one embodiment. Thus, appearances of the phrases in one embodiment, in an embodiment, one example or an example, one aspect or an aspect in various places throughout this specification are not necessarily all referring to the same embodiment or example or aspect.

[0116] Furthermore, the particular features, structures, or characteristics may be combined in any suitable combinations and/or sub-combinations in one or more embodiments or examples or aspects.