Simultaneous identification and quantification of amino acids in biofluids by reactive 19 F-tags

19 F NMR has been extensively used in simultaneous analysis of multicomponent due to its 100% natural isotope abundance, high NMR-sensitivity, and wide-range chemical shifts. The solvent effects are usually observed in NMR spectroscopy and cause large changes in 19 F chemical shifts. Herein, we propose that the simultaneous analysis of a complex mixture can be achieved using solvent effects via 19 F NMR spectroscopy, such as a mixture solution of amino acids (AAs). AAs are not only cell-signaling molecules, but are also considered as biomarkers of some diseases. Hence, the analysis of AAs is important for human health and the diagnosis of diseases. In this work, the key to the success of sensing 19 biogenic AAs is the use of 2-fluorobenzaldehyde (2FBA) as a highly sensitive derivatizing agent and solvent effects to produce distinguishable 19 F NMR signals. As a result, the resolution of 19 F NMR spectroscopy of multiple 2FBA-labeled AAs is obviously higher than other methods based on 19 F NMR. Moreover, 14 and 18 AAs can be satisfactorily differentiated and unambiguously identified in different complicated media supporting the growth of mammalian cells. Furthermore, quantification of the concentration of AAs can be made, and the limit of detection reaches 10 μM.Our work provides new insights into the simultaneous analysis of a multicomponent mixture based on solvent effects by 19 F NMR spectroscopy.

Section: ■ Results and Discussionmentioning

confidence: 95%

Solvent Effects Used for Optimal Simultaneous Analysis of Amino Acids via ¹⁹F NMR Spectroscopy

Huang

Hou

et al. 2023

“…The previous work showed that qualitative and quantitative analyses of L-amino acids in biofluids by a reactive 19 F tag are feasible in aqueous solution. 38 However, the 19 F tag lacks a chiral center and is unable to discriminate the stereospecific difference between the D-type and L-type analytes (Figure S1). In this work, we aimed to quantify the enantiomeric amino acids by using a reactive 19 F tag that contains a sensitive 19 F reporter anchored in a stereogenic carbon center and a reactive moiety toward the amino groups of amino acids in an irreversible manner, which permits the reproducibility and easy handling of multiple analytes.…”

Section: ■ Introductionmentioning

confidence: 99%

“…To achieve this goal, we therefore designed a reactive 19 F NMR tag by introducing a fluorine group in a stereogenic carbon to sense the stereodifference between enantiomeric amino acids and a N-hydroxysuccinimide ester (NHS) group to form a stable amide complex with the amino acid analyte (Scheme 1), which permits the irreversible detection and reliable quantification method in mild aqueous solution. To distinguish from the previous 19 F tag, 38 we referred the new 19 F tag containing a stereogenic carbon center to a chiral 19 F NMR tag. The feasibility of the simultaneous discrimination and quantification of enantiomeric amino acids in a mixture under physiological conditions was testified.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The complete transformation of amines to Schiff base products and the stability of Schiff base complexes in aqueous solution remains elusive. The previous work showed that qualitative and quantitative analyses of l -amino acids in biofluids by a reactive 19 F tag are feasible in aqueous solution . However, the 19 F tag lacks a chiral center and is unable to discriminate the stereospecific difference between the d -type and l -type analytes (Figure S1).…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Discrimination and Quantification of Enantiomeric Amino Acids under Physiological Conditions by Chiral ¹⁹F NMR Tag

Chen

et al. 2022

Self Cite

Enantiomeric analysis is of great significance in chemistry, chemical biology and pharmaceutical research. We herein propose a chiral 19F NMR tag containing an amino reactive NHS group to discriminate the enantiomeric amino acids under physiological conditions by NMR spectroscopy. The chiral 19F NMR tag readily forms stable amide products with the amino acids in aqueous solution. The stereospecific chemistry of enantiomeric amino acids is discriminated by a stereogenic carbon bonded with a 19F atom and is therefore decoded by the 19F reporter and manifested in the distinct 19F chemical shift. The chemical shift difference (ΔΔδ) of the chiral 19F NMR tag derived enantiomeric amino acids variants has a broad chemical shift range between −1.13 to 1.68 ppm, indicating the high sensitivity of the chiral 19F NMR tag to the stereospecific environment surrounding the individual amino acids. The distinguishable chemical shift produced by the chiral 19F NMR tag permits simultaneous discrimination and quantification of the enantiomeric amino acids in a mixture. The high fidelity of the chiral 19F NMR tag affords high-accuracy determination of the enantiomeric composition of amino acids by simple 1D NMR under physiological conditions.

“…Moreover, the lack of naturally occurring fluorinated compounds in the body fluid eliminates background signals and makes the spectrum analysis easier . Consequently, fluorine-labeled molecules combined with 19 F NMR to generate characteristic signals as powerful sensors have been extensively utilized, ranging from organic small molecule discrimination, − biological relevant molecule sensing, − chiral recognition, − drug studies, , and so forth. Furthermore, the combination of fluorinated phenylboronic acid compounds with 19 F NMR has turned out to be a powerful method for sensing of diol-containing analytes. − In particular, a series of fluorinated phenylboronic acid sensor molecules were synthesized by Schiller and co-workers for the identification and discrimination of diols. , Despite remarkable progress, it is still a challenge to identify specific saccharides in a mixture containing multiple potential interferents.…”

Section: Introductionmentioning

confidence: 99%

Rapid and Selective ¹⁹F NMR-Based Sensors for Fingerprint Identification of Ribose

Gao

Wang

et al. 2022

Ribose plays an important role in the process of life. Excessive ribose in the human cerebrospinal fluid or urine can be used as an early diagnostic marker of leukoencephalopathy. Fluorinated phenylboronic acid combined with 19F NMR spectroscopy was a powerful method for molecular recognition. However, phenylboronic acid-based sensors for selective detection of ribose are rarely reported in the literature. In this study, the rapid and highly selective recognition of ribose was studied by 19F NMR and 2-fluorophenylboric acid. It was found that 2-fluoro-phenylboric acid was an appropriate 19F NMR-based sensor molecule for the determination of ribose under physiological conditions with high selectivity and robust anti-interference ability. When 2-fluorophenylboric acid was used for the detection of ribose in human urine without any sample pretreatment, a limit of detection of 78 μM was obtained at room temperature under given 19F NMR experimental conditions (400 MHz, 512 scans, ca. 12 min), which can well meet the needs of practical application.