•A new stationary phase of P-fSiO2 was immobilized to fabricated open tubular column.•The process of column preparation was convenient and easy-to- handle.•Both electrophoretic and chromatographic mechanisms were demonstrated in the OT-CEC separation of proteins.A novel fibrous mesoporous silica nanoparticles (fSiO2) stationary phase grafted with polymer (Poly (2-(dimethylamino) ethyl methacrylate) (PDMAEMA) was developed for open tubular capillary electrochromatography (OT-CEC). The preparation procedure included synthesizing fSiO2 through biphase stratification approach, removing the surfactants, silanization and in situ graft polymerization with monomers via atom transfer radical polymerization (ATRP). Subsequently, PDMAEMA-modified mesoporous silica nanoparticles (P-fSiO2)/ethanol solution was immobilized onto the inner surface of the pretreated capillary and functionalized with octadecylsilane to fabricate the open-tubular column. Separation of polycyclic aromatic hydrocarbons (PAHs) and proteins were carried out to evaluate the performance of the column in CEC. The run-to-run, day-to-day and column-to-column reproducibility in terms retention time of naphthalene was 1.9%, 2.2%, and 3.7%, respectively. The effects of solvent concentration and pH on the separation were evaluated. The method was also used for the separation of real bio-sample, egg white proteins.

The paper describes a microfluidic evaporative light scattering detector (μELSD) for capillary electrochromatography and capillary liquid chromatography. The detector, consisting of a microfluidic nebulizer, a miniaturized evaporative module, a sheath gas module, and a light scattering chamber, was developed and optimized. Carrier gas exits from an extremely narrow circular gap (about 5 μm) between the spraying capillary o.d. and the nozzle i.d., impacting on the mobile phase liquid with supersonic velocity, to nebulize the effluent of a few hundred nL/min from the capillary outlet. The evaporation process was found to be accomplished at ambient temperature. A sheath gas module featuring a structural necking subsequent to drift tube endings was found to enhance the reproducibility and increase the S/N. Excellent linearity of the optimal μELSD was 3 orders of magnitude (0.2–40 ng; R2 = 0.9998). The limit of detection (LOD) for glucose with a capillary column was 100 pg. Finally, the μELSD coupled to pressurized capillary eletrochromatography (pCEC) was applied to the analysis of six active components in traditional Chinese medicine extract, demonstrating the feasibility of the detector for capillary liquid separation system.

A quantitative capillary electrophoresis (qCE) apparatus has been developed and evaluated in order to improve the accuracy and precision of the currently commercially available CE. A four-port nano-valve with a 4-nL internal loop is employed in the apparatus to precisely inject the amount of sample. A micro-fluidic device based on a syringe pump provides a stable and mild flow to ensure the stability and reliability of the instrument. The separation capillary has an inner diameter of 50 µm i.d. and 40-cm effective length. Run-to-run reproducibility in terms of the relative standard deviation lower than 1 % for the peak area and 0.5 % for retention time were respectively achieved using a test sample of dimethylsulfoxide. Six synthetic adulterants, namely fenfluramine, sibutramine, pseudoephedrine, amfebutamone, clenbuterol and norepinephrine, were used to test the feasibility of the qCE system under the following experimental condition: an electrolyte containing 20 mM NaH2PO4/H3PO4 at pH 2.0 with a thermostat temperature of 15 °C and voltage at 15 kV.

•Describe an UPLC-QTRAP/MS/MS method to detect eicosanoids.•Monitor a total of 184 eicosanoids in a single 5 min UPLC run.•The method was validated by using a human plasma sample.•The method was shown to be fast, sensitive and reliable.Over the past decade, the number of known eicosanoids has expanded immensely and we have now developed an ultra-performance liquid chromatography–electrospray ionization triple quadrupole mass spectrometric (UPLC-QTRAP/MS/MS) method to monitor and quantify numerous eicosanoids. The UPLC-QTRAP/MS/MS approach utilizes scheduled multiple reaction monitoring (MRM) to optimize sensitivity, number of metabolites that can be analyzed and the time requirement of the analysis. A total of 184 eicosanoids including 26 deuterated internal standards can be separated and monitored in a single 5 min UPLC run. To demonstrate a practical application, human plasma samples were analyzed following solid-phase extraction (SPE) and the recovery rate and matrix effects were determined for the 26 deuterated internal standards added to the plasma. The method was validated and shown to be sensitive with the limit of quantitation at pg levels for most compounds, accurate with recovery rates of 70–120%, and precise with a CV < 30 for all compounds. Also, the method showed a linear response over a range spanning several orders of magnitude. In a QC human plasma sample, we identified and rigorously quantified over 120 eicosanoids.

•Titania-coated silica microspheres (TiO2/SiO2) were synthesized and characterized.•TiO2/SiO2 microspheres were used as solid-phase extraction (SPE) sorbent.•The SPE strategy for selective capture of phospholipids (PLs) was developed by RPLC–ELSD.•This SPE approach was applied in serum PLs profiling prior to UPLC–MS analysis.•This SPE strategy used in PLs screening has high selectivity and efficiency.A novel strategy for selectively adsorbing phospholipids (PLs) on titania-coated silica core–shell microspheres (TiO2/SiO2) was developed. The TiO2/SiO2 microspheres were prepared through water-vapor-induced internal hydrolysis and then characterized by SEM, UV–vis spectroscopy, X-ray diffraction, and measurements of Brunauer–Emmett–Teller surface area. Analyses showed that the titania layer was uniformly distributed onto the surface of silica particles. The TiO2/SiO2 microspheres were employed as sorbent in solid-phase extraction (SPE), and their absorptive ability was investigated by reversed-phase liquid chromatography–evaporative light scattering detection (RPLC–ELSD). Important factors that affect the extraction, such as loading buffer, eluting buffer, and elution volume, were investigated in detail and optimized by using standard samples. Results reveal that the developed SPE approach had higher recoveries for PLs than that based on pure TiO2 particles. The proposed SPE method was used for extraction of PLs from serum and showed great potential for identifying more kinds of endogenous PL metabolites by ultra performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC–QTOF MS). The proposed SPE method with the composite sorbent was used to screen PLs from a biological matrix with high selectivity and efficiency. This approach is a promising method for selective extraction of PLs in lipidomics or phospholipidomics.