Light and heavy dansyl reporter groups in food chemistry: amino acid assay in beverages

Abstract

5-Dimethylamino-1-sulfonyl naphthalene (DNS, commonly referred as dansyl) is a functionality, bearing well-established properties in directing the fragmentation, by mass spectrometry (MS), of the corresponding ionized sulfonylated derivatives. This property is shared also by its labeled analogs. The use of d(0)/d(6) DNS derivatives is now exploited in the application of the well-established isotope dilution mass spectrometric approach in the assay of complex mixtures. A new method for the quantitation of amino acids (AAs) in beverages is therefore presented, which relies on liquid chromatographic separation of their N-dansylated derivatives followed by comparative electrospray tandem MS/MS of the d(0)/d(6) isobaric mixtures. Labeled and unlabeled DNS derivatives of the selected AAs are readily available by microwave-assisted synthetic protocols. The novelty of the method is represented by the use of heavy and light DNS-isotopologue providing suitable reporter groups. Multiple-reaction monitoring has been applied in the assay of AAs in wine, pineapple juice and bergamot juice with good-to-excellent results as proved by both relative standard deviation, lower than 15%, and by the accuracy values in the range 90-110%.

Development of versatile isotopic labeling reagents for profiling the amine submetabolome by liquid chromatography–mass spectrometry

“…To date, several CIL reagents have been developed to quantify organic amines, carboxylic acids, carbonyl compounds and some other types of metabolites with varying degrees of performance [1,4,5,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. These research activities are mainly driven by the need of dealing with different classes of metabolites; a universally applicable derivatization reagent for LC-MS is not available at the present.…”

Effect of Fermentation and Subsequent Pasteurization Processes on Amino Acids Composition of Orange Juice

“…Analysis of amino acids in most matrices has classically used HPLC with UV detection or HPLC with diode-array detection after derivatization [11]. Subsequently, MS/MS detection coupled with HPLC was developed for the analysis of amino acids in fruit juice [12]. More recently, other authors have used UHPLC-MS/MS to quantify amino acids in pearjujube fruits (Z. jujube) [13] and different cheese varieties [14].…”

Quantitative Metabolome Analysis Based on Chromatographic Peak Reconstruction in Chemical Isotope Labeling Liquid Chromatography Mass Spectrometry

“…IsoMS-Quant is demonstrated to provide better precision and accuracy for both untargeted and targeted metabolic profiling work using CIL LC-MS. IsoMS-Quant, along with IsoMS and Zero-fill, forms a complete workflow for rapid processing of raw LC-MS data generated by CIL LC-MS. 21 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Table 1. Results of targeted quantification of 20 metabolites in a human serum sample by LC-MS analysis of a mixture of the 12 C-labeled sample and the 13 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 …”

“…12 C.peak), and int. 13 C.peak, refer to retention time, m/z value, and intensity of the labeled peak in the metabolite-intensity table, respectively.…”

“…(A) Extracted ion chromatograms (EICs) of a relatively high abundance or easily ionizable 13 C-/ 12 C-labeled peak pair (green: 12 C-labeled metabolite; red:13 C-labeled metabolite) found in a mixture of a 12 C-labeled individual human serum and a 12 Clabeled pooled serum prepared from 100 healthy individuals and (B) the highest intensity mass spectrum of the pair. (C) EICs of a relatively low abundance or not readily ionizable peak pair and (D) the high intensity mass spectrum of the pair.…”