Identification of tyrosinase inhibitors in defatted seeds of evening primrose (Oenothera biennis L.) by affinity-labeled molecular networking.

The defatted seeds of evening primrose (DE), a by-product of evening primrose oil extraction, are currently underutilized. This study aimed to valorize DE by examining its effects on melanogenesis and tyrosinase activity in zebrafish embryos and in vitro, and an innovative affinity-labeled molecular networking workflow was proposed for the rapid identification of tyrosinase inhibitors in DE. Our results indicated DE significantly reduced melanin content (53.3 % at 100 µg/mL) and tyrosinse activity (80.05 % for monophenolase and 70.40 % for diphenolase at 100 µg/mL). Furthermore, through the affinity-labeled molecular networking approach, 20 compounds were identified as potential tyrosinase inhibitors within DE, predominantly flavonoids and tannins characterized by catechin and galloyl substructures. Seven of these compounds were isolated and their inhibitory effects on tyrosinase were validated using functional assays. This study not only underscores the potential of DE as a rich source of natural tyrosinase inhibitors but also establishes the effectiveness of affinity-labeled molecular networking in pinpointing bioactive compounds in complex biological matrices.

Miniaturized centrifugation accelerated pipette-tip matrix solid-phase dispersion based on poly(deep eutectic solvents) surface imprinted graphene oxide composite adsorbent for rapid extraction of anti-adipogenesis markers from Solidago decurrens Lour.

Overweight and obesity are the causes of many diseases and have become global "epidemics". Research on natural active components with anti-adipogenesis effects in plants has aroused the interest of researchers. One of the most critical problems is establishing sample preparation and analytical techniques for quickly and selectively extracting and determining the active anti-adipogenesis components in complex plant matrices for developing new anti-adipogenic drugs. In this study, a new poly(deep eutectic solvents) surface imprinted graphene oxide composite (PDESs-MIP/GO) with high selectivity for phenolic acids was prepared using deep eutectic solvents as monomers and crosslinkers. A miniaturized centrifugation-accelerated pipette-tip matrix solid-phase dispersion method (CPT-MSPD) with PDESs-MIP/GO as adsorbent, coupled with high-performance liquid chromatography, was further developed for the rapid determination of anti-adipogenesis markers in Solidago decurrens Lour. (SDL). The established method was successfully used to determination anti-adipogenesis markers in SDL from different regions, with the advantages of accuracy (recoveries: 94.4 - 115.9 %, RSDs ≤ 9.8 %), speed (CPT-MSPD time: 11 min), selectivity (imprinting factor: ∼2.0), and economy (2 mg of adsorbent and 1 mL of solvents), which is in line with the current advanced principle of "3S+2A" in analytical chemistry.

Separation and purification of glycosides from medicinal plants based on strong polar separation medium with online closed-loop mode.

Natural glycosides widely distributed in medicinal plants are valuable sources of therapeutic agents, showing various pharmacological effects. The separation and purification of natural glycosides are meaningful for their pharmacological research, which face with great challenges due to the complex of medicinal plants samples. In this work, two kinds of functional monolithic separation mediums A and S were fabricated and fully applied in the online extraction, separation and purification of active glycoside components from medicinal plants with a simple-procedure closed-loop mode. Chrysophanol glucoside and physcion glucoside were detected and separated from Rhei Radix et Rhizoma using separation medium A as a solid-phase extraction adsorbent. Rhapontin was isolated and purified from Rheum hotaoense C. Y. Cheng et Kao using separation medium S as the stationary phase of high-performance liquid chromatography. Compared to the reported literatures, high yield of 5.68, 1.20 and 4.76 mg g-1 of these three products were obtained with high purity. These two online closed-loop mode methods were carried out using high-performance liquid chromatography system, in which the sample injection, isolation and purification procedures are all online mode, and reduced loss compared to offline extraction and purification procedures, thus achieving high recovery and high purity.

Impact of iron supplementation on gestational diabetes mellitus: A literature review.

Gestational diabetes mellitus (GDM) is a common complication of pregnancy, affecting 14% of pregnancies worldwide, and the prevention of pathological hyperglycaemia during pregnancy is meaningful for global public health. The role of iron supplementation in the progression of GDM has been of significant interest in recent years. Iron is a micronutrient that is vital during pregnancy; however, given the toxic properties of excess iron, it is probable that prophylactic iron supplementation will increase the risk of adverse pregnancy outcomes, including GDM. It is critical to clarify the effect of iron supplementation on the risk of GDM. Therefore, in this review, we comprehensively assess the role of iron in pregnancy. This review aimed to analyse the necessity of iron supplementation and maintenance of iron homeostasis during pregnancy, particularly reviewing the role and function of iron in beta cells and examining the mechanisms of excess iron contributing to the pathogenesis of GDM. Moreover, we aimed to discuss the association of haemoglobin and ferritin with GDM and identify priority areas for research.

[Analysis and evaluation of paddy-upland rotation of Gastrodia elata- Oryza sativa in Dabie Mountains].

Gastrodia elata, as the valuable Chinese medicinal material, has been used for more than 2 000 years in China. With the increasing market demand for G. elata, the traditional wild resources have been unable to transform into commodities. At present, local authorities give full play to the advantages of natural resources and vigorously cultivate G. elata to form the cultivation mode and technical system with local characteristics. Huanggang Comprehensive Experimental Station of National Technical System of Chinese Medicinal Materials Industry has optimized and summarized the paddy-upland rotation of G. elata-Oryza sativa in Dabie Mountains of Hubei province through field visits and guidance for four consecutive years. Based on the ecological adaptability and planting characteristics of G. elata and O. sativa, and the actual production experience of farmers, analyzed the principle of paddy-upland rotation from production environment selection and fungus treatment, and evaluated the paddy-upland rotation of G. elata-O. sativa from production status, ecological benefits, and economic benefits. The paddy-upland rotation of G. elata-O. sativa has achieved efficient cultivation of G. elata and produced considerable economic benefits. Through the summary, analysis, and evaluation of the paddy-upland rotation mode of G. elata-O. sativa in Dabie Mountains, the present study put forward the optimization strategy of cultivation technology for G. elata in low-altitude areas, i.e., to use artificial Armillaria sticks instead of traditional cut-log for substitute cultivation of G. elata, which can effectively alleviate the "bacteria-forest contradiction" arising from the cultivation of G. elata. It can also improve the ecological environment and production status of the Dabie Mountains and even the G. elata producing areas at the same altitude.

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.

In situ net fishing of α-glucosidase inhibitors from evening primrose (Oenothera biennis) defatted seeds by combination of LC-MS/MS, molecular networking, affinity-based ultrafiltration, and molecular docking.

Defatted seeds of evening primrose (DSEP), the by-product of evening primrose oil manufacture, exhibit potential α-glucosidase inhibitory activity; however, presently they are routinely discarded as waste. In this study, an in situ net fishing strategy was proposed for rapid recognition of α-glucosidase inhibitors from DSEP. Firstly, the DSEP extraction method was optimized employing a response surface methodology for the recovery of α-glucosidase inhibitors, just like "finding a good fishery before net fishing". Then, molecular networks of DSEP were generated by GNPS-based molecular networking after LC-MS/MS analysis, just like "casting tight nets in the fishery". Subsequently, affinity-based ultrafiltration was carried out for fishing the "hit" together with its structural analogues according to the molecular networks, just like "hauling the specific net fishing". Finally, molecular docking analysis was performed to rapidly verify α-glucosidase inhibitory activities of the potential bioactive components and predict their inhibition mechanisms. In the results, DSEP displayed significant inhibitory effects against yeast and rat intestinal α-glucosidase, and the results of an oral starch tolerance test suggested that DSEP showed postprandial blood-glucose-lowering activity. Moreover, 1-galloyl-glucose, gallic acid, methyl gallate, 1,6-digalloyl-ß-D-glucose, and 1,3,6-trigalloylglucose were rapidly identified as potential α-glucosidase inhibitors present in DSEP.

Preparation of poly(ionic liquid@MOF) composite monolithic column and its application in the online enrichment and purification of tectochrysin in medicinal plants.

Herein, a poly(ionic liquid@MOF) composite monolithic column was prepared via in situ radical polymerization using ionic liquid (1-allyl-3-methylimidazolium hexafluorophosphate) and MOF (derivatized UIO66-2COOH) as copolymer monomers. The composite monolithic column was characterized via scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherms and mercury intrusion porosimetry. Subsequently, the composite monolithic column combined with high performance liquid chromatography (HPLC) was used as a solid-phase extraction (SPE) absorbent for online purification and enrichment of tectochrysin in medicinal plants. The results indicated that the addition of the ionic liquid and MOF not only increased the surface area but also increased the adsorption capacity of the monolith for tectochrysin. The method showed good linearity in the concentration range of 0.01-500 µg mL-1. The calibration equation was y = 2154.6x - 8.3785 and the limit of detection (LOD, S/N = 3) and the limit of quantification (LOQ, S/N = 10) were 3.33 ng mL-1 and 10 ng mL-1, respectively. The relative standard deviation (RSD) of the intra-day and inter-day precision was less than 2.62%, the RSD of inter-column was less than 3.16%, and the recoveries ranged from 100.58% to 105.00%. Thus, results showed that this method is simple, accurate and convenient for the online enrichment and purification of tectochrysin from 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.

[Analysis and evaluation of mineral elements of Chrysanthemum morifolium for medicinal and tea use of different germplasm resources].

In this study, 23 germplasm resources of Chrysanthemum morifolium used in medicine and tea were collected from Dabie Mountains and its surrounding producing areas, and the contents of 13 mineral elements were determined and compared. The thermal maps of correlation analysis, principal component analysis and cluster analysis were used for comprehensive evaluation. The results showed that the average content of each element in Ch. morifolium of different germplasm resources was: K>N>P>Mg>Ca>Fe>Mn>Zn>Cu>Ni>Cr>Pb>Cd, and the leaves were: K>N>Ca>Mg>P>Fe>Mn>Zn>Cr>Cu>Ni>Pb>Cd. There are rich contents of N, P, K, Ca, Mg and Fe in Ch. morifolium flowers and their leaves, among them, K element has the largest change range, while N, Ca, Fe, Mg and Zn elements have a larger change range. The absorption and accumulation of each element in the leaves of different germplasm resources varied greatly. The correlation analysis shows that there is a strong positive correlation between Ca element, Mg, Mn and Cd element.Principal component analysis in Ch. morifolium flowers characteristic elements for Mn, Cr, Cu, P, K, can be used as a Ch. morifolium resources to identify the characteristics of the elements, choose top five principal component(F1-F5) comprehensive evalua-tion of medicinal Ch. morifolium, scored in the top five varieties for Hangiu-Fuhuangju, Hangju-Xiaoyangju, Hangju-Sheyangju, Hangju-Dayanghua, Hangju-Subeiju,indicates that in terms of mineral elements, the five medicinal Ch. morifolium resources quality is better. The PCA score chart can divide 23 Ch. morifolium resources into 4 groups, and the cluster analysis heat map divides 23 Ch. morifolium resources into 5 groups. All the Ch. morifolium resources of the same type can be well clustered together, indicating that the difference in mineral element content of Ch. morifolium germplasm resources is closely related to genetic factors.

On-line enrichment and determination of aristolochic acid in medicinal plants using a MOF-based composite monolith as adsorbent.

In this study, modified UiO-66-NH2 and N-methylolacrylamide (NMA) were used as common monomers to prepare a metal organic framework (MOF)-based composite monolith through in-situ polymerization, which was used as a new adsorbent to purify and enrich aristolochic acid-I (AA-I) in medicinal plants. The MOF-based composite monolithic column was characterized by nitrogen adsorption-desorption isotherm, mercury intrusion porosimetry and scanning electron microscopy (SEM). The adsorption ability of MOF-based composite monolith for AA-I was compared with that of the polymer monolith without MOF added. The results proved that the addition of UiO-66-NH2 can increase both the specific surface area and the permeability of the monolith. Moreover, the adsorption amount of AA-I on the monolith improved. This proposed on-line solid phase extraction (SPE) method showed good linear relationship in the range 0.044 ~ 400 µg/mL with r = 0.9994; the limit of detection (LOD) was 13.08 ng/mL and the limit of quantification (LOQ) was 44.00 ng/mL; the intra-day and inter-day accuracies were less than 0.97%; the inter-column accuracies was less than 6.11%; the recovery was in the range of 91.11%~106.48%. The method was found to be easy, accurate and convenient for on-line enrichment and purification of AA-I in medicinal plants.

Ionic liquid-organic-functionalized ordered mesoporous silica-integrated dispersive solid-phase extraction for determination of plant growth regulators in fresh Panax ginseng.

The massive accumulation of plant growth regulators (PGRs) in Panax ginseng causes serious harm to human health. A new analytical method for the simultaneous determination of multiple PGRs in 19 types of fresh Panax ginseng is developed by a new designed wool cluster-inspired ionic liquid-functionalized ordered mesoporous silica-integrated dispersive solid-phase extraction coupled to high performance liquid chromatography (IL-WFOMS-I-DSPE-HPLC). The proposed method combines the advantages of the multiple adsorption mechanisms, high mass transfer rate and large adsorption capacity of the synthesized IL-WFOMS adsorbent with the safe, convenient operation of the new designed I-DSPE method. Under optimized conditions, the recoveries at three spike levels were in a range of 77.6-98.3% for 3-indole acetic acid (IAA), 3-indole propionic acid (IPA), 3-indole butyric acid (IBA), and 1-naphthaleneacetic acid (NAA) with the relative standard deviations (RSD) ≤8.6%, n = 3. This method exhibits the advantages of safety, convenience, reliability, and has great potential for simultaneous determination of multiple trace PGRs in complex sample matrices.

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.

A metal organic framework polymer monolithic column as a novel adsorbent for on-line solid phase extraction and determination of ursolic acid in Chinese herbal medicine.

A metal organic framework (MOF)-polymer monolithic column was prepared by redox initiation using modified MOF and N-methylolacrylamide (NMA) as co-monomers. The obtained monolithic column was characterized by scanning electron microscopy (SEM) and nitrogen adsorption-desorption isotherm measurement. It was used as a solid phase extraction (SPE) absorbent for the online enrichment of ursolic acid (UA) by high performance liquid chromatography. The adsorption amount of UA on the monolith was compared with that of silica gel-C18 adsorbent and the monolith without MOF material. The MOF-polymer monolithic column showed high selectivity and good permeability. Under the optimum conditions for extraction and determination, the calibration equation was y = 79.854× + 0.1939; the linear range was 0.001-0.9 mg/mL; the linear regression coefficient was 0.9993; the limit of detection (LOD) and the limit of quantification (LOQ) were 0.17 µg/mL and 0.57 µg/mL, respectively; the inter-day and intra-day accuracies were <6.44%; the recovery was in the range of 86.52-105.26%. The MOF-polymer monolithic column was successfully used as SPE column for enrichment and determination of UA in Chinese herbal medicine.

Screening and Isolating Major Aldose Reductase Inhibitors from the Seeds of Evening Primrose (Oenothera biennis).

Aldose reductase (AR) is a drug target for therapies to treat complications caused by diabetes mellitus, and the development of effective AR inhibitors (ARIs) of natural origin is considered to be an attractive option for reducing these complications. In this research, the rat lens AR (RLAR) inhibitory activity of evening primrose (Oenothera biennis) seeds was investigated for the first time. In our results, the 50% (v/v) methanol extract of evening primrose seeds exhibits excellent RLAR inhibitory activity (IC50 value of 7.53 µg/mL). Moreover, after enrichment of its bioactive components, the ARIs are more likely to be present in the ethyl acetate fraction of 50% (v/v) methanol extract (EME) of evening primrose seeds, which exhibits superior RLAR inhibitory activity (IC50 value of 3.08 µg/mL). Finally, gallic acid (1), procyanidin B3 (2), catechin (3), and methyl gallate (4) were identified as the major ARIs from the EME by affinity-based ultrafiltration-high-performance liquid chromatography and were isolated by high speed countercurrent chromatography, with gallic acid (11.46 µmol/L) and catechin (14.78 µmol/L) being the more potent inhibitors of the four ARIs identified. The results demonstrated that evening primrose seeds may be a potent ingredient of ARIs.

A novel poly (NMA-co-DEA-co-EDMA) monolithic column as a sorbent for online solid-phase extraction and its application in the determination of ß-sitosterol in plant oil samples.

A novel monolithic column was prepared by in-situ free radical polymerization using N-methylolacrylamide (NMA) and N,N-diethylacrylamide (DEA) as co-monomers. The monolith was characterized by scanning electron microscopy (SEM) and its nitrogen adsorption-desorption isotherm, and it was used as a solid phase extraction (SPE) absorbent for the online enrichment of ß-sitosterol by high performance liquid chromatography. The optimized method had good linearity, and the linear regression coefficient was 0.998. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.006 mg/mL and 0.02 mg/mL, respectively. The interday and intraday accuracies were less than 7.28%. The spiked recoveries of ß-sitosterol in the six plant oil were 90.96-103.56%. The maximum amount of ß-sitosterol adsorbed on the monolithic column was 12.69 mg/g, and the enrichment factor of ß-sitosterol was 78. The results showed that the monolith could be used as an online SPE absorbent for the determination of ß-sitosterol in plant oil samples.

[Quality assessment of soil fertility of planting Chrysanthemum morifolium areas of Macheng city based on minimum data set].

A minimal data set( MDS) for soil fertility evaluation of Chrysanthemum plantation areas of Macheng city was established by principal component analysis( PCA) combined with Norm values of soil fertility indices and correlation coefficients among indices. A radar map was used to visually reflect the fertility level of individual indicators. Then,the comprehensive index model was used to calculate the soil fertility quality index( SFQI),and the values of SFQI was used to cluster,and the results showed that MDS was composed of five indicators: organic matter( OM),total phosphate( TP),available phosphorus( Av P),available magnesium( Av Mg) and available ferrum( Av Fe). Radar maps showed that the fertility of available phosphorus( Av P) and available copper( Av Cu) was mostly different in the two town,and the fertility of available ferrum( Av Fe) is smallest different. Except for the effective manganese( Av Mn) fertility level of Huangtugang town was higher than that of Futianhe town,the rest were lower than that of Futianhe town. Through analysis,the sensitivity of SFQI value calculated by taking the contribution rate of MDS index in the principal component of the whole data set( TDS) as the weight was the highest,MDS could better replace TDS. The value of SFQI-MDS ranged from 0. 353 to 0. 833,with an average value of 0. 604 and a coefficient of variation of 22%. The results of SFQI-MDS clustering showed that soil fertility could be divided into four categories: grade Ⅰ( 0. 727-0. 833) was superior,accounting for 25. 0%,grade Ⅱ( 0. 615-0. 681)was good,accounting for 29. 2%,mainly distributed in Futianhe Town,grade Ⅲ( 0. 494-0. 589) was medium,accounting for29. 1%,and grade Ⅳ( 0. 353-0. 419) was poor,accounting for 16. 7%,mainly distributed in Huangtugang town. Soil fertility of Futianhe town was better than that of Huangtugang town. It is suggested that boron fertilizer and potassium fertilizer should be supplemented to Chrysanthemum morifolium in production practice,and the amount of phosphate fertilizer,magnesium fertilizer and nitrogen fertilizer should be increased appropriately. At the same time,the amount of organic fertilizer should be increased to enhance soil fertility and improve soil physical and chemical properties.

Graphene oxide-based composite monolith as new sorbent for the on-line solid phase extraction and high performance liquid chromatography determination of ß-sitosterol in food samples.

A composite monolithic column was prepared by redox initiation method for the on-line purification and enrichment of ß-sitosterol, in which graphene oxide (GO) was embedded. The obtained monolithic column was characterized by scanning electron microscopy (SEM) and nitrogen adsorption-desorption isotherm measurement, which indicated that the monolith possessed characteristics of porous structure and high permeability. Under the optimum conditions for extraction and determination, the calibration equation was y = 47.92 × -0.1391; the linear range was 0.008-1.0 mg mL-1; the linear regression coefficient was 0.998; the limit of detection (LOD) is 2.4 µg mL-1; the limit of quantitation (LOQ) was 8 µg mL-1; precisions for intra-day and inter-day assays presented as relative standard deviations were less than 4.3% and 6.8%, respectively. Under the selective conditions, the enrichment factor of the method was 119. The recovery was in the range of 80.40-98.00%. Moreover, the adsorption amount of the monolith was compared with silica gel-C18 adsorbent and the monolith without graphene oxide being embedded. The polymerization monolithic column showed high selectivity and good permeability, and it was successfully used as on-line solid-phase extraction (SPE) column for determination of ß-sitosterol in edible oil.

Vortex-assisted magnetic dispersive solid-phase microextraction for rapid screening and recognition of dicofol residues in tea products.

A simple and rapid vortex-assisted magnetic dispersive solid-phase microextraction (VAMDSME) method coupled with gas chromatography-electronic capture detection was developed for rapid screening and selective recognition of dicofol in tea products. The magnetic molecularly imprinted microspheres (mag-MIMs) synthesised by aqueous suspension polymerisation using dichlorodiphenyltrichloroethane (DDT) as a dummy template showed high selectivity and affinity to dicofol in aqueous solution and were successfully applied as special adsorbents of VAMDSME for rapid isolation of dicofol from complex tea matrix. Good linearity was obtained in a range of 0.2-160 ng g(-1) and the limit of detection based on a signal to noise ratio of 3 was 0.05 ng g(-1). The recoveries at three spiked levels ranged from 83.6% to 94.5% with the related standard deviations (RSD) ⩽ 5.0%. The VAMDSME-GC protocol, which took advantages of the selective adsorption of molecularly imprinted microspheres and rapid magnetic phase separation, as well as the short equilibrium time by vortex-assisted, could avoid the time-consuming procedures related to other traditional extraction methods.