scholarly journals Analysis of Seven Biogenic Amines and Two Amino Acids in Wines Using Micellar Electrokinetic Chromatography

2019 ◽  
Vol 9 (6) ◽  
pp. 1193 ◽  
Author(s):  
Chih-Ying Huang ◽  
Yu-Xian Wang ◽  
Xin-Zhi Wang ◽  
Cho-Chun Hu ◽  
Tai-Chia Chiu
Keyword(s):  
Amino Acids ◽  
Biogenic Amines ◽  
Micellar Electrokinetic Chromatography ◽  
Low Cost ◽  
Background Electrolyte ◽  
Sodium Dodecyl ◽  
Fast Method ◽  
Electrokinetic Chromatography ◽  
Optimal Separation

A low-cost, simple, and fast method utilizing micellar electrokinetic chromatography for the simultaneous determination of seven biogenic amines and two amino acids was developed. A background electrolyte containing 5 mM phosphate buffer (pH 3.7) and 20 mM sodium dodecyl sulfate was used. The optimal separation of nine investigated analytes was achieved in 11 min, with limits of detection (S/N = 3) ranging from 0.11 to 0.61 µM. The linear ranges for all analytes were observed between 0.55 and 10.0 μM (R2 > 0.990). The developed approach was extended to the analysis of analytes in commercial wine and beer samples. The recoveries of the proposed method ranged from 98.8% to 115.6%.

scholarly journals A fast and efficient method for the study of caffeine levels in energy drinks using micellar electrokinetic chromatography (MEKC)

2012 ◽  
Vol 32 (2) ◽  
pp. 401-404 ◽  
Author(s):  
Cristiano Augusto Ballus ◽  
Adriana Dillenburg Meinhart ◽  
Carolina Schaper Bizzotto ◽  
José Teixeira Filho ◽  
Helena Teixeira Godoy
Keyword(s):  
Micellar Electrokinetic Chromatography ◽  
Brain Activity ◽  
Low Cost ◽  
Sodium Dodecyl ◽  
Energy Drinks ◽  
Electrokinetic Chromatography ◽  
The Central Nervous System ◽  
The Mean ◽  
High Doses

Energy drinks are becoming popular in Brazil and in the world due to their stimulant properties. Caffeine is present in energy drinks with the aim of stimulating the central nervous system and intensifying brain activity. On the other hand, the ingestion of high doses of caffeine can cause undesirable symptoms such as anxiety and tachycardia. Therefore, it is necessary to monitor the caffeine content added to energy drinks to guarantee that the levels in the final product are in accordance with the labeling and within the legislation limits. The goal of this work was to validate a fast, efficient, and low-cost method for the determination of caffeine in energy drinks by micellar electrokinetic chromatography (MEKC). A total of seven brands were analyzed, each in three lots. The electrolyte was prepared with 50 mmol.L-1 of sodium dodecyl sulfate (SDS) and 10 mmol.L-1 of sodium carbonate (pH 11.0). The mean concentration of caffeine ranged from 122.8 to 318.6 mg.L-1. None of the brands had caffeine levels above the maximum limit. Considering the interval of confidence (95%), 72% of the samples had less caffeine than the amount informed on the product label.

scholarly journals Separation of ketoprofen enantiomers at nanomolar concentration levels by micellar electrokinetic chromatography with on-line electrokinetic preconcentration

2013 ◽  
Vol 11 (3) ◽  
pp. 335-340 ◽  
Author(s):  
Jan Petr ◽  
Pavlína Ginterová ◽  
Joanna Znaleziona ◽  
Radim Knob ◽  
Markéta Lošťáková ◽  
...  
Keyword(s):  
Micellar Electrokinetic Chromatography ◽  
Concentration Level ◽  
Background Electrolyte ◽  
Electrokinetic Chromatography ◽  
Nanomolar Concentration ◽  
Enhancement Factors ◽  
Simple Filtration ◽  
On Line ◽  
Concentration Levels

AbstractAbstract Separation of enantiomers represents an extremely important task in the field of analytical chemistry. This paper contributes to the field of the on-line preconcentration of enantiomers by developing a novel setup based on the electrokinetic accumulation of ketoprofen enantiomers on the pH boundary followed by enantioselective mobilization by a mixture of SDS, sulfated-β-cyclodextrin (S-β-CD), and trimethyl-β-cyclodextrin (TM-β-CD). Under the best conditions, where the injection electrolyte was composed of 50 mmol L−1 borate/NaOH pH 9.5 with 60% (v/v) methanol, the background electrolyte contained 50 mmol L−1 phosphate/NaOH pH 2.5, and the mobilization electrolyte consisted of 50 mmol L−1 phosphate/NaOH pH 2.5 with 4.0% (w/v) S-β-CD, 0.5% (w/v) TM-β-CD, and 20 mmol L−1 SDS, the determination of nanomolar concentration levels of ketoprofen enantiomers was successful by using micellar electrokinetic chromatography with a common UV detection. LODs were 2.5 nmol L−1 and 3.4 nmol L−1, which represent enhancement factors of 9921 and 8529, respectively. The method was also applied to the determination of ketoprofen enantiomers in waste water samples by using simple filtration as a clean-up step. Here, the recovery of ketoprofen enantiomers was 91% at the concentration level of 5×10−9 mol L−1. Graphical abstract

scholarly journals A sweeping-micellar electrokinetic chromatography method for the detection of three chlorophenols in cosmetic samples

2020 ◽  
Author(s):  
Zhihan Zheng ◽  
Xiaobin Li ◽  
Fangfang Gao ◽  
Huitao Liu ◽  
Yuan Gao
Keyword(s):  
Micellar Electrokinetic Chromatography ◽  
Signal To Noise Ratio ◽  
Sodium Dodecyl ◽  
Electrokinetic Chromatography ◽  
Chromatography Method ◽  
Sample Matrix ◽  
Pressure Injection ◽  
Relative Standard ◽  
On Line

AbstractA sweeping micellar electrokinetic chromatography (sweeping-MEKC) enrichment model was established for the determination of three chlorophenols (CPs) in cosmetics, namely, bithionol, pentachlorophenol (PCP), and 2,4,6-trichlorophenol (2,4,6-TCP). The optimum electrophoretic conditions were 20 mM NaH2PO4-80 mM sodium dodecyl sulfate (SDS) and 30% (v/v) acetonitrile (pH 2.3). The optimum on-line concentration conditions were as follows: sample matrix, 100 mM NaH2PO4; pressure injection at 20.67 kPa (3 psi) for 25 s. The linear range of bithionol, PCP, and 2,4,6-TCP are 0.20–4.00 μg mL−1, 0.10–2.00 μg mL−1, and 0.05–2.00 μg mL−1 respectively, with correlation coefficient (r) over 0.9972. The limits of detection (LOD) based on three times the signal-to-noise ratio (S/N = 3) are in the range of 0.0061–0.024 μg mL−1. Recoveries for the three CPs in powder and lotion samples are between 79.7 and 110.2% with relative standard deviation (RSD) of 1.38–5.54% and 92.2–121.3% with RSD of 0.72–6.09%, respectively. The proposed method can provide reference for the determination of trace CPs in different sample matrix.

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