Nanozymes,a class of nanomaterials with intrinsic enzyme-mimetic catalytic activities,have shown great potential in analytical chemistry,particularly in the field of sample pretreatment,owing to their unique physicochemical properties and catalytic functions.Although relevant research has been increasing continuously,the findings are largely dispersed,and no systematic review dedicated to the application of nanozymes in sample pretreatment has yet emerged.To facilitate the in-depth development and continuous investigation of this field,it is imperative to systematically consolidate the current application status,existing challenges,and future directions of nanozymes in sample pretreatment.The concept,classification,and development of nanozymes were systematically summarized,with an emphasis on their applications in sample pretreatment,including the enrichment,separation,transformation,and matrix interference elimination of target analytes based on their enzyme-like activities.The aim is to offer new strategies and insights for the accurate analysis of trace components in complex samples.
Conventional sample pretreatment usually requires large amounts of toxic organic reagents,which may cause environmental pollution and even harm human health.Therefore,it is urgent to develop green alternatives to replace traditional hazardous solvents.Deep eutectic solvents(DESs)are eutectic mixtures composed of hydrogen bond acceptors(HBAs)and hydrogen bond donors(HBDs)in a certain stoichiometric ratio,which possess excellent thermal stability,simple and rapid preparation process,and favorable biodegradability.Magnetic deep eutectic solvents(MDESs)are a new type of green solvent developed by introducing magnetic components such as paramagnetic anions or magnetic nanoparticles into conventional DESs.MDESs not only inherit the excellent physicochemical properties of DESs but also exhibit sensitive response to external magnetic fields.The composition and preparation methods of MDESs are reviewed in this paper,their research progress and applications in extraction and separation are summarized,and the prospects for future development trends of MDESs are put forward.
Efficient chiral separation technologies are of great significance in fields such as drug development,agricultural chemistry,and food science.Chromatography is currently the mainstream approach for chiral separation,and its technological advancement heavily relies on the development of high-performance chiral stationary phases(CSPs).Traditional CSPs suffer from limitations including poorly understood separation mechanisms and relatively blind structural design.Chiral covalent organic frameworks(CCOFs)have emerged as a promising platform for the development of novel CSPs,owing to their high specific surface area,designable pore architectures,good stability,and well-defined structures that facilitate mechanistic investigations.The synthetic strategies for CCOFs,categorizing them into four types:direct synthesis,post-synthetic modification,chiral induction,and chiral memory were summarized.Meanwhile,recent advances in the application of CCOFs for chiral separation using high-performance liquid chromatography(HPLC),gas chromatography(GC),and capillary electrochromatography(CEC)are presented.This review aims to provide a systematic overview and reference for the development of novel CCOF-based CSPs,and to offer perspectives on future research directions.
Adzuki beans are rich in active substances called adzuki saponins,which have various physiological functions such as prevention of hyperlipidemia,antioxidation,anticancer,and antiviral effects.A high-speed counter-current chromatography was established,and high-purity active component azukisaponin V was successfully isolated from crude adzuki bean extracts.By screening different types of chromatographic columns and optimizing the elution mode of the mobile phase,the analytical conditions were determined as follows:a C18 reversed-phase chromatographic column was adopted,and an acetonitrile-water system was used as the mobile phase for gradient elution.The gradient elution procedure was set as follows:acetonitrile maintained at 10%for 0～5 min,linearly increased from 10%to 65%during 5～15 min,then decreased back to 10%from 15～20 min.The detection wavelength was set at 205 nm,the flow rate was 1.0 mL/min,the injection volume was 10 μL,and the column temperature was 30℃.The partition coefficients of adzuki saponins in different solvent systems were calculated using the established high-performance liquid chromatography,and four solvent systems were selected for the separation of azukisaponin V using high-speed counter-current chromatography.Combining with the retention rate of the stationary phase in the counter-current chromatography system and the separation effect of adzuki saponins,the optimal solvent system was identified as n-hexane:n-butanol:water(volume ratio 3:4:7).Under this system,5.8 mg of azukisaponin V with a purity of 93.0%was successfully isolated and purified from 500 mg of crude adzuki bean extract in a single run.This method not only provides technical support for the efficient separation of azukisaponin V but also offers a technical approach for the separation of other natural products.
High-speed counter-current chromatography(HSCCC)is a liquid-liquid partition chromatographic technique that eliminates the need for a solid stationary phase.Owing to its distinct advantages including no irreversible adsorption,high sample loading capacity,and excellent recovery rates,HSCCC has been extensively applied in the separation and purification of natural products,pharmaceuticals,and biomacromolecules.However,the efficient separation of complex samples remains severely constrained by three persistent bottlenecks:solvent system selection relies heavily on empirical trial-and-error,conventional solvent systems suffer from a narrow polarity window,excessive consumption of organic reagents,and insufficient separation selectivity,and the limited theoretical plate number,low throughput of existing separation modes,and difficulties in continuous scale-up collectively impede separation efficiency.To address these challenges,the recent advances in HSCCC across three core domains:solvent system screening and design,separation mode innovation,and technological hyphenation are systematically reviewed in this paper.First,multi-scale solvent screening strategies ranging from the semi-empirical GUESS and HPLC-assisted mathematical screening(HSMR)approaches to quantum-chemical predictions via Conductor-like Screening Model for Real Solvents(COSMO-RS)are delineated.Second,the characteristics,applicability,and technical limitations of various solvent systems,including three-phase systems and green solvent systems,are critically evaluated.Third,the continuous scale-up performance and mathematical modeling advances of diverse elution modes,particularly dual-mode elution and elution-extrusion chromatography,are reviewed,and the core advantages and research advances of multi-dimensional hyphenation techniques are elaborated.Finally,future perspectives on HSCCC development are discussed from the perspectives of solvent system greening and intelligentization,as well as continuous and modular evolution of separation modes.This review aims to provide theoretical references and technical support for the efficient separation and purification of complex samples such as natural products and pharmaceuticals.
Metal-organic frameworks(MOFs)are a class of porous materials self-assembled from metal ions or metal clusters and organic ligands.Owing to their high surface areas,tunable pore structures,and facile functionalization,MOFs have shown great potential in adsorption,catalysis,and separation.In recent years,MOFs have attracted extensive attention as novel chromatographic stationary phases.The recent advances of UiO,ZIF,MIL,PCN,HKUST-1,two-dimensional Zr-BTB MOFs,and their composites in gas chromatography(GC)and high-performance liquid chromatography(HPLC)are systematically summarized,with emphasis on the structure-property relationships between MOF architectures and chromatographic separation performance.In terms of stationary-phase design,UiO,MIL,and PCN series MOFs possess hierarchical pore structures that can simultaneously facilitate molecular recognition and mass transfer.ZIF materials exhibit characteristic narrow-window and large-cavity structures,leading to pronounced molecular sieving effects.MIL series MOFs and HKUST-1 contain abundant open metal sites,which are beneficial for the separation of polar compounds through specific interactions.For two-dimensional Zr-BTB materials,the pore system originates from both intrinsic MOF pores and interlayer stacking channels.By regulating the interlayer stacking structures,the diffusion behavior of analytes can be optimized,thereby improving separation selectivity.In addition,the preparation strategies and chromatographic performances of various MOF core-shell composite stationary phases and MOF-polymer composite stationary phases are systematically discussed.Representative applications of MOF-based stationary phases in the separation of alkane isomers,substituted benzenes,polycyclic aromatic hydrocarbons,polar organic compounds,and complex environmental pollutants are also reviewed.Finally,the current challenges and future prospects of MOFs as chromatographic stationary phases are discussed.
A rapid one-step non-covalent coating method based on electrostatic interaction was developed for the fast preparation of layered double hydroxide(LDH)coated open tubular capillary,and it was applied to open tubular capillary electrochromatography(OT-CEC).The morphology and elemental composition of the coated capillary were characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy.Using neutral,acidic,and basic small organic molecules as analytes,the separation performance of the coated capillary was systematically evaluated,and the separation mechanism was investigated.The results showed that the LDH coated capillary exhibited excellent repeatability and stability.The intra-day,inter-day,and column-to-column relative standard deviations of the migration times of the analytes were 0.8%～3.8%,0.7%～4.7%,and 2.0%～6.3%,respectively.Moreover,no significant decrease in separation efficiency was observed after 200 consecutive runs.
High-performance liquid chromatography(HPLC)is crucial in separation science,with the stationary phase playing a key role in separation technology.Conventional silica-based materials have restricted applicability and poor acid/base resistance.Therefore,significant research is dedicated to developing novel stationary phase materials that offer stability and excellent separation performance to address various separation requirements.Covalent organic frameworks(COFs)are crystalline porous organic polymers constructed from light elements through covalent bonds.They possess characteristics such as designability,high specific surface area,tunable pore size,ease of functionalization,and strong stability.These attributes position them as a promising stationary phase for chromatographic separation.COFs can efficiently separate complex samples,including polar compounds and positional isomers,by utilizing various intermolecular interactions such as hydrophobic,π-π,and hydrogen bonding interactions.Chiral COFs(CCOFs)integrate chiral recognition sites to combine the structural stability of COFs with chiral selectors,allowing for the separation of chiral drugs and stereoisomers.The recent research progress of COFs as stationary phases in liquid chromatography and chiral separation over the past five years is reviewed in this paper,and their future development is also discussed.
Graphene/polystyrene composite porous microspheres(PSDC)were prepared by suspension polymerization.The structure of the material was characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and nitrogen adsorption-desorption analysis,and their performance was evaluated in solid-phase extraction(SPE)of quinolone antibiotics and chromatographic separation of natural products from traditional Chinese medicines.The results showed that graphene was mainly incorporated into the polystyrene microspheres through physical compounding,without disrupting the regular spherical morphology or the polystyrene matrix.Compared with porous polystyrene microspheres(PSD),PSDC exhibited increased surface roughness,more local pore defects,and wrinkled and folded graphene sheets.The specific surface area,pore volume,and average pore diameter of PSD were 729.696 m2/g,1.714 cm3/g,and 9.396 nm,respectively;while those of PSDC were 627.738 m2/g,1.514 cm3/g,and 9.737 nm,respectively.The introduction of graphene induced reconstruction of the pore structure of the material.As a result,PSDC exhibited a lower specific surface area and total pore volume than PSD,but a slightly larger average pore diameter,and formed a hierarchical pore structure more favorable for interfacial contact and mass transfer diffusion.In SPE experiments,with recoveries above 80%for 12 of the 19 quinolone analytes,PSDC showed higher recoveries for quinolone antibiotics than PSD,indicating that graphene enhanced the enrichment capability of the material for target analytes under relatively high organic-phase conditions.In the chromatographic separation of Uncaria macrophylla and Strychnos nux-vomica L.samples,PSDC exhibited improved separation performance and altered retention selectivity for some alkaloid components.The enhanced performance of PSDC was mainly attributed to the rough interface,reconstructed pore structure,and strengthened π-π and hydrophobic interactions introduced by graphene sheets.This composite microsphere material shows promising potential for complex sample pretreatment and natural product separation.
Solid-phase extraction,as an efficient sample pre-treatment method,the optimization and design of its extraction device and extraction stationary phase are the core steps to achieve efficient extraction.With the increasing demands of analytical testing,various emerging extraction technologies have continuously emerged based on solid-phase extraction.Meanwhile,among various extraction stationary phases,metal-organic framework(MOFs)composite nanofiber membranes,due to their high specific surface area and adjustable pores of MOFs,three-dimensional connected network of nanofiber membranes,and easy separation characteristics,have shown unique advantages in sample pretreatment.The research progress of MOF composite nanofiber membranes over the past decade and their application in pipette-tip solid-phase extraction is reviewed.The future development directions and research focuses are also prospected.
The toxicity and biological effects of heavy metal elements are determined by their chemical forms,so elemental species analysis constitutes a crucial part of environmental and health monitoring.Organic-inorganic hybrid systems synergistically integrate the respective advantages of organic and inorganic components.Featuring tunable structures and functions,high stability,and good selectivity,they have become ideal adsorbents for sample pretreatment in element speciation analysis.The recent advances in the application of organic-inorganic hybrid materials in solid-phase extraction and their derived techniques(dispersive solid-phase extraction,magnetic solid-phase extraction,and solid-phase microextraction)for analyzing elemental species are reviewed in this paper.The future development directions of organic-inorganic hybrid materials in the field of element speciation are outlined.
Zein has promising application potential in separation and analysis,owing to its abundance of hydrophobic amino acids such as proline and glutamic acid,and active functional groups including hydroxyl,amino,and sulfhydryl groups.The research progress on the preparation of multi-morphological Zein-based functional materials via physical and chemical modifications and their applications in separation and analysis are summarized.The regulatory effects of physical and chemical modifications on the structure and properties of Zein are systematically elaborated,and the controllable preparation methods for various morphologies,such as nanoparticles,fibers,and films are introduced.On this basis,the mechanisms of different Zein-based functional materials for the adsorption and removal of target analytes,separation of components from complex matrices,and analytical detection are further discussed.Finally,the main challenges currently faced by Zein in this field are summarized.Future research directions are outlined,to provide a reference for further studies on Zein-based functional materials in separation and analysis.
With the continuous advancement of modern science,the efficient,highly selective,and sensitive separation and analysis of complex matrix systems has become a core challenge demanding breakthroughs in the field of separation science.As a pivotal technique in this domain,chromatography plays an irreplaceable role across numerous fields due to its superior separation efficiency.The chromatographic stationary phase,serving as the core functional unit of a chromatographic column,represents the primary avenue for enhancing chromatographic performance.Traditional stationary phases,such as those based on silica gel or polymers,are often hampered by inherent limitations,including complex preparation processes,a narrow applicable pH range,insufficient mechanical stability,and significant swelling effects.These shortcomings render them inadequate for the separation demands of complex systems,making the development of novel,high-performance stationary phases a major research focus in separation science.Metal-organic frameworks(MOFs)and covalent organic frameworks(COFs),as two representative classes of porous framework materials,offer a novel approach to overcoming the technical bottlenecks of traditional stationary phases.They possess outstanding advantages,such as precisely designable pore structures,high specific surface areas,and excellent chemical and thermal stability.The research progress on MOF-and COF-based porous framework materials as chromatographic stationary phases is systematically reviewed over the past five years.It details the primary preparation methods for these materials,summarizes their latest application achievements in key areas including environmental monitoring,pharmaceutical purification,and food safety testing.Furthermore,in light of the current challenges and bottlenecks,the article offers a perspective on their future development directions,potential technological breakthroughs,and application prospects.
Pillararenes have a highly symmetrical and rigid pillar-shaped structure with a π-electron-rich cavity,which can selectively recognize guest molecules matching their cavity.In this work,pillar[5]arene was derivatized and modified with polyethylene glycol to prepare an amphiphilic pillar[5]arene polymer(P5A-C10-mPEG),and its molecular structure was confirmed by infrared(IR)and 1H NMR spectra.The synthesized P5A-C10-mPEG was coated onto the inner wall of a capillary gas chromatographic column by a static method(the inner diameter of the column was 250 μm,and the column length was 5 m).The experimental results showed that the P5A-C10-mPEG column was of medium polarity and had a high column efficiency(3 597 plates/m).The P5A-C10-mPEG column achieved baseline separation of nine aromatic positional isomers,including alkylbenzenes,halobenzenes,benzaldehydes,phenols and anilines.Notably,the P5A-C10-mPEG column showed distinctly superior separation performance for toluidine isomers compared with commercial imported columns(HP-5,HP-35,DB-17),presenting promising application prospects.Moreover,it realized baseline separation of six types of cis/trans isomers.This work provides a new strategy for the development of novel highly selective chromatographic stationary phases.
制备了一种三维多孔镍钼硫化物纳米花修饰碳纳米管(CNT)的复合材料(NiMoS@CNT).通过扫描电子显微镜和X射线衍射表征所合成材料的形貌和结构.利用循环伏安法和计时电流法对所制备材料的电化学催化性能进行研究.基于NiMoS@CNT对过氧化氢(H2O2)优异的电催化性能,构建了一种检测脑利钠肽的夹心型电化学传感器.在最优条件下,电流响应强度和脑利钠肽质量浓度的对数在 0.20～20 ng/mL范围内呈线性关系.结果表明免疫传感器具有高的灵敏度、选择性和稳定性,可用于实际样品的检测.
紫外光化学蒸气发生(UV-PVG)是一种绿色的样品引入技术,作为接口已被成功应用于结合光谱与质谱检测领域,实现对目标元素的检测.方法简单高效,试剂用量少,可用于现场式检测.同时,UV-PVG也拓宽了化学蒸汽发生元素范围,不仅可应用于As、Hg、Sb、Pb等可氢化物发生元素,还可以应用于过渡金属元素包括Cd、Fe、Co、Ni、Os以及非金属元素中的I、Br.从机理推测、应用范围、优缺点和发展趋势方面对UV-PVG进行了阐述.
建立特色蒙药十八味欧曲丸中游离汞的含量测定方法,为十八味欧曲丸质量标准中游离汞的限量检测提供技术支撑.利用游离汞易溶于硝酸而炮制品不溶于硝酸的性质,以硝酸为溶剂提取,通过原子荧光光谱法对十八味欧曲丸中游离汞进行含量测定.汞在0.1～2.0 μg/L范围内呈现良好的线性关系,回归方程为Y=1467.1976X+3.3915,相关系数R2 为 0.99959,平均回收率为 95.0%,相对标准偏差(RSD)为 4.436%(n=6),测得十八味欧曲丸中游离汞的平均质量分数为 0.671 mg/g.方法操作简单、结果准确可靠,可用作特色蒙药十八味欧曲丸质量标准提升研究中游离汞的限量测定.
