Extraction and Determination of Evodiamine from Euodia Fructus with SPE-HPLC Based on a Homemade Phenyl-Based Monolithic Cartridge.

A phenyl-based monolithic adsorbent was prepared in a 50-mm-long stainless steel tube, which was initiated by the redox system, using ethylene glycol phenyl ether acrylate as the monomer and ethylene glycol dimethacrylate as the crosslinker. The effects of monomer/crosslinker ratio and the porogens on the permeability and morphology of the resulting adsorbents were investigated, and the optimal adsorbent shows relatively uniform pore structure according to the characterizations of scanning electron microscopy and nitrogen adsorption-desorption method. The column that filled with the adsorbent was used as the solid-phase extraction (SPE) cartridge, exhibiting unique selectivity for the extraction of evodiamine from Euodia fructus (the fruits of Euodia rutaecarpa (Juss.)Benth.), which attributes to the interactions of π-π and hydrogen bonding between the adsorbent and evodiamine. Combined with a C18 analytical column via high-performance liquid chromatography (HPLC) system, an online SPE-HPLC method was established for extraction, enrichment and determination of evodiamine from Euodia fructus. Method validation demonstrates that the relative standard deviation of the precision is less than 0.66%, and the spiked recovery is in the range of 93.11-98.06%. Furthermore, it is worth noting that the prepared SPE cartridge can be reused for no less than 100 times. These results show that the developed method is simple and efficient for online extraction and enrichment of evodiamine from Euodia fructus.

Fabrication of edge-curled petals-like covalent organic frameworks and their properties for extracting indole alkaloids from complex biological samples.

In this study, a functionalized covalent-organic framework (COF) was first synthesized using porphyrin as the fabrication unit and showed an edge-curled, petal-like and well-ordered structure. The synthesized COF was then introduced to prepare porous organic polymer monolithic materials (POPMs). Two composite POPM/COF monolithic materials with rod shapes, referred to as sorbent A and sorbent B, were prepared in stainless steel tubes using different monomers. Sorbents A and B exhibited relatively uniform porous structures and enhanced specific surface areas of 153.14 m2/g and 80.01 m2/g, respectively. The prepared composite monoliths were used as in-tube solid-phase extraction (SPE) sorbents combined with HPLC for the on-line extraction and quantitative analytical systems. Indole alkaloids (from Catharanthus roseus G. Don and Uncaria rhynchophylla (Miq.) Miq. Ex Havil.) contained in mouse plasma were extracted and quantitatively analyzed using the online system. The two composite multifunctional monoliths showed excellent clean-up ability for complex biological matrices, as well as superior selectivity for target indole alkaloids. Method validation showed that the RSD values of the repeatability (n=6) were ≤ 3.46%, and the accuracy expressed by the spiked recoveries was in the ranges of 99.38%-100.91% and 96.39%-103.50% for vinca alkaloids and Uncaria alkaloids, respectively. Furthermore, sorbents A and B exhibited strong reusability, with RSD values ≤ 5.32%, which were based on the peak area of the corresponding alkaloids with more than 100 injections. These results indicate that the composite POPM/COF rod-shaped monoliths are promising media as SPE sorbents for extracting trace compounds in complex biological samples.

Fabrication and characterization of a composite monolithic guard column for the analysis of active components contained in medicinal plants using high-performance liquid chromatography.

A composite monolithic column was prepared via polymerization in a 10-mm-long tube, using a porphyrin-based covalent organic framework (COF) as the co-monomer. The fabricated monolith exhibit good permeability, relatively uniform porous structure and high specific surface area, which was used as a guard column prior to an analytical column for the analysis of active components in medicinal plants with HPLC. Ten kinds of medicinal plants were used as the samples, in which sixteen target components were separated and analyzed, as well as the fingerprints of herb and herb couple. Compared to a generally used commercial VAST silica gel-C18 guard column, the homemade guard column shows good permeability with fast mass transfer, short analytical time and strong reusability with more than 100 injections, thus indicating the present monolith is an outstanding guard column prior to the C18 analytical column for the analysis of multiple active components in various medicinal plants.

Extraction and determination of tussilagone from Farfarae Flos with online solid-phase extraction-high-performance liquid chromatography using a homemade monolithic cartridge doped with porous organic cage material.

A solid-phase extraction cartridge was fabricated using diallyl isophthalate as the monomer with the addition of porous organic cage material via in situ free-radical polymerization in a stainless-steel column. The resulting monolithic adsorbent exhibited a relatively uniform porous structure, a high specific surface area of 113.98 m2 /g, and multiple functional chemical groups according to the characterization results. An online solid-phase extraction-high-performance liquid chromatography procedure was fabricated to extract and determine tussilagone from Farfarae Flos. The results show that the complex sample matrices can be removed in the solid-phase extraction procedure. Simultaneously, tussilagone can remain, which can be subsequently switched to an octadecylsilane bonded analytical column. The methodological validation showed that the correlation coefficient was 0.9999 with a linear range of 0.6-200.0 µg/mL, the limit of detection was 0.2 µg/mL, the limit of quantification was 0.6 µg/mL, accuracy was 100.3-100.6%, and relative standard deviation of precision was ≤1.9%. The present monolithic cartridge exhibits good reusability of not more than 100 times. The real sample of Farfarae Flos was determined with a tussilagone content of 0.74 mg/g.

A rapid method for on-line solid-phase extraction and determination of dioscin in human plasma using a homemade monolithic sorbent combined with high-performance liquid chromatography.

A phenyl-based polymer monolithic column was prepared via free radical polymerization in a stainless steel column with the size of 4.6 mm i.d. × 50 mm, using ethylene glycol phenyl ether acrylate as the monomer. The resulting monolithic column shows high porosity of 73.42% and relative uniform pore structure, as characterized by mercury porosimetry and scanning electron microscopy, respectively. The optimized polymer monolith column was used for on-line solid-phase extraction prior to the reversed phase mode HPLC-UV analysis for the determination of dioscin in human plasma, using a COSMOSIL C18 column (4.6 mm × 150 mm, 4.5 µm). Water was used to wash non-retained components from the SPE sorbent, and methanol water (80:20, V/V) was used as the mobile phase for isocratic elution of dioscin. The maximum adsorbed quantity of dioscin to the SPE column is 6.79 mg/g, which is high enough for the quantitative analysis of dioscin in plasma, due to the low content of dioscin in plasma. The method was validated by assessing the linearity, lower limit of quantification, intra- and inter-day precision, accuracy, and repeatability. The developed method was applied for the analysis of dioscin in plasma from a volunteer who had orally administered an aqueous extract of dioscorea nipponica rhizome, showing the method capable of detecting dioscin in the plasma. These results show that the developed method is a rapid method for on-line solid-phase extraction and determination of dioscin from plasma, exhibiting good selectivity with hydrogen bond interaction and hydrophobic interaction, good clean-up ability, cost-saving, and time-saving. Graphical abstract.

Fabrication of a cycloalkyl-monolith for on-line solid-phase extraction and determination of four polyphyllins in plasma.

A cycloalkyl-based polymer monolithic column for solid-phase extraction was prepared via radical polymerization using cyclohexyl methacrylate as the monomer. The preparative conditions such as crosslinker/monomer ratio and the amount of the porogens were optimized and the resulting monoliths were characterized by scanning electron microscopy and nitrogen adsorption-desorption method. On-line solid-phase extraction-high-performance liquid chromatography was performed to quantitatively analyse polyphyllin I, II, VI and VII contained in herbal medicine of paridis rhizome in mouse plasma using the homemade optimized monolithic SPE column combined with a C18 column, in which water was used to remove the plasma matrix while the polyphyllins in the mouse plasma were eluted by acetonitrile-water (42:58, V/V). Results obtained from the method validation show that the present method is feasible for the quantitative analysis of the four polyphyllins in plasma. The developed method was further applied for the real mouse plasma sample. These results show that the homemade cycloalkyl-based polymer monolithic SPE column has good ability for clean-up of the interfering bio-matrix and simultaneously extracting the four polyphyllins from mouse plasma. Furthermore, the present method is a promising method for quantitative determination of saponins compounds from complex bio-samples with the advantages of simple and efficient.

Simple quantitative analytical methods for the determination of alkaloids from medicinal and edible plant foods using a homemade chromatographic monolithic column.

A polymer-based chromatographic monolithic column was prepared via in-situ radical polymerization using tetrahydrofurfuryl methacrylate as the monomer. The homemade column was used for the separation and quantitative analysis of alkaloids, including piperine from Piper longum (fruit of Piper longum Linn.) and pepper (fruit of Piper nigrum L.), hydroxy-α-sanshool, and hydroxy-γ-sanshool from zanthoxylum (fruit of Zanthoxylum bungeanum Maxim), as well as caffeine from Wuyi rock tea. The chromatographic fractions were identified by mass spectrometry. Single factor test and orthogonal test were both carried out to optimize the extraction conditions. The method validation indicated that the accuracy represented by spiked recovery ranged in 98.89%-102.06%, the correlation coefficients in 0.99986-0.99999. These results show that the prepared monolithic column can be successfully used to quantitatively analyse alkaloids from the real medicinal and edible plant foods with reversed-phase mechanism, which can avoid the long analytical time using traditional packed C18 column. The present method is a simple, and inexpensive method for quantitatively analysing alkaloids from medicinal and edible plant foods, exhibiting good specificity and durability.

Co-digestion of oat straw and cow manure during anaerobic digestion: Stimulative and inhibitory effects on fermentation.

Impacts of adding different amounts of cow manure (CM) on the anaerobic digestion (AD) of oat straw (OS) with total solids content (TS) values of 4%, 6%, 8% and 10% was assessed over 50 days using batch experiments. A modified Gompertz model was introduced to predict the methane yield and determine the kinetic parameters. The optimum addition was a 1:2 ratio of CM to the OS added, which resulted in a suitable C/N ratio of 27 and a higher degradation rate of lignocellulose. The best cumulative methane yield of 841.77 mL/g volatile solids added (VSadded) was 26.64% greater than that of digesting OS alone. In addition, the amount of CM added produced larger effects than that of changes in the TS. However, higher CM concentrations were found to be inhibitory. Clustering analysis could provide significant guidance for demonstrating project process and combining farming and animal husbandry.

Methane production and characteristics of the microbial community in the co-digestion of spent mushroom substrate with dairy manure.

Spent mushroom substrate (SMS) is a potential biomass material generated during mushroom cultivation. In this study, the methane yield and microbial community resulting from co-digestion of SMS and dairy manure (DM) at different mixing ratios (0:4, 1:1, 3:1, and 1:3), were evaluated. Co-digestion analysis showed that the methane yield from the mixtures was 6%-61% higher than the yield from SMS or DM alone, indicating a synergistic effect of co-digestion of SMS with DM. For the SMS of F.velutipes (SFv) and P.erygii var. tuoliensis (SPt), co-digestion of DM/SMS at a ratio of 1:1 was optimal, but for the SMS of P. eryngi (SPe), co-digestion of DM/SMS at a ratio of 3:1 was ideal. The pH at all co-digestion ratios was in the range of 6.8-8.0, indicating that adding DM could increase the systemic buffering capacity. Methanosaetaceae was shown to be the predominant methanogens present during the co-digestion of DM/SMS.