Quantitation of structural isomers using maldi ms/ms
AssigneeCouncil of Scientific and Industrial Research
InventorsVENKATESWARLU PANCHAGNULA, NIVEDITA BHATTACHARYA, AVINASH DATTATRAYA GHANATE
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Abstract
The present invention relates to a quantitative determination of structural isomers implicated in diseases, the said process is completely independent of chromatographic separation, internal standard, and labeled isotopic references. Further, the present invention provides a diagnostic kit for quantitative determination of structural isomers.
Claims13
A method for quantitatively determining structural isomers comprising:
- a) subjecting an equimolar mixture containing the reference isomers to ionization and selecting precursor ions having a mass to charge ratio in an m/z range between 1 to 40000 (z=1) followed by fragmentation to generate product ions that are both common and unique in nature to the reference isomers;
- b) selecting product ions that are common to the isomer pairs to normalize the unique product ions followed by measuring the peak area/peak intensity ratios of the unique and common product ions to generate equimolar concentration response curves for each individual isomer pair as a function of equimolar ratios;
- and
- c) subjecting a sample containing unknown quantities of the isomers/isomer pairs in context to ionization and selecting precursor ions having a mass to charge ratio in an m/z range between 1 to 40000 (z=1) followed by fragmentation to generate product ions that are both common and unique in nature as in step (a);
- measuring the unique to common product ion ratio(s), and determining the corresponding equimolar ratio(s) of the isomer pairs present based on the equimolar concentration response curve(s) generated in step (b).
A method of diagnosing a disease caused by altered concentrations of isomer ratio by measuring the ratio of the isomers in a biological sample, which process comprises:
- a) isolating and providing a biological sample from a subject;
- b) subjecting an equimolar mixture containing the reference isomers to ionization and selecting precursor ions having a mass to charge ratio in an m/z range between 1 to 400000 (z=1) followed by fragmentation to generate product ions that are both common and unique in nature to the reference isomers;
- c) selecting product ions that are common to the isomer pairs to normalize the unique product ions followed by measuring the peak area/peak intensity ratios of the unique and common product ions to generate equimolar concentration response curves for each individual isomer pair as a function of equimolar ratios;
- and
- d) subjecting a sample containing unknown quantities of the isomers/isomer pairs in context to ionization and selecting precursor ions having a mass to charge ratio in an m/z range between 1 to 40000 (z=1) followed by fragmentation to generate product ions that are both common and unique in nature as in step (a);
- measuring the unique to common product ion ratio(s), and determining the corresponding equimolar ratio(s) of the isomer pairs present based on the equimolar concentration response curve(s) generated in step (b)
- wherein altered ratio of isomers in the biological sample compared to the reference is indicative that the subject has, or is at a risk of developing a disease characterized by altered ratio of the isomer.
Dependencies are inferred from the claim text.