INTERFERENCE MONITORING FOR PROVIDING A VERIFIED ANALYTE MEASUREMENT

Abstract

The present invention relates to a method for providing a verified analyte measurement of a sample with a chromatography mass spectrometer device, said method comprising the following steps: a) admixing an interferent monitoring compound and, optionally an internal standard, to the sample; b) determining a chromatogram of the sample by acquiring a plurality of data points for signal intensities over time for said interferent monitoring compound, said analyte, and optionally said internal standard; and c) comparing a property of an interferent monitoring compound peak to a property of an internal standard peak and/or to a property of an analyte peak; and to methods and systems related thereto.

Claims

1. A method for providing a verified analyte measurement of a sample with a chromatography mass spectrometer device, said method comprising : a) admixing an interferent monitoring compound to the sample; b) determining a chromatogram of the sample by acquiring a plurality of data points for signal intensities over time for said interferent monitoring compound, said analyte ; and c) comparing a property of an interferent monitoring compound peak to a property of an analyte peak.

2. The method of claim 1, wherein said interferent monitoring compound is an isotopologue of an interferent.

3. The method of claim 1, wherein in step b) the chromatogram is determined based on signals being (I) non-identical between the analyte and the interferent monitoring compound; or (II) identical between the analyte and the interferent monitoring compound.

4. The method of claim 1, wherein A) in step a) an interferent monitoring compound and an internal standard are admixed to the sample; and wherein said interferent monitoring compound and said internal standard are isotope-labelled, said; B) in step b) the chromatogram is determined based on signals being non-identical between the analyte, the internal standard, and the interferent monitoring compound; and C) wherein in step c) the property of the internal standard peak is compared to the property of the interferent monitoring compound peak.

5. The method of claim 1, wherein A) in step a) an interferent monitoring compound and an internal standard are admixed to the sample; wherein said interferent monitoring compound and said internal standard are isotope-labelled said; B) in step b) the chromatogram is determined based on signals being identical between the internal standard and the interferent monitoring compound and non-identical between the analyte and the internal standard; and C) wherein in step c) the property of the internal standard peak is compared to the property of the interferent monitoring compound peak.

6. The method of claim 1, wherein A) in step a) an interferent monitoring compound is admixed to the sample; wherein said interferent monitoring compound is isotope-labelled, said compound; B) in step b) the chromatogram is determined based on signals being non-identical between the analyte and the interferent monitoring compound; and C) wherein in step c) the property of the analyte peak is compared to the property of the interferent monitoring compound peak; or wherein A) in step a) an interferent monitoring compound and an internal standard are admixed to the sample; wherein said internal standard is isotope-labelled said; B) in step b) the chromatogram is determined based on signals being non-identical between the internal standard and the interferent monitoring compound; and C) wherein in step c) the property of the internal standard peak is compared to the property of the interferent monitoring compound peak; or wherein A) in step a) an interferent monitoring compound is admixed to the sample; B) in step b) the chromatogram is determined based on signals being identical between the analyte and the interferent monitoring compound; and C) wherein in step c) the property of the analyte peak is compared to the property of the interferent monitoring compound peak.

7. The method of claim 1, wherein said method further comprises performing peak identification of at least one interferent monitoring compound peak and at least one analyte peak.

8. The method of claim 1, wherein said comparing in step c) comprises determining a resolution between the analyte peak and the interferent monitoring compound peak, wherein, resolution is calculated based on the retention times and the full width at half maximum values of the respective peaks according to: $R=2\frac{t_2-t_1}{w_2+w_1}$ with R = resolution, t.sub.1 = retention time of the first peak, t.sub.2 = retention time of the second peak, w.sub.1 = full width at half maximum of the first peak; and w.sub.2 = full width at half maximum of the second peak.

9. The method of claim 1, wherein said method comprises additional step d) providing a verified analyte measurement based on comparison step c), wherein, the analyte measurement is accepted in case the resolution between the analyte peak and the interferent monitoring compound peak or between the internal standard peak and the interferent monitoring compound peak is higher than 1.5 .

10. The method of claim 1, wherein said interferent is an isomer of the analyte .

11. The method of claim 1, wherein said analyte is Vitamin D and the interferent is Epi-Vitamin D said.

12. The method of claim 1, wherein said method is a method of routine analyte measurement and/or of interference checking and/or interference monitoring.

13. A method of quality control of a chromatography mass spectrometry (MS) measurement of an analyte in a sample, comprising: A) measuring the analyte in the sample using the chromatography mass spectrometer device and determining at least one chromatogram; B) verifying the analyte measurement according to the method of claim 1, and C) evaluating quality of said chromatography-MS measurement based on the results of step B).

14. A system for determining an amount of at least one analyte in a sample comprising: (I) at least one chromatography mass spectrometer device, wherein the chromatography mass spectrometer device is configured for performing step b) of a method according to claim 1; and (II) at least one evaluation device, wherein the evaluation device is configured for performing at least step c) of the method according to claim 1.

15. (canceled)

16. The method of claim 9, wherein the interferent monitoring compound peak is higher than 2.

17. The method of claim 10, wherein said interferent is a stereoisomer of the analyte.

18. The method of claim 10, wherein said interferent is a diastereomer, an enantiomer, or a cis-trans isomer.

19. The method of claim 1, wherein said analyte is Testosterone and the interferent is Epitestosterone.

20. The method of claim 1, wherein step a) comprises admixing an interferent monitoring compound and an internal standard to the sample; step b) comprises determining a chromatogram of the sample by acquiring a plurality of data points for signal intensities over time for said interferent monitoring compound, said analyte, and said internal standard; and step c) comprises comparing a property of an interferent monitoring compound peak to a property of an internal standard peak and/or to a property of an analyte peak.

21. The method of claim 20, wherein said internal standard is an isotopologue of the analyte.

22. The method of claim 20, wherein in step b) the chromatogram is determined based on signals being (I) non-identical between the analyte, the internal standard, and the interferent monitoring compound; (II) identical between the internal standard and the interferent monitoring compound and non-identical between the analyte and the internal standard, (III) non-identical between the analyte and the interferent monitoring compound, (IV) non-identical between the internal standard and the interferent; or (V) identical between the analyte and the interferent monitoring compound.

Description

FIGURE LEGENDS

[0147] FIG. 1: Schematic representation of a result of Example 1: addition of internal standard (Testosterone-D3) and interferent monitoring compound (Epitestosterone-.sup.13C3), measuring three different transitions; x-axis: time; y-axes: relative intensity of the respective transition.

[0148] FIG. 2: Schematic representation of a result of Example 2: addition of intemal standard (Testosterone-D3) and interferent monitoring compound (Epitestosterone-D3), measuring of two different transitions; x-axis: time; y-axes: relative intensity of the respective transition.

[0149] FIG. 3: Schematic representation of a result of Example 3: addition of A) Epitestosterone-D3, B) Epitestosterone-.sup.13C3 as interferent monitoring compound, measurement of two different transitions; x-axis: time; y-axes: relative intensity of the respective transition;.

[0150] FIG. 4: Schematic representation of a result of Example 4: addition of internal standard (Testosterone-D3), measurement of two different transitions; x-axis: time; y-axes: relative intensity of the respective transition.

[0151] FIG. 5: Schematic representation of a result of Example 5: addition of interferent monitoring compound (Epitestosterone): measurement of one transition; x-axis: time; y-axes: relative intensity of the respective transition.

EXAMPLES

[0152] The following Examples shall merely illustrate the invention. They shall not be construed, whatsoever, to limit the scope of the invention.

Example 1

[0153] To a routine sample for LC-MS/MS measurement of testosterone, an internal standard (Testosterone-D3) and an interferent monitoring compound (Epitestosterone-.sup.13C3) were admixed. Intensities of m/z 289 -> 109, m/z 292 -> 112, and m/z 292 -> 109 transitions over LC progress were recorded; a possible result is schematically shown in FIG. 1.

[0154] By comparing properties of the m/z 292 -> 112 and m/z 292 -> 109 peaks, quality of separation of the internal standard from the interferent monitoring compound, which is a measure of separation between analyte and an interferent which may possibly be present, can be provided.

[0155] From the analyte peak of the m/z 289 -> 109 transition, optionally in combination with peak. of the internal standard m/z 292 -> 112 transition, the amount of testosterone can be derived.

Example 2

[0156] To a routine sample for LC-MS/MS measurement of testosterone, an internal standard (Testosterone-D3) and an interferent monitoring compound (Epitestosterone-D3) were admixed. Intensities of m/z 289 -> 109 and m/z 292 -> 112 transitions over LC progress were recorded; a possible result is schematically shown in FIG. 2.

[0157] By comparing properties of the m/z 292 -> 112 peaks of internal standard and interferent monitoring compound, quality of separation of the internal standard from the interferent monitoring compound, which is a measure of separation between analyte and an interferent which may possibly be present, can be provided.

[0158] From the analyte peak of the m/z 289 -> 109 transition, optionally in combination with peak of the internal standard m/z 292 -> 112 transition, the amount of testosterone can be derived.

Example 3

[0159] To a routine sample for LC-MS/MS measurement of testosterone, an internal standard (Testosterone-D3) and an interferent monitoring compound (Epitestosterone-D3 or Epitestosterone-.sup.13C3) was admixed. Intensities of m/z 289 -> 109 and (i) m/z 292 -> 112 transitions if Epitestosterone-D3 was used, or (ii) m/z 292 -> 109 transitions if Epitestosterone-.sup.13C3 was used, over LC progress were recorded; a possible result is schematically shown in FIGS. 3 A) and B).

[0160] By comparing properties of (i) the m/z 292 -> 112 peak or (ii) the m/z 292 -> 109 peak of the interferent monitoring compound to the analyte m/z 289 -> 109 peak, quality of separation of the analyte from the interferent monitoring compound, which is a measure of separation between analyte and an interferent which may possibly be present, can be provided.

[0161] From the analyte peak of the m/z 289 -> 109 transition, the amount of testosterone can be derived.

Example 4

[0162] To a routine sample for LC-MS/MS measurement of testosterone, an internal standard (Testosterone-D3) and an interferent monitoring compound (Epitestosterone) were admixed. Intensities of m/z 289 -> 109 and m/z 292 -> 112 transitions over LC progress were recorded; a possible result is schematically shown in FIG. 4.

[0163] By comparing properties of the internal standard m/z 292 -> 112 peak to the interferent monitoring compound m/z 289 -> 109 peak, quality of separation of the internal standard from the interferent monitoring compound, which is a measure of separation between analyte and an interferent which may possibly be present, can be provided.

[0164] From the analyte peak of the m/z 289 -> 109 transition, optionally in combination with the the internal standard m/z 292 -> 112 transition peak, the amount of testosterone can be derived.

Example 5

[0165] To a routine sample for LC-MS/MS measurement of testosterone, an interferent monitoring compound (Epitestosterone) was admixed. Intensities of the m/z 289 -> 109 transition over LC progress was recorded; a possible result is schematically shown in FIG. 5.

[0166] By comparing properties of the analyte m/z 292 -> 112 peak to the interferent monitoring compound m/z 292 -> 112 peak, quality of separation of the analyte from the interferent monitoring compound, which is a measure of separation between analyte and an interferent which may possibly be present, can be provided.

[0167] From the analyte peak of the m/z 289 -> 109 transition the amount of testosterone can be derived.