Analysis of nucleosides and nucleobases by microemulsion electrokinetic capillary chromatography coupled with field-amplified sample injection

Abstract

A microemulsion electrokinetic capillary (MEEKC) chromatography method was online-coupled with fieldamplified sample injection (FASI) for the analysis of nucleosides and nucleobases, namely cytidine, guanosine, N 6 -methyladenosine, fluorouracil, thymine, adenine, mercaptopurine, 6-hydroxypurine, and guanine. A microemulsion background electrolyte containing 10 mM sodium dodecyl sulfate (SDS), 0.6%(v/v) 1-butanol, 0.5% (v/v) ethyl acetate and 98.9% (v/v) borate buffer (10 mM; pH 9.0) was used as the running buffer. An online field-amplified sample injection (FASI) technique was adopted to improve the detection sensitivity. Baseline separation of nine nucleosides was achieved within 12 min with detection limits (S/N ¼ 3) between 0.22 and 2.97 mg mL À1 with the DAD detector at 200 nm under optimized conditions. The proposed method was applied to the determination of nine nucleoside compounds in spiked urine and serum samples with the recoveries ranging 91.2-113% and 85.2-112% and the relative standard deviations (RSDs, n ¼ 3) at less than 5.90% and 8.22%, respectively.

Recent progress of sample stacking in capillary electrophoresis (2014–2016)

“…He et al. reported online‐coupling of MEEKC and FASI for the analysis of nucleosides and nucleobases in urine and serum. A microemulsion BGE containing 10 mM borate buffer (pH 9.0), 10 mM SDS, 0.6% 1‐butanol, 0.5% ethyl acetate was used.…”

An on-line SPE-LC-MS/MS method for quantification of nucleobases and nucleosides present in biological fluids

“…While quantitative analysis of a variety of small molecule analytes present in biological uids can be readily achieved by reversed phase liquid chromatography, the analysis of highly polar nucleobases and nucleosides can be challenging due to the high polarity and the resulting lack of retention that these molecules exhibit on reversed phase columns. To overcome this difficulty, column separation mechanisms based on ion-exchange chromatography, 18,19 ion-pairing chromatography, 20 porous graphitized carbon chromatography in reversephase mode, 21 capillary electrophoresis, 22 and hydrophilic interaction liquid chromatography (HILIC) 14,23,24 were deployed. In HILIC a polar stationary phase is used in combination with a mobile phase consisting of water (or an aqueous buffer solution) and organic solvents (e.g., acetonitrile or methanol).…”

A simple and efficient sequential electrokinetic and hydrodynamic injections in micellar electrokinetic chromatography method for quantification of anticancer drug 5‐fluorouracil and its metabolite in human plasma

“…Numerous analytical methods have been developed for the analysis of 5‐FU, such as high‐performance liquid chromatography (HPLC; da Silva, Julio, Donadel, & Martins, 2016; Woo, Kim, Jeong, & Kim, 2008), gas chromatography (Zambonin & Palmisano, 1996) and capillary electrophoresis (CE) (Forough et al, 2017; He et al, 2015; Yang, Liu, Tao, Nie, & Yao, 2007). The use of liquid chromatography coupled to a mass spectrometry detector remains the best technique to analyze 5‐FU and its metabolites in biological matrices owing to its high sensitivity, which allows quantification of targeted analytes at low detection levels (ng and ml levels; Li et al, 2018).…”

“…Diode array detection (DAD) is also frequently employed because it is simple to operate and relatively inexpensive. Fewer studies have used CE to detect 5‐FU and its metabolites, although some have described the measurement of 5‐FU using CE with online preconcentration strategies with detection limits of 7.9–680 ng/ml (Forough et al, 2017; He et al, 2015; Yang, Liu, Tao, Nie, & Yao, 2007).…”