Abstract: Described herein are methods for determining an amount of an analyte in a test sample. The methods involve preparing a calibration curve using standard samples containing an isotopically-labeled standard in a biological matrix.

Abstract: Described herein are methods for determining an amount of an analyte in a test sample. The methods involve preparing a calibration curve using standard samples containing an isotopically-labeled standard in a biological matrix.

Abstract: This invention relates, inter alia, to detecting and/or measuring succinylacetone and one or more additional biological analytes using mass spectrometry, e.g., tandem mass spectrometry, by derivatizing succinylacetone in a sample by contacting the sample with an extraction solution comprising a C1-3 linear or branched chain monoalcohol and a strong base selected from the group consisting of hydrazine, a modified hydrazine, and hydroxylamine.

Abstract: Described herein are methods for determining an amount of an analyte in a test sample. The methods involve preparing a calibration curve using standard samples containing an isotopically-labeled standard in a biological matrix.

Abstract: This invention relates, inter alia, to detecting and/or measuring succinylacetone and one or more additional biological analytes using mass spectrometry.

Abstract: Described herein are methods for determining an amount of an analyte in a test sample. The methods involve preparing a calibration curve using standard samples containing an isotopically-labeled standard in a biological matrix.

Abstract: Methods of evaluating molecular isomers of branched-chain amino acids are featured. The methods can include: derivatizing one or more molecular isomers of branched-chain amino acids in a sample comprising a branched-chain amino acid labeled with one or more heavy atoms as a first standard; adding, to the sample, after derivatization, a nonderivatized or derivatized branched chain amino acid that is labeled with one or more heavy atoms, as a second standard; evaluating the sample using tandem mass spectrometry; and detecting peaks indicative of derivatized and nonderivatized forms of one or more branched-chain amino acids in the sample.

Abstract: This invention relates, inter alia, to detecting and/or measuring succinylacetone and one or more additional biological analytes using mass spectrometry.

Abstract: Described herein are methods for determining an amount of an analyte in a test sample. The methods involve preparing a calibration curve using standard samples containing an isotopically-labeled standard in a biological matrix.

Abstract: Methods of evaluating molecular isomers of branched-chain amino acids are featured. The methods can include: derivatizing one or more molecular isomers of branched-chain amino acids in a sample comprising a branched-chain amino acid labeled with one or more heavy atoms as a first standard; adding, to the sample, after derivatization, a nonderivatized or derivatized branched chain amino acid that is labeled with one or more heavy atoms, as a second standard; evaluating the sample using tandem mass spectrometry; and detecting peaks indicative of derivatized and nonderivatized forms of one or more branched-chain amino acids in the sample.

Abstract: This invention relates, inter alia, to detecting and/or measuring succinylacetone and one or more additional biological analytes using mass spectrometry.

Abstract: Methods of evaluating molecular isomers of branched-chain amino acids are featured. The methods can include: derivatizing one or more molecular isomers of branched-chain amino acids in a sample comprising a branched-chain amino acid labeled with one or more heavy atoms as a first standard; adding, to the sample, after derivatization, a nonderivatized or derivatized branched chain amino acid that is labeled with one or more heavy atoms, as a second standard; evaluating the sample using tandem mass spectrometry; and detecting peaks indicative of derivatized and nonderivatized forms of one or more branched-chain amino acids in the sample.

Abstract: This invention relates, inter alia, to detecting and/or measuring succinylacetone and one or more additional biological analytes using mass spectrometry.

Abstract: Methods of evaluating molecular isomers of branched-chain amino acids are featured. The methods can include: derivatizing one or more molecular isomers of branched-chain amino acids in a sample comprising a branched-chain amino acid labeled with one or more heavy atoms as a first standard; adding, to the sample, after derivatization, a nonderivatized or derivatized branched chain amino acid that is labeled with one or more heavy atoms, as a second standard; evaluating the sample using tandem mass spectrometry; and detecting peaks indicative of derivatized and nonderivatized forms of one or more branched-chain amino acids in the sample.

Abstract: Described herein are methods for determining an amount of an analyte in a test sample. The methods involve preparing a calibration curve using standard samples containing an isotopically-labeled standard in a biological matrix.

Abstract: This invention relates, inter alia, to detecting and/or measuring succinylacetone and one or more additional biological analytes using mass spectrometry.

Abstract: Methods of evaluating molecular isomers of branched-chain amino acids are featured. The methods can include: derivatizing one or more molecular isomers of branched-chain amino acids in a sample comprising a branched-chain amino acid labeled with one or more heavy atoms as a first standard; adding, to the sample, after derivatization, a nonderivatized or derivatized branched chain amino acid that is labeled with one or more heavy atoms, as a second standard; evaluating the sample using tandem mass spectrometry; and detecting peaks indicative of derivatized and nonderivatized forms of one or more branched-chain amino acids in the sample.