Abstract: A composition, method, and kit for calibrating a mass spectrometer including a predetermined concentration of a calibrant having a mixture of amino acid polyethylene glycol compounds and a solvent for dissolving the calibrant. The calibrant can be used in either positive or negative ionization mode, and it can be used in calibrating an atmospheric pressure chemical ionization or an electrospray mass spectrometer. The calibrant can include a mixture to enable calibration across a broad range of masses.

Abstract: Labeling reagents, sets of labeling reagents, and labeling techniques are provided for the relative quantitation, absolute quantitation, or both, of ketone or aldehyde compounds including, but not limited to, analytes comprising steroids or ketosteroids. The analytes can be medical or pharmaceutical compounds in biological samples. Methods for labeling, analyzing, and quantifying ketone or aldehyde compounds are also disclosed as are methods that also use mass spectrometry.

Abstract: Quantification of vitamin D2, vitamin D3, and the monohydroxy and diihydroxy metabolites of vitamin D2 and vitamin D3, can comprise labeling analytes with mass spectrometry (MS) tagging reagents and performing LC-MSMS analysis of the labeled analytes. The labeled analytes can include a labeled standard and can have distinct retention times on a reversed phase column, as well as distinct masses. Under high energy collisions, reporter groups can be generated. The intensity or the peak area detected for each reporter group can be used for quantitation. In some embodiments, a one-step tagging reagent is used that is a dienophile-containing, labeled Diels Alder reagent.

Abstract: The present teachings provide methods for analyzing one or more amine-containing compounds in one or more samples using isobaric labels and parent-daughter ion transition monitoring (PDITM). In various embodiments, the methods comprise the steps of: (a) labeling one or more amine-containing compounds with different isobaric tags from a set of isobaric tags, each isobaric tag comprising a reporter ion portion; (b) combining at least a portion of each of the isobarically labeled amine-containing compounds to produce a combined sample; (c) subjecting at least a portion of the combined sample to PDITM; (d) measuring the ion signal of one or more of the transmitted reporter ions; and (e) determining the concentration of one or more of the isobarically labeled amine-containing compounds based at least on a comparison of the measured ion signal of the corresponding reporter ion to one or more measured ion signals of a standard compound.

Abstract: In some embodiments, this invention pertains to active esters of N-substituted piperazine acetic acid, including isotopically enriched versions thereof. In some embodiments, this invention pertains to methods for the preparation of active esters of N-substituted piperazine acetic acid, including isotopically enriched versions thereof.

Abstract: This invention pertains to methods, mixtures, kits and/or compositions for the determination of analytes by mass analysis using unique labeling reagents or sets of unique labeling reagents. The labeling reagents can be isomeric or isobaric and can be used to produce mixtures suitable for multiplex analysis of the labeled analytes.

Abstract: This invention pertains to methods, mixtures, kits and compositions pertaining to analyte determination by mass spectrometry using labeling reagents that comprise a nucleophilic reactive group that reacts with a functional group of an analyte to produce a labeled analyte. The labeling reagents can be used as isobaric sets, mass differential labeling sets or in a combination of isobaric and mass differential labeling sets.

Abstract: This invention pertains to methods, mixtures, kits and compositions pertaining to analyte determination and/or quantification by mass spectrometry using compounds comprising a reporter moiety and a non-encoded detectable label. The compounds can be used in sets for the analysis of mixtures of labeled analytes.

Abstract: A molecule identification and quantitation method is provided wherein a mass tag is conjugated to an analyte and the signature ion of the mass tag remains attached to the analyte after tandem mass spectrometry fragmentation (MS-MS or MS2). Rather than losing the signature ion, a mass-balance part of the structure can be lost as a charge neutral group under tandem mass spectrometry fragmentation. The signature ion can be used for quantitation and, upon further fragmentation, can also provide ion-signals characteristic of the analyte and useful in identifying the analyte. In some embodiments, the ion-signals generated from a third mass spectrometry fragmentation (MS3) can be compared with a known mass spectrum, for example, from a look-up table, from a library, or from a database, to provide an unambiguous identification of the analyte.

Abstract: This invention pertains to methods, mixtures, kits and compositions pertaining to analyte determination and/or quantification by mass spectrometry using compounds comprising a reporter moiety and a non-encoded detectable label. The compounds can be used in sets for the analysis of mixtures of labeled analytes.

Abstract: This invention pertains to isobarically labeled analytes and fragment ions thereof.

Abstract: In various aspects, the present teachings provide labeling reagents and sets of labeling reagents for the relative quantitation, absolute quantitation, or both, of hydroxylated compounds including, but not limited to, hydroxylated ring containing compounds, steroids and sterols. In various aspects, the present teachings also provide methods for the analysis hydroxylated compounds including, but not limited to, hydroxylated ring containing compounds, steroids and sterols my MS/MS methods.

Abstract: This invention pertains to methods, mixtures, kits and compositions pertaining to analyte determination by mass spectrometry using labeling reagents that comprise a nucleophilic reactive group that reacts with a functional group of an analyte to produce a labeled analyte. The labeling reagents can be used as isobaric sets, mass differential labeling sets or in a combination of isobaric and mass differential labeling sets.

Abstract: A molecule identification and quantitation method is provided wherein a mass tag is conjugated to an analyte and the signature ion of the mass tag remains attached to the analyte after tandem mass spectrometry fragmentation (MS-MS or MS2). Rather than losing the signature ion, a mass-balance part of the structure can be lost as a charge neutral group under tandem mass spectrometry fragmentation. The signature ion can be used for quantitation and, upon further fragmentation, can also provide ion-signals characteristic of the analyte and useful in identifying the analyte. In some embodiments, the ion-signals generated from a third mass spectrometry fragmentation (MS3) can be compared with a known mass spectrum, for example, from a look-up table, from a library, or from a database, to provide an unambiguous identification of the analyte.

Abstract: Quantification of vitamin D2, vitamin D3, and the monohydroxy and diihydroxy metabolites of vitamin D2 and vitamin D3, can comprise labeling analytes with mass spectrometry (MS) tagging reagents and performing LC-MSMS analysis of the labeled analytes. The labeled analytes can include a labeled standard and can have distinct retention times on a reversed phase column, as well as distinct masses. Under high energy collisions, reporter groups can be generated. The intensity or the peak area detected for each reporter group can be used for quantitation. In some embodiments, a one-step tagging reagent is used that is a dienophile-containing, labeled Diels Alder reagent.

Abstract: A plurality of mass differential tagging reagents is used to label amine functionality in amine-containing compounds. The labeled analytes have distinct retention times on a reversed phase column, and distinct masses. Under high energy collision, reporter groups can be generated and the intensity or the peak area detected for each reporter group can be used for quantitation. One exemplary set of reagents includes a set of three different mass differential reagents comprising tagging weights of 140 atomic mass units, 144 atomic mass units, and 148 atomic mass units, respectively, with reporter groups of 113, 117, and 121 atomic mass units, respectively. A package including each of the mass differential reagents is also provided and can include separate respective containers, for example, one for each of the different reagents. The package can also include one or more standards each comprising a respective known concentration of a respective known amine-containing compound.

Abstract: A method for screening a drug for cytochrome P450 (CYP) induction is provided and can include incubating the drug with a microsome-containing biological sample and then quantitating at least one cytochrome P450 isoform. The isoforms can be selected from 2B6, 3A4, 1A2, and 3A5 isoforms. In some embodiments, the method uses liquid chromatography tandem mass spectrometry (LC-MSMS). A quantitated value can be compared to a threshold value and the drug can be determined to exhibit an acceptable CYP induction potential when the quantitated value does not exceed the threshold value. Isolated peptides are also provided.

Abstract: This invention pertains to methods, mixtures, kits and compositions pertaining to analyte determination by mass spectrometry using labeling reagents that comprise a nucleophilic reactive group that reacts with a functional group of an analyte to produce a labeled analyte. The labeling reagents can be used as isobaric sets, mass differential labeling sets or in a combination of isobaric and mass differential labeling sets.

Abstract: This invention pertains to methods, mixtures, kits and compositions pertaining to analyte determination and/or quantification by mass spectrometry using compounds comprising a reporter moiety and a non-encoded detectable label. The compounds can be used in sets for the analysis of mixtures of labeled analytes.

Abstract: Labeling reagents, sets of labeling reagents, and labeling techniques are provided for the relative quantitation, absolute quantitation, or both, of ketone or aldehyde compounds including, but not limited to, analytes comprising steroids or ketosteroids. The analytes can be medical or pharmaceutical compounds in biological samples. Methods for labeling, analyzing, and quantifying ketone or aldehyde compounds are also disclosed as are methods that also use mass spectrometry.