Analysis of the enzymatic racemization of d-aspartic acid to l-aspartic acid by the on-line coupling of a solid-phase extraction column and a ligand-exchange high-performance liquid chromatography column

Cheng, Cheanyeh; Wu, Shouh-Chwan

doi:10.1016/s0021-9673(00)00756-1

Cited by 17 publications

(5 citation statements)

References 19 publications

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“…It has been reported that aspartame can be absorbed by the human body completely, and does not cause any harm to human body, and thus is considered to be a safe and reliable additive [3]. Even if the methanol disengages due to hydrolysis, the extremely small intake of methanol does not harm the human body because the amount of aspartame is extremely low [4,5,6]. Nevertheless, its safety has been questioned after all in that it is suspected if aspartic acid in aspartame would cause brain damage, endocrine disorders, or tumors.…”

Section: Introductionmentioning

confidence: 99%

Organic–Inorganic Nanohybrid Electrochemical Sensors from Multi-Walled Carbon Nanotubes Decorated with Zinc Oxide Nanoparticles and In-Situ Wrapped with Poly(2-methacryloyloxyethyl ferrocenecarboxylate) for Detection of the Content of Food Additives

Cui

et al. 2019

Nanomaterials

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An electrochemical sensor for detection of the content of aspartame was developed by modifying a glassy carbon electrode (GCE) with multi-walled carbon nanotubes decorated with zinc oxide nanoparticles and in-situ wrapped with poly(2-methacryloyloxyethyl ferrocenecarboxylate) (MWCNTs@ZnO/PMAEFc). MWCNTs@ZnO/PMAEFc nanohybrids were prepared through reaction of zinc acetate dihydrate with LiOH·H2O, followed by reversible addition-fragmentation chain transfer polymerization of 2-methacryloyloxyethyl ferrocenecarboxylate, and were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), scanning electron microscope (SEM), and transmission electron microscope (TEM) techniques. The electrochemical properties of the prepared nanohybrids with various composition ratios were examined by cyclic voltammetry (CV), and the trace additives in food and/or beverage was detected by using differential pulse voltammetry (DPV). The experimental results indicated that the prepared nanohybrids for fabrication of electrochemical modified electrodes possess active electroresponse, marked redox current, and good electrochemical reversibility, which could be mediated by changing the system formulations. The nanohybrid modified electrode sensors had a good peak current linear dependence on the analyte concentration with a wide detection range and a limit of detection as low as about 1.35 × 10−9 mol L−1, and the amount of aspartame was measured to be 35.36 and 40.20 µM in Coke zero, and Sprite zero, respectively. Therefore, the developed nanohybrids can potentially be used to fabricate novel electrochemical sensors for applications in the detection of beverage and food safety.

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Section: Introductionmentioning

confidence: 99%

Organic–Inorganic Nanohybrid Electrochemical Sensors from Multi-Walled Carbon Nanotubes Decorated with Zinc Oxide Nanoparticles and In-Situ Wrapped with Poly(2-methacryloyloxyethyl ferrocenecarboxylate) for Detection of the Content of Food Additives

Cui

et al. 2019

Nanomaterials

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“…It has been reported that the concentration of Cu(II) and the ratio of Cu(II) to the ligand in the mobile phase affect the separation of enantiomers of several amino acids [18][19][20]. In this study, the ratio of Cu(II) to ligand in the mobile phase was also considered.…”

Section: Effect Of Cu(ii) To L-apm Ratio Of Molar Concentrationmentioning

confidence: 99%

Validated chiral separation of M9, a Mannich ketone compound, by chiral ligand‐exchange chromatography

Yang

et al. 2007

J of Separation Science

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Enantioseparation of the Mannich ketone M9, a potential antifungal compound, was examined using chiral ligand-exchange chromatography. The chiral mobile phase contained complexes of Cu(II) with the optically active selector L-aspartame (APM) and the organic modifier methanol. The separation was optimized with respect to the concentration of the Cu(II)-(L-APM) complexes, pH of mobile phase, methanol content, and column temperature. A baseline separation (R(s) = 3.08) was achieved for enantiomers of M9 under optimal conditions, and the analysis was accomplished in eleven minutes. The developed method was extensively validated. The sample stability, linearity, precision (method repeatability and intermediate precision) and accuracy, and the limits of detection and quantification of the developed method were studied. The proposed method was shown to be accurate and suitable for the quantitative determination of each enantiomer of M9.

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“…However, sample preparation techniques before amino acid detections are still indispensable and complemental step in their analytical methodologies . LLE and SPE methods can be used for the separation of amino acids from biological matrices. On the other hand, these methods are known as time consuming, environmentally hazardous, and expensive techniques .…”

Section: Introductionmentioning

confidence: 99%

Combination of ultrasound‐assisted ethyl chloroformate derivatization and switchable solvent liquid‐phase microextraction for the sensitive determination of l‐methionine in human plasma by GC–MS

Erarpat

Bodur

et al. 2020

J of Separation Science

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A green and fast analytical method for the determination of l‐methionine in human plasma is presented in this study. Preconcentration of the analyte was carried out by switchable solvent liquid phase microextraction after ethyl chloroformate derivatization reaction. Instrumental detection of the analyte was performed by means of gas chromatography–mass spectrometry. N,N‐Dimethyl benzylamine was used in the synthesis of switchable solvent. Protonated N,N‐dimethyl benzylamine volume, volume/concentration of sodium hydroxide, and vortex period were meticulously fixed to their optimum values. Besides, ethyl chloroformate, pyridine, and ethanol volumes were optimized in order to get high derivatization yield. After the optimization studies, limit of detection and quantitation values were attained as 3.30 and 11.0 ng/g, respectively, by the developed switchable solvent liquid phase microextraction gas chromatography–mass spectrometry method that corresponding to 76.7‐folds enhancement in detection power of the gas chromatography–mass spectrometry system. Applicability and accuracy of the switchable solvent liquid phase microextraction–gas chromatography–mass spectrometry method were also checked by spiking experiments. Percent recovery results were ranged from 97.8 to 100.5% showing that human plasma samples could be analyzed for its l‐methionine level by the proposed method.

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Analysis of the enzymatic racemization of d-aspartic acid to l-aspartic acid by the on-line coupling of a solid-phase extraction column and a ligand-exchange high-performance liquid chromatography column

Cited by 17 publications

References 19 publications

Organic–Inorganic Nanohybrid Electrochemical Sensors from Multi-Walled Carbon Nanotubes Decorated with Zinc Oxide Nanoparticles and In-Situ Wrapped with Poly(2-methacryloyloxyethyl ferrocenecarboxylate) for Detection of the Content of Food Additives

Organic–Inorganic Nanohybrid Electrochemical Sensors from Multi-Walled Carbon Nanotubes Decorated with Zinc Oxide Nanoparticles and In-Situ Wrapped with Poly(2-methacryloyloxyethyl ferrocenecarboxylate) for Detection of the Content of Food Additives

Validated chiral separation of M9, a Mannich ketone compound, by chiral ligand‐exchange chromatography

Combination of ultrasound‐assisted ethyl chloroformate derivatization and switchable solvent liquid‐phase microextraction for the sensitive determination of l‐methionine in human plasma by GC–MS

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