最新刊期
卷 40 ， 期 5 ， 2021
- 摘要：The contamination of foodborne pathogenic bacteria is an important factor leading to food safety problems.The detection of foodborne pathogenic bacteria has become a research hotspot in recent years.Rapid detection methods based on immunoassay,molecular biology,biosensors,metabolomics,and nucleic acid aptamers have been developing rapidly,and have become the main detection methods for foodborne pathogenic bacteria.Combined with the research progress of various rapid detection methods in recent years,the rapid detection methods for foodborne pathogens based on the above-mentioned technologies are introduced in this article.Meanwhile,the existing problems and future development directions are also discussed.It is anticipated to provide a reference for the prevention and control of foodborne pathogens and the protection of consumers' physical and mental health.关键词：foodborne pathogenic bacteria;rapid detection;immunoassay;molecular biology
- 5
- |
- 7
- |
- 4
发布时间：2023-04-18 - 摘要：African swine fever is a devastating and highly contagious disease affecting pigs of all ages and breeds,which is characterized by high fever,cyanosis of the skin and severe hemorrhages in lymph nodes,with a mortality up to 100%.The World Organization for Animal Health(International Epizootic Office,OIE) has classified it into a kind of notifiable animal disease,while China has listed it as a predominantly exotic animal disease.since the African swine fever was reported to be endemic in sub-Saharan African countries in the 1920s,it has gradually become prevalent in the Europe,South America and Caucasus region of Russia,and broke out all over the world.It has caused a huge threat to swine industry and resulted in large economic losses.African swine fever virus,the causative agent of the African swine fever,is a double-stranded DNA arbovirus which is the only member of the family Asfarviridae,genus Asfivirus with icosahedral morphology and an average diameter of 200 nm.At present,there is no specific medicine or vaccine available to prevent African swine fever virus,and the main control strategy mainly relies on implement of sanitary measures and slaughtering of infected and exposed animals.Therefore,early diagnosis and detection on African swine fever virus is vitally important for epidemic identification and control.In this article,the detection methods for African swine fever virus are divided into virus separation methods,immunological detection methods and molecular detection methods according to the detection principles.The immunological detection methods are subdivided into immunofluorescence test,immunoblotting test,enzyme linked immunosorbent assay,immunochromatographic test strip and other immunological detection methods.The molecular detection methods are subdivided into polymerase chain reaction,isothermal amplification techniques,CRISPR(clustered regularly interspaced short palindromic repeats)/Cas system and other molecular detection methods.The principles and characteristics of these methods are introduced in this article,and the research progress in detection of African swine fever virus is summarized.The future development direction of detection methods for African swine fever virus is determined as there still remain some deficiencies of these methods in detection ability and application scenarios,of which the detection limits and the application ability for Point-of-Care diagnosis will improved in the future,based on the precondition ensuring sensitivity and specificity.The future research will focus on lowering the cost,industrializing production and improving the throughput and performance.关键词：African swine fever;detection methods;virus separation methods;immunological detection methods;molecular detection methods
- 5
- |
- 5
- |
- 1
发布时间：2023-04-18 - 摘要：Ochratoxin A(OTA) is a secondary metabolite originated from fungi penicillium and aspergillus,which is widely distributed in nature,with various strong toxicities such as hepatotoxicity,nephrotoxicity,carcinogenic and mutagenic effects.Considering these potential toxic effects of OTA,the International Agency for Research on Cancer(IARC) has classified it as a human carcinogen(Ⅱ B).Therefore,how to develop OTA detection methods with high sensitivity have arouse wide attention.The development and applications of electrochemical sensors for OTA detection for the past 10 years are summarized in this paper.Based on different identification elements,the main types of OTA electrochemical sensors,adaptor and immune sensing,and the advantages and disadvantages of the corresponding sensings are described.The prospect for the future development of OTA electrochemical sensors is put forward.This review provides a certain reference for the further research and application of OTA electrochemical sensors.关键词：ochratoxin A(OTA);electrochemical sensing;research advance
- 3
- |
- 4
- |
- 2
发布时间：2023-04-18 - 摘要：Click chemistry has attracted much attention due to its excellent reaction performances such as reaction modularity,no toxic and harmful by-products,and high reaction efficiency.It is another new type of synthesis technology after combinatorial chemistry,which has been widely used in the functionalization of material surface,synthesis of high polymers,bio-labeling and other fields.In addition,the active groups of click reaction reagents are easily modified on other chemical groups,indicating that the click reaction could be used as a promising intermediate reaction for mediating signal conversion or amplification in certain reactions.In recent years,a large number of click chemistry-based reagents have emerged,and have been applied to develop a series of analysis and detection methods.Due to the advantages of low detection limit,wide linear range and accurate quantification of target analytes,this type of analysis methods have a good application prospect.The classic copper-catalyzed alkyene/azide cycloaddition(CuAAC) is the most widely used click reaction which has several unique advantages required for sensing reactions:firstly,the use of Cu+ as a catalyst could greatly improve the reaction efficiency and sensitivity,secondly,the orthogonal reaction between alkyne and azide determines the good specificity of the reaction,and thirdly,the reaction is not sensitive to environmental conditions including temperature,water,pH,etc.,and could be performed at room temperature or water solvent conditions.These good reaction properties make it possible to use CuAAC reaction to construct sensing methods with high sensitivity,good specificity and strong stability.Food safety detection is an important means to control hazards in food and protect public health.At present,the commonly used methods for food safety monitoring almost all rely on the cumbersome instruments and equipments,and thus resulting in the reduction of detection efficiency.In this context,the superior performance of click chemistry provides new ideas for food safety detection.The concept,main reaction types,reaction principles and characteristics of click chemistry are reviewed in this article,and a series of rapid detection methods based on click chemistry such as colorimetry,fluorescence method,electrochemical method,etc.are also compared.Moreover,the application examples of CuAAC reaction in the detection of food ingredients and additives,pesticide and veterinary drug residues,mycotoxins,heavy metals and food-borne pathogens are highlighted.Finally,the shortcomings of click chemistry reactions at the current stage are pointed out,and the future application prospects of click chemistry in food safety detection and other research fields are presented.关键词：click chemistry;food safety;analysis and detection;application
- 3
- |
- 4
- |
- 1
发布时间：2023-04-18 - 摘要：Resonance energy transfer(RET) is a process of non-radiative energy transfer occurring between energy transfer donor and energy transfer acceptor.The energy transfer efficiency of RET is very sensitive to changes in the distance between energy transfer donor and energy transfer acceptor,which thus could be used to develop new optical biosensors.Compared with traditional biosensors,RET-based biosensors could be used to significantly simplify the detection procedure by eliminating steps such as washing and separating excess markers.The new biosensing analysis technology based on RET have attracted more and more attention in the fields of medical diagnosis,life science research,environmental monitoring and food safety due to its high sensitivity,easy operation and rapidness.Based on the difference of energy transfer donors,the RET is divided into three types in this article,i.e.fluorescence resonance energy transfer(FRET),bioluminescence resonance energy transfer(BRET) and chemiluminescence resonance energy transfer(CRET).By far,the application of FRET is the most common,whose development has gone through several stages.Meanwhile,the luminescent materials of FRET are further divided into organic fluorescent dyes,quantum dots(QDs),noble metal nanomaterials and up-conversion nanoparticles(UCNPs) in order,and typical application pairs are selected respectively.In addition,their advantages and disadvantages are summarized and compared.Compared with FRET,BRET and CRET do not require excitation of external light,so they can avoid many side-effects caused by external light,greatly reducing background interference and “false positive” problems.The research progresses of biosensors based on the above three types of RET in food safety detection are summarized in this article,and their application prospects and development trends are also anticipated.关键词：resonance energy transfer;food safety detection;fluorescence resonance energy transfer;bioluminescence resonance energy transfer;chemiluminescence resonance energy transfer
- 3
- |
- 4
- |
- 3
发布时间：2023-04-18 - 摘要：Development of detection techniques for pesticide residues such as dichlorodiphenyltrichloroethane(DDT),endosulfan and isocarbophos is of great importance to ensure the safety of agricultural products and environment due to their high toxicity.Meanwhile,immunoassay has the advantages of economy and simplicity in the rapid detection of a large number of samples.In this paper,anti-DDT,anti-endosulfan and anti-isocarbophos monoclonal antibodies were prepared.An indirect competitive enzyme-linked immunosorbent assay(ic-ELISA) for the pesticides was developed with a commercial horse radish peroxidase-labeled goat anti-mouse antibody as secondary antibody.Under optimal conditions,the 50% inhibitory concentrations and detection limits of the method for DDT,endosulfan and isocarbophos were 10.72 ng·mL-1 and 1.85 ng·mL-1,9.69 ng·mL-1 and 2.19 ng·mL-1,13.26 ng·mL-1 and 3.04 ng·mL-1,respectively.The ic-ELISA for DDT showed that the cross-reactivities(CRs) of DDT with o,p-2,2-bis(4-chlorophenyl)-1,1-dichloroethylene(DDE),p,p-DDE and o,p-DDT were in the range of 9.0%-33.4%.The ic-ELISA for endosulfan showed that CRs of endosulfan with aldrin,chlordane,dieldrin,β-endosulfan and α-endosulfan were in the range of 17.4%-84.3%.The ic-ELISA for isocarbophos showed that isocarbophos had no significant CR with its six analogues(CR＜0.1%).The average recoveries of the ic-ELISA for DDT,endosulfan and isocarbophos in paddy water,soil,apple and banana samples were in the ranges of 71.4%-93.3%,74.0%-97.4% and 70.8%-97.0%,with relative standard deviations of 3.8%-9.6%,3.0%-11% and 4.2%-12%,respectively.Meanwhile,the results of ic-ELISA showed good correlations with those of chromatography in the detection of DDT,endosulfan and isocarbophos.The related results showed that the monoclonal antibodies of DDT,endosulfan and isocarbophos prepared in this study could be used to establish an ic-ELISA with good sensitivity and accuracy.关键词：indirect competitive enzyme-linked immunosorbent assay;dichlorodiphenyltrichloroethane;endosulfan;isocarbophos;pesticide residue;monoclonal antibody
- 6
- |
- 7
- |
- 4
发布时间：2023-04-18 -
Rapid Detection of Carmine in Beverages Using a Fluorescence Method Based on Red Carbon Quantum Dots
摘要：Carmine as a kind of food colorants is commonly used in food industry.However,irrational and inappropriate use of carmine will seriously threaten human health.At present,the detection of carmine mainly relies on the traditional methods such as high-performance liquid chromatography(HPLC),high performance capillary electrophoresis,etc.,which always involve expensive instruments,professional personnel and complicated pretreatment procedures.Thus,its indispensable to develop rapid,sensitive and visual detection methods for carmine.To meet this demand,a fluorescence method was established for the rapid detection of carmine in beverages specifically.Firstly,red carbon quantum dots(RCDs) were synthesized via hydrothermal treatment at 180 ℃ by using p-phenylenediamine as the carbon source.The morphology and particle size distribution of the prepared RCDs were observed by transmission electron microscopy(TEM).Furthermore,Fourier transform infrared spectroscopy(FTIR) was used to characterize the functional groups on the surface of RCDs,while the element composition of RCDs and their chemical states of elements were determined by X-ray photoelectron spectroscopy(XPS).To state the fluorescence quenching mechanism clearly,the fluorescence lifetime,the UV-Vis absorption spectra and fluorescence spectra were investigated.It was found that the absorption peak of carmine overlaps with the fluorescence emission spectrum of the prepared RCDs.Thus,a possible mechanism for fluorescence quenching was proposed as inner filter effect mechanism.Based on this mechanism,a fluorescence sensor for sensitive determination of carmine was designed,of which the detection performance depended on the detection conditions.To obtain the optimal analytical performance,the experimental parameters,including the excitation wavelength and pH values,were optimized.Under the optimized experimental conditions,the proposed sensor exhibited a linear response to carmine in the concentration range of 0.5-50 μg·mL-1,with a linear equation of IF0/IF=0.059c+0.979,a correlation coefficient(r2) of 0.978 and a detection limit of 0.397 μg·mL-1.The practical application of the proposed sensor was verified by HPLC with spiked beverage samples.The recoveries at three spiked levels ranged from 93.1% to 101%,with relative standard deviations(RSDs) of 0.97%-2.1%.Moreover,the color variation could be directly observed under the illumination of a 365 nm UV lamp with the naked eye,which could be used in the semiquantitative analysis for carmine content.With the advantages of rapidness,high sensitivity and stability,this method could be used for the detection of carmine in actual beverage samples.The research on this fluorescent method is of great theoretical value to develop new methods for carmine detection.In addition,the established method has a practical application value for on-site safety regulation on the illegal use of carmine.关键词：red quantum dots(RCDs);carmine;fluorescence method;rapid detection- 3
- |
- 6
- |
- 2
发布时间：2023-04-18 - 摘要：Ascorbic acid(AA),also known as vitamin C(Vc),is a type of reducing substance with an enediol structure.Ascorbic acid plays an important role in maintaining the normal physiological functions of the human body.Appropriate intake of ascorbic acid is beneficial to enhance the bodys anti-stress ability and immunity,promote the absorption of calcium,iron,folic acid,etc.,and prevent cancer and cardiovascular disease.In addition,ascorbic acid as an antioxidant is also widely used in the fields of medical pharmacy,food processing and cosmetic products.Therefore,it is very necessary to develop an accurate and sensitive method for ascorbic acid detection.Colorimetric analysis methods based on nanozymes have attracted more and more research interest owing to their fascinating advantages of low cost,good stability,high sensitivity and excellent selectivity.In this paper,a simple,sensitive,rapid and selective colorimetric method for ascorbic acid detection was developed.Inspired by the fact that nanozymes with redox-active metal center are prone to possess good catalytic performance,a novel metal-organic framework nanozyme Ce-BDC was first prepared by using terephthalic acid (H2BDC) as organic ligand and Ce as active metal center.The as-prepared Ce-BDC was well characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS).Then the oxidase-like activity of Ce-BDC was revealed and Ce-BDC could catalyze the colorless 3,3,5,5-tetramethylbenzidine(TMB) to produce a deep blue oxidation product oxTMB which has a strong UV absorption peak at 652 nm.The catalytic activity of Ce-BDC follows the Michaelis-Menten kinetics,which could be affected by pH value and temperature condition.Results showed that the optimal reaction temperature is 30 ℃,the optimal reaction pH value is 3.0,and the optimal reaction time is 120 s.Due to the strong reducing property of ascorbic acid,the addition of ascorbic acid could reduce oxTMB into colourless TMB,resulting in the fading of blue color and the decrease of absorbance at 652 nm.Based on this phenomenon,a colorimetric method was established for ascorbic acid detection.Under the optimum reaction conditions,the absorbance of the reaction solution at 652 nm has a good linear relationship with the concentration of ascorbic acid in the range of 1.0-30 μmol/L,and the detection limit for ascorbic acid was found to be 0.32 μmol/L,which could satisfy the requirements for the practical detection of ascorbic acid.The established method was applied in the detection of ascorbic acid in fruit juice sample via standard addition test.The recovery for ascorbic acid was in the range of 98.2%-102%,with the relative standard deviations of 1.2%-7.2%,demonstrating that the method is promising for the rapid and selective detection of ascorbic acid.In a word,this work provides a new approach for the colorimetric detection of ascorbic acid in fruit juice based on nanozyme.关键词：ascorbic acid;metal-organic framework;oxidase-like activity;colorimetric detection
- 3
- |
- 4
- |
- 2
发布时间：2023-04-18 - 摘要：In order to fulfill the rapid,high throughput and high sensitive analysis of paraquat and diquat in complex biological samples,a convenient matrix assisted laser desorption ionization fourier transform ion cyclotron resonance mass spectrometric(MALDI-FTICR-MS) was developed for rapid detection of paraquat and diquat in seven vegetable samples,including benincasa hispida,cucumber,pakchoi,greengrocery,garlic chives,celery and lactuca sativa.In this study,the impacts of low concentrations of 2,5-dihydroxybenzoic acid(2,5-DHB) and α-cyano-4-hydroxycinnamic acid(CHCA) on the ionization response strength of paraquat and diquat were we compared.Simultaneously,the analytical results of different concentrations of CHCA mixed separately with pure standard solution and sample matrix standard solution in equal proportion were investigated.Ultimately,the extraction conditions for seven vegetable samples were optimized.The vegetable samples were extracted with acetonitrile solution containing 1% formic acid after homogenization by liquid-liquid extraction.After mixed with 2 g/L CHCA,the extracted solution was injected immediately.Results showed that different concentrations of CHCA as MALDI matrix had a noticeable influence on the ionization efficiency of paraquat and diquat in blank solvent and sample matrix.The response of pure standard solution was similar to that of the standard solution prepared with sample substrate as the concentration of CHCA was 2 g/L,which was more suitable for the establishment of detection method.There were good linear relationships for paraquat and diquat in seven vegetable samples in the mass concentration range of 2-200 μg/L,with their correlation coefficients(r) of 0.997 2-0.999 6.The limits of detections(LODs) and limits of quantitations(LOQs) of the method for paraquat were in the ranges of 1.0-1.5 μg/kg and 3.0-4.5 μg/kg,while the LODs and LOQs for diquat were 5.0-7.5 μg/kg and 15-23 μg/kg,respectively.The recoveries for paraquat at spiked levels ranged from 73.0% to 109%,with the relative standard deviations(RSDs) of 1.0%-8.2%,while the recoveries for diquat ranged from 81.7% to 117%,with the RSDs of 1.0%-7.0%.The analysis results were obtained by this method within 30 minutes.With the merits of rapidness,high sensitivity,reliability,stability,low solvent consumption and simple operation,this method could be used for the rapid and high throughput detection of paraquat and diquat in vegetables.关键词：paraquat;diquat;matrix assisted laser desorption ionization-Fourier transform ion cyclotron resonance mass spectrometry;vegetables
- 3
- |
- 4
- |
- 1
发布时间：2023-04-18 - 摘要：Synthetic cannabinoids(SCs) such as 5F-MDMB-PICA(Methyl 2.［［1.(5.fluoropentyl) indole-3.carbonyl］amino］-3,3.dimethyl-butanoate) usually undergo extensive metabolization under the hydrolysis of specific cytochrome P450 enzymes and uridine diphosphate glucuronosyltransferase after being ingested.Due to their lipophilicity,many,but not all parent SCs could not be detected or could be detected in much lower proportions than their metabolites in the urine of authentic users within a relatively short duration,which brings great challenges to the monitoring of drug abuse of SCs.Therefore,to establish an analysis method for the metabolites of SCs is beneficial to confirm the use of SCs from body fluids in emergency,toxicology and forensic practices.The specific goal of this work is to study the in vivo metabolism of 5F-MDMB-PICA by zebrafish model.Adult zebrafishes were randomly divided into 2 groups with 3 fishes in each group,including the blank zebrafish group without 5F-MDMB-PICA and the experimental group.After exposed to 1 μg/mL 5F-MDMB-PICA in tank water for 24 h,the zebrafishes were transferred to a tank with clean water and euthanized.The euthanized zebrafishes were placed in a 2-mL tube containing 300 μL acetonitrile and several ceramic beads,followed by homogenization using an Omni Bead Ruptor 24 coupled with an Omni BR-Cryo cooling unit(OMNI International IM,GA) in the following conditions: speed: 6 m/s,time: 40 s,dwell: 20 s and 10 repetitions.Afterwards,the samples were centrifuged for 3 min at 12 500 r/min,then the supernatant was filtered through a 0.22-μm PTFE filter,and 5 μL of each prepared sample was injected into sample bottle for instrument analysis.5F-MDMB-PICA and its metabolites were identified and structurally illustrated by liquid chromatography-quadrupole/orbitrap mass spectrometry(LC-Q-Orbitrap MS) with Mass Frontier software.In total,22 metabolites of 5F-MDMB-PICA in the zebrafish samples were detected,including 15 phase-I metabolites and 7 phase-II metabolites.Results showed that the metabolites of 5F-MDMB-PICA in zebrafish were formed via N-dealkylation(A17) followed by hydroxylation on the aromatic ring(A2,A13),glucuronidation(A1) or sulfation(A3) followed by hydroxylation on the aliphatic chain(A21),glucuronidation(A6) or sulfation(A14),oxidative defluorination(A20) followed by conversion to pentanoic acid(A18) or glucuronidation(A7),then amide hydrolysis(A4) followed by hydroxylation(A5) and propionic acid(A16).The ester hydrolysis products(A19) were one of the most prevalent metabolites detected in zebrafish.Ester hydrolysis(A19) metabolites were further metabolized via hydroxylation(A12),glucuronidation(A8),oxidative defluorination(A11),oxidative defluorination to pentanoic acid(A10),or dehydrogenation(A22) followed by N-dealkylation(A9),or oxidative defluorination(A15).Therefore,A19 could be recommended to be a potentially good biomarker for screening the suspected intoxications arising from 5F-MDMB-PICA,which were recently reported to be detected in urine samples from 5F-MDMB-PICA drug abusers.The metabolic pathway and main metabolites of 5F-MDMB-PICA in zebrafish were preliminarily elucidated in this paper,and six phase-II metabolites,ie.A1,A3,A5,A7,A6 and A14 were reported for the first time.关键词：5F-MDMB-PICA;zebrafish;liquid chromatography-quadrupole/orbitrap mass spectrometry(LC-Q-Orbitrap MS);metabolites
- 3
- |
- 4
- |
- 5
发布时间：2023-04-18 - 摘要：Long-chain triacylglycerols(TAGs) play an important role in maintaining human health and normal development,so it is necessary to establish a rapid and effective method for accurate determination of the contents of TAGs in edible vegetable oils.The polarities and structures of TAGs are very similar,which makes it difficult to separate them by either gas chromatography or liquid chromatography.A method based on ultra performance convergence chromatography-tandem mass spectrometry(UPC2-MS/MS) was established for the quantitative analysis of 12 kinds of TAGs in vegetable oils.The samples were firstly dissolved and diluted with n-hexane,then separated by gradient elution using an analytical column combining two HSS C18 SB(100 mm×2.1 mm,1.8 μm) columns together,with supercritical carbon dioxide and methanol containing 0.1% formic acid as mobile phases at a flow rate of 1.5 mL/min.The separated compounds were analyzed by MS/MS with an electrospray ionization source in positive ions and multiple reaction monitoring(MRM) modes.Water containing 97% methanol and 0.2% ammonia water was used as the auxiliary pump mobile phase at a flow rate of 0.3 mL/min.The external standard method was used for quantitative analysis of the 12 TAGs in sample solutions.Results showed that there were good linear relationships for the 12 TAGs in the corresponding mass concentration ranges with their correlation coefficients(r2) not less than 0.990 2.The limits of detection(LOD,S/N=3) and limits of quantitation(LOQ,S/N=10) were in the ranges of 1.0-8.0 mg/g and 3.0-25 mg/g,respectively.The average recoveries(n=9) of the method ranged from 95.7% to 104%,with relative standard deviations of 1.5%-4.2%,and good precisions.The developed method was successfully used for the determination of 12 long-chain TAGs in actual samples.Furthermore,some long-chain TAGs outside the scope of the investigation were analyzed.The method is high specific,rapid,simple,reliable,environmentally friendly and compatible for oils matrixes,providing an effective way for determining the contents of TAGs in vegetable oils,and it is also suitable for the analysis of TAGs in other samples.关键词：ultra performance convergence chromatography-tandem mass spectrometry;long-chain triacylglycerols;vegetable oils
- 8
- |
- 4
- |
- 0
发布时间：2023-04-18 - 摘要：A time-resolved immunofluorescence chromatography was established for the rapid and sensitive evaluation of SARS-CoV-2 antibody level in patients suffering Corona Virus Disease 2019,with a truncated severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) N protein and a full-length SARS-CoV-2 N protein.The test strip cards were prepared with fluorescent microspheres as markers,which were assembled for negative and positive detection to pick out the superior antigen pairing combination.Meanwhile,the precision and stability of the optimized test strip card were further evaluated for preliminary performance,and compared with those of the marketed SARS-CoV-2 antibody detection method on this basis.According to the negative and positive detection results,preferably,the truncated N protein was labeled and the full-length N protein was coated.This method could complete the detection of SARS-CoV-2 antibody level within 15 minutes,and could effectively distinguish the negative and positive results.The intra-assay precision CV was between 3.48% and 10.05%,and the inter-assay precision CV was between 4.77% and 11.73%.The strips could be stably stored at 37 ℃ for 21 days.The detection results by this method were well correlated with those by colloidal gold assay,with a total coincidence rate of 96.13%,a positive coincidence rate of 90.63% and a negative coincidence rate of 97.56%,respectively.The fluorescence immunochromatographic assay preliminarily established based on truncated N protein could effectively evaluate the SARS-CoV-2 antibody level in patients with good precision and stability,which was convenient for popularization in primary care units and had a good application prospect.关键词：Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2);Corona Virus Disease 2019(COVID-19);N protein;fluorescence immunochromatography;detection
- 7
- |
- 6
- |
- 1
发布时间：2023-04-18 - 摘要：Sodium trithiocyanurate(TMT) is a chelating agent,which could be used to precipitate metal ions from industrial waste waters and polluted natural waters.Recently,a non-edible substance TMT was detected in wheat flour,which had become a serious food safety hazard.It was urgent to establish a detection method suitable for total TMT in wheat flour and its additives.Wheat flour and different types of flour additives were extracted with acetonitrile-ammonium formate buffer for total TMT,then purified with a pass-through cleanup solid phase extraction column(SPE).In chromatographic analysis,the separation was carried out on a HSS T3 column using methonal-ammonium formate(pH 3.0) as mobile phase under gradient elution mode by ultra high performance liquid chromatography(UPLC),which exhibited an excellent chromatographic retention as well as a good anti-interference ability.The target compound was detected by MS/MS with electrospray ionization(ESI) under multiple reaction monitoring(MRM) mode.Acetonitrile-100 mmol/L formic acid/ammonium formate buffer solution(pH 2.5,8∶2) was selected as the best extraction solvent,of which the effect on total TMT extraction was optimized in detail.Firstly,the optimized extraction system of acetonitrile-ammonium formate not only has a high extraction efficiency,but also could overcome the problem of easy gluing of flour treatment agents 2(FTA2).The pH value of the extraction solvent had a significant influence on the extraction efficiency for TMT in three matrixes.With the decrease of pH,the extraction efficiency for TMT presented an increasing trend.As the increase of buffer salt concentration of ammonium formate,the extraction efficiency showed an upward trend,and reached to the highest percentage in three matrixes when the buffer salt concentration was set at 100 mmol/L.It was found that,with the increase of acetonitrile ratio from 40% to 90%,the recoveries for wheat flour and FTA1 merely changed a little,while the recovery for FTA2 increased significantly.Results showed that the buffer salt concentration,pH value,ion concentration,content of organic phase and the sample amount had great influence on the extraction efficiency for TMT in wheat flour and its additives.Thus,different factors should be considered comprehensively.The established method showed that TMT had a good linearity in the range of 0.5-250 ng/mL with correlation coefficients of 0.997 7.The average recoveries for TMT in wheat flour and flour additives at three spiked levels ranged from 95.0% to 110% with relative standard deviations(RSD) not more than 5.6%.The limits of detection(LOD,S/N=3) and the limits of quantitation(LOQ,S/N=10) were 0.02 mg/kg and 0.05 mg/kg,respectively.This method was successfully applied to the analysis for 76 batches of wheat flour,composite flour treating agent and single ingredient additive with the advantages of simplicity,preciseness,good feasibility and applicability.Results indicated that the optimized rapid detection method provided a technical support for ensuring the quality and safety of wheat flour.关键词：wheat flour;flour additives;sodium trithiocyanurate;solid phase extraction;ultra performance liquid chromatography-tandem mass spectrometry
- 4
- |
- 4
- |
- 2
发布时间：2023-04-18 - 摘要：Electrochemiluminescence(ECL) is a new analysis technique that combines electrochemistry and chemiluminescence.With various advantages of simplicity,rapidness,high sensitivity and high controllability,ECL has been widely used for the analysis in food,environment,pharmaceutical and clinical diagnosis fields.Iridium(Ⅲ) complex,as a new type of ECL material,exhibits excellent light stability,long luminescence life,large Stokes shift,and tunable luminous efficiency and emission wavelength.However,the weak solubility of iridium(Ir) complex in aqueous solution restricted its application in ECL field.In this paper,tris(2.phenylpyridine)iridium(Ⅲ)(Ir(ppy)3) was firstly functionalized with poly(styrene-maleic anhydride)(PSMA) through a simple nano-precipitation method to obtain iridium nanorods(Ir NDs) which were then characterized by transmission electron microscopy(TEM),infrared spectroscopy(IR) and X-ray electron spectroscopy(XPS).The TEM image showed that the lengths of Ir NDs were in the range of 204-1 158 nm,and the average length was 543 nm.The prepared Ir NDs had a large number of carboxyl groups on their surface,thus displaying an outstanding dispersibility in aqueous solution.Furthermore,Ir NDs also presented a strong ECL emission in the presence of the co-reactant tripropylamine(TPrA).Then,the dispersion of Ir NDs was used to modify the glassy carbon electrode(GCE) to obtain an ECL biosensor.The construction process of the biosensor was characterized by cyclic voltammetry(CV) and electrochemical impedance(EIS),and the experimental conditions including concentration of TPrA in detection solution and volume of the dispersion of Ir NDs modified on the GCE were optimized.Under the optimized experimental conditions,namely,0.75 mmol/L of TPrA and 10.0 μL of Ir NDs,the response of the biosensor to dopamine(DA) was further explored.Based on the high quenching effect of DA on ECL emission of Ir NDs-TPrA system,a highly sensitive detection of DA was realized with a wide linear response range of 2.0×10-8-4.0×10-4 mol/L and a low detection limit of 6.3×10-9 mol/L.The continuous scanning for 10 cycles was performed at the biosensor,with a relative standard deviation(RSD) for ECL signals of 1.7%,which indicated that the biosensor had a good stability.Four biosensors constructed from various batches were applied to the inter-assays,while four biosensors from the same batch were applied to the intra-assays,with corresponding RSDs of 1.4% and 2.8%,respectively,showing a satisfactory reproducibility.Glucose(Glu),uric acid(UA),ascorbic acid(AA),arginine(L-Arg),glycine(Gly),K+ and norepinephrine(NA) were selected as potential interfering substances to test the selectivity.It was found that the mentioned substances except NA made no interference to the determination of DA.Finally,the detection of real samples showed that the biosensor had a good practical application potential.The carboxyl-functionalized Ir NDs provided an ideal platform for application of iridium(Ⅲ) complexes in ECL field,and a novel method for DA detection.关键词：electrochemiluminescence;dopamine(DA);biosensor;Ir nanorods
- 4
- |
- 4
- |
- 0
发布时间：2023-04-18 - 摘要：An ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) was developed for the rapid screening of 49 kinds of illegally-added chemical drugs divided into eight categories in Chinese patent medicine.The samples were extracted with acetonitrile by ultrasonic extraction,then separated on a C18 chromatographic column(2.1 mm×100 mm,1.8 μm) by gradient elution,with 0.1% formic acid-2 mmol/L ammonium acetate aqueous solution and acetonitrile containing 0.1% formic acid as mobile phases.The qualitative and quantitative analyses were performed under dynamic multiple reaction monitoring(d-MRM) acquisition mode,and external standard method was used for quantitative detection.Results showed that there were linear relationships for 49 drugs in the concentration range of 0-60 ng/mL with their correlation coefficients(r2) of 0.993 2-0.999 5.The limits of detection were in the range of 0.290-2.546 ng/g.Recoveries for the analytes at three spiked levels ranged from 86.4% to 107%,with relative standard deviations of 0.80%-3.5%.Metformin,phenformin,glibenclamide,sildenafil,tadalafil and sibutramine were detected in 5 batches(20 batches in total) of samples,with their detectable amounts of 0.076 97,1.153,0.013 41,69 500,2 400,724.0 mg/kg,respectively.With the advantages of simple pretreatment,accurate result and high sensitivity,this method is suitable for the rapid screening of illegally-added chemical drugs in Chinese patent medicine.关键词：Chinese patent medicine;chemical drug;ultra performance liquid chromatography-tandem mass spectrometry;illegally-added;screening
- 5
- |
- 7
- |
- 4
发布时间：2023-04-18 - 摘要：An effective method was developed for the determination of 16 polycyclic aromatic hydrocarbons(PAHs) in Alpinia oxyphylla Miq based on gas chromatography-mass spectrometry(GC-MS).The samples were separated on a DB-EUPAH capillary chromatography column,detected by GC-MS with electron ionization source in selective ion mode,and quantified by stable isotope internal standard method.The optimal extraction conditions were as follows:2.0 g of sample was added with isotope standard solution,then mixed with absolute ethanol and water to dissolve,followed by addition of 10 mL n-hexane for extraction.The extract was firstly subjected to solid-phase extraction with a Florisil column,then saponified with KOH-ethanol solution,and extracted again by solid-phase extraction with a polycyclic aromatic hydrocarbon molecularly imprinted column,finally,eluted with 5 mL dichloromethane-n-hexane(1∶1,by volume).Results showed that the 16 PAHs presented good linear relationships in the concentration range of 1.0-200.0 μg/L with correlation coefficients(r2) not less than 0.992 5.The limits of detection were in the range of 0.3-1.0 μg/kg,and the limits of quantitation were 1.0-3.0 μg/kg.The average recoveries(n=6) for benzo［c］ fluorene(BcFL) ranged from 65.4% to 72.8%,with intra-day relative standard deviations(RSD,n=6) of 6.0%-7.4% and inter-day relative standard deviations(RSD,n=6) of 8.5%,respectively,while the average recoveries for the other 15 PAHs were in the range of 89.3%-116%,with intra-day RSDs(n=6) of 0.10%-6.1% and inter-day RSDs(n=6) of 1.2%-7.5%,respectively.The developed method showed excellent purification effect,sensitivity and high accuracy,and was suitable for the simultaneous determination of 16 PAHs in Alpinia oxyphylla Miq.关键词：gas chromatography-mass spectrometry(GC-MS);stable isotope internal standard method;Alpinia oxyphylla Miq;polycyclic aromatic hydrocarbon(PAHs);matrix effect
- 3
- |
- 4
- |
- 4
发布时间：2023-04-18 - 摘要：A high performance liquid chromatography(HPLC) was established for determination of the characteristic spectra as well as the multi-index contents of substance benchmarks for classical prescription Danggui Sini decoction,which elucidated the critical quality attributes and improved the quality control system.The chromatographic analysis was performed on a Pomenex Luna C18 column(250 mm×4.6 mm,5 μm) at 30 ℃.The gradient elution was carried out with a linear gradient system consisted of acetonitrile-0.05% phosphoric acid water solution.The signal was monitored at 230 nm and 290 nm.The flow rate was maintained at 1.0 mL·min-1.The similarity of characteristic spectra for 15 batches of substance benchmarks was more than 0.89,while 45 common peaks were assessed,and 7 common components were identified as paeoniflorin,ferulic acid,liquiritin,ammonium glycyrrhizinate,asarinin,cinnamaldehyde and ligustilide.The average yield of dry extract for 15 batches of substance benchmarks was 15.00%.The contents of paeoniflorin,ammonium glycyrrhizinate,asarinin,cinnamaldehyde and ligustilide in the 15 batches of substance benchmarks were 8.226-13.46，1.929-6.535，0.020 02-0.034 30，0.076 61-0.543 3 and 0.075 94-0.140 6 mg·g-1,respectively.This study provides a scientific basis for the quality control of substance benchmarks as well as the development of compound preparation of Danggui Sini decoction.关键词：classical prescription;Danggui Sini decoction;substance benchmarks;critical quality attributes
- 3
- |
- 4
- |
- 6
发布时间：2023-04-18 - 摘要：In order to realize the rapid,accurate and nondestructive identification of heavy mineral oil evidence in the field of forensic science,a multi-derivative spectral data combination analysis method based on spectral analysis technology was proposed in this paper.The spectral data for 80 kinds of heavy mineral oil samples of different models and manufacturers were collected by Fourier transform Raman spectral analysis method,and the classification models were constructed by combining the stoichiometry.In the constructed classification model of principal component analysis(PCA) combined with radial basis function neural network(RBF),the classifications of single original spectrum,first derivative spectrum and second derivative spectrum data were presented.The classification accuracies for the training set were 80.0%,86.7% and 86.2%,while those for the test set were 73.3%,80.0% and 72.7%,respectively.In the classifications of original spectrum-first derivative spectrum,original spectrum-second derivative spectrum and first derivative spectrum-second derivative spectrum after combination,the accuracies for the training set were 97.0%,96.7% and 100%,and those for the test set were 85.7%,90.0% and 100%,respectively.Results showed that the classification accuracy was higher when the derivative spectra and ordinary spectra were constructed.Among them,the classification model of PCA combined with RBF based on first derivative spectrum and second derivative spectrum data was the most ideal,with an accuracy of 100%.However,the model of K nearest neighbor algorithm had a low classification accuracy due to the influence of uneven samples.Construction of a classification model by the combination of derivative spectrum and the original spectral data could realize the fast,accurate and nondestructive identification of the heavy mineral oil samples,which could provide a certain reference for the application of spectral combination technology in forensic science and other analytical testing fields.关键词：spectroscopy;heavy mineral oil;Raman spectrum;radial basis function neural network(RBF);K nearest neighbor algorithm;classification
- 3
- |
- 4
- |
- 1
发布时间：2023-04-18 - 摘要：An high performance liquid chromatography with solidification-floating dispersive liquid-liquid microextraction(SFO-DLLME) based on saturated medium chain fatty acid was developed for the determination of four ultraviolet filters in environmental water samples.Octanoic acid,saturated medium chain fatty acid with a high melting point and a density less than water was used as the extractant,of which the existence form was changed by adjusting the pH of solution.An anionic extractant was dispersed in the solution for extraction at high pH,while a neutral extractant with high hydrophobicity emerged for separation from water at low pH.After optimization of the single factor condition and calculation of response surface method,the optimal conditions were as follows:the volume of extractant,ammonia and concentrated sulfuric acid were 100 μL,100 μL and 1.2 mL,respectively.The linearity range for the four ultraviolet filters were between 0.01 mg/L and 10.0 mg/L,with their detection limits of 0.18-0.76 μg/L and enrichment factors of 42-49.The recoveries for the samples at three spiked levels ranged from 73.8% to 103%,with the intra-day and inter-day relative standard deviations(RSD) of 1.9%-9.6%.The proposed method was simple,rapid and environmentally friendly,which further broadened the application ranges and provided a new idea for the development of dispersive liquid-liquid microextraction.关键词：saturated medium chain fatty acids;ultraviolet filters;dispersive liquid-liquid microextraction;high performance liquid chromatography
- 3
- |
- 4
- |
- 1
发布时间：2023-04-18 - 摘要：Non-steroidal anti-inflammatory drugs,are one of the most widely used pharmaceutically active compounds in veterinary medicine.Dispersive liquid-liquid microextraction(DLLME) is a mini-extraction technique with merits of low cost,environment friendliness and high extraction efficiency.Moreover,this method is easy to operate and requires only a short operation time.In this paper,a deep eutectic solvent(DES) based on choline chloride was used for the first time as the liquid-liquid microextraction solvent for efficient and safe extraction of non-steroidal anti-inflammatory drugs in horse meat.DES was simply synthesized via just mixing choline chloride and phenol at room temperature.The analytes were extracted into acetate buffer,and then back-extracted to the DES phase simply by oscillation.Meanwhile,acetonitrile was used as a dispersive solvent and the DES phase was collected by centrifugation.An ultra high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) with liquid-liquid microextraction based on the DES was established for the determination of ten non-steroidal anti-inflammatory drugs in horse meat.A series of analytical factors such as extraction agent,dispersing agent and dosage of sodium chloride were optimized.The optimum conditions were as follows:DES was prepared with choline chloride and phenol at a 1∶2 molar ratio,while the horse meat sample was extracted with 5 mL 20 mmol/L acetate buffer(adjusting to pH 3.5 with acetic acid) containing 10 mmol/L ascorbic acid,and subsequently added 1.0 g sodium chloride,0.8 mL extractant and 0.8 mL dispersant,then vortex extracted for 1 min and followed by a centrifugation,finally detected by UPLC-MS/MS.Results showed that there existed good linear relationships for ten non-steroidal anti-inflammatory drugs in the respective concentration ranges with their correlation coefficients(r2) larger than 0.996.The limits of detection(LOD) and the limits of quantitation(LOQ) were in the ranges of 0.05-2.0 μg/kg and 0.10-5.0 μg/kg,respectively.Recoveries for ten non-steroidal anti-inflammatory drugs at three spiked levels ranged from 73.5% to 94.6% with relative standard deviations of 1.1%-8.1%．Results indicated that the DES could be used as an alternate of traditional solvents for dispersive liquid-liquid microextraction.The method was simple,rapid,accurate and reliable,and could be used for the analysis of non-steroidal anti-inflammatory drugs in horse meat．关键词：deep eutectic solvent;dispersive liquid-liquid microextraction;horse meat;non-steroidal anti-inflammatory drugs;ultra high performance liquid chromatography-tandem mass spectromety
- 9
- |
- 5
- |
- 4
发布时间：2023-04-18 - 摘要：Laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) is a powerful technique for detection of elements and biological imaging,in which the sample is firstly ablated by laser to produce aerosol particles,then passed into the ICP with a carry gas,and finally detected by MS.LA-ICP-MS has a number of advantages in the field of environment analysis,such as direct analysis of solid samples without pretreatment,simultaneous determination of multiple elements,high throughput,high sensitivity and wide linear range.Compared with other analytical techniques in terms of micro-area imaging,LA-ICP-MS could not only avoid high vacuum operating environment,but also detect low content elements with high spatial resolution.In addition,it reduces the use of organic solvents and thus becomes more environmentally friendly.LA could also be combined with different MS instruments,for example,combination of LA with inductively coupled plasma time of flight mass spectrometry(LA-ICP-TOF-MS) might increase the ability for multi-element detection and biological imaging.Furthermore,LA could be combined with multi-collector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS) for stable isotopic composition determination,which not only avoids cumbersome sample preparation procedures,but also enables in-situ micro-zone isotopic analysis of solid samples.It should be noted that the LA-MC-ICP-MS results might be affected by the fractionation effect,matrix effect and isotopic heterogeneity,while the development of LA device from nanosecond(ns) LA to femtosecond(fs) LA could dramatically decrease the fractionation effect.LA-ICP-MS has been widely used in geology,archaeology and other fields in recent years,while its application in environmental science has started later but developed very rapidly.The development of LA-ICP-MS-based analytical methods in recent years and their applications in environmental research are summarized in this paper.The principle of LA-ICP-MS and the matrix effect and fractionation effect in LA-ICP-MS detection are firstly introduced.The corresponding calibration methods are also discussed.Then,the recent typical applications of LA-ICP-MS in analysis of soils,sediments,ice cores,plants,and biological samples are reviewed.The affecting factors of LA-MC-ICP-MS and its environmental applications are also discussed.Finally,the perspectives on the future trends in this field are anticipated.Regarding analytical methodology,it is necessary to further improve the laser efficiency and sensitivity,decrease matrix effect and improve the spatial resolution to achieve more accurate imaging of samples.It is necessary to develop more standard reference materials and purification methods to adapt to complex environment and biological media.The combined use of multiple imaging techniques has become an important trend in biological sample analysis.Due to the minimal sample consumption and simple sample pretreatment procedures,LA-ICP-MS is expected to be applied to in vivo analysis.It also needs to develop high-precision methods to realize isotopic imaging analysis.In summary,LA-ICP-MS has shown great potentials in environmental applications and will play a more and more important role in environmental research.关键词：inductively coupled plasma mass spectrometry;laser ablation;metal;environmental analysis;mass spectrometry;review
- 5
- |
- 4
- |
- 0
发布时间：2023-04-18 - 摘要：In recent years,smartphone-based detection has been more and more applied in medical diagnosis,environmental monitoring,food supervision and other research fields due to its advantages of portability,low cost,personalized customization and no need of professional training.Meanwhile,smartphone-based detection is a representative of the ingenious combination of many research fields.The applications of smartphone-based detection in food safety from 2015 to early 2020 are summarized in this review,including food additives,antibiotics,microorganisms,pesticides and heavy metals,biotoxins,and food freshness.And a prospect on this research hotspot is expected.关键词：smartphone;smartphone-based detection;food safety;colorimetry;fluorometry;electrochemistry
- 3
- |
- 4
- |
- 1
发布时间：2023-04-18
- Address：100 Xianlie Middle Road, Guangzhou Postal code：510070
- Tel：020-87684776,37656606 Fax：020-87684776 Email：fxcsxb@china.com
- Technical support is provided by Beijing Founder electronics co., LTD 粤ICP备12017312号-3
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0