A new way to fast and high resolution determination of modified nucleosides

Hydrophilic interaction chromatography-type sorbent prepared by the modification of methacrylate-base resin with polyethyleneimine for solid-phase extraction of polar compounds

Hydrophilic interaction chromatography (HILIC)-type sorbents were newly developed for the solid-phase extraction (SPE) of polar compounds. Two methacrylate-base resins with different cross-linking monomers and pore properties were synthesized, and three polyethyleneimines (PEIs) with different molecular weights were modified onto each base resin. In both cases, PEIs with a molecular weight of 10,000 (PEI-10,000) exhibited the highest adsorption properties for polar compounds (uracil, uridine, adenosine, cytidine, and guanosine). To control the water-enriched layer at the surface of the PEI-10,000-modified sorbents, the additive amount of PEI-10,000 in the modified reaction was also optimized. When 10 times the amount of PEI-10,000 to each base resin was added, an improvement in adsorption property was observed. Moreover, the use of a nonaqueous sample solution (100% acetonitrile) during the sample loading process drastically improved adsorption, especially for uracil (about 80%) and adenosine (100%). These results indicate that the formation of a strong water-enriched layer at the surface of sorbents with an effective expression of hydrophilic interaction was an important factor in the adsorption properties of polar compounds in HILIC mode-SPE.

Gallic acid-affinity molecularly imprinted polymer adsorbent for capture of cis-diol containing Luteolin prior to determination by high performance liquid chromatography

A gallic acid-affinity molecularly imprinted polymer (G-MIP) was first used as an adsorbent for selective identification and capture of luteolin (LTL) in herbal medicine samples. The G-MIP was prepared by using LTL as the template, gallic acid (GA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent, and 2,2'-azobis(2-methylpropionitrie) (AIBN) as the initiator. The properties of G-MIP were characterized by FT-IR, transmission electron microscope, scanning electron microscope, dynamic light scattering, specific surface area, and X-ray photoelectron spectrum. The adsorption conditions were optimized, and the adsorption equilibrium model and adsorption kinetics model of the adsorbent were investigated under the best experimental conditions. The saturated adsorption capacity is 1.24 mg g^-1, which is not only higher than the adsorption capacity of 4-carboxyphenylboronic acid-affinity MIP adsorbent but also superior to those of many reported adsorbents for enriching of LTL. The LTL was quantified by HPLC. The linear range is 0.05-100 mg L^-1, the detection limit is 0.020 mg L^-1. This method was successfully applied in the selective recognition of LTL in herbal medicines with recoveries of 93.9-114.2%, and the relative standards deviations (RSDs) are 0.4-5.6%. Thus, this work provides a potential possibility and practical platform for the determination of LTL in complex matrices.

Extraction of nucleobases, nucleosides and nucleotides by employing a magnetized graphene oxide functionalized with hydrophilic phytic acid and titanium(IV) ions

A magnetite@graphene oxide nanocomposite was first coated with polyethylenimine and then modified with phytic acid and titanium(IV) ions. The high loading with Ti(IV) and the good hydrophilicity of PEI and PA result in a material that can be applied to the efficient extraction of highly polar nucleobases, nucleosides and nucleotides. The physicochemical properties of the composite were investigated by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, water contact angle measurements, thermogravimetric analysis, and vibrating sample magnetometry. A series of parameters that affect extraction and elution under the conditions of immobilized metal affinity chromatography (IMAC) and hydrophilic interaction liquid chromatography (HILIC) were examined. The analytes were eluted from the nanocomposites using 10 mM trisodium phosphate as the elution solution in the IMAC mode, and 50% methanol-water as elution solution in the HILIC mode. Figures of merit include (a) an intra-day precision of 0.1-1.0% in the IMAC mode; (b) an intra-day precision of 0.4%-0.8% in the HILIC mode; (c) detection limits between 1.8-2.8 ng mL^-1 in the IMAC mode; and (d) detection limits of 4.0-10.5 ng mL^-1 in the HILIC mode. The method was applied to the extraction of the nucleotides cytidine-5'-monophosphate (CMP), uridine-5'-monophosphate (UMP), guanosine-5'-monophosphate (GMP), and adenosine-5'-monophosphate (AMP), and the nucleobases and nucleosides hypoxanthine, adenosine, cytosine, inosine and cytidine from Cordyceps sinensis, Lentinus edodes and plasma samples. Graphical abstract Schematic presentation of the workflow for the extraction of nucleobases, nucleosides and nucleotides using phytic acid-Ti(IV) functionalized magnetite@graphene oxide nanocomposites under two distinct modes.

Urinary Nucleosides and Deoxynucleosides

Urinary nucleosides and deoxynucleosides are mainly known as metabolites of RNA turnover and oxidative damage of DNA. For several decades these metabolites have been examined for their potential use in disease states including cancer and oxidative stress. Subsequent improvements in analytical sensitivity and specificity have provided a reliable means to measure these unique molecules to better assess their relationship to physiologic and pathophysiologic conditions. In fact, some are currently used as antiviral and antitumor agents. In this review we provide insight into their molecular characteristics, highlight current separation techniques and detection methods, and explore potential clinical usefulness.

Boronate-affinity hollow molecularly imprinted polymers for the selective extraction of nucleosides

Preparation of a boronate-affinity hollow molecularly imprinted polymer and its application as an SPE adsorbent for the selective enrichment of nucleosides.

Hydrophilic interaction ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometry for determination of nucleotides, nucleosides and nucleobases in Ziziphus plants

In this study, a rapid and sensitive analytical method was developed for the determination of 20 nucleobases, nucleosides and nucleotides in Ziziphus plants at trace levels by using hydrophilic interaction ultra-high performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (HILIC-UHPLC-TQ-MS/MS) in multiple-reaction monitoring (MRM) mode. Under the optimized chromatographic conditions, good separation for 20 target compounds were obtained on a UHPLC Amide column with sub-2μm particles within 10min. The overall LODs and LOQs were between 0.11-3.12ngmL(-1) and 0.29-12.48ngmL(-1) for the 20 analytes, respectively. It is the first report about simultaneous analysis of nucleobases, nucleosides and nucleotides in medicinal plants using HILIC-UHPLC-TQ-MS/MS method, which affords good linearity, precision, repeatability and accuracy. The developed method was successfully applied to Ziziphus plant (Z. jujuba, Z. jujuba var. spinosa and Z. mauritiana) samples. The analysis showed that the fruits and leaves of Ziziphus plants are rich in nucleosides and nucleobases as well as nucleotides, and could be selected as the healthy food resources. Our results in present study suggest that HILIC-UHPLC-TQ-MS/MS method could be employed as a useful tool for quality assessment of the samples from the Ziziphus plants as well as other medicinal plants or food samples using nucleotides, nucleosides and nucleobases as markers.