Method for quality inspection of at least one LC-MS measurement

Abstract

The present invention proposes a method for quality inspection of at least one liquid chromatography-mass spectrometry (LC-MS) measurement of a sample comprising a target analyte and a defined amount of at least one internal standard. The method comprises the following steps: a) (120) determining information (peakAreaaqn) about an analyte signal and information (peakAreaaqn) about an internal standard substance signal measured by the LC-MS; b) (122) determining at least one monitoring parameter by using at least one processing device (114) by using the information about the analyte signal and the information about the internal standard signal, where the monitoring parameter comprises a minimum limit of the internal standard signal for the analyte signal of the sample; c) (124) comparing the information about the internal standard signal with the monitoring parameter by using the processing device (114), marking the LC-MS measurement as fulfilling the quality check if the information about the internal standard signal is greater than or equal to the monitoring parameter by using the processing device (114); or otherwise, marking as unqualified.

Description

Technical Field

[0001] The present disclosure relates to a method and a system for quality checking of at least one liquid chromatography-mass spectrometry measurement. Background Art

[0002] For the quality assurance of liquid chromatography-mass spectrometry (LC-MS) determination, a single sample is usually measured with a target compound of known concentration. Usually, a quality control (QC) sample is tested at a certain frequency in the analysis run, and the calculation result is checked according to the acceptance range. In addition, each sample is usually spiked with a limited amount of internal standard (IStd), which allows monitoring of its chromatographic parameters, such as absolute peak area, retention time and peak width. Signal monitoring of IStd in LC-MS determination is a common method to ensure sufficient performance and quality of the obtained results of the measurement and therefore the sample. This concept is a part of several international guidelines for mass spectrometry, such as the guidelines formulated by CLSI (Clinical and Laboratory Standards Institute), EMA (European Medicines Agency) or GTFCh (German Society of Toxicology and Forensic Chemistry). Such technology is described, for example, in US 9,606,088 B2, US 9,465,911 B2, US 7,451,052 B2, US 2011 / 0101215 A1 and DE 10 2020 200 915 A1.

[0003] The corresponding IStd parameter should meet acceptance requirements for maximum deviations or specific cutoff values. Changes in IStd ideally cover the variations throughout the assay. Therefore, IStd can be used on the one hand to normalize the target analyte signal and thus improve the result precision. However, on the other hand, these changes may lead to high rates of false sample flagging in cases where the parameter is outside the acceptance range, or these changes may result in the need for a wide acceptance range for the corresponding IStd parameter. A high sample flagging rate increases the workload, as the corresponding samples need to be reviewed by experts, for example, and a wide acceptance range reduces the flagging rate, but also reduces the ability of IStd monitoring and there is a risk of overlooking bad measurements. Therefore, alternative or complementary technologies are needed to fill the above-mentioned gaps and avoid frequent manual chromatogram reviews by experts for validation.

[0004] DE 10 2020 200915A1 describes a chromatographic device including a control section and a storage section. The storage section stores a diagnostic reference based on a waveform W0-W2 or an intensity A0-A2 of a standard chromatogram CR of a standard sample as a measurement object. When measuring a measurement chromatogram CR of a standard sample whose amount or ratio is known in advance, the control section notifies management information related to the chromatographic device based on the diagnostic reference related to the waveform W0a, W0c-W2c or the intensity A0b-A2b of the measurement chromatogram.

[0005] Issues to be resolved

[0006] Therefore, the object of the present invention is to provide a method and system for quality checking of at least one liquid chromatography-mass spectrometry measurement, which avoids the above-mentioned disadvantages of known methods and devices. In particular, the method and system should reduce the need for manual review without reducing the ability to monitor parameters for quality assurance purposes. Summary of the invention

[0007] This problem is solved by a method and a system for quality checking of at least one liquid chromatography-mass spectrometry measurement having the features of the independent claims. In the dependent claims and throughout the description, advantageous embodiments are listed which can be realized individually or in any combination.

[0008] As used below, the terms "having", "comprising" or "including" or any grammatical variations thereof are used in a non-exclusive manner. Thus, these terms may refer to the absence of other features in the entity described in this context in addition to the features introduced by these terms, or the presence of one or more other features. As an example, the expressions "A has B", "A includes B" and "A contains B" may refer to the absence of other elements in A in addition to B (i.e., the presence of A solely and exclusively consisting of B); or to the presence of one or more other elements in entity A in addition to B (such as element C, element C and element D, or even other elements).

[0009] Further, it should be noted that the terms "at least one", "one or more" or similar expressions indicating that a feature or element may be present once or more than once are usually used only once when introducing the corresponding feature or element. In the following, in most cases, when referring to the corresponding feature or element, the expression "at least one" or "one or more" is not repeated even though the corresponding feature or element may be present only once or more than once.

[0010] Further, as used hereinafter, the terms "preferably", "more preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with optional features without limiting the possibilities of alternatives. Therefore, the features introduced by these terms are optional features and are not intended to limit the scope of the claims in any way. As the skilled person will recognize, the present invention may be carried out by using alternative features. Similarly, the features introduced by "in one embodiment of the present invention" or similar expressions are intended to be optional features without any limitation on alternative embodiments of the present invention, without any limitation on the scope of the present invention, and without any limitation on the possibility of combining the features introduced in this manner with other optional or non-optional features of the present invention.

[0011] In a first aspect of the present invention, a method for quality checking of at least one liquid chromatography-mass spectrometry (LC-MS) measurement of a sample comprising a target analyte and a defined amount of at least one internal standard is disclosed.

[0012] The method comprises the following steps, which may be performed in a given order as an example. However, it should be noted that different orders are possible. Further, one or more method steps may be performed once or repeatedly. Further, two or more method steps may be performed simultaneously or in a timely overlapping manner. The method may include other method steps not listed.

[0013] The method comprises the following steps

[0014] a) Determine the peakArea of ​​the analyte signal measured by the LC-MS aqn and information about the internal standard signal peakArea iqn , where qn specifies the quantity factor;

[0015] b) determining at least one monitoring parameter by using at least one processing device using the information about the analyte signal and the information about the internal standard signal, wherein the monitoring parameter comprises a minimum limit value of the internal standard signal for the analyte signal of the sample;

[0016] c) comparing the information about the internal standard signal with the monitoring parameter by using the processing device, wherein by using the processing device the LC-MS measurement is marked as meeting the quality check if the information about the internal standard signal is greater than or equal to the monitoring parameter, and is marked as failing otherwise.

[0017] The method may be computer-implemented. As used herein, the term "computer-implemented method" is a broad term and is given a common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or customary meaning. The term may specifically refer to, but is not limited to, a method involving at least one computer and / or at least one computer network. The computer and / or computer network may include at least one processor configured to perform at least one of the method steps of the method according to the present invention. Preferably, each method step is performed by a computer and / or a computer network. The method may be performed completely automatically (particularly, without user interaction). As used herein, the terms "automatically" and "automatically" are broad terms and should be given their common and customary meanings to a person of ordinary skill in the art, and should not be limited to a special or customary meaning. The term may specifically refer to, but is not limited to, a process performed entirely with the aid of at least one computer and / or at least one computer network and / or at least one machine, in particular, without the need for manual operation and / or interaction with a user.

[0018] LC-MS measurements can be performed using at least one mass spectrometer configured to perform at least one LC-MS measurement on a sample containing a target analyte and a defined amount of an internal standard. As used herein, the term "mass spectrometer" is a broad term and will be given its common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term specifically may refer to, but is not limited to, an analytical technique for determining the mass-to-charge ratio of an ion. As used herein, the term "mass spectrometer", also referred to as a "mass analyzer", is a broad term and is given its common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term specifically may refer to, but is not limited to, an analyzer configured to detect at least one analyte based on a mass-to-charge ratio.

[0019] The mass spectrometer may be or may include at least one quadrupole analyzer. As used herein, the term "quadrupole mass analyzer" is a broad term and is given its ordinary and customary meaning to ordinary technicians in the field, and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, a mass analyzer that includes at least one quadrupole as a mass filter. A quadrupole mass analyzer may include multiple quadrupoles. For example, a quadrupole mass analyzer may be a triple quadrupole mass spectrometer. For example, a mass spectrometer may include an ionization source, a skimmer, three quadrupole segments Q1, Q2 and Q3, and a detector. Each of the quadrupole segments Q1, Q2 and Q3 includes a quadrupole.

[0020] As used herein, the term "mass filter" is a broad term and is given a common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a device configured to select ions injected into the mass filter according to the mass-to-charge ratio m / z of the ions. The mass filter may include two pairs of electrodes. The electrodes may be rod-shaped, particularly cylindrical. Ideally, the electrodes may be hyperbolic. The electrodes may be designed to be identical. The electrodes may be arranged to extend in parallel along a common axis, such as the z-axis. The quadrupole mass analyzer may include at least one power supply circuit, which is configured to apply at least one direct current (DC) voltage and at least one alternating current (AC) voltage between the two pairs of electrodes of the mass filter. The power supply circuit may be configured to keep each relative electrode pair at the same potential. The power supply circuit may be configured to periodically change the charge sign of the electrode pair so that only ions within a certain mass-to-charge ratio m / z range may have a stable trajectory. The trajectory of the ions in the mass filter may be described by the Mathieu differential equation. In order to measure ions with different m / z values, the DC voltage and the AC voltage may be adjusted in time so that ions with different m / z values ​​may be transmitted to the detector mass spectrometer.

[0021] The mass spectrometer device may further include at least one ionization source. As used herein, the term "ionization source", also referred to as "ion source" or "ion generator", is a broad term and is given its ordinary and customary meaning to those of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a device configured to generate ions, for example, from neutral gas molecules. The ionization source may be or may include at least one source selected from the group consisting of: at least one gas phase ionization source, such as at least one electron impact (EI) source or at least one chemical ionization (CI) source; at least one desorption ionization source, such as at least one plasma desorption (PDMS) source, at least one fast atom bombardment (FAB) source, at least one secondary ion mass spectrometry (SIMS) source, at least one laser desorption (LDMS) source, and at least one matrix-assisted laser desorption (MALDI) source; at least one spray ionization source, such as at least one thermal spray (TSP) source, at least one atmospheric pressure chemical ionization (APCI) source, at least one electrospray (ESI) and at least one atmospheric pressure ionization (API) source.

[0022] The mass spectrometer may include at least one detector. As used herein, the term "detector" is a broad term and is given its common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a device configured to detect input ions. The detector may be configured to detect charged particles. The detector may be or may include at least one electron multiplier. The mass spectrometer, in particular the detector and / or at least one processing device of the mass spectrometer, may be configured to determine at least one mass spectrogram of the detected ions. As used herein, the term "mass spectrogram" is a broad term and is given its common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a two-dimensional representation of signal intensity relative to charge-to-mass ratio m / z, wherein the signal intensity corresponds to the abundance of the corresponding ions. The mass spectrogram may be a pixelated image. In order to determine the resulting intensity of the mass spectrogram pixel, the signal detected by the detector within a certain m / z range may be integrated. The analyte in the sample may be identified by the processing device. In particular, the processing means may be configured to associate a known mass with an identified mass or by a characteristic fragmentation pattern.

[0023] LC-MS measurement may be or may include at least one measurement by using a mass spectrometer. The mass spectrometer may include at least one liquid chromatograph, also referred to as a liquid chromatography (LC) device. The mass spectrometer may be a liquid chromatography mass spectrometer. The liquid chromatograph may be used as a sample preparation for a mass spectrometer. As used herein, the term "liquid chromatography (LC) device" is a broad term and is given its common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, an analytical module configured to separate one or more target analytes of a sample from other components of the sample for use in detecting the one or more analytes using a mass spectrometer. The LC device may include at least one LC column. For example, the LC device may be a single-column LC device or a multi-column LC device having a plurality of LC columns. The LC column may have a stationary phase through which a mobile phase is pumped to separate and / or elute and / or transmit the target analyte. The liquid chromatography mass spectrometer may further include a sample preparation station for automated pretreatment and preparation of samples, each sample including at least one target analyte. As used herein, the term "liquid chromatography mass spectrometry device" is a broad term and is given a common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a combination of liquid chromatography and mass spectrometry. The liquid chromatography mass spectrometry device may be or may include at least one high performance liquid chromatography (HPLC) device or at least one microfluidic liquid chromatography (μLC) device. The liquid chromatography mass spectrometry device may include a liquid chromatography (LC) device and a mass spectrometry (MS) device, in the present case a mass filter, wherein the LC device and the mass filter are coupled via at least one interface. The interface coupling the LC device and the MS device may include an ionization source, which is configured to generate molecular ions and transfer molecular ions to a gas phase. The interface may further include at least one ion migration module arranged between the ionization source and the mass filter. For example, the ion migration module may be a high field asymmetric waveform ion mobility spectrometry (FAIMS) module.

[0024] The mass spectrometer can be configured to perform an end-to-end workflow (also referred to as a sample measurement workflow), wherein the sample is injected into the inlet of a liquid chromatography column, the sample is separated into components on the column, and each component is eluted from the column. The eluted components are directed to a mass spectrometer, where they are ionized and analyzed. The mass spectrometer can measure the ion fragmentation pattern associated with each of the components. Each ion fragmentation pattern consists of one or more peaks corresponding to ion fragments with a specific m / z ratio. The peak pattern of a specific analyte (e.g., the m / z ratio and intensity of the peak) effectively serves as the "fingerprint" of the analyte. Due to the complexity of the fragmentation pattern, a variety of components can be identified and quantified based on these measurements. Typically, identification is performed by comparing the measured ion fragmentation pattern with reference information (e.g., a previously measured or simulated ion fragmentation pattern of a known component). The identification of a specific component can also be performed based on the time interval between the initial introduction of the sample (e.g., injection into the inlet of the LC-MS system) and the elution of the component from the LC column, or the time interval between the initial introduction of the sample and the measurement of the component ion fragmentation pattern in the mass spectrometer. Certain components can migrate through an LC column at specific rates, and the elapsed time interval can be used as an indicator of the identity of the component. As with the ion fragmentation pattern, the elapsed time interval can be compared to reference information (e.g., previously measured migration and / or measurement times of known components) to determine the identity of the component.

[0025] As used herein, the term "sample" is a broad term and is given its ordinary and customary meaning to those of ordinary skill in the art, and is not limited to a special or customary meaning. The term specifically refers to, but is not limited to, any test sample, such as a biological sample. A mass spectrometer can be configured to measure a variety of biological samples. Examples of such samples include, but are not limited to, physiological fluids, including blood, serum, plasma, urine, sweat, saliva, lens fluid, cerebrospinal fluid, milk, ascites, mucus, synovial fluid, peritoneal fluid, amniotic fluid, lymph fluid, interstitial fluid, cerebrospinal fluid, tissue, cells, etc.

[0026] The sample can include one or more target analytes, also referred to as target analytes. The sample can be used directly when obtained from the corresponding source, or can be subjected to pretreatment and / or sample preparation workflow. For example, the sample can be pretreated by adding an internal standard and / or by diluting with another solution and / or by mixing with a reagent, etc. For example, in general, the target analyte can be vitamin D, drugs of abuse, therapeutic drugs, hormones and metabolites. For further details about the corresponding sample, reference is made to, for example, EP 3 425 369 A1, the entire disclosure of which is included herein by reference. Other target analytes are also possible.

[0027] As used herein, the term "internal standard" (ISTD) is a broad term and is given a common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term specifically may refer to, but is not limited to, a known amount of a substance. When experiencing the workflow of a mass spectrometer, the internal standard may exhibit properties similar to the target analyte. The workflow may include any pretreatment, enrichment, and actual detection steps. For example, the internal standard may be an isotope-labeled variant of the target analyte (comprising markers such as 2H, 13C, or 15N). The method may include adding a marker to the sample with the at least one internal standard.

[0028] As used herein, the term "quantitative factor", also expressed as "quantitative ion", is a broad term and is given a common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a conversion for analyte quantification. The quantitative factor may be the most enriched ion. As used herein, the term "qualitative factor", also expressed as "qualifier ion", is a broad term and is given a common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a further conversion to confirm the measurement. As used herein, the term "quantitative factor-qualitative factor ratio" is a broad term and will be given a common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a signal intensity ratio or peak area ratio of a quantitative factor and a qualitative factor.

[0029] As used herein, the term "quality" is a broad term and will be given a common and customary meaning to one of ordinary skill in the art, and is not limited to a special or customary meaning. The term specifically may refer to, but is not limited to, a measure of the reliability of a measurement result obtained by using a mass spectrometer. The measurement result may be a quantitative and / or qualitative measurement, such as the presence and / or concentration of an analyte in a sample. The quality may depend on a variety of factors, such as measurement conditions, background, interference, instrument performance, shift in retention time, peak width, peak height, and peak area.

[0030] As used herein, the term "quality check" is a broad term and should be given its common and customary meaning for those of ordinary skill in the art, and will not be limited to a special or custom meaning. The term may specifically refer to, but is not limited to, at least one test process that satisfies at least one predefined quality requirement after data acquisition. Quality check can be used to distinguish between credible and untrustworthy measurements. As used herein, the term "credible" measurement result is a broad term and is given its common and customary meaning for those of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, one or more measurements that are considered to be reliable, acceptable or "good quality". A credible measurement result may be a measurement result whose corresponding internal standard signal meets at least one predefined requirement. A credible measurement result may be a measurement result with precision and / or accuracy within a predefined tolerance range. As used herein, the term "untrustworthy" measurement result is a broad term and is given its common and customary meaning for those of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a measurement result that is considered to be one or more of unreliable, unacceptable, or "bad quality." An untrustworthy measurement result may be a measurement result whose corresponding internal standard signal fails to meet at least one predefined requirement. An untrustworthy measurement result may be a measurement result having a precision and / or accuracy that is outside of a tolerance range.

[0031] For example, a quality check may be performed for each measurement.For example, a quality check may be performed at a predefined frequency, such as one or more of after a predefined time span, after a new calibration, after a column change, or after a maintenance activity at the instrument.

[0032] As used herein, the term "analyte signal" is a broad term and should be given its common and customary meaning for those of ordinary skill in the art, and should not be limited to special or custom meanings. The term specifically may refer to, but is not limited to, a signal associated with an analyte measured by LC-MS, such as a peak in a chromatogram and / or mass spectrum of an analyte. As used herein, the term "internal standard signal" is a broad term and should be given its common and customary meaning for those of ordinary skill in the art, and should not be limited to special or custom meanings. The term specifically may refer to, but is not limited to, a signal associated with an internal standard measured by LC-MS, such as a peak in a chromatogram and / or mass spectrum of an internal standard. Information about analyte signal may be at least one of peak area, peak height, peak width, or retention time. Information about internal standard signal may be at least one of peak area, peak height, peak width, or retention time.

[0033] Determining the information about the analyte signal and the information about the internal standard signal may include one or more of measuring, obtaining, or retrieving measurement data.

[0034] For example, information about the analyte signal and information about the internal standard signal can be determined by performing at least one LC-MS measurement using a mass spectrometry device. For example, step a) can include performing at least one LC-MS measurement on the sample. In step a), at least one liquid chromatography mass spectrometry device can be used.

[0035] For example, information about analyte signals and information about internal standard signals can be determined by retrieving measurement data via at least one communication interface of a processing device, for example. The measurement data retrieved by the communication interface can be obtained by using a mass spectrometer and can be transmitted to the processing device. For example, the measurement data can be retrieved from at least one database by the communication interface. For example, the determination can include retrieving at least one chromatogram and / or mass spectrum by the processing device, for example, via its communication interface. As used herein, the term "communication interface" is a broad term and will be given a common and customary meaning for a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, items or elements forming a boundary, which is configured to transmit information. In particular, the communication interface may be configured to transmit information from a computing device (e.g., a computer), such as sending or outputting information to, for example, another device. Additionally or alternatively, the communication interface may be configured to transmit information to a computing device (e.g., on a computer), such as, in order to receive information. The communication interface may specifically provide a path for transmitting or exchanging information. In particular, the communication interface may provide a data transmission connection, such as Bluetooth, NFC, inductive coupling, etc. As an example, the communication interface may be or may include at least one port including one or more of a network or Internet port, a USB port, and a disk drive. The communication interface may be at least one Web interface.

[0036] As used herein, the term "database" is a broad term and is given a common and customary meaning for a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, an organized collection of data that is usually stored and accessed electronically from a computer or computer system. The database may include a data storage device, or may consist of a data storage device. The database may include at least one database management system, which includes software running on a computer or computer system, which allows interaction with one or more of a user, an application, or the database itself, such as to capture and analyze the data contained in the database. The database management system may further encompass facilities for managing the database. Therefore, a database containing data may consist of a database system that, in addition to the data, includes one or more associated applications. The database may be part of a processing device or may be external to the processing device. The processing device and / or the database may be at least partially based on the cloud. As used herein, the term "cloud-based" is a broad term and should be given its common and customary meaning for a person of ordinary skill in the art, and should not be limited to a special or custom meaning. The term may particularly refer to, but is not limited to, outsourcing the processing means or parts of the processing means to at least partially interconnected external devices, in particular computers or computer networks with large computing power and / or data storage capacity. The external devices may be arbitrarily distributed in space. The external devices may vary over time, in particular according to demand. The external devices may be interconnected by using the Internet. The external devices may each include at least one communication interface.

[0037] The determination may also include processing the measured or retrieved measurement data using a processing device to determine information about the analyte signal and information about the internal standard signal. For example, the determination may include applying at least one peak fitting modeling to a chromatogram and / or a mass spectrum using a processing device. As used herein, the term "processing device" is a broad term and is given a common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, any logic circuit system configured to perform basic operations of a computer or system; and / or, in general, a device configured to perform calculations or logical operations. The processing device may be configured to process basic instructions that drive a computer or system. As an example, the processing device may include at least one arithmetic logic unit (ALU), at least one floating point unit (FPU) (such as a math coprocessor or a numerical coprocessor), a plurality of registers (specifically registers configured to provide operands to the ALU and store operation results) and a memory (such as L1 and L2 cache memory). The processing device may be a multi-core processor. The processing device may be or may include a central processing unit (CPU). Additionally or alternatively, the processing device may be or may include a microprocessor, and thus, in particular, the elements of the processor may be contained in a single integrated circuit (IC) chip. Additionally or alternatively, the processing device may be or may include one or more application specific integrated circuits (ASICs) and / or one or more field programmable gate arrays (FPGAs) and / or one or more tensor processing units (TPUs) and / or one or more graphics processing units (GPUs) and / or one or more chips, such as dedicated machine learning optimization chips, etc. The processing device may be configured (such as by software programming) to perform one or more evaluation operations. The processing device may be configured to perform specified method steps. Therefore, as an example, the processing device may include software code stored thereon, which includes multiple computer instructions. The processing device may provide one or more hardware elements for performing one or more indicated operations, and / or may provide one or more processors with software for performing one or more method steps running thereon.

[0038] As used herein, the term "monitoring parameter" is a broad term and is given its common and customary meaning to those of ordinary skill in the art, and is not limited to a special or custom meaning. The term may specifically refer to but is not limited to one or more of the readout parameters, measured or measurable parameters suitable as the basis for quality inspection, such as for distinguishing between credible and untrustworthy measurement results. As described above, the concept of quality inspection is known, for example, from several international guidelines for mass spectrometry, such as guidelines formulated by CLSI (Clinical and Laboratory Standards Institute), EMA (European Medicines Agency) or GTFCh (German Society of Toxicology and Forensic Chemistry). The monitoring parameters according to the present invention can be advanced monitoring parameters. The monitoring parameters according to the present invention can allow supplementing known and common parameters, for example, in the case of lack of reliability due to, for example, high variability. The use of the monitoring parameters can allow the need for manual peak audits by experts to be reduced due to erroneous sample markings, without reducing the ability of parameter monitoring for quality assurance purposes.

[0039] The determination of monitoring parameters includes the use of information about the analyte signal and information about the internal standard signal by the processing device. The monitoring parameters include the minimum limit of the internal standard signal for the analyte signal of the sample. The determination of monitoring parameters can include the use of information about the analyte signal and information about the internal standard signal by the processing device to calculate the monitoring parameters. The monitoring parameters can be determined by combining the value of the minimum IStd signal limit with the dependence of the measured analyte signal of each sample. The determination of monitoring parameters can be carried out by performing a software algorithm.

[0040] This monitoring parameter can allow for minimizing the flagging of erroneous results (false positives) and neglect of bad measurements (false negatives). This monitoring parameter may be superior to a simple absolute minimum IStd signal limit. Its rationale may be based on the fact that the accuracy required for the assay and the accuracy depend on the signal. Generally speaking, a reduction in the signal will also typically result in a reduction in accuracy. The analyte signal can be normalized by the IStd signal. Therefore, the final measurement result may depend on both the analyte and the IStd signal. After determining the parameters required on one system, the minimum limit of the IStd signal can be calculated separately for each analyte signal on each other system to achieve the accuracy required for the assay in a specific sample.

[0041] The monitoring parameters can be determined by

[0042]

[0043] where a and b are predetermined parameters, and CV psd is a predefined precision acceptance criterion for the coefficient of variation of the assay.

[0044] The derivation of the monitoring parameters is described below:

[0045] If the signal ratio of the analyte and IStd signals is measured, represented below by the area ratio of the analyte quantification factor (aqn) and the IStd quantification factor (iqn), the precision can be estimated by Equation 1, represented below by CV.

[0046]

[0047] The correlation of the area values ​​of aqn and iqn may not be known in advance. However, since a certain degree of similarity in the physicochemical behavior of, for example, the analyte and IStd is usually required, a negative correlation is not assumed (Assumption 1). Therefore, only a positive correlation can be assumed, and no correlation represents the worst case (Assumption 2). When calculating the area ratio aqn / iqn, any positive correlation of the area values ​​of aqn and iqn may result in a reduction in the resulting CV (aqniqn), i.e., it becomes better. Assumptions 1 and 2 are described below. If there is a correlation, the corresponding coefficients may need to be applied to the equation accordingly. The dependence of the signal and the corresponding CV of the area of ​​aqn and iqn can follow one of two types of functions. According to equation 2 for aqn and equation 3 for iqn or according to equation 4 for aqn and equation 5 for iqn.

[0048]

[0049] Equations 2 and 3 are explained below. In addition, for MS measurements, the behavior of the analyte and the internal standard should be highly similar. In these cases, it can also be assumed that CV(aqn)≈CV(iqn), so the parameters c=a and d=b (Assumption 3). Assumption 3 is explained below. Equation 1 is combined with Equations 2 and 3 to yield Equation 6, which is given as follows

[0050]

[0051] The accuracy acceptance criterion for the assay is given by CV(assay). The actual accuracy of the result CV(result) needs to meet this criterion according to Equation 7.

[0052] (eq.7)CV 测定 ≥CV 结果

[0053] The main part of the imprecision is based on the signal itself, i.e., CV(aqniqn), rather than on the calibration that converts the signal to concentration and thus to result. Therefore, it is assumed below that CV(result)≈CV(aqniqn) (Assumption 4). This leads to Equation 8 from Equation 7. Combining Equation 6 with Equation 8 leads to Equation 9.

[0054] (eq.8)CV 测定 ≥CVaqniqn

[0055]

[0056] Solving Equation 9 for peakArea(iqn) yields the following Equation 10 and monitoring parameters.

[0057]

[0058] Equation 10 can represent the basis for the minimum limit of the IStd signal required for the measured analyte signal to achieve the desired accuracy of the measurement result. This calculation can be based on the assumption that the accuracy of the measurement result depends primarily on the measured signal, regardless of its underlying cause. This means that it does not matter whether the signal loss is due to, for example, low sample concentration or due to low MS performance (Assumption 5). Additional factors of MS performance loss (such as background increase or noise increase) may also have an impact on the measurement result.

[0059] The method may include using at least one check rule to take into account discontinuities in the monitored parameters. Assume that a>0, b>0, peakArea(aqn)>0 and CV(assay)>0. The check rule may use multiple criteria, where the criteria are

[0060]

[0061] iv.-b 2 ×(peakArea aqn ) 2 ×(b+(a-CV psd )×peakArea aqn )×(b+(a+CV psd )×peakAreq aqn )<0;

[0062] v.peakArea iqn =+∞;

[0063] The inspection rules include

[0064] - Determine if equation iv holds, then equation v is used as the monitoring parameter, otherwise

[0065] - Determine if both equations ii and iii hold, then equation v is used as the monitoring parameter, otherwise

[0066] - Determine if equation i holds true, then equation v is used as the monitoring parameter, otherwise

[0067] - Use the monitoring parameters of Equation 10 as monitoring parameters.

[0068] Equation i may allow checking the denominator of equation 10 for negative peakArea(iqn) values. Equations ii and iii may allow checking for peakArea(iqn) values ​​below discontinuities in peakArea(aqn). Equation iv may allow checking for negative roots in the denominator.

[0069] The parameters a and b may be determined by performing a plurality of LC-MS measurements on the sample. For each measurement, information about the analyte signal may be determined. The method may include determining the median or mean of the information about the analyte signal and its CV (aqn) by using a processing device, and calculating the parameters a and b by using at least one regression fit according to:

[0070]

[0071] The method includes comparing the information about the internal standard signal with the monitoring parameters by using a processing device. The comparison may include at least one mathematical operation. The comparison may include determining the deviation between the information about the internal standard signal and the monitoring parameters. By using a processing device, when the information about the internal standard signal is greater than or equal to the monitoring parameters, the LC-MS measurement is marked as meeting the quality check, otherwise, that is, when the information about the internal standard signal is lower than the monitoring parameters, it is marked as unqualified. The comparison may include considering a predefined tolerance range. The predefined tolerance range may be a deviation of ± 20% from the monitoring parameters, preferably ± 15%, more preferably ± 10%. The predefined tolerance range may be fixed or may be adjustable, such as adjusted by a user. The comparison may be performed by performing a software algorithm.

[0072] The method may also include providing the results of the quality check, such as whether the measurement result is marked. The provision may include displaying the results to the user. The display may be performed using at least one user interface. As used herein, the term "user interface" is a broad term and should be given a common and customary meaning to a person of ordinary skill in the art, and is not limited to a special or customized meaning. The term may refer to, but is not limited to, an element or device configured to interact with its environment, such as for the purpose of exchanging information unidirectionally or bidirectionally, such as for the exchange of one or more data or commands. For example, a user interface may be configured to share information with a user and receive information from a user. The user interface may have features for visual interaction with a user, such as a display, or features for acoustic interaction with a user. As an example, the user interface may include one or more of the following: a graphical user interface; a data interface, such as a wireless and / or wired data interface. The method may include a request, for example, to manually review the measurement result, repeat the measurement, or perform instrument maintenance if the measurement result is marked as not meeting the quality check. For example, in the case where the measurement result is marked as not meeting the quality check, the method may include the following actions, for example in a given order:

[0073] 1. Re-measurement of samples

[0074] 2. Material investigation (batch expiration, etc.)

[0075] 3. Analyzer Calibration

[0076] 4. Monitoring analyzer (maintenance, failure, etc.)

[0077] 5. Monitor the environment (humidity, temperature, etc.)

[0078] 6. Additional Investigations

[0079] Method steps a) to c) can be performed using at least one computer. In particular, the determination of information about the analyte signal and the internal standard signal, for example by measuring, can be performed fully automatically. In addition, the determination and comparison of the monitoring parameters in steps b) and c) can be performed fully automatically. In particular, the method can be fully or partially computer-implemented, in particular implemented on a computer (such as a processor).

[0080] On the other hand, a computer program is disclosed, which includes computer executable instructions for executing the method according to any one of the embodiments described herein (specifically method steps a) to c)) when the program is executed on a computer or a computer network (specifically on a processing device). Specifically, the computer program can be stored on a computer-readable data carrier and / or a computer-readable storage medium.

[0081] As used herein, the terms "computer-readable data carrier" and "computer-readable storage medium" may specifically refer to a non-transitory data storage device, such as a hardware storage medium having computer-executable instructions stored thereon. A computer-readable data carrier or storage medium may specifically be or may include a storage medium such as a random access memory (RAM) and / or a read-only memory (ROM).

[0082] Thus, in particular, one, more than one or even all of the method steps i) to iii) as indicated above may be performed by using a computer or a computer network, preferably by using a computer program.

[0083] This article further discloses and proposes a computer program product with program code means, so that when the program is executed on a computer or computer network, the method according to the present invention is performed in one or more embodiments attached hereto. Specifically, the program code means can be stored on a computer-readable data carrier and / or on a computer-readable storage medium.

[0084] The present invention further discloses and proposes a data carrier having a data structure stored thereon, which, after being loaded into a computer or a computer network, such as after being loaded into a working memory or a main memory of the computer or the computer network, can execute a method according to one or more embodiments disclosed herein.

[0085] Further disclosed and proposed herein is a non-transitory computer-readable medium comprising instructions, which, when executed by one or more processors, cause the one or more processors to perform a method according to one or more of the embodiments disclosed herein.

[0086] This article further discloses and proposes a computer program product having a program code tool stored on a machine-readable carrier so that when the program is executed on a computer or computer network, a method according to one or more embodiments disclosed herein is performed. As used herein, a computer program product refers to a program that is a tradable product. The product can generally exist in any format (such as in paper format) or on a computer-readable data carrier and / or on a computer-readable storage medium. Specifically, the computer program product can be distributed on a data network.

[0087] Further disclosed and proposed herein is a modulated data signal containing instructions readable by a computer system or a computer network for performing a method according to one or more embodiments disclosed herein.

[0088] With reference to the computer-implemented aspects of the present invention, one or more method steps or even all method steps of the method according to one or more embodiments disclosed herein may be performed using a computer or a computer network. Therefore, generally speaking, any method step including providing and / or manipulating data may be performed using a computer or a computer network. Generally speaking, these method steps may include any method step other than method steps that typically require manual operation (such as providing samples and / or performing certain aspects of actual measurement).

[0089] Specifically, this article further discloses the following:

[0090] - a computer or a computer network comprising at least one processor, wherein the processor is adapted to perform a method according to one of the embodiments described in this specification,

[0091] - a computer-loadable data structure adapted to carry out a method according to one of the embodiments described in this specification when the data structure is executed on a computer,

[0092] - a computer program, wherein the computer program is adapted to carry out a method according to one of the embodiments described in the present description when the program is executed on a computer,

[0093] - a computer program comprising program means for carrying out a method according to one of the embodiments described in the present description when the computer program is executed on a computer or on a computer network,

[0094] - a computer program comprising program means according to the preceding embodiment, wherein the program means is stored on a computer-readable storage medium,

[0095] a storage medium, on which a data structure is stored and on which the data structure is suitable, after being loaded into a main memory and / or a working memory of a computer or a computer network, for carrying out a method according to one of the embodiments described in the present description, and

[0096] A computer program product having program code means, wherein the program code means can be stored or are stored on a storage medium for carrying out the method according to one of the exemplary embodiments described in the present description if the program code means is executed on a computer or a computer network.

[0097] In a further aspect of the present invention, a system is disclosed. As used herein, the term "system" is a broad term and is to be given the ordinary and customary meaning to those of ordinary skill in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, a group of any interacting or interdependent components that form a whole. Specifically, the components may interact with each other to achieve at least one common function. The system may include at least two components, wherein the at least two components may be processed independently, or may be coupled or connectable. The system includes

[0098] - at least one mass spectrometry device configured to perform at least one liquid chromatography-mass spectrometry (LC-MS) measurement on a sample comprising a target analyte and a defined amount of an internal standard;

[0099] - at least one processing device configured to obtain and / or retrieve information peakArea about the analyte signal measured by LC-MS aqn and information about the internal standard signal peakArea iqn , wherein qn specifies a quantity factor, wherein the processing device is further configured to determine at least one monitoring parameter by using information about the analyte signal and information about the internal standard signal, wherein the monitoring parameter comprises a minimum limit value of the internal standard signal for the analyte signal of the sample, wherein the processing device is further configured to compare the information about the internal standard signal with the monitoring parameter, wherein the processing device is configured to mark the LC-MS measurement as meeting the quality check if the information about the internal standard signal is greater than or equal to the monitoring parameter, and otherwise mark it as failing.

[0100] The system may be configured for carrying out the method according to the invention.With regard to the definition and embodiments of the system, reference is made to the definition and embodiments of the method described above.

[0101] The system may further include at least one sample preparation unit configured to spike the sample with at least one internal standard.

[0102] To summarize and without excluding other possible embodiments, the following embodiments may be envisaged:

[0103] Example 1. A method for quality checking of at least one liquid chromatography-mass spectrometry (LC-MS) measurement of a sample comprising a target analyte and a defined amount of at least one internal standard, wherein the method comprises the following steps

[0104] a) Determine the peakArea of ​​the analyte signal measured by LC-MS aqn and information about the internal standard signal (peakArea iqn ), where qn specifies the quantity factor;

[0105] b) determining at least one monitoring parameter by using at least one processing device using the information about the analyte signal and the information about the internal standard signal, wherein the monitoring parameter comprises a minimum limit value of the internal standard signal for the analyte signal of the sample;

[0106] c) comparing the information about the internal standard signal with the monitoring parameter by using the processing device, wherein by using the processing device the LC-MS measurement is marked as meeting the quality check if the information about the internal standard signal is greater than or equal to the monitoring parameter, and is marked as failing otherwise.

[0107] Embodiment 2. A method according to the preceding embodiments, wherein the information about the analyte signal is at least one of peak area, peak height, peak width or retention time, and wherein the information about the internal standard signal is at least one of peak area, peak height, peak width or retention time.

[0108] Embodiment 3. The method according to any one of the preceding embodiments, wherein the monitoring parameter is determined by

[0109]

[0110] where a and b are predetermined parameters, and CV psd is a predefined precision acceptance criterion for the coefficient of variation of the assay.

[0111] Embodiment 4. A method according to the preceding embodiment, wherein the method comprises using at least one check rule to take into account discontinuities in the monitored parameters, wherein the check rule uses a plurality of criteria, wherein the criteria are

[0112]

[0113]

[0114] iv.-b 2 ×(peakArea aqn ) 2 ×(b+(a-CV psd )×peakArea aqn )×(b+(a+CV psd )×peakArea aqn )<0;

[0115] v.peakArea iqn =+∞;

[0116] The inspection rules include

[0117] - Determine if equation iv holds, then equation v is used as the monitoring parameter, otherwise

[0118] - Determine if both equations ii and iii hold, then equation v is used as the monitoring parameter, otherwise

[0119] - Determine if equation i holds true, then equation v is used as the monitoring parameter, otherwise

[0120] - Using the monitoring parameters according to Example 3 as monitoring parameters.

[0121] Embodiment 5. The method according to any one of the two preceding embodiments, wherein the parameters a and b are determined by performing a plurality of LC-MS measurements on the sample, wherein for each measurement, information about the analyte signal is determined, wherein the method comprises determining the median or mean of the information about the analyte signal and its CV (aqn) by using a processing device, and calculating the parameters a and b by using at least one regression fit according to:

[0122]

[0123] Embodiment 6. The method according to any one of the preceding embodiments, wherein step a) comprises performing at least one LC-MS measurement on the sample.

[0124] Embodiment 7. The method according to the preceding embodiment, wherein at least one liquid chromatography mass spectrometry device is used in step a).

[0125] Embodiment 8. The method according to any one of the preceding embodiments, wherein the method comprises spiking the sample with the at least one internal standard.

[0126] Embodiment 9. A method according to any one of the preceding method embodiments, wherein the method is implemented by a computer.

[0127] Embodiment 10. A computer program comprising instructions, which, when executed by a processing device, cause the processing device to perform a method according to any one of the preceding embodiments.

[0128] Embodiment 11. A computer-readable storage medium comprising instructions, which, when executed by a processing device, cause the processing device to perform a method according to any of the preceding embodiments relating to methods.

[0129] Embodiment 12. A non-transitory computer readable medium comprising instructions which, when executed by one or more processors, cause the one or more processors to perform a method according to any of the preceding embodiments relating to methods.

[0130] Embodiment 13. A system comprising:

[0131] - at least one mass spectrometry device configured to perform at least one liquid chromatography-mass spectrometry (LC-MS) measurement on a sample comprising a target analyte and a defined amount of an internal standard;

[0132] - at least one processing device configured to obtain and / or retrieve information peakArea about the analyte signal measured by LC-MS aqn and information about the internal standard signal peakArea iqn , wherein qn specifies a quantity factor, wherein the processing device is further configured to determine at least one monitoring parameter by using information about the analyte signal and information about the internal standard signal, wherein the monitoring parameter comprises a minimum limit value of the internal standard signal for the analyte signal of the sample, wherein the processing device is further configured to compare the information about the internal standard signal with the monitoring parameter, wherein the processing device is configured to mark the LC-MS measurement as meeting the quality check if the information about the internal standard signal is greater than or equal to the monitoring parameter, and otherwise mark it as failing.

[0133] Embodiment 14. A system according to the preceding embodiment, wherein the system is configured to perform a method according to any one of the embodiments relating to methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0134] Other optional features and embodiments will be disclosed in more detail in the subsequent description of embodiments, preferably in conjunction with the dependent claims. Wherein, as will be appreciated by those skilled in the art, each optional feature can be implemented in a separate manner and in any arbitrarily feasible combination. The scope of the present invention is not limited by the preferred embodiments. Embodiments are schematically depicted in the accompanying drawings. Wherein, the same reference numerals in these drawings refer to the same or functionally equivalent elements.

[0135] In the attached picture:

[0136] Figure 1 An embodiment of a system according to the present invention is shown;

[0137] Figure 2 a flow chart showing an embodiment of a method according to the present invention; and

[0138] Figures 3A to 3C The experimental results are shown. DETAILED DESCRIPTION

[0139] Figure 1 An embodiment of a system 110 according to the invention is shown in a highly schematic manner.

[0140] System 110 includes at least one mass spectrometer 112, which is configured to perform at least one liquid chromatography-mass spectrometry (LC-MS) measurement on a sample containing a target analyte and a limited amount of an internal standard. Mass spectrometer 112 may be or may include at least one quadrupole analyzer. A quadrupole mass analyzer may include a plurality of quadrupoles. For example, a quadrupole mass analyzer may be a triple quadrupole mass spectrometer. For example, a mass spectrometer may include an ionization source, a skimmer, three quadrupole segments Q1, Q2, and Q3, and a detector. Each of quadrupole segments Q1, Q2, and Q3 includes a quadrupole. Mass spectrometer 112 may further include at least one ionization source. The ionization source may be or may include at least one source selected from the group consisting of: at least one gas phase ionization source, such as at least one electron impact (EI) source or at least one chemical ionization (CI) source; at least one desorption ionization source, such as at least one plasma desorption (PDMS) source, at least one fast atom bombardment (FAB) source, at least one secondary ion mass spectrometry (SIMS) source, at least one laser desorption (LDMS) source, and at least one matrix assisted laser desorption (MALDI) source; at least one spray ionization source, such as at least one thermal spray (TSP) source, at least one atmospheric pressure chemical ionization (APCI) source, at least one electrospray (ESI), and at least one atmospheric pressure ionization (API) source. The mass spectrometer 112 may include at least one detector. The detector may be configured to detect charged particles. The detector may be or may include at least one electron multiplier. The mass spectrometer 112, in particular the detector and / or at least one processing device of the mass spectrometer, may be configured to determine at least one mass spectrum of the detected ions. The LC-MS measurement may be or may include at least one measurement using the mass spectrometer 112. The mass spectrometer 112 may be a liquid chromatography mass spectrometer. The mass spectrometer 112 may include at least one liquid chromatograph, also referred to as a liquid chromatography (LC) device. The liquid chromatograph may be used as a sample preparation for the mass spectrometer. The LC device may include at least one LC column. For example, the LC device may be a single-column LC device or a multi-column LC device having a plurality of LC columns. The LC column may have a stationary phase through which a mobile phase is pumped to separate and / or elute and / or transmit a target analyte. The liquid chromatography mass spectrometer may further include a sample preparation station for automated pretreatment and preparation of samples, each sample including at least one target analyte. The liquid chromatography mass spectrometer may be or may include at least one high performance liquid chromatography (HPLC) device or at least one microfluidic liquid chromatography (μLC) device. The liquid chromatography mass spectrometer may include a liquid chromatography (LC) device and a mass spectrometer (MS) device, in the present case a mass filter, wherein the LC device and the mass filter are coupled via at least one interface. The interface coupling the LC device and the MS device may include an ionization source configured to generate molecular ions and transfer the molecular ions into a gas phase.The interface may further include at least one ion mobility module disposed between the ionization source and the mass filter. For example, the ion mobility module may be a high-field asymmetric waveform ion mobility spectrometry (FAIMS) module.

[0141] The mass spectrometer 112 can be configured to perform an end-to-end workflow (also referred to as a sample measurement workflow), wherein the sample is injected into the inlet of a liquid chromatography column, the sample is separated into components on the column, and each component is eluted from the column. The eluted components are directed to a mass spectrometer, where they are ionized and analyzed. The mass spectrometer 112 can measure the ion fragmentation pattern associated with each component. Each ion fragmentation pattern consists of one or more peaks corresponding to ion fragments with a specific m / z ratio. The peak pattern of a specific analyte (e.g., the m / z ratio and intensity of the peak) effectively serves as the "fingerprint" of the analyte. Due to the complexity of the fragmentation pattern, a variety of components can be identified and quantified based on these measurements. Typically, identification is performed by comparing the measured ion fragmentation pattern with reference information (e.g., a previously measured or simulated ion fragmentation pattern of a known component). The identification of a specific component can also be performed based on the time interval between the initial introduction of the sample (e.g., injection into the inlet of the LC-MS system) and the elution of the component from the LC column, or the time interval between the initial introduction of the sample and the measurement of the component ion fragmentation pattern in the mass spectrometer. Certain components can migrate through an LC column at specific rates, and the elapsed time interval can be used as an indicator of the identity of the component. As with the ion fragmentation pattern, the elapsed time interval can be compared to reference information (e.g., previously measured migration and / or measurement times of known components) to determine the identity of the component.

[0142] The mass spectrometer 112 can be configured to measure a variety of biological samples. Examples of such samples include, but are not limited to, physiological fluids, including blood, serum, plasma, urine, sweat, saliva, lens fluid, cerebrospinal fluid, breast milk, ascites, mucus, synovial fluid, peritoneal fluid, amniotic fluid, lymph fluid, interstitial fluid, cerebrospinal fluid, tissues, cells, etc.

[0143] The sample can include one or more target analytes, also referred to as target analytes. The sample can be used directly when obtained from the corresponding source, or can be subjected to pretreatment and / or sample preparation workflow. For example, the sample can be pretreated by adding an internal standard and / or by diluting with another solution and / or by mixing with a reagent, etc. For example, in general, the target analyte can be vitamin D, drugs of abuse, therapeutic drugs, hormones and metabolites. For further details about the corresponding sample, reference is made to, for example, EP 3 425 369 A1, the entire disclosure of which is included herein by reference. Other target analytes are also possible.

[0144] System 110 can be configured to perform at least one quality check. Quality can be a measure of the reliability of the measurement result obtained by using mass spectrometry device 112. The measurement result can be a quantitative and / or qualitative measurement, such as the presence and / or concentration of an analyte in a sample. Quality may depend on a variety of factors, such as measurement conditions, background, interference, instrument performance, shift of retention time, peak width, peak height and peak area. The quality check may be or may include at least one test process of whether at least one predefined quality requirement is met after data acquisition. The quality check can be used to distinguish between credible and uncredible measurement results. A credible measurement result can be a measurement result whose corresponding internal standard signal meets at least one predefined requirement. A credible measurement result can be a measurement result with precision and / or accuracy within a predefined tolerance range. An uncredible measurement result can be a measurement result whose corresponding internal standard signal fails to meet at least one predefined requirement. An uncredible measurement result can be a measurement result with precision and / or accuracy beyond the tolerance range.

[0145] For example, a quality check may be performed for each measurement.For example, a quality check may be performed at a predefined frequency, such as one or more of after a predefined time span, after a new calibration, after a column change, or after a maintenance activity at the instrument.

[0146] The system 110 includes at least one processing device 114 configured to obtain and / or retrieve information about the analyte signal peakArea measured by LC-MS. aqn and information about the internal standard signal peakArea iqn , where qn specifies the quantity factor.

[0147] The analyte signal may be a signal associated with the analyte measured by LC-MS, such as a peak in a chromatogram and / or mass spectrum of the analyte.

[0148] When experiencing the workflow using mass spectrometer 112, the internal standard can show properties similar to the target analyte. The workflow can include any pretreatment, enrichment and actual detection steps. For example, the internal standard can be an isotope-labeled variant of the target analyte (including markers such as 2H, 13C or 15N). System 110 can be configured to add a mark to the sample with at least one internal standard. The internal standard signal can be a signal related to the internal standard measured by LC-MS, such as a peak in the chromatogram and / or mass spectrum of the internal standard. Information about the analyte signal can be at least one of peak area, peak height, peak width or retention time. Information about the internal standard signal can be at least one of peak area, peak height, peak width or retention time.

[0149] Determining the information about the analyte signal and the information about the internal standard signal may include one or more of measuring, obtaining, or retrieving measurement data.

[0150] For example, information about the analyte signal and information about the internal standard signal can be determined by performing at least one LC-MS measurement using the mass spectrometry device 112. For example, the determination can include performing at least one LC-MS measurement on the sample, such as by using at least one liquid chromatography mass spectrometry device 112.

[0151] For example, information about the analyte signal and information about the internal standard signal can be determined by retrieving measurement data via, for example, at least one communication interface 116 of the processing device 114. The measurement data retrieved by the communication interface 114 can be obtained by using a mass spectrometer (e.g., mass spectrometer 112) and can be transmitted to the processing device 114. For example, the measurement data can be retrieved from at least one database by the communication interface 114. For example, the determination can include retrieving at least one chromatogram and / or mass spectrum by the processing device 114, for example, via its communication interface 116. The processing device 114 and / or the database can be at least partially cloud-based.

[0152] The determination may also include processing the measured or retrieved measurement data to determine information about the analyte signal and information about the internal standard signal by using the processing device 114. For example, the determination may include applying at least one peak fitting modeling to the chromatogram and / or mass spectrum by using the processing device 114.

[0153] The processing device 114 is further configured to determine at least one monitoring parameter by using the information about the analyte signal and the information about the internal standard signal. The monitoring parameter comprises a minimum limit value of the internal standard signal for the analyte signal of the sample.

[0154] Monitoring parameters can be one or more of the readout parameters, measured or measurable parameters suitable as the basis for quality inspection, for example, for distinguishing between credible and untrustworthy measurement results. As mentioned above, the concept of quality inspection is known, for example, from several international guidelines for mass spectrometry, such as the guidelines formulated by CLSI (Clinical and Laboratory Standards Institute), EMA (European Medicines Agency) or GTFCh (German Society of Toxicology and Forensic Chemistry). Monitoring parameters according to the present invention can be advanced monitoring parameters. Monitoring parameters according to the present invention can allow supplementing known and common parameters, for example, in the case of lack of reliability due to, for example, high variability. Using the monitoring parameters can allow reducing the need for manual peak audits by experts due to erroneous sample markings, without reducing the ability of parameter monitoring for quality assurance purposes.

[0155] The determination of monitoring parameters includes the use of information about the analyte signal and information about the internal standard signal by the processing device 114. The monitoring parameters include the minimum limit of the internal standard signal for the analyte signal of the sample. The determination of monitoring parameters can include the use of information about the analyte signal and information about the internal standard signal by the processing device 114 to calculate the monitoring parameters. The monitoring parameters can be determined by combining the value of the minimum IStd signal limit with the dependence of the measured analyte signal of each sample. The determination of monitoring parameters can be performed by performing a software algorithm.

[0156] Monitoring parameters can allow for minimizing the flagging of erroneous results (false positives) and overlooking of bad measurements (false negatives). This monitoring parameter may be superior to a simple absolute minimum IStd signal limit. The rationale may be based on the accuracy required for the assay and the fact that accuracy depends on the signal. Generally speaking, a reduction in signal will also typically result in a reduction in accuracy. The analyte signal can be normalized by the IStd signal. Therefore, the final measurement result may depend on both the analyte and the IStd signal. After determining the parameters required on one system, the minimum limit of the IStd signal can be calculated separately for each analyte signal on each other system to achieve the accuracy required for the assay in a specific sample.

[0157] The monitoring parameters can be determined by

[0158]

[0159] where a and b are predetermined parameters, and CV psd is a predefined precision acceptance criterion for the coefficient of variation of the assay.

[0160] The derivation of the monitoring parameters is described below:

[0161] If the signal ratio of the analyte and IStd signals is measured, represented below by the area ratio of the analyte quantification factor (aqn) and the IStd quantification factor (iqn), the precision can be estimated by Equation 1, represented below by CV.

[0162]

[0163] The correlation of the area values ​​of aqn and iqn may not be known in advance. However, since a certain degree of similarity in the physicochemical behavior of, for example, the analyte and IStd is usually required, a negative correlation is not assumed (Assumption 1). Therefore, only a positive correlation can be assumed, and no correlation represents the worst case (Assumption 2). When calculating the area ratio aqn / iqn, any positive correlation of the area values ​​of aqn and iqn may result in a reduction in the resulting CV (aqniqn), i.e., it becomes better. Assumptions 1 and 2 are described below. If there is a correlation, the corresponding coefficients may need to be applied to the equation accordingly. The dependence of the signal and the corresponding CV of the area of ​​aqn and iqn can follow one of two types of functions. According to equation 2 for aqn and equation 3 for iqn or according to equation 4 for aqn and equation 5 for iqn.

[0164]

[0165] exist Figure 3A , a graph of Equation 2 is shown as an example. In this exemplary graph of Equation 2, for ease of explanation, peakArea(aqn) on the x-axis and CV(aqn) on the y-axis are shown.

[0166] Equations 2 and 3 are explained below. In addition, for MS measurements, the behavior of the analyte and the internal standard should be highly similar. In these cases, it can also be assumed that CV(aqn)≈CV(iqn), so the parameters c=a and d=b (Assumption 3). Assumption 3 is explained below. Equation 1 is combined with Equations 2 and 3 to yield Equation 6, which is given as follows

[0167]

[0168] The accuracy acceptance criterion for the assay is given by CV(assay). The actual accuracy of the result CV(result) needs to meet this criterion according to Equation 7.

[0169] (eq.7)CV 测定 ≥CV 结果

[0170] The main part of the imprecision is based on the signal itself, i.e., CV(aqniqn), rather than on the calibration that converts the signal to concentration and thus to result. Therefore, it is assumed below that CV(result)≈CV(aqniqn) (Assumption 4). This leads to Equation 8 from Equation 7. Combining Equation 6 with Equation 8 leads to Equation 9.

[0171] (eq.8)CV 测定 ≥CV aqniqn

[0172]

[0173] Solving Equation 9 for peakArea(iqn) yields the following Equation 10 and monitoring parameters.

[0174]

[0175] Equation 10 can represent the basis for the minimum limit of the IStd signal required for the measured analyte signal to achieve the desired accuracy of the measurement result. This calculation can be based on the assumption that the accuracy of the measurement result depends primarily on the measured signal, regardless of its underlying cause. This means that it does not matter whether the signal loss is due to, for example, low sample concentration or due to low MS performance (Assumption 5). Additional factors of MS performance loss (such as background increase or noise increase) may also have an impact on the measurement result.

[0176] The method may include using at least one check rule to take into account discontinuities in the monitored parameters. Assume that a>0, b>0, peakArea(aqn)>0 and CV(assay)>0. The check rule may use multiple criteria, where the criteria are

[0177]

[0178] iv.-b 2 ×(peakArea aqn ) 2 ×(b+(a-CV psd )×peakArea aqn )×(b+(a+CV psd )×peakArea aqn )<0;

[0179] v.peakArea iqn =+∞;

[0180] The inspection rules include

[0181] - Determine if equation iv holds, then equation v is used as the monitoring parameter, otherwise

[0182] - Determine if both equations ii and iii hold, then equation v is used as the monitoring parameter, otherwise

[0183] - Determine if equation i holds true, then equation v is used as the monitoring parameter, otherwise

[0184] - Use the monitoring parameters of Equation 10 as monitoring parameters.

[0185] Equation i may allow checking the denominator of equation 10 for negative peakArea(iqn) values. Equations ii and iii may allow checking for peakArea(iqn) values ​​below discontinuities in peakArea(aqn). Equation iv may allow checking for negative roots in the denominator.

[0186] exist Figure 3B , an exemplary graph of Equation 10 incorporating the above rules is shown. Signal values ​​above or to the right of the curve are within the acceptance criteria of the inspection, while signal values ​​below or to the left of the curve are not within the acceptance criteria of the inspection and should be marked.

[0187] The parameters a and b may be determined by performing a plurality of LC-MS measurements on the sample. For each measurement, information about the analyte signal may be determined. The method may include determining the median or mean of the information about the analyte signal and its CV (aqn) by using a processing device, and calculating the parameters a and b by using at least one regression fit according to:

[0188]

[0189] The processing device 114 is also configured to compare the information about the internal standard signal with the monitoring parameter. The processing device 114 is configured to mark the LC-MS measurement as satisfying the quality check when the information about the internal standard signal is greater than or equal to the monitoring parameter, otherwise it is marked as unqualified. The comparison may include at least one mathematical operation. The comparison may include determining the deviation between the information about the internal standard signal and the monitoring parameter. By using the processing device, when the information about the internal standard signal is greater than or equal to the monitoring parameter, the LC-MS measurement is marked as satisfying the quality check, otherwise, that is, when the information about the internal standard signal is lower than the monitoring parameter, it is marked as unqualified. The comparison may include considering a predefined tolerance range. The predefined tolerance range may be a deviation of ± 20% from the monitoring parameter, preferably ± 15%, more preferably ± 10%. The predefined tolerance range may be fixed or may be adjustable, such as adjusted by a user. The comparison may be performed by performing a software algorithm.

[0190] The system 110 may include at least one user interface 118. The system 110 may be configured to provide the results of the quality check, such as whether the measurement result is marked. The providing may include displaying the results to a user. The display may be performed using the user interface 118. As an example, the user interface 118 may include one or more of the following: a graphical user interface, a data interface, such as a wireless and / or wired data interface. The user interface 118 may be configured to request, for example, a manual review of the measurement result, a repeat measurement, or instrument maintenance in the event that the measurement result is marked as not meeting the quality check. For example, in the event that the measurement result is marked as not meeting the quality check, the method may include the following actions, for example in a given order:

[0191] 1. Re-measurement of samples

[0192] 2. Material investigation (batch expiration, etc.)

[0193] 3. Analyzer Calibration

[0194] 4. Monitoring analyzer (maintenance, failure, etc.)

[0195] 5. Monitor the environment (humidity, temperature, etc.)

[0196] 6. Additional Investigations

[0197] Figure 2 A flow chart showing an embodiment of a method according to the present invention is shown. The method comprises the following steps

[0198] a) (120) Determine the peakArea of ​​the information about the analyte signal measured by the LC-MS aqn and information about the internal standard signal peakArea iqn , where qn specifies the quantity factor;

[0199] b) (122) determining at least one monitoring parameter by using the information about the analyte signal and the information about the internal standard signal using at least one processing device 114, wherein the monitoring parameter includes a minimum limit value of the internal standard signal for the analyte signal of the sample;

[0200] c) (124) comparing the information about the internal standard signal with the monitoring parameter by using the processing device 114, wherein the LC-MS measurement is marked as meeting the quality check by using the processing device 114 if the information about the internal standard signal is greater than or equal to the monitoring parameter, otherwise it is marked as unqualified.

[0201] Method steps a) to c) can be performed using at least one computer. In particular, the determination of information about the analyte signal and the internal standard signal, for example by measuring, can be performed fully automatically. In addition, the determination and comparison of the monitoring parameters in steps b) and c) can be performed fully automatically. In particular, the method can be fully or partially computer-implemented, in particular implemented on a computer (such as a processor).

[0202] For an embodiment of this method, refer to Figure 1 Description of system 110 is shown.

[0203] Figure 3C The experimental results are shown. Serum samples were spiked with estradiol and testosterone to ten different concentrations, covering the entire measurement range of the corresponding assay. Constant amounts of the compounds estradiol-13C3 and testosterone-13C3 were spiked as IStd before sample preparation. Each sample was analyzed and measured 21 times by LC-triple quadrupole (QqQ)-MS, and the chromatographic data were integrated to obtain the peak areas of the analyte and IStd as signals. Subsequently, the median analyte area and its CV (aqn) were determined and plotted. An exemplary curve diagram of estradiol is shown in FIG. Figure 3C shown.

[0204] A regression fit was performed according to equation 2, which was the best fit compared to equation 3, and the parameters "a" and "b" were calculated. The parameter "a" was 2.69 for estradiol and 3.84 for testosterone, and the parameter "b" was 5682 for estradiol and 34659 for testosterone. For further calculations, assumptions 1 to 5 (see above) were considered. In addition, a simple minimum IStd signal limit (as an established universal parameter) was optimized and determined for estradiol and testosterone (hereinafter referred to as a simple IStd check).

[0205] For validation, three analytical replicates were performed on ten serum samples spiked with estradiol and testosterone to different concentrations at two different instruments and at four different time points. Between each time point, hundreds of serum samples were run using the system to affect system performance. The required assay accuracy was set to a CV (assay) of 20%. According to the rules given above, the minimum limit of the IStd signal was determined for each analyte and sample using equation 10 and standards i, ii, iii, iv and v and predefined parameters "a" and "b". Then, (i) relative to the advanced minimum IStd signal limit calculated for each sample (advanced IStd check) and (ii) relative to the simple IStd signal limit (simple IStd check), the corresponding measured values ​​were checked. As a reference, CV (aqniqn) was calculated for each analyte and sample based on analytical replicates, and was checked and marked accordingly relative to the required CV (assay) (assay result check). The assay result check showed that 77% of the measurements were normal and 23% of the measurements were abnormal. The following table summarizes the relative labeling rates for all analytes and samples in both the Advanced IStd check and the Simple IStd check relative to the Assay Result check.

[0206]

[0207] Table: Relative flagging rates for Advanced IStd check vs. Measurement Result check and Simple IStd check vs. Measurement Result check.

[0208] The table shows that the Advanced IStd check correctly flagged 93.6% of all samples (76.9% were normal and 16.7% were abnormal), while the Simple IStd check correctly flagged 79.6% (70.1% were normal and 9.5% were abnormal).

[0209] Overall, the Advanced IStd test correctly flagged +14.0% more samples compared to the established Simple IStd test. This suggests that the proposed advanced monitoring parameters can minimize the flagging of erroneous results (false positives) and overlooking of poor measurements (false negatives), and compares favorably to the established monitoring parameters.

[0210] Reference numerals list

[0211] 110 System

[0212] 112 Mass Spectrometry Device

[0213] 114 Processing device

[0214] 116 Communication Interface

[0215] 118 User Interface

[0216] 120 Step a)

[0217] 122 Step b)

[0218] 124 Step c)

Claims

1. A method for quality checking of at least one liquid chromatography-mass spectrometry (LC-MS) measurement of a sample comprising a target analyte and a defined amount of at least one internal standard, wherein the method comprises the following steps a) (120) determining peakArea of ​​information about the analyte signal measured by the LC-MS aqn and information about the internal standard signal (peakArea iqn ), where qn refers to the quantitation factor, aqn relates to the analyte quantitation factor, and iqn relates to the internal standard quantitation factor; b) (122) determining at least one monitoring parameter by using the information about the analyte signal and the information about the internal standard signal using at least one processing device (114), wherein the monitoring parameter comprises a minimum limit value of the internal standard signal for the analyte signal of the sample, wherein the monitoring parameter is determined by: Where a and b are predetermined parameters, and CV psd is a predefined precision acceptance criterion for the coefficient of variation of the assay, wherein the parameters a and b are determined by performing a plurality of LC-MS measurements on the sample, wherein for each measurement the information about the analyte signal is determined, wherein the method comprises determining a median or mean of the information about the analyte signal and its CV (aqn) by using the processing means (114), and calculating the parameters a and b by using at least one regression fit according to: Wherein CV(aqn) is the coefficient of variation of the analyte quantitative factor; c) (124) comparing the information about the internal standard signal with the monitoring parameter by using the processing device (114), wherein the LC-MS measurement is marked as meeting the quality check if the information about the internal standard signal is greater than or equal to the monitoring parameter by using the processing device (114), or is marked as failing otherwise.

2. The method according to the preceding claim, wherein the information about the analyte signal is at least one of the following: the peak area of ​​the analyte quantitative factor, the peak height of the analyte quantitative factor, the peak width of the analyte quantitative factor, or the retention time of the analyte quantitative factor, and wherein the information about the internal standard signal is at least one of the following: the peak area of ​​the internal standard quantitative factor, the peak height of the internal standard quantitative factor, the peak width of the internal standard quantitative factor, or the retention time of the internal standard quantitative factor.

3. A method according to any one of the preceding claims, wherein the method comprises using at least one checking rule to take into account discontinuities in the monitoring parameter, wherein the checking rule uses a plurality of criteria, wherein the criteria are i. ii. iii. iv.-b 2 × ( peakArea aqn ) 2 ×(b+(a-CV). psd )×peakArea aqn )×(b+(a+CV psd )×peakArea aqn )<6 v.peakArea iqn =+∞; The inspection rules include - Determine if equation iv holds, then equation v is used as the monitoring parameter, otherwise - Determine if both equations ii and iii hold, then equation v is used as the monitoring parameter, otherwise - Determine if equation i holds true, then equation v is used as the monitoring parameter, otherwise - Using the monitoring parameter of claim 1 as monitoring parameter.

4. A method according to any of the preceding claims, wherein step a) (120) comprises performing at least one LC-MS measurement on the sample.

5. The method according to the preceding claim, wherein at least one liquid chromatography-mass spectrometry device is used in step a) (120).

6. The method according to any one of the preceding claims, wherein the method comprises spiking the sample with the at least one internal standard.

7. The method according to any one of the preceding method claims, wherein the method is computer-implemented.

8. A computer program comprising instructions which, when executed by a processing device (114), cause the processing device (114) to carry out the method according to any one of the preceding claims.

9. A computer-readable storage medium comprising instructions which, when executed by a processing device (114), cause the processing device (114) to perform a method according to any of the preceding claims relating to methods.

10. A non-transitory computer readable medium comprising instructions which, when executed by one or more processors, cause the one or more processors to perform a method according to any of the preceding claims relating to a method.

11. A system (110), comprising: - at least one mass spectrometry device (112) configured to perform at least one liquid chromatography-mass spectrometry (LC-MS) measurement on a sample comprising a target analyte and a defined amount of an internal standard; - at least one processing device (114) configured to obtain and / or retrieve information about the analyte signal peakArea of ​​the LC-MS measurement aqn and information about the internal standard signal peakArea iqn , wherein qn refers to a quantitative factor, wherein the processing device (114) is further configured to determine at least one monitoring parameter by using the information about the analyte signal and the information about the internal standard signal, wherein the monitoring parameter comprises a minimum limit value of the internal standard signal for the analyte signal of the sample, wherein the monitoring parameter is determined by: Where a and b are predetermined parameters, and CV psd is a predefined precision acceptance criterion for the coefficient of variation of the assay, wherein the parameters a and b are determined by performing a plurality of LC-MS measurements on the sample, wherein for each measurement the information about the analyte signal is determined, wherein the method comprises determining a median or mean of the information about the analyte signal and its CV (aqn) by using the processing means (114), and calculating the parameters a and b by using at least one regression fit according to: or Wherein CV(aqn) is the coefficient of variation of the analyte quantitative factor; - wherein the processing means (114) is further configured to compare the information about the internal standard signal with the monitoring parameter, wherein the processing means (114) is configured to mark the LC-MS measurement as satisfying the quality check if the information about the internal standard signal is greater than or equal to the monitoring parameter, or as failing otherwise.

12. The system (110) according to the preceding claim, wherein the system (110) is configured for carrying out a method according to any one of the method-related claims.

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