最新刊期
卷 41 ， 期 2 ， 2022
- 摘要：A non-targeted metabolomics with automatic chemometric data analysis platform based on ultrahigh performance liquid chromatography－high resolution mass spectrometry（UHPLC－HRMS） was developed for investigation of the differences of chemical components in five tea cultivars．In this study，a total number of forty－five fresh tea samples （one bud and one leaf） from five cultivars，ie．Wuniuzao，Shuchazao，Baihaozao，Pingyangtezao and Shaancha 1 were collected directly from the same tea garden in Xinyang，Henan province of China，which is famous for the main producing area of Xinyang Maojian green tea．The samples were ultrasonically extracted with methanol－water （1∶9，by volume） for 30 min，and centrifuged twice．The supernatant was separated on a Waters Acquity UPLC HSS T3 （2.1 mm × 100 mm，1.8 μm） column by gradient elution，with acetonitrile－water（both with 0.1% formic acid） as mobile phase．The analysis was performed using a UHPLC－Q Exactive－HRMS system with an injection volume of 1 μL．The mass spectra was acquired using an ESI source in the FULL MS/DD－MS2 （TOP4） under positive ionization mode over the range of mass to charge（m/z） 120－1 000．The automatic non-targeted data analysis strategy was introduced to screen the metabolites that expressed significantly among different cultivars．The chromatographic and mass spectrographic features of the metabolites could be extracted and registered automatically．Meanwhile，metabolite identification was performed based on high-resolution mass values and mass spectra of screened peaks．The raw UHPLC－HRMS files were analyzed in the automatic data analysis platform and a set of thirty－three metabolites were identified，including one alkaloid，five amino acids，three catechins，four phenolic acids，six nucleotides，and fourteen flavonoids，which primarily enable the varietal discrimination．Finally，hierarchical clustering analysis （HCA），partial least squares－discriminant analysis （PLS－DA） and heatmap analysis were used for discrimination of the samples from various tea cultivars．The results showed that each cultivar has its own characteristics，in which Wuniuzao，Shuchazao and Baihaozao show a certain similarity to each other，but obviously different with the other two cultivars．Furthermore，the metabolites of five tea cultivars are significantly different under the same growth environment and agronomic conditions．Wuniuzao has higher levels of （－）-epigallocatechin and other eight flavonoids including isoquercetin，quercetin-3-O-xyloside and naringenin，etc．Shuchazao has higher levels of catechins and nucleotides．Baihaozao has higher levels of phenolic acids．Shaancha 1 has higher levels of theobromine，phenolic acids and flavonoids．The contents of theanine and arginine in Pingyangtezao were significantly higher than the other four varieties．The results obtained could offer a theoretical guidance for the quality evaluation，breeding and promotion of tea cultivars．关键词：tea cultivar;ultrahigh performance liquid chromatography－high resolution mass spectrometry;non-targeted metabolomics;chemometrics;automatic data analysis strategy
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发布时间：2023-01-04 - 摘要：Technetium－99 has β-radioactivity and a relatively long half-life．With perrhenate as the non-radioactive structural substitute for pertechnetate，an ion imprinted covalent organic frameworks（IICOFs） were prepared in this paper．Owing to the high specific surface area of COF and the selectivity of ion imprinting technology，the prepared IICOFs were applied successfully to the rapid adsorption and extraction of perrhenate anions in real water samples．Firstly，the vinyl functionalized COF－V was obtained，based on the reaction between 1，4-dialdehyde-2，5-divinylbenzene（Dva） and 1，3，5-tris（4-aminophenyl）benzene（Tab） under the microwave assistance. And then，with N-vinylimidazole（VI） and 4-chloromethylstyrene（4-VBC） as the functional monomers，the positively charged binding sites were achieved on the COF－V．Finally，the IICOFs were synthesized through the electrostatic action and radical polymerization．Meanwhile，effects of pH value，adsorption time，temperature，adsorption dose and initial concentration on the adsorption performance of the IICOFs were investigated，and the specific recognition of IICOFs was explored through interference experiments．The adsorption equilibrium could be achieved within 2 min．The study of adsorption thermodynamics showed that the adsorption for perrhenate anions was a spontaneous exothermic process，following a pseudo-second order model in kinetics．At 298.15 K，the maximum adsorption capacity was calculated to be 416.67 mg/g according to the Langmuir model．Compared with the non imprinted composites，IICOFs exhibited a higher selectivity，a faster kinetics and a larger adsorption capacity．For the Pearl River water and the tailings leachate water samples that were spiked with perrhenate anion of 2.0 × 10－4 mol/L，the adsorption efficiencies reached 87% and 98%，respectively，indicating that the IICOFs could be used for the effective removal of perrhenate anion in real environment．This technique provides a new way for the effective adsorption，separation and extraction of pertechnetate，as well as the recycle of pertechnetate resource from environments．关键词：rhenium;covalent organic framework;ion-imprinting;technetium;radioactive
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发布时间：2023-01-04 - 摘要：Bisphenols（BPs） may dissolve from pipeline or other plastic products and pollute water．It is very important to analyze the BPs in water rapidly and accurately，though the matrix of the water sample is complex and the target analytes are usually at trace level．Therefore，how to enrich and separate the target objects efficiently is the key point for the determination of BPs．In this paper，a Ce（Ⅲ） doped metal organic framework composite（CeDUT－52） was synthesized via a solvothermal method，and used as an effective adsorbent for dispersive solid phase extraction（DSPE） to enrich three BPs in water，including bisphenol A（BPA），bisphenol F（BPF） and bisphenol AF（BPAF）．The structure and morphology of the CeDUT－52 was characterized by X-ray diffractometry（XRD），Fourier－transform infrared spectroscopy（FT－IR），scanning electron microscopy（SEM） and energy dispersive spectrometry（EDS）．The XRD，FT－IR and EDS results revealed that Ce was successfully doped into the octahedral DUT－52．Meanwhile，it was found in the SEM that the particle size of the doped adsorbent decreased from 2 μm to 500 nm．To acquire the optimal extraction conditions，effects of the CeDUT－52 usage（10，20，30，40 and 50 mg），adsorption time（5，10，15，20 and 25 min），elution solvent（methanol，acetonitrile，acetone and isopropanol） and elution volume（0.5 mL × 1，0.5 mL × 2，0.5 mL × 3 and 0.5 mL × 4） were investigated for the three BPs in water．Results showed that BPs could be completely adsorbed with 40 mg of adsorbent in 50 mL water within 20 minutes．Elution efficiency could reach 88.9%－101% with 0.5 mL × 3 of methanol．Under the optimal conditions，a simple and sensitive method for the detection of three BPs was established by high performance liquid chromatography－ultraviolet detection（HPLC－UV） with the CeDUT－52 based DSPE．The limits of detection（LOD），limits of quantitation（LOQ），accuracy and precision of the method were evaluated．The developed method showed a good linear relationship in the range of 0.3－300 μg/L for BPA and BPF，0.6－600 μg/L for BPAF with correlation coefficients（r） not less than 0.999 8．The LODs and LOQs were in the range of 0.1－0.2 μg/L and 0.3－0.6 μg/L，respectively．The recoveries for BPs in water samples at 3 spiked levels of 1， 5 and 10 μg/L ranged from 82.5% to 101%，with relative standard deviations（RSD） not more than 10%．The enrichment factors of the method were between 92 and 102．The proposed method was suitable for the rapid and sensitive determination of BPs in water samples．关键词：bisphenol compounds;metal organic framework;doping;dispersive solid phase extraction;high performance liquid chromatography;water
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发布时间：2023-01-04 - 摘要：A gas chromatography－electrostatic field orbitrap high resolution mass spectrometry（GC－Orbitrap MS） was developed for the rapid screening and confirmation of 222 kinds of pesticide residues in agricultural products，based on QuEChERS method. The samples were preprocessed with an integrated solid phase dispersion extraction sample processing machine（Sio－dSPE）. Experimental conditions including types of salting-out agent and water removal agent，type of cleaning agent and its amount，matrix effect were investigated and optimized in detail. Under the optimized conditions，the linear ranges of 222 pesticides were in the range of 1-200 μg/L，the average recoveries for 222 pesticide residues in lettuce，rice and tea samples at three spiked levels of 10，20 and 50 μg/kg were in the ranges of 70.5%－121%，70.2%－119% and 65.2%－125%，with their relative standard deviations（RSDs） not more than 11%，10% and 12%，respectively. The limits of quantitation（LOQs） of this method for lettuce，rice and tea were 0.5－5 μg/kg，1－10 μg/kg and 2.5－25 μg/kg，respectively. With the advantages of simplicity，easy pretreatment and high purifying efficiency，the method was suitable for the fast screening and confirmation of pesticide residues in agricultural products.关键词：gas chromatography－electrostatic field orbitrap high resolution mass spectrometry （GC－Orbitrap MS）;solid phase dispersion extraction sample processing machine（Sio－dSPE）;rapid screening and confirmation;multi-pesticide residues;agricultural product
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发布时间：2023-01-04 - 摘要：A magnetic macroporous material（Fe3O4@SiO2@PLS） and a metal organic framework composite（Fe3O4@ZIF－8） were synthesized in this paper，and they both were combined to use as a mixed magnetic adsorbent．Based on this，a high performance liquid chromatography－tandem mass spectrometry（HPLC－MS/MS） with the mixed magnetic adsorbent solid phase extraction（MSPE） was established for the quantitative analysis of 4 sulfonamides and 8 quinolones in water samples．The morphologies，chemical structure information and crystalline structures of the prepared materials were characterized by scanning electron microscopy（SEM），Fourier－transform infrared spectroscopy（FT－IR） and X-ray diffractometry（XRD）．The results showed that the prepared Fe3O4@SiO2@PLS appeared nearly spherical in shape，with a large specific surface and an average size of 500－600 nm，nearly without Fe3O4 on the surface，suggesting the formation of core－shell structure Fe3O4@SiO2@PLS，while Fe3O4@ZIF－8 was nearly spherical in shape，with an average diameter about 200 nm and a rough surface．The crystalline structures of Fe3O4 and ZIF－8 in Fe3O4@ZIF－8 did not change after the preparation reaction，indicating that the spherical Fe3O4 particles were unifomly attached to the surfaces of the orthohexagnal ZIF－8 crystals．And then the two magnetic nanoparticles were simultaneously introduced to extract 12 antibiotics residues in water samples by MSPE followed by HPLC－MS/MS．In order to establish the optimal extraction conditions，the key parameters influencing MSPE，i.e．magnetic adsorbent amount，adsorption mode，adsorption time，sample pH，elution solvent and elution time were investigated in detail．All the experiments were performed in parallel for three times．In the adsorption procedure of MSPE，12 antibiotics could be extracted completely by the mixture use of 35 mg Fe3O4@SiO2@PLS and 15 mg Fe3O4@ZIF－8 within 10 min．Elution was performed using 10 mL 5% ammonia methanol for 5 min．The target compounds were separated on an Agilent ZORBAX Eclipse Plus C18 column（100 mm × 3.0 mm，1.8 μm） by gradient elution，analysed in multiple reaction monitoring（MRM） mode using positive electrospray ionization（ESI+）．Under the optimized conditions，good linearities were obtained for 12 antibiotics in the range of 0.5－10 μg/L，with correlation coefficients（r2） of 0.996 1－0.999 8. The limits of detection（LOD，S/N = 3） and the limits of quantitation（LOQ，S/N = 10） were in the ranges of 0.01－0.14 μg/L，0.04－0.45 μg/L，respectively．The recoveries for 12 antibiotics at three spiked levels ranged from 75.0% to 107%，with relative standard deviations（RSD） of 0.50%－5.5%．The proposed method is suitable for the simultaneous determination of trace sulfonamides and quinolones antibiotic residues in water samples．关键词：mixed magnetic adsorbents;magnetic solid phase extraction（MSPE）;high performance liquid chromatography－tandem mass spectrometry（HPLC－MS/MS）;antibiotics residues
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发布时间：2023-01-04 - 摘要：A comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry was established for the detection of 21 antiknock additives in gasoline．The instrument analysis conditions and quantitative parameters were optimized. Taking full advantage of the superiority in column capacity and separation ability of comprehensive two-dimensional gas chromatography，21 antiknock additives，including 10 alcohols，5 ethers，3 esters，2 amines and 1 ketone，were detected simultaneously．The quantitative accuracies for low concentration samples were improved by weighted least square method．Results showed that there were good linear relationships for 21 additives in the concentration range of 50－10 000 mg/L，with their correlation coefficients（r2）greater than 0.995．The recoveries at four concentration levels of 0.5%，2.0%，5.0% and 10.0% ranged from 91.1% to 109%，with the relative standard deviations（RSDs， n = 6）less than 5.0%．The limits of detection（S/N ≥ 3）and the limits of quantification（S/N ≥ 10）were in the range of 0.000 4%－0.014 1% and 0.001 4%－0.046 9%，respectively．This method could satisfy the requirements for detection of antiknock additives in actual samples.关键词：comprehensive two-dimensional gas chromatography－time-of-flight mass spectrometry;gasoline;antiknock additive;weighted least square method
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发布时间：2023-01-04 - 摘要：Iron is one of the essential elements in the human body，while the confusion of iron content might cause a range of functions of the central nervous system disorder，including motional，physical and cognitive，and other aspects．Therefore，it is very important to develop a convenient and low-cost detection method．Amino acid is one of the ideal carbon sources for carbon dots，while heteroatom doping could be realized during the preparation process，and the fluorescence quantum yield will be raised．The carbon dots prepared by utilizing amino acids also have good biocompatibility，which could be used as a probe to label cell and living organisms．In this study，the water-soluble blue fluorescent nitrogen-doped carbon dots（N－CDs） were prepared by one-step hydrothermal method，with natural amino acid molecules tryptophan and threonine as the precursors．Meanwhile，the N－CDs were used for the detection of Fe3+ in actual water samples and cell imaging. The structure，composition and optical properties of N－CDs were characterized by high-resolution transmission electron microscopy，X-ray diffraction spectrum，X-ray photoelectric energy spectrum，Fourier transform infrared absorption spectroscopy，ultraviolet spectroscopy and fluorescence spectroscopy．The results showed that the N－CDs have a uniform-size structure similar to graphite，with an average particle size of 4.1 nm．Combined with Fourier transform infrared，ultraviolet and X-ray photoelectric energy spectral characterization，it was found that there were carboxyl，hydroxyl and amino groups on N－CDs surface，which made the N－CDs have good water solubility．The composition of N－CDs was determined by X-ray photoelectric energy spectroscopy，in which the contents of carbon，nitrogen and oxygen accounted for 70.8%，8.4% and 20.8%，respectively．The N－CDs showed a good fluorescence stability towards the irradiation by sunlight and the ionic strength．The fluorescence intensity of the N－CDs maintained stable in weak acid and neutral solution，with a fluorescence quantum yield high up to 87.09%．The results showed that Fe3+ could significantly quench the fluorescence of the aqueous N－CDs solution．Base on the fluorescence quenching，a new analysis method was established for the detection of Fe3+ in drinking water samples．There were good linear relationships for Fe3+ in the range of 1－20 μmol/L and 20－50 μmol/L，respectively，with two linear fitting equations of I0/I = 0.001 09［Fe3+］ + 1.011 7 and I0/I = 0.003 81［Fe3+］ + 0.954 9，and the correlation coefficients （r2） of 0.999 4 and 0.997 3．The limits of detection （LODs，S/N = 3） were 0.36 μmol/L．In addition，the N－CDs were applied to the determination of Fe3+ in drink bottled mineral water，with recoveries of 97.3%－107%（RSD ≤ 2.0%）．With low detection limit，good selectivity，high sensitivity and good accuracy，this method could be used for the detection of Fe3+ content in water body．Furthermore，a study on cytotoxicity was performed with HL－7702 cells by this method，in which the N－CDs exhibited low cytotoxicity and good biocompatibility，and was successfully used for in vitro imaging in HL－7702 cell to achieve the visualization of Fe3+ in cells．In conclusion，the N－CDs with excellent optical properties have a great application potential in the field of analytical detection and cell imaging．关键词：carbon dots;hydrothermal synthesis;fluorescence quenching;cellular imaging;Fe3+ detection
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发布时间：2023-01-04 - 摘要：Nanobody，derived from the variable domain of heavy chain only antibodies（VHHs），is the smallest antigen recognition unit．It is an ideal candidate for the next generation of immunoassays due to its high structural stability and high expression yields compared with the conventional antibody．This study aimed to investigate effects of the multivalency and gene fusion of anti-aflatoxin B1（anti-AFB1） nanobody on the bioactivities of recombinant proteins．The anti-AFB1 nanobody，namely G8，was screened from an immune VHH phage display library in a previous work．The coding sequence of G8 was cloned into the vector pET30 between the restriction enzyme sites NdeⅠ and SfiⅠ，generating vector pET30－G8．The overlap PCR was performed to assemble the tandem structures（DiG8 and TriG8） with flexible linker（GGSGG）．The overlap PCR products encoding DiG8 and TriG8 were purified，and cloned into the vector pET30 at the same site as the G8，generating vector pET30－DiG8 and pET30－TriG8，respectively．To construct expression vectors for the recombinant fusion proteins，the green fluorescent protein （GFP） encoded gene was firstly amplified by PCR with specific primers F0 and R0，and then subcloned into the restriction sites between Sfi Ⅰ and Not Ⅰ of vectors pET30－G8，pET30－DiG8，and pET30－TriG8，respectively. The resulting vectors（pET30－G8－GFP，pET30－DiG8－GFP，and pET30－TriG8－GFP），which fused GFPs at the C terminals of monomeric，dimer and trimer anti-AFB1 nanobody，were confirmed via colony PCR，restrictive digestion，and sequencing．The vectors were transformed to Escherichia coli BL21 （DE3），respectively．To induce the expression of the target proteins，isopropyl β-D-1-thiogalactopyranoside（IPTG） was added to the culture．Fusion proteins each contain six histidine tag at their C-terminals which were purified by affinity chromatography，respectively．SDS－PAGE analysis showed that the three fusion proteins（G8－GFP，DiG8－GFP and TriG8－GFP） were solubly expressed in E. coli yielding at least 6.0，7.5，4.0 mg/L，respectively．Enzyme-linked immunosorbent assay（ELISA） and fluorescence scanning were employed to estimate the antigen recognition bioactivity and fluorescence features of recombinant fusion proteins．The half inhibitory concentrations（IC50） of the recombinant proteins G8，G8－GFP，and DiG8－GFP were 12.10，14.10 and 2.19 ng/mL，respectively．The results showed that the IC50 of the monomeric G8－GFP was similar to the non-fused G8，wheras the IC50 of the divalent DiG8－GFP was improved 5.5 times higher than that of G8．Both G8－GFP and DiG8－GFP emitted fluorescence intensity above 3 000 at the concentration of 0.7 mg/mL，and the DiG8－GFP showed better performance．Indirect ELISA showed that the trimeric recombinant protein TriG8－GFP could bound to AFB1－BSA．However，the IC50 cannot be calculated using the TriG8－GFP as its fluorescence intensity was only 1 700．This study lays a foundation for the subsequent establishment of immunological detection methods based on fluorescence signals，and also provides a reference for the optimization of affinity activity of nanobodies in immunological detection．关键词：aflatoxin B1;nanobody;tandem fusion;prokaryotic expression;enzyme linked immunosorbent assay
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发布时间：2023-01-04 - 摘要：A method was developed for the simultaneous determination of six illegally added analgesic drugs，i.e aminopyrine，phenacetin，diclofenac sodium，indometacin，phenylbutazone and chlorpheniramine in cosmetics by ultra-high performance liquid chromatography－tandem mass spectrometry（UHPLC－MS/MS）．Four kinds of cosmetics such as cream，facial mask，gel and spray were selected as the representative matrixes．The sample pretreatment conditions were optimized in detail．The cosmetic samples were firstly extracted with acetonitrile by ultrasonic-assisted liquid－liquid extraction，then separated on an ACQUITY UPLC BEH C18 column（2.1 mm × 100 mm，1.7 μm） by gradient elution，with acetonitrile and water both containing 5 mmol/L ammonium acetate as the mobile phases at a flow rate of 0.3 mL/min and an injection volume of 10 μL，and finally detected by tandem mass spectrometry under multiple reaction monitoring（MRM） scanning mode．Retention times and charge－mass ratio of the compounds（parent ion and two daughter ions） were used for qualitative analysis．Quantitative analyses were carried out by the matrix standard curves using the peak areas of the daughter ions with higher intensity．The results showed that there were good linear relationships for six compounds in the range of 5－200 μg/L with their correlation coefficients（r） larger than 0.99．The limits of detection（LOD） and limits of quantitation（LOQ） of the method were 0.15 μg/g and 0.50 μg/g，respectively．The recoveries at three spiked levels for the six components in four matrixes ranged from 75.0% to 120%，with intra-day relative standard deviations（RSD） not more than 7.9% and inter-day RSD no more than 9.7%．With the advantages of simplicity，high sensitivity and accuracy，this method is suitable for the determination of analgesic chemical components in various cosmetics substrates，and it also provides a technical support for the safety supervision of cosmetics.关键词：ultra-high performance liquid chromatography－tandem mass spectrometry（UHPLC－MS/MS）;cosmetics;analgesic;drugs
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发布时间：2023-01-04 - 摘要：A large number of β2-agonist poisoning or death cases have been reported. It is urgent to establish a toxicological assay for β2-agonist poisoning in blood applicable to forensic toxicology analysis since the current methods for β2-agonists detection mainly focus on the edible tissues of animal products or the illegal addition of drugs．Compared with traditional whole blood collection techniques，the dried blood spots（DBSs） offers several advantages. It is a simple and minimally invasive sample collection technique，involving collecting a small sample volume，easy to transport and store．In recent years，the DBSs have been gradually applied to drug metabolism and toxicological analysis，and a large number of quantitative methods for the detection of drug abuse and psychoactive substances have been reported．An ultra-high performance liquid chromatography－tandem mass spectrometry（UPLC－MS/MS） was developed for the qualitative and quantitative determination of 29 β2-agonists in dried blood spots in this paper．The mobile phase，type and proportion of extraction solvents were optimized. Stability of 29 β2-agonists in the DBS sample was investigated. The DBSs were firstly extracted with methanol， then separated on a Phenomenex Kinetex F5（3.0 mm × 100 mm，2.6 μm） column，with 1 mmol/L ammonium formate－0.01% formic acid aqueous solution and acetonitrile as mobile phases，and finally analyzed by UPLC－MS/MS．Results showed that there were good relationships for 29 β2-agonists in DBSs in a certain concentration range， with their correlation coefficients（r2） of 0.995 8－0.999 9 and limits of detection（LOD） of 1－10 ng·mL－1. The spiked recoveries for 28 β2-agonists were in the range of 60.9%－124% except fenoterol，with relative standard deviations（RSD） less than 20%．The analytes in DBSs stored at －20 ℃ for 8 weeks showed the same stability as those of the whole blood sample．The method was accurate and simple，and was convenient to storage and transport．It provided a new method and thought for forensic toxicological analysis.关键词：β2-agonists;dried blood spots;forensic toxicological analysis;ultra-high performance liquid chromatography－tandem mass spectrometry（UPLC－MS/MS）
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发布时间：2023-01-04 - 摘要：A new method was developed for the simultaneous determination of organic fluorine，organic chlorine，organic bromine and organic iodine compounds in textiles by ion chromatography with high temperature combustion and water vapor absorption．The samples were firstly oscillated to remove the inorganic halides in textiles，then burned，cracked and gasified with a new type of high temperature combustion absorption device in temperature programmed heating mode．The produced free halogen and hydrogen halide gases were absorbed with water vapor，and completely transformed into inorganic halogen anions．After condensation and collection，they were separated and determined by ion chromatography and quantified by external standard method．In the experiment，the pre-treatment conditions were optimized，including the sample weight，the combustion method，the combustion gas and its flow rate，the water evaporation and the condensate collection method．In addition，the analytical conditions for ion chromatography such as column，column temperature and the flow rate of eluent were also optimized．The results showed that the method was linear in the concentration range of 0.02－10 mg/L for the standard solutions of fluorine，chlorine，bromine and iodine ions，and the correlation coefficients（r2） were greater than 0.999．The limits of quantitation were both 1.0 mg/kg for organic fluorine and organic chlorine，2.5 mg/kg for organic bromine and 5.0 mg/kg for organic iodine．The negative textile samples of cotton and polyester were used as the sample matrixes，and typical organic halides were selected for the standard addition and recovery．The average recoveries for organic halides in cotton and polyester at spiked levels of 5，50，200 mg/kg were in the ranges of 86.6%－100% and 85.4%－99.6%，with their relative standard deviations（RSD，n = 7） of 2.3%－5.6% and 1.9%－5.7%，respectively，indicating that the method had good recovery and precision．This method was used in the determination of different contents of organic fluorine，organic chlorine and organic bromine in actual textile samples with good repeatability．The established method overcomes the problems of incomplete combustion and absorption，and low recovery existing in conventional combustion methods．With the advantages of high accuracy，sensitivity and good repeatability，the method is suitable for the determination of organic halides in textiles，and provides a reference for the establishment of standard and the quality and safety control of textiles in China．关键词：organic halides;ion chromatography;textiles;high temperature combustion;water vapor absorption
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发布时间：2023-01-04
Scientific Papers
- 摘要：The polyvinylpyrrolidone functionalized magnetic graphene oxide（polyvinylpyrrolidone/Fe3O4/graphene oxide，PVP/Fe3O4/GO）composites were prepared in this paper．The results of transmission electron microscopy and infrared spectroscopy showed that there were a lot of binding sites on the surface of the composites，which could greatly improve the extraction efficiency．The PVP/Fe3O4/GO composites exhibited a strong adsorption ability towards Cu（Ⅱ），Zn（Ⅱ），Cr（Ⅲ）and Cd（Ⅱ）ions，especially for Pb（Ⅱ）ions．The maximum adsorption capacities were 68.03，103.63，13.82，36.51 and 555.56 mg/g，respectively．The adsorption and desorption process only took 20 min. In the extraction experiment，the concentrations of Cu（Ⅱ），Zn（Ⅱ），Cr（Ⅲ），Cd（Ⅱ） and Pb（Ⅱ） ions were detected by flame atomic absorption spectrometry．It was found that the limits of detection ranged from 0.021 to 3.46 μg/L，which were comparable to those reported in previous literatures．Furthermore，the other coexisting metal ions showed no significant interference to the proposed method．Besides，the proposed method was successfully used for the rapid extraction of 5 metal ions in three kinds of chicken feed samples．The recoveries were in the range of 80.0%－120%，and the results showed a good consistency with those of microwave digestion method．The relative errors were in the range of －18.73%－7.50%．Therefore，the proposed method displayed a high application potential in the extraction of heavy metal ions in feed due to its superiorities，such as high extraction rate，timesaving，easy separation，low acid consumtion and environment-friendly.关键词：magnetic solid phase extraction;polyvinylpyrrolidone functionalized magnetic graphene oxides;heavy metal ions;chicken feed
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发布时间：2023-01-04 - 摘要：A carboxyl-functionalized magnetic carbon nanotube of Fe3O4－Cys@CNT was synthesized by a facile oxidation－precipitation method under the ultrasonic-assisted condition，with Fe2+，oxygen and L-cysteine（L-Cys） as ferrous precursor，oxidant and protectant，respectively．The obtained magnetic carbon nanotube was characterized by Fourier transform－infrared spectroscopy（FT－IR），X-ray diffractometry（XRD） and transmission electron microscopy（TEM）．The results showed that Fe3O4－Cys NPs with a diameter of 20 nm was homogeneously distributed on the surface of CNT．Based on this，an ultra-high performance liquid chromatography with magnetic solid-phase extraction（MSPE/UPLC） was established for the analysis of clenbuterol（CLB） and ractopamine（RAC） in pork samples via using Fe3O4－Cys@CNT as the adsorbent．Under the optimal extraction conditions，there were good linear relationships for CLB and RAC in the concentration range of 0.5－100 μg/L，with correlation coefficients（r） not less than 0.997 4 and the limits of detection（LOD） of 0.15 μg/L．The recoveries for CLB and RAC ranged from 95.1% to 112%，with relative standard deviations（RSD） less than 11%．The extraction efficiency of Fe3O4－Cys@CNT reduced less than 3% after it was used repeatedly for 4 times，indicating that the adsorbent was recyclable．With the advantages of simple preparation，short synthesis time and environmental protection，the Fe3O4－Cys@CNT prepared is a promising MSPE adsorbent，which could separate and enrich CLB and RAC in complex matrix rapidly．The preparation method of the new adsorbent and the established method provide new ideas for the detection of clenbuterol in complex food and biological samples．关键词：clenbuterol;ractopamine;oxidation－precipitation;carbon nanotube;magnetic solid extraction;ultra-high performance liquid chromatography
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发布时间：2023-01-04 - 摘要：The near-infrared spectra of a certain water content and different mass concentrations of luteolin solutions were collected，and the spectral peak changes were studied by means of a multivariate analysis method．A model for luteolin detection was established based on the disturbance of the water spectra．By comparing different spectral preprocessing methods，it was finally determined that the standard normal transformation（SNV） method was used for spectral preprocessing，and the partial least squares（PLS） method was used to establish a quantitative prediction model for luteolin．The results showed that the correlation coefficient R of the model selected by Kennard－Stone（KS） was 0.994 7，and the root mean square error of cross validation（RMSECV） was 1.947 8，ratio of performance to deviation（RPD） was 4.292 7，it indicated that the model was robust and the error was small．Meanwhile，the predicted root mean square error（RMSEP） of the prediction set samples was 2.077 7，and the recovery ranged from 98.0% to 105%．The results showed that the luteolin content could be determined based on the perturbation of the near-infrared spectra of water．The method is simple，rapid and accurate，and it provides a new method for the determination of bio-active ingredients．关键词：water spectromics;near infrared spectroscopy;perturbation;luteolin
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发布时间：2023-01-04 - 摘要：A method based on centrifugal ultrafiltration combing with ion chromatography－triple quadrupole mass spectrometry（IC－MS） was established for the simultaneous determination of ethephon and 2，4-dichlorophenoxy－acetic acid（2，4-D） in vegetables．Four vegetables，i.e eggplant，tomato，corn and chili were pulped with a homogenizer．The samples were purified by centrifugal ultrafiltration with a 0.22 μm inorganic syringe filter．The separation of ethephon and 2，4-D were carried out on an IonPac AS19 analytical column by isocratic elution with 60.0 mmol/L KOH as mobile phase．After reducing the conductance with an in-line suppressor，the target compounds in the eluent were detected by MS with negative electrospray ionization under multiple reaction monitoring（MRM） mode，and quantified by the external spiked method．The results showed that the calibration curves were linear（r ≥ 0.999 5） in the range of 0.5－200.0 μg/L．The limits of detection for ethephon and 2，4-D were 0.2 μg/L and 0.05 μg/L，the limits of quantitation were 0.7 μg/L and 0.17 μg/L，respectively．The average recoveries for ethephon and 2，4-D in four vegetables were in the range of 88.3%－96.8% and 92.5%－102%，with intra-RSDs（n = 6） of 2.6%－5.9% and 1.2%－4.4%，and inter-RSDs（n = 6） of 2.2%－5.4% and 1.1%－3.4%，respectively．Furthermore，the established method was successfully applied to the determination of the pesticides in 4 vegetable samples purchased from local markets in Nanjing．Both ethephon and 2，4-D were detected with contents of 17.5－412.6 μg/kg and 1.1－4.1 μg/kg，respectively．The results showed that the method could meet the requirements for the simultaneous and rapid determination of ethephon and 2，4-D in vegetables，and provide a guidance for the detection of food safety cases in actual combat of public security.关键词：centrifugal ultrafiltration;ion chromatography－triple quadrupole mass spectrometry（IC－MS）;vegetables;ethephon;2，4-dichlorophenoxy－acetic acid （2，4-D）
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发布时间：2023-01-04 - 摘要：A micro gas chromatography was established for the quantitative analysis of hydrogen and deuterium components in fusion reactor fuel cycle system．An alumina column（4～6 m × 0.53 mm） was modified with MnCl2 solution．Effects of concentration of modified liquid，length of column and flow rate of carrier gas on the analysis of H/D components were studied．The mixture of H2，HD and D2 were separated at LN2 cryogenic temperature（77 K）．The results indicated that the column treated with 19% MnCl2 solution was better than that treated with 15% MnCl2 solution for the separation of hydrogen isotopes．The longer the column length，the better the separation effect of H2 and HD. Under the experimental conditions，H2 and HD components could be completely separated when the column length was longer than 5 m，and the peak resolution between H2 and HD was larger than 1.5，resulting in the effective separation of the hydrogen isotope．Furthermore，the minimum values of HETP for HD and D2 were 0.013 cm and 0.016 cm in the experiment，respectively．As for the three hydrogen isotopes in He，there were good linear relationships for the three components in the concentrations range of 0%－10%，with their correlation coefficients not less than 0.993 and the detection limits（LODs） of 600.1，343.8，654.5 μL/L for H2，HD and D2，respectively．The peak area relative standard deviations（RSDs） were in the range of 0.34%－1.5%．The method is a rapid，accurate and applicable analysis method for hydrogen isotope，which is expected to be applied to the analysis of hydrogen isotope gases in the D/T fuel cycle system of fusion reactor．关键词：hydrogen deuterium components;fuel cycle;micro gas chromatography
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发布时间：2023-01-04 - 摘要：A gas chromatography－mass spectrometry（GC－MS）coupled with ultrasonic extraction and headspace solid phase microextraction（HS－SPME） was established for the rapid analysis of seven volatile sulfur compounds（VSCs），including dimethyl sulfide（DMS），carbon disulfide（CS2），methyl ethyl sulfide（MES），diethyl sulfide（DES），dimethyl disulfide（DMDS），diethyl disulfide（DEDS），dimethyl trisulfide（DMTS） in plastic track surface．The HS－SPME extraction conditions，ultrasonic extraction conditions and GC－MS parameters were optimized．Under the optimized conditions，7 VSCs had good linearities in the range of 5－500 ng/g for DES and DMDS，and 10－500 ng/g for other five VSCs，with correlation coefficients（r） of 0.984 7－0.998 9．The limits of detection（LODs，S/N = 3） were in range of 0.4－1.4 ng/g，and the limits of quantitation（LOQs，S/N = 10） were 1.3－4.7 ng/g．The average recoveries at low，medium and high spiked levels ranged from 89.6% to 104%，with relative standard deviations（RSDs，n = 6） of 3.5%－12%．The method integrates separation，enrichment and injection into one step，and is suitable for the routine detection of VSCs in the synthetic surfaces.关键词：headspace solid phase microextraction（HS－SPME）;gas chromatography－mass spectrometry（GC－MS）;plastic track surface;volatile sulfur compounds（VSCs）
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发布时间：2023-01-04 - 摘要：In order to maintain the public safety and order of the society，and achieve fast non-destructive and accurate qualitative analysis for drugs，the infrared spectrum data for benzodiazepines and phenothiazines samples were collected in the experiment to construct different data classification models and compare the effects of different spectral data sets on the accuracy of their analysis．In the process of identifying and classifying the two types of psychotropic substances，benzodiazepines and phenothiazines，the second-derivative model based on the full spectra was better than other single models，whose overall classification accuracy rate reached 92.7%．Combined with Bayes discriminant analysis，the second-derivative classification model based on the full spectra and fingerprint spectra fusion performed the best in the process of identifying and classifying the two types of psychotropic substances，benzodiazepines and phenothiazines，with an overall classification accuracy rate reaching to 100%．Meanwhile，in the process of identifying and classifying different kinds of psychotropic substances in the same type，its overall classification accuracy rates for various kinds of psychotropic substances in benzodiazepines and phenothiazines reached 96.7% and 100%，respectively．This research realized the rapid and accurate qualitative analysis of different types，as well as different kinds of sleeping pills of the same type，providing a certain technical support for the accurate qualitative analysis of such smuggling controlled drug cases．关键词：spectral fusion;public security;psychotropic drugs;Bayes discriminant analysis;multilayer perceptron
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发布时间：2023-01-04
Experimental Techniques and Methods
- 摘要：Membrane inlet mass spectrometry（MIMS） utilizes a semi-permeable membrane to selectively transfer the target molecules in gas，liquid or solid mixtures into a mass spectrometer，yielding on line monitoring volatile organic compounds. It has been widely used for the continuous monitoring on line without chromatographic separation and sample pretreatment，where the inferences from the bulk of the sample matrix could be avoided．In this review，the principle and structure of MIMS instrument were introduced，including the membrane materials，ionization sources，the mass spectrometers and also interface configurations．The progresses of MIMS instruments in the laboratory were presented，especially on the combination of membrane with the single photon ionization time of flight mass spectrometry．A new membrane inlet with buffer cell for time of flight mass spectrometry was developed to increase the limit of detection．Then，the combination of helical hollow fiber membrane inlet with time of flight mass spectrometry and ion mobility spectrometry was introduced for detection trace volatile organic compounds in air and water．Moreover，the in-source stretched hollow fiber membrane inlet and in-source helical hollow fiber membrane interface were also developed for higher limit of detection and faster responding time．Recently，MIMS has been widely used in a lot of field including environmental pollutions monitoring，also the field of ecology，life sciences，microbial metabolism．In the field of environment，some methods based on MIMS were developed to measure the chlorinated and brominated-amines，aromatic pollutants in drinking water．MIMS also was used for direct analysis of the naphthenic acids in constructed wetland samples and polyaromatic hydrocarbons in soil and aqueous samples．In the field of ecology，MIMS was used to investigate the abundance and concentration of aqueous nitrate，nitrite and ammonium．It also used to measure the denitrification，anammox，DNRA rates，and net N2 flux in paddy soil．In the field of life sciences，membrane inlet ion mobility spectrometry was used for on-line measurement of trace propofol in exhaled air．MIMS was used to detect the representative bacteric metabolites and classify four kinds of bacteria．In the field of microbial metabolism，MIMS was used for quantitative understanding of inorganic carbon uptake flux and carbon concentrating mechanisms in metabolically engineered cyanobacteria．MIMS was also used to study the CO2 and HCO
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发布时间：2023-01-04 - 摘要：Potassium permanganate（KMnO4），as a powerful oxidant，is widely used in chemical production，water purification and wastewater treatment．While excessive emission can cause severe environmental pollution and excessive intake can lead to irreversible organ necrosis．Moreover，it is one of the most frequently used raw materials in preparing improvised explosives．Hence，a rapid，highly sensitive and visual identification of trace KMnO4 is of great significance for environment monitoring and public security．Recently，fluorescence technique has been widely applied for KMnO4 detection due to the features of high sensitivity and selectivity，rapid response，various optional function group and visualization．At present，the fluorescent involved functional materials for detecting KMnO4 can be divided as nanomaterials，coordination polymers and hybrid materials，the detection mechanism relies on inner filter effect（IFE），fluorescence resonance energy transfer（FRET），static quenching，redox and complexation. Among them，the IFE-based method is the main mechanism employed in KMnO4 detection due to the advantages of simple operation，sensitive response and material reusability．Hence，this review systematically summarizes the recent progress within five years of the IFE-based approaches for KMnO4 determination．It starts with a brief introduction of strategic designs focusing on performance improvement of IFE-involved sensing detection towards KMnO4．The influence from the modulation of the mono-/multi-emission wavelength on the sensing sensitivity is comprehensively discussed．To end，a prospective is forecasted regarding the future development of IFE-involved sensing strategy for KMnO4 detection and the potential application，providing a guide for the IFE-based sensing platform to ultra-sensitively detect KMnO4．关键词：KMnO4;inner filter effect;fluorescent detection;improvised explosive;regulation strategy
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发布时间：2023-01-04
Reviews
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