最新刊期
卷 42 ， 期 1 ， 2023
- 摘要：A solvent extraction/gas chromatography－tandem mass spectrometry（GC－MS/MS） was established for the simultaneous detection of 78 allergenic aromatics and 4 pesticide compounds in plant mosquito repellent products．The polar chromatographic column Agilent VF－WAXms was used for chromatographic separation，and some of the co-efflux compounds were analyzed qualitatively and quantitatively by different characteristic ion pairs．The extraction conditions of samples were optimized by using positive samples as the research object．The contents of multiple target substances in the samples were compared under different extraction solvents and different extraction time conditions．The optimal extraction conditions were determined by using dichloromethane as the extraction solvent and ultrasonic extraction at 30 ℃ for 30 min．The results showed that there were good linear relationships for 82 target compounds in the respective concentration ranges，with their correlation coefficients（r） larger than 0.992 0．The limits of quantitation were in the range of 0.02－5.0 mg/kg．The recoveries ranged from 60.0% to 120%，with relative standard deviations（RSDs） not more than 9.5%．The method was used to screen 29 samples including mosquito repellent stickers，mosquito repellent buttons，mosquito repellent liquids and mosquito repellent gels．A total of 33 allergenic aromatics and 1 pesticide（ethyl butylacetylaminopropionate） were detected．11 allergenic aromatics including α-pinene，β-pinene and D-limonene were found in more than 80% of the samples，with a maximum content range of 116－21 140 mg/kg．Meanwhile，ethyl butylacetylaminopropionate was detected in 3 mosquito repellent liquids，with a content range of 10 200－21 350 mg/kg．This method is simple，accurate and reliable，and it could be used for the simultaneous targeted screening and determination on allergenic aromatics and pesticides in mosquito repellent products.关键词：gas chromatography－tandem mass spectrometry（GC－MS/MS）;mosquito repellent product;allergenic aromatics;pesticide
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发布时间：2023-05-25 - 摘要：The elemental composition of fragment ions was obtained by directly collecting the high precision mass number of fragment ions（resolution > 70 000，m/z 200），and then the cracking laws of chloropropanol diesters were investigated by elemental simulation．Results showed that chloropropanol diesters have neutral ions in the form of fatty acids or ketoacids，forming a series of fragmentation fragments，including ［RCH2COOH + H］+，［RCH
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发布时间：2023-05-25 - 摘要：Three composite substrates，TiN@Ag sol，TiN－Ag film and TiN－Ag@Ag sol were prepared for surface-enhanced Raman spectroscopy（SERS） detection of adenine，and the enhancement effect of Raman performance was studied and analyzed．It was found that the peak position of the adenine SERS spectrum was somewhat shifted compared with the theoretical one，where the molecular configuration and dipole moment changed probably when adenine was adsorbed on the enhanced substrate．Meanwhile，the participation of excessive electrons and external solvents in the theoretical calculation might cause peak shift．It was also found that the adenine signal on the TiN－Ag@Ag sol substrate was the strongest since the substrate not only has “hot spots”that can significantly improve the SERS activity due to the resonance coupling between the TiN film and silver nanoparticles，but also has more “hot spots”provided by the Ag nanoparticles on the TiN－Ag@Ag sol substrate aggregated between the Ag nanorods on TiN to form a nano-band gap．Furthermore，TiN－Ag@Ag sol substrate was applied to the sensitive detection of adenine，with a detection limit of 10-5 mol/L．Finally，the enhancement mechanisms for each substrate were analyzed by UV photoelectron spectroscopy combined with Gaussian and FDTD calculations.关键词：surface-enhanced Raman spectroscopy;TiN;nano silver;adenine
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发布时间：2023-05-25 - 摘要：In order to meet the rapidly growing demands for safety evaluation and management on the genetically modified organisms（GMOs），the research and application of efficient and reliable GMOs detection technology has become more and more important．A novel electrochemical genosensor was prepared for sensitive detection of GMO components by utilizing the enhanced mimic peroxidase activity of cPPy－hemin to H2O2 and signal amplification strategy of point-triggered strand displacement reaction（TSDR） in this paper．Carboxylated polypyrrole（cPPy） and hemin（cPPy－hemin） nanocomposites were synthesized by a one-step method，which was used as signal tags to immobilize double-stranded DNA to form DNA－cPPy－hemin signal nanotags．Using the -NH2 groups in DNA duplex structure composed of signal probe（Ps），template strand（Ts） and auxiliary strand（As），the prepared cPPy－hemin was biofunctionalized to form Ts/As/Ps－cPPy－hemin．In presence of target transgenic cauliflower mosaic virus 35S promoter（CaMV35S） and fuel strand（Fs），the TSDR was triggered by the target CaMV35S，the released Ps－cPPy－hemin was captured by the immobilized capture probes（Cs） on the surface of GCE through hybridization．The quantitative detection of the target CaMV35S was realized by recording the catalytic reduction signal of H2O2 by cPPy-hemin. Under the optimal conditions，the fabricated biosensor had a good linear range of 1.0 × 10-14 -1.0 × 10-9 mol/L，with a detection limit（S/N = 3） of 3.2 × 10-15 mol/L．The biosensor possessed good selectivity，reproducibility and stability，which could be used for the detection of the CaMV35S segments in total DNA extracts from genetically modified soybeans.关键词：carboxylated polypyrrole;hemin;point-triggered strand displacement reaction;mimic peroxidase;transgene;electrochemical genosensor
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发布时间：2023-05-25 - 摘要：Based on the whale optimization algorithm（WOA） of swarm intelligence，an improved whale optimization algorithm（iWOA） for the selection of near-infrared spectral wavelengths was proposed. Firstly，a chaotic strategy was introduced to initialize the population to avoid the algorithm from falling into local optimization prematurely. Secondly，a nonlinear time-varying Sigmoid transfer function and greedy algorithm were introduced to improve the algorithm's optimization ability and make the model obtain better prediction accuracy. In order to verify the effectiveness of the algorithm，the near-infrared spectral data of four indicators for corn fat，protein，starch and water were used for PLS modeling and analysis，and compared with other algorithms. The results showed that the iWOA algorithm could effectively filter out the wavelength variable in the shortest possible time，reduce the complexity of the model and improve the prediction accuracy of the model. The root mean square errors of prediction（RMSEPs） of the model decreased from 0.077 2，0.122 4，0.334 4 and 0.059 5 to 0.033 2，0.050 7，0.139 2 and 0.004 4，and the prediction accuracy was improved by 57.0%，58.6%，58.3% and 92.6%，respectively，compared with those of the full spectrum. The numbers of wavelengths selected by the algorithm were 84，69，87 and 66，respectively.关键词：near-infrared spectroscopy;wavelength selection;improved whale optimization algorithm;transfer function;greedy thinking
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发布时间：2023-05-25 - 摘要：A high-throughput screening method for 167 illegally added chemical drugs in traditional Chinese veterinary medicine oral liquid was established by ultra-high performance liquid chromatography－quadrupole electrostatic field orbit trap mass spectrometry．The samples were extracted with 0.5% formic acid acetonitrile－water by oscillation ultrasonic extraction，and the data were collected with electrospray ionization source（ESI） in positive and negative ion scanning mode．By comparing the self-built the basic information and MS information database of 167 compounds，the chromatographic conditions，MS conditions，extraction solvent types and purification conditions were optimized，and the test results were analyzed．The results showed that the oral liquid samples after pretreatment were tested on the machine，and the data results were analyzed by Trace Finder screening software．It was found that the concentrations of illegally added drugs could be qualitatively detected when their concentrations were 50 ng/mL（cephalosporin and lactam drugs were 100－200 ng/mL）．The detection rates for illegally added drugs were slightly different due to the influence of matrixes．With the characteristics of simple operation，rapidness and efficiency，this method could basically achieve the purpose of high-throughput rapid screening of illegally added chemical drugs in traditional Chinese veterinary medicine oral liquid，and it lays a foundation for the screening of illegally added chemical drugs in other veterinary drug formulations.关键词：traditional Chinese veterinary medicine oral liquid;illegally added;high-resolution mass spectrometry;high-throughput screening
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发布时间：2023-05-25 - 摘要：A high-throughput method for rapid and qualitative screening of nine prostaglandin F2α compounds，i.e. bimatoprost，travoprost，tafluprost，tafluprost ethyl amide，latanoprost，bimatoprost acid methyl ester，cloprostenol isopropyl ester，15-keto travoprost，N-norbimatoprost in eyelash cosmetics was established by ultra-performance liquid chromatography－quadrupole time-of-flight mass spectrometry（UPLC－Q－TOF MS/MS）．The samples were ultrasonically extracted with acetonitrile，separated on a Waters ACQUITY UPLC BEH C18（2.1 mm × 100 mm，1.7 μm） chromatographic column with 2 mmol/L ammonium formate aqueous solution containing 0.05% formic acid－acetonitrile as the mobile phase，then data-acquisitioned by quadrupole time-of-flight mass spectrometry in MSE mode using electrospray ionization source in positive ion mode（ESI+），and a high-throughput screening database for 9 prostaglandin F2α compounds was established．There were good linear relationships for the 9 analytes in their respective concentration ranges，with correlation coefficients（r2） all greater than 0.99．The detection limits and the quantitation limts of 9 analytes were in the ranges of 0.075－0.75 μg/g and 0.25－2.5 μg/g，respectively．The screening database collected and established by high-resolution mass spectrometry can screen 9 kinds of prostaglandin F2α compounds in cosmetics without reference substances．The results showed that the established method has good selectivity in high-throughput qualitative screening of 48 batches of eyelash cosmetics with good specificity．The method is suitable for the screening and analysis of prostaglandin F2α compounds in cosmetics，and it could provide a technical support for the qualitative analysis of five prostaglandin F2α compounds in cosmetics.关键词：prostaglandin F2α;cosmetics;ultra-performance liquid chromatography－quadrupole time-of-flight mass spectrometry
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发布时间：2023-05-25 - 摘要：A method for evaluation on the removal effect of dialyzer to protein-bound uremic toxins（PBUTs） was established based on high performance liquid chromatography－triple quadrupole mass spectrometry．The dialysis simulated fluid with the same concentration of PBUTs as the dialysis patients’ blood was prepared instead of blood to conduct dialysis treatment in vitro due to the difficulty to obtain clinical blood samples and the complexity of patient blood composition，and the simulated fluid before and after dialysis was taken as the sample to be tested．After acetonitrile precipitation of protein and ultrafiltration centrifugation，the samples were separated on a Hypersil GOLD VANQUISH C18（100 mm × 2.1 mm，1.9 µm） column by gradient elution，using 5 mmol/L ammonium acetate solution and methanol as mobile phases．The mass spectrometric analysis was carried out under negative ion selective reaction monitoring mode（SRM），and the internal standard method was used for quantitative analysis of 3 PBUTs．The calibration curves of 3 PBUTs showed good linear relationships in the concentration range of 25－1 000 ng/mL，and the correlation coefficients（r） were more than 0.99．The limits of quantitation（LOQs） were 25 ng/mL．The average recoveries for 3 analytes at three added concentrations of 75，250 and 750 ng/mL ranged from 92.5%－114%，with the intra-day and inter-day RSDs both less than 5.0% and the matrix effects of 80.6%－105%．This method had the characteristics of low cost，simple pretreatment，short run-time and high accuracy，which provided a reliable technical support for evaluation on the removal effect of dialyzer to PBUTs.关键词：protein-bound uremic toxins;dialyzer;simulated fluid;high performance liquid chromatography－triple quadrupole mass spectrometry;removal effect
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发布时间：2023-05-25 - 摘要：Glycosidic compounds in tobacco are vital aroma precursors．It is of great significance to understand the types and structures of glycosides in tobacco for its cultivation and processing，as they are very important aroma precursors．In this paper，60 glycosides were screened by untargeted liquid chromatography－mass spectrometry（LC－MS） with the characteristic neutral loss of glycosyl groups，of which 23 glycosides were identified according to their MS/MS spectra and literatures．The results showed that the glycosyl groups were mainly composed of hexose，deoxyhexose or disaccharide of both．The aglycones of phenolic acids，flavonoids，alkaloids，terpenes，sterols and ceramide aglycones were identified．This paper provides a method for screening glycosides in tobacco and important structural informations for the following study on the influencing factors of aroma change in tobacco.关键词：glycosides;tobacco;liquid chromatography－mass spectrometry;neutral loss
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发布时间：2023-05-25
Scientific Papers
- 摘要：A gas chromatography－mass spectrometry was developed for the simultaneous determination of 54 volatile organic pollutants in infant food．1 g of milk powder or 2 g of other sample was firstly put into a 20 mL headspace bottle，then 5 mL sodium chloride saturated solution was added．The sample was heated in a headspace at 90 ℃ for 30 min，and the top gas was injected into the gas chromatography for separation．54 volatile organic pollutants were separated on a DB－VRX capillary chromatographic column，and determined by quadrupole mass spectrometry in full scan mode．The results showed that the linear ranges for each compound in milk powder were from 0.010 to 0.100 mg/kg，with a quantitation limit of 0.010 mg/kg，those for each compound in the powdered infant food ranged from 0.010 mg/kg to 0.250 mg/kg，with a quantitation limit of 0.010 mg/kg，while those for each compound in the muddy infant food ranged from 0.002 mg/kg to 0.250 mg/kg，with a quantitation limit of 0.002 mg/kg．Average recoveries at different spiked levels ranged from 80.6% to 130%，with the relative standard deviations（RSDs） not larger than 19%．35 batches of commercially available infant foods were detected．4-Isopropyltoluene，styrene，toluene，tetrachloroethylene and 1，2-dichloropropane were found in 9 samples．This method is simple and rapid，and it is suitable for the detection of 54 volatile organic pollutants in infant food.关键词：infant food;volatile organic pollutants;headspace/gas chromatography－mass spectrometry
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发布时间：2023-05-25 - 摘要：An ultra performance liquid chromatography－tandem mass spectrometry（UPLC－MS/MS） with dichloromethane solvent induced extraction was established for the determination of 12 herbicides in environmental water．The volume of extractant acetonitrile，the type and dosage of extractant，and the centrifugation time were determined by single factor test．Combined with response surface analysis，an optimal pretreatment method was obtained．Meanwhile，mass spectrum parameters，chromatographic column and different mobile phases were also optimized during the establishment of the instrument method．Under the optimal conditions，the calibration curves for 12 herbicides were in good linear relationships，with their correlation coefficients（r） greater than 0.999 5．The limits of detection and the limits of quantitation were in the ranges of 0.05－0.5 μg/L and 0.2－5.0 μg/L，respectively．Average recoveries ranged from 83.0% to 110%，with relative standard deviations of 0.30%－5.0%．The method is simple，sensitive and low organic solvent consumption，and it is suitable for the high throughput inspection of actual samples.关键词：herbicide;solvent induced extraction;ultra performance liquid chromatography-tandem mass spectrometry;environmental water
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发布时间：2023-05-25 - 摘要：A high performance liquid chromatography－tandem mass spectrometry（HPLC－MS/MS） method was developed for the determination of nine banned dyes in aquatic products，including bright green，methylene blue and its three metabolites，malachite green and leucomalachite green，crystal violet and leucocrystal violet．After pretreatment procedure，samples were extracted with acetonitrile－0.1 mol/L ammonium acetate（pH 4.5） solution．Extract solution were purified by salt-out extraction of sodium chloride，n-hexane and PRS solid phase extraction column．The targets were separated on a Luna C18（2.1 mm × 50 mm，5 μm） column with a mobile phase consisting of acetonitrile-5 mmol/L ammonium acetate（0.1% formic acid） for gradient elution．Mass spectrometry multiple reaction monitoring（MRM） and positive ion ionization mode were used for testing and external standard method was used for quantitative analysis．Good linear relationships were obtained for nine compounds in the content range of 0.5－20.0 μg/L，with correlation coefficients（r2） greater than 0.99．The limits of detection（LODs）were 0.5 μg/kg，and limits of quantitation（LOQs）were 1.0 μg/kg．Tilapia，pomfret，shrimp and crab were used as the blank matrix，and spiked at the levels of 0.5，1.0，5.0 μg/kg．The average recoveries were 76.8%－104%，and the relative standard deviations（RSDs，n = 7） were 4.3%－10%．By using this method，methylene blue and azure B were detected in tilapia samples which were treated with methylene blue medicine bath．The method is accurate，reliable and reproducible，so it can be used for the quantitative analysis of 9 banned dyes in aquatic products.关键词：high performance liquid chromatography－tandem mass spectrometry（HPLC－MS/MS）;banned dyes drugs;aquatic products
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发布时间：2023-05-25 - 摘要：A high performance liquid chromatography（HPLC） and mass spectrometry method was established for the determination and confirmation of hydroxypyridinone in dandruff shampoo．The samples were extracted with acetonitrile，then separated on a Waters Atlantis Hilic（4.6 mm × 250 mm × 5 μm） column with a mixed solution of 95% acetonitrile and 5% 400 mmol/L oxalic acid as the mobile phase，and detected by HPLC．Mass spectrometry confirmation on hydroxypyridone in positive multiple reaction monitoring（MRM） mode after derivatization of hydroxypyridone with dimethyl sulfate．Results showed that there were good linear relationships for the analytes in the range of 1.0－100.0 mg/L，with correlation coefficients（r） of 0.999．The limits of detection（LODs） and limits of quantitation（LOQs） for hydroxypyridone were 8.0 μg/g and 20.0 μg/g，respectively．The spiked recoveries ranged from 91.8% to 96.7%，with RSDs of 1.3%－3.7%．The method is rapid，efficient and accurate，and it could be applied to the determination of hydroxypyridone in shampoo and zinc pyrithione．In this paper，a series of comparisons were carried out by liquid chromatography and infrared spectroscopy with respect to hydroxypyridone and its tautomer，2-hydroxypyridine-N-oxide．In addition，the possible source of hydroxypyridinone，a prohibited raw material in shampoo，was clarified.关键词：hydroxypyridinone;2-hydroxypyridine-N-oxide;anti-dandruff agent;high performance liquid chromatographic（HPLC）;liquid chromatography－tandem mass spectrometry（LC－MS/MS）
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发布时间：2023-05-25 - 摘要：In this paper，a quantitative analysis model was established by partial least squares method（PLS），based on the contents of glycine，glycyrrhizin and cysteine hydrochloride in compound glycyrrhizin by collecting near infrared spectrum（NIRS） of 70 batches of samples，and verified．Results showed that linear correlation coefficients（R） of the established model for glycine，glycyrrhizin and cysteine hydrochloride were 0.999 54，0.947 01 and 0.999 95，while the root mean squared error of correction set（RMSECs） were 0.289，0.098 0 and 0.001 07，respectively．Furthermore，the mean relative deviations between the reference values and the predicted values of the three components in 13 batches of samples were 0.41%，0.72% and 0.86%，respectively，and there was no significant difference in the T test（P > 0.05）.关键词：near infrared spectrum（NIRS）;quantitative model;compound glycyrrhizin for injection
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发布时间：2023-05-25
Experimental Techniques and Methods
- 摘要：Monolithic column（MC） is a uniform and stable rod-shaped entity formed by in-situ polymerization of reaction monomer，crosslinking agent and pore-forming agent in tubular materials such as capillary or chromatographic column under certain conditions，so it is also called rod-shaped column，continuous bed，etc．MC could be divided into three types according to the types of material used，i.e．organic monolithic columns，inorganic monolithic columns and organic-inorganic hybrid monolithic columns．Capillary monolithic column has all the advantages of solid-phase microextraction（SPME） as it belongs to in-tube solid-phase microextraction（In-tube SPME），integrating sampling，extraction，concentration，injection and other steps．Compared with coating fiber and open tubular capillary，MC possesses more extraction sorbent and exhibits higher extraction capacity．In comparison to the particle-filled column，the preparation procedure of MC does not need to be packed．In addition，the monolithic porous structure facilitates convective mass transfer procedure preferable in extraction process，which helps to complete the extraction procedure within a shorter time．With the advantages of simple operation，rapidness，high efficiency，low consumption and high sensitivity，MC is suitable for the analysis of constant，trace and even ultra-trace samples，which is on-line with the trend of environment-friendly，miniaturized and automated sample pretreatment technology，and is of great significance in the field of sample pretreatment．In this review，the design，preparation and application progress of MC in the field of sample pretreatment in recent years are summarized，and its future development trend is prospected，which provides a reference for the design and preparation of MC in this field.关键词：monolithic column（MC）;sample pretreatment;solid phase microextraction（SPME）;preparation;application
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发布时间：2023-05-25 - 摘要：Carbon fiber ionization technology is a new kind of ambient ionization mass spectrometry technology，which could be used for detection on various forms of samples or sample surface material in open environment．This technology could simplify the work flow，reduce the matrix effect of samples and expand its application with the advantages of low cost，high throughput，simplicity，real time and rapidness．The main factors affecting the ionization efficiency，such as carbon fiber shape，carbon fiber temperature，voltage applied to carbon fiber，distance between carbon fiber and ion injection port，and sample adding method are introduced in this paper，based on the principle of carbon fiber ionization mass spectrometry technology．Furthermore，the improvement and development of the technology in recent years，and its application in the food and drug safety，forensic toxicology test，species identification and biological samples and environmental analysis are summarized，and the applications of the characteristics and advantages of this technology are introduced in detail．Finally，the existing shortcomings and future research directions of carbon fiber ionization mass spectrometry are discussed.关键词：ambient ionization mass spectrometry（AIMS）;carbon fiber ionization mass spectrometry;principle of carbon fiber ionization mass spectrometry;effecting factors;application
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发布时间：2023-05-25 - 摘要：Fingerprints，as one of the most common physical evidences at the case scenes，contain not only the morphological characteristics that could be used for personal identification，but also the rich chemical information reflecting the personal characteristics of the person left behind．It is difficult to prove forensically that the poisoner has committed the crime when drug addicts or poisoners in drug-related cases need to be confirmed by using biological samples such as blood and urine，while detection on drug substances in fingerprints could provide the information on the drug used and the exposure of those left behind in fingerprints，link them to specific cases，reflect personal lifestyle information，and further provide new ideas for the discovery of drug-involved persons．The development lineage as well as the current status and hot spots of research in this field are summarized by bibliometric methods in this paper，also，the various technical methods and features for the established drug analysis in fingerprint substances are mainly summarized，and the future research directions and difficult points are reviewd，in order to provide a reference for detection on drug in fingerprint residues in actual cases.关键词：fingerprint residues;instrumental analysis;drug detection;progress
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发布时间：2023-05-25
Reviews
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