Separation and determination of flavonoids using microemulsion EKC with electrochemical detection

Abstract

A selective and sensitive method of microemulsion EKC (MEEKC) with electrochemical detection (ED) was developed for separation and determination of 14 flavonoids. In order to obtain the better stability for the studied flavonoids, oil (ethyl acetate) with low interfacial surface tension was employed as organic solvent. A running buffer composed of 0.9% (w/v, 30 mM) SDS, 0.9% (w/v, 21 mM) sodium cholate (SC), 0.9% (w/v, 121 mM) butan-1-ol, 0.6% (w/v, 68 mM) ethyl acetate, and 98.2% v/v 10 mM Na(2)B(4)O(7)-20 mM H(3)BO(3) buffer (pH 7.5) was applied for the separation of flavonoids. Under the optimum conditions, the relationship between peak currents and analyte concentrations was linear over about 1.3 and 1.7 orders of magnitude with detection limits (defined as S/N = 3) ranging from 0.02 to 0.5 microg/mL for all analytes. This method was applied for the determination of flavonoids in real samples with simple extraction procedures, and the assay results were satisfactory.

Separation and detection of isoquinoline alkaloids using MEEKC coupled with field‐amplified sample injection induced by ACN

“…In order to improve the sensitivity, some sensitive detectors, such as laser-induced fluorescence and MS [29][30], can be used to improve the sensitivity for several orders, but they are not widely applicable due to their expensive cost for common user. We have proposed an MEEKC electrochemical detection method for separation and determination of flavonoids [31]. However, treatment of the microelectrode was time-consuming and tedious.…”

Advances in the theory and application of MEEKC

“…Improved LODs have also been achieved through use of LIF [69] and electrochemical detection [70]. Yu et al [70] achieved the separation of 14 flavanoids using MEEKC and reported detection limits ranging from 0.02 to 0.5 mg/L with electrochemical detection.…”

“…Yu et al [70] achieved the separation of 14 flavanoids using MEEKC and reported detection limits ranging from 0.02 to 0.5 mg/L with electrochemical detection.…”

“…Separation of highly hydrophobic structurally related corticosteroids 3.6% w/w SDS, 6.6% w/w 1-butanol, 0.8% w/w n-octane and 89% w/w 40 mM sodium dihydrogen phosphate buffer pH 8.0 [49] Enantioseparation of ephedrine and pseudoephedrine 2% R/S DDCV, 1.65% v/v 2-hexanol, 1.23% v/v diethyl tartrate and 50 mM sodium phosphate buffer pH 7.0 [59] Detection and separation of ephedrine and pseudoephedrine employing laser-induced fluorescence detection 3.24% w/w n-heptane, 3.24% w/w SDS, 26.44% w/w 1-butanol and 95% 50 mM sodium borate buffer containing 16% ACN pH 7 [69] Separation and determination of flavonoids employing electrochemical detection 0.9% w/v SDS, 0.9% w/v SC, 0.9% w/v 1-butanol, 0.6% w/v ethyl acetate and 98.2% v/v 10 mM sodium tetraborate buffer pH 7.5 [70] Determination of the coenzyme Q10 (2,3-dimethoxy-5-methyl-6-decaprenyl-1,4-benzoquinone) in human plasma 1.4% w/w sodium bis(2-ethylhexyl) sulphosuccinate (AOT), 4% w/w cholic acid, 8.5% w/w butanol, 1% w/w octane, 0.1% w/w PVA and 85% w/w 10 mM Tris buffer pH 9.0 [51] Fingerprint analysis and extraction of resina draconis 3.3% w/v SDS, 6.6% w/v 1-butanol, 0.8% w/v n-octane and 10 mM sodium tetraborate buffer pH 9.2 [79] Separation and determination of NF antibiotics in fish 3.48% w/w SDS, 6.48% w/w 1-butanol, 0.82% w/w octane and 10 mM sodium tetraborate buffer pH 9.70 [80] Separation of phenolic acids and diterpenoids using W/O MEEKC 48% w/v 1-butanol, 18% w/v SDS, 8.0% w/v 2-propanol and 26% v/v sodium acetate buffer pH 6.0 [82] Electrophoresis 2010, 31,[755][756][757][758][759][760][761][762][763][764][765][766][767] have been shown to be both mutagenic and carcinogenic. The ME was optimised in terms of surfactant, co-surfactant and oil concentration with the optimum buffer being composed of 0.82% w/w octane, 3.48% w/w SDS and 6.48% w/w butanol in a 10 mM sodium borate buffer pH 9.70.…”

Electrochromatographic characterization of methacrylate ester-based monolith and capillary electrochromatography separation of flavonoids

“…These properties are mainly correlated to their antioxidant activity, such as anticancer, antiviral, anti-inflammatory, effects on capillary fragility, and their ability to inhibit human platelet aggregation [2,3]. Various methods have been developed for the separation and detection of flavonoids in medicinal plants, such as polyamide chromatography, gas chromatography (GC) [4,5], high performance liquid chromatography-mass spectrometry (HPLC-MS) [6][7][8], capillary electrophoresis (CE) [9][10][11][12], micellar electrokinetic capillary chromatography (MECC) [13][14][15][16] and microemulsion electrokinetic chromatography (MEEKC) [17]. To the best of our knowledge, there are few reports about the separation and determination of flavonoids by capillary electrochromatography (CEC) using methacrylate ester-based monolithic columns [3,18].…”