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: Provided herein are labeling reagents for analyte determination in a sample, and methods of manufacturing the labeling reagents. By way of non-limiting example, analytes may include one or more of peptides, proteins, nucleic acid molecules, carbohydrates, lipids, steroids and/or small molecules. Also provided are labeled analytes themselves after one or more labeling reagents binds to an analyte. Analytes may be labeled for determination of the analyte by mass analysis, such as by mass spectrometry. Further provided are compounds that may be used in making the labeling reagents and labeled analytes, such as reporter group compounds. Also provided are kits that include at least one labeling reagent, and may further include or more other reagents, containers, enzymes, buffers, a labeled analyte (e.g., as a standard) and/or instructions. Further examples are also possible.

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: 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.