Accurate Determination of Amino Acids in Serum Samples by Liquid Chromatography-Tandem Mass Spectrometry Using a Stable Isotope Labeling Strategy.
An accurate and sensitive liquid chromatography-tandem mass spectrometry method was developed for the analysis of amino acids (isoleucine, leucine, valine, tyrosine, phenylalanine and tryptophan) in serum samples using a stable isotope labeling strategy. Amino acid samples and standards were, respectively, derivatized by 10-methyl-acridone-2-sulfonyl chloride (d0-MASC) and its deuterated counterpart d3-MASC to form isotopic pairs which co-eluted and were detected by an MS detector at the same time. Accurate internal standard-based quantification was thereby achieved without the use of any internal standard analogy. The labeling reaction of MASC with amino acids is fast, simple and robust. Besides, derivatization increased the molecular weight of amino acids, and therefore they were shifted out of the background noise which was often observed in low mass region. The instrument LODs were in the range of 1.0-2.5 nmol/L. Linearities calculated by comparing theoretical peak area ratios of d0-/d3-MASC derivatives with the experimental peak area ratios were excellent with correlation coefficients of >0.995. The proposed method was successfully applied to the analysis of amino acids in serum samples with high sensitivity and accuracy.
Shandong Province Key Laboratory of Life-Organic Analysis, Qufu Normal University, Qufu 273165, PR China.
Cuihua
C
Song
Shandong Province Key Laboratory of Life-Organic Analysis, Qufu Normal University, Qufu 273165, PR China sjzhang156@163.com.
Shijuan
S
Zhang
Shandong Province Key Laboratory of Life-Organic Analysis, Qufu Normal University, Qufu 273165, PR China Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, PR China.
Zhongyin
Z
Ji
Qufu People's Hospital, Qufu, PR China.
Yipeng
Y
Li
Shandong Province Key Laboratory of Life-Organic Analysis, Qufu Normal University, Qufu 273165, PR China Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, PR China.
Jinmao
J
You
D000596:Amino Acids / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D007553:Isotope Labeling; D057230:Limit of Detection; D016014:Linear Models; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
D000596:Amino Acids