最新刊期
卷 41 ， 期 3 ， 2022
- 摘要：An ultra-performance liquid chromatography－quadrupole time-of-flight mass spectrometry（UPLC－Q－TOF MS） was applied to construct the fingerprints of raw Fingered Citron and processed Fingered Citron. Meanwhile，the chemical components differences between raw Fingered Citron and processed Fingered Citron were analyzed by chemical pattern recognition methods．The sample was firstly ultrasonically extracted with methanol，and then separated on an Agilent Poroshell 120 EC－C18（3.0 mm × 150 mm，2.7 μm） column by gradient elution，with 0.1% formic acid + 5 mmol/L ammonium acetate and acetonitrile as the mobile phases．The MS system with electrospray ionization（ESI） source was operated under positive and negative ion mode．Based on the accurate mass， fragment ions， retention behaviors， previous reports，net-work database and the fragmentation pathways，a total of 37 components in the raw Fingered Citron and the processed Fingered Citron were identified，including 10 flavonoids and flavonoid glycosides，4 coumarins，12 organic acids，5 glycosides，2 limonin and 4 other compounds．The fingerprints for the two Fingered Citrons were established，and analyzed by a similar evaluation system for chromatographic fingerprint of traditional Chinese medicine（version 2004 A，National Committee of Pharmacopoeia，China）．The mass of each peak was accurately measured，and their chemical formula were generated via the MassHunter software．The MS/MS spectrum for each peak was compared with the mass database and literature，and their chemical structures were deduced based on the MS/MS fragment，and finally verified by the reference substance．In total，the UPLC－Q－TOF MS fingerprint for raw Fingered Citron contained 24 common peaks，of which 19 were identified. In addition，there were 22 common peaks in the UPLC－Q－TOF MS fingerprint for processed Fingered Citron，and 14 peaks were identified．The principal component analysis（PCA） and orthogonal partial－least squares discriminant analysis（OPLS－DA） were adopted to analyze these data of two herbal medicines via SIMCA－P software（pretreatment with Profinder software）．The results of PCA and OPLS－DA showed that the two Fingered Citrons were significantly discriminated．Nomilin acid，5-isopentenyloxy-7-methoxycoumarin，palmitic acid，oleic acid and oxypeucedanin hydrate were identified，and screened as the chemical markers that attributed to classification. Among them，the content of 5-isopentenyloxy-7-methoxycoumarin changed prominently，and was chosen as the chemical marker for differentiation on raw Fingered Citron and processed Fingered Citron．This study provides a data support for the quality control of raw Fingered Citron and processed Fingered Citron.关键词：Fingered Citron;ultra-performance liquid chromatography－quadrupole time-of-flight mass spectrometry（UPLC－Q－TOF MS）;fingerprint;processing
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发布时间：2022-07-01 - 摘要：A liquid chromatography－quadrupole/electrostatic field orbitrap high-resolution mass spectrometry with on-line cleanup was established for the rapid screening of 123 veterinary drug residues in aquatic products，including fifteen types of 123 wide-range veterinary drugs，i.e．20 sulfonamides，6 macrolides，16 quinolones，12 β-agonists，17 benzimidazoles，4 tetracyclines，2 sedatives，6 hormones，4 β-lactams，1 dapsone，2 anticoccidials，2 dyes，24 glucocorticoids，1 chloramphenicols and 6 resorcylic acid lactones．The samples were extracted with acetonitrile－water（8∶2） by ultrasonic extraction，followed by an automated turbulent flow cyclone chromatography sample clean-up system．The online purification technology TurboFlow is mainly used to achieve the purpose of purification by means of diffusion and dissolution，size exclusion，etc．as it has more advantages than traditional solid phase extraction and matrix dispersion extraction．Sample extraction solution was purified and collected with a CycloneTM P column（0.5 mm × 50 mm）．The analytes were eluted from the extraction column and put into an Atlantis T3 analytical column（100 mm × 4.6 mm，3 μm） prior to chromatographic separation and detection in Full Scan/ddMS2 mode．The target compounds were monitored in both positive and negative full scan modes．The confirmatory analysis was carried out by determining the retention time and accurate masses of all compounds and fragment ions upon target MS/MS，and the external standard method was used for quantification. The total run time was within 18 min，including analytical chromatography and re-equilibration of the turboflow system．The optimization of different experimental parameters including extraction，separation and detection were evaluated separately in this paper．The developed method was validated，and good performing characteristics were obtained．The screening of analytes was performed by library searching．The method could be used for the rapid screening of 123 drugs in aquatic products by means of accurate mass of quasi-molecular ion，retention time and the secondary fragment ion spectra for confirmation. The results showed that the calibration curves of the 123 drugs were linear in their respective concentration ranges with correlation coefficients（r2） more than 0.99．The limits of quantitation were between 0.1 μg/kg and 50 μg/kg．The spiked recoveries for the analytes ranged from 53.7% to 129%，with relative standard deviations of 2.7%－19%．The developed method exhibits a great potential in the routine laboratory analysis of large number of samples belonging to different classes of compounds．Meanwhile，in comparison to traditional procedures，the automated sample clean up could ensure the rapid，effective，simple and sensitive analysis of veterinary drugs for the screening of residues in batches of aquatic products．关键词：on-line cleanup;quadrupole/electrostatic field orbitrap high-resolution mass spectrometry;rapid screening;aquatic products;veterinary drugs
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发布时间：2022-07-01 - 摘要：An ultra performance liquid chromatography－tandem mass spectrometry with solid phase extraction was established for the determination of 18 perfluorinated and polyfluoroalkyl compounds（PFASs） in soil，including 14 types of perfluorocarboxylic acids，3 types of perfluorosulfonic acids and 1 perfluoroether carboxylic acid．The extraction procedure for the target pollutants was optimized by comparing extraction conditions，contained soil particle size，ultrasonic temperature，ultrasonic time，types of solid phase extraction column and eluent concentration．The optimal pretreatment conditions were as follows：the soil was sieved through 60 meshes，then ultrasonically extracted at 40 ℃ with methanol for 10 min．Then the supernatant was separated，and condensed to 1－2 mL under N2．The target was solved in ultrapure water and purified with a WAX Oasis column（150 mg/6 mL）．2 mL methanol and 4 mL methanol containing 0.1% ammonia were applied to the PFASs elution．Eluent was condensed to dryness under N2．Finally，the soil sample was concentrated into 1 mL．The target analytes were separated on an ACQUITY UPLC BEH C18 column using 5 mmol/L ammonium acetate solution and methanol as mobile phases．The negative electrospray ionization （ESI－） was utilized to analyze 18 PFASs. Results showed that there existed good linearity for 18 PFASs in the concentration range of 0.05－200 μg/L with correlation coefficients（r2） greater than 0.996．The detection limits and the quantitation limits of the method were in the ranges of 0.003－0.100 μg/L and 0.010－0.300 μg/L，respectively. The recoveries ranged from 76.3% to 132%，with relative standard deviations（RSDs） of 0.40%－11%．With simple pretreatment and high sensitivity，the method could be applied to the rapid and precise quantification of 18 PFASs including GenX in soils.关键词：perfluorinated and polyfluoroalkyl compounds;soil;solid phase extraction;ultra performance liquid chromatography－tandem mass spectrometry;GenX
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发布时间：2022-07-01 - 摘要：A high performance liquid chromatography－fluorescence detection（HPLC－FLD） method combined with an effervescent assisted liquid phase microextraction（EA－LPME） was established for the determination of seven quinolones（QNs） in honey，based on a switchable hydrophilic solvent（SHS），nonanoic acid with switchability and density lower than water．In the proposed method，the pH value of the solution was adjusted by adding Na2CO3 and H2SO4 separately to make nonanoic acid complete the conversion from hydrophobicity to hydrophilicity and then to hydrophobicity．Meanwhile，the CO2 bubbles generated in-situ increased the contact area，and consequently promoting the extraction of analytes．Unlike traditional liquid phase microextraction（LPME）performed in a centrifuge tube，this method with simultaneous extraction and enrichment was completed in the syringe to realize the phase separation without centrifugation．In order to improve the extraction efficiency，the type and volume of extractant，the type and volume of pH regulator and the extraction time were optimized．The optimum extraction conditions were as follows：extraction solvent：nonanoic acid（200 μL），pH regulators：2.0 mol/L Na2CO3（400 μL） and 2.0 mol/L H2SO4（300 μL），and extraction time：1.5 min．There were linear ranges of 2.0－100 μg/L for norfloxacin and ciprofloxacin，and 2.0－200 μg/L for the other five drugs，with correlation coefficients（r2） of 0.999 5－0.999 9．The recoveries at three spiked levels of 10，100 and 500 ng/g for analytes ranged from 62.8% to 117%，with intra-day relative standard deviation（RSDs， n = 3） and inter-day（n = 6） RSDs not more than 6.2%．The limits of detection and the limits of quantitation were 3.0 ng/g and 10 ng/g，respectively. To evaluate the practicability of the present metnod，three kinds of honey samples spiked with 100 ng/g QNs were examined under the optimized conditions for the extraction（n = 3），the recoveries for seven analytes ranged from 78.8% to 120%，with RSDs less than 5.1%．The results demonstrated that the developed method is simple，accurate，effective and environmentally friendly，which could be used for the determination of quinolones in honey samples．关键词：high performance liquid chromatography;switchable hydrophilic solvent;effervescent assisted liquid phase microextraction;honey;quinolones
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发布时间：2022-07-01 - 摘要：A porous organic cage（POC） with large specific surface area，uniform porosity and tetrahedral structure was synthesized with（1R，2R）-diphenylethylenediamine and 2-hydroxy-1，3，5-pyromellitic formaldehyde．The porous material was characterized by X-ray powder diffraction，nuclear magnetic resonance spectrometry，Fourier transform infrared spectroscopy，thermogravimetric analysis，scanning electronic microscopy and nitrogen adsorption determinations．Meanwhile，a capillary electrochromatographic column was prepared by using the POC as chiral stationary phase．After optimizing the operating voltage，buffer solution concentration and pH value，the chiral recognition performance of the column was investigated in capillary electrochromatography．The experimental results showed that the chiral column could separate dihydroflavonoids and ketoprofen chiral compounds，as well as o，m，p-nitrophenol and o，m，p-nitroaniline positional isomers．The optimized conditions for separation of dihydroflavonoids and ketoprofen were：100 mmol/L buffer solution，pH values of 4.5 and 3.5，separation voltages of 16 kV and 14 kV，respectively．The relative standard deviations（RSDs） of the retention time were 1.2% for five consecutive injections of ketoprofen on the column and 4.0% for three consecutive days．The POC chiral capillary electrochromatographic column possesses a good stability and reproducibility．The POC is a excellent chiral stationary phase，which indicates a great prospect in the resolution of chiral drugs and positional isomers．关键词：porous organic cages;chiral stationary phase;capillary electrochromatographic column;chiral separation
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发布时间：2022-07-01 - 摘要：An analytical method was developed for the determination of choline and acetylcholine in honey using ultra performance liquid chromatography－tandem mass spectrometry（UPLC－MS/MS）．The samples were firstly extracted with water－acetonitrile solution（2∶3，by volume），then diluted with acetonitrile－water solution（8∶2） and filtered through a 0.22 μm microporous membrance，and finally determined using the UPLC－MS/MS system．The choline and acetylcholine were separated on an ACQUITY UPLC BEH HILIC column（100 mm × 2.1 mm，1.7 μm）by gradient elution，using 10 mmol/L ammonium acetate solution containing 0.1% acetic acid and acetonitrile as mobile phases．The target compounds were analyzed with electrospray ion source in positive electrospray ionization mode under the multi-reaction monitoring（MRM） mode，and quantified by the external standard method．Results showed that，under the optimal conditions，choline and acetylcholine showed good linearities（r2 > 0.99） in the ranges of 0.5－50 ng/mL and 0.05－5 ng/mL，while the limits of detection（LODs，S/N = 3） for them were 0.5 mg/kg and 0.05 mg/kg，and the limits of quantification（LOQs，S/N = 10） were 1.0 mg/kg and 0.1 mg/kg，respectively．The recoveries for choline and acetylcholine in blank high fructose syrup at three levels of LOQs，10LOQs and 50LOQs ranged from 100% to 103%，with relative standard deviations（RSDs） less than 5.0%，while the recoveries for the analytes in a honey sample at the spiked level of 50LOQs were 97.3% and 97.8%，respectively，with RSDs not more than 5.1%．With the advantages of convenience，sensitivity，good recoveries and repeatability，the method was suitable for the detection of choline and acetylcholine in honey．This method was successfully applied to the analysis on 70 batches of honey and 10 batches of syrup．关键词：choline;acetylcholine;honey;ultra performance liquid chromatography－tandem mass spectrometry（UPLC－MS/MS）
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发布时间：2022-07-01 - 摘要：Based on the fluorescence quenching property of copper-based metal organic framework（Cu－MOF），the selective recognition ability of aptamers and the catalytic hydrolysis of exonuclease，a rapid aptameric fluorescence method was developed for the detection of Vibrio parahaemolyticus（V.P）．The Cu－MOF was prepared at room temperature．The morphology，structure and fluorescence quenching mechanism of Cu－MOF were systematically studied．The analytical conditions such as volume of Cu－MOF，quenching time，volume of exonuclease，recovery time and addition order of agents were investigated．Based on the optimized conditions，an aptameric fluorescence method was established for the detection of V.P．There was a linear relationship between logarithm of concentration（lgc） and increase of fluorescence recovery intensity（∆F） in the range of 8.44 × 102－2.03 × 105 CFU/mL，with a correlation coefficient（r2） of 0.998 6 and a linear equation of ∆F = 7.30lgc－19.58．The detection of limit was 37 CFU/mL．The method could be carried out within 30 min．The proposed method was applied to the determination of V.P in shrimp and octopus samples with recoveries of 88.8%－109%．The method is rapid，sensitive and selective，and has a certain application potential in the analysis of V.P in complex samples.关键词：Vibrio Parahaemolyticus（V.P）;aptamer;metal organic frameworks;exonuclease;fluorescence method
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发布时间：2022-07-01 - 摘要：Eugenol was derived with tert-butyl 4-bromobutanoate to obtain a hapten 4-（4-allyl-2-methoxy-phenoxy）-butyric acid（Eul－4－Tbl）．The hapten was coupled to carrier protein as immunogen for animal immunization，and a polyclonal antibody against eugenol was raised．Thus，an indirect competitive chemiluminescent enzyme-linked immunosorbent assay（ic－CLEIA）was developed for the determination of eugenol．The samples were extracted with acetonitrile，and then cleaned up with an Oasis PRiME HLB solid-phase extraction column．Results showed that the optimized assay conditions were as follows：coating antigen concentration：0.125 μg/mL，dilution ratio of antibody：40 000，reaction time of antibody：30 min，dilution solution for analyte：PBS．The half inhibition concentration（IC50）of the developed ic－CLEIA was 1.28 μg/L，the liner range was 0.25－6.43 μg/L，and the limit of detection（LOD，IC10） was 0.11 μg/L．The spiked recoveries of eugenol in aquatic products were in the range of 76.6%－108%，with relative standard deviations of 5.9%－12%．The results obtained by this method exhibited good correlation to those of HPLC－MS/MS（r = 0.990 4）．The developed method was suitable for rapid determination of anaesthetic eugenol residues in aquatic product．关键词：eugenol;anaesthetic;chemiluminescene enzyme immunoassay;polyclonal antibody;aquatic product
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发布时间：2022-07-01 - 摘要：Under simulated physiological conditions，the adsorption mode of nonivamide（OC） on the surface of AuNPs was determined with AuNPs as the Raman substrate．Surface-enhanced Raman spectroscopy（SERS） revealed that the phenolic group of OC combined with human serum albumin（HSA）．The influence of HSA on the adsorption mode of OC after recognition was analyzed，and the thermodynamic parameters for the interaction between OC and HSA were calculated．The main binding forces were hydrogen bonds，hydrophobic interaction force and Vander Waals force．and the interaction was strong．The results of fluorescence spectroscopy indicated that OC slightly affected the secondary structure of HSA，and increased the hydrophobicity of the microenvironment around the tryptophan residue．The information could be used not only as a reference for study on the mechanism of interaction between drugs and blood plasma or serum albumin，but also as a guidance to understand the metabolism of drugs in human body.关键词：surface-enhanced Raman spectroscopy（SERS）;fluorescence spectrum;nonivamide;interaction;human serum albumin（HSA）
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发布时间：2022-07-01
Scientific Papers
- 摘要：Corticosteroids are important signaling molecules in organisms．Although the content of corticosteroids in human body is very low，they play an important role in regulating physiological activities such as immune system and stress response．In order to establish a rapid quantitative method for the detection of four endogenous corticosteroids，including aldosterone（ALD），cortisol（F），corticosterone（CORT） and cortisone（COR） in human serum by ultra-performance liquid chromatography－tandem mass spectrometry（UPLC－MS/MS）．The sample was pretreated by protein precipitation combined with liquid－liquid extraction（PPT－LLE） using 0.3 mol/L zinc sulfate solution and tert-butyl methyl ether．The separation of target compounds were performed on an ACQUITY UPLC BEH C18 column（2.1 mm × 100 mm，1.7 μm） using 0.01 mmol/L ammonia－acetonitrile system as mobile phase by gradient elution．The four endogenous corticosteroids were detected by UPLC－MS/MS under multiple reaction monitoring（MRM）mode in positive or negative fast-switching ESI mode，and quantified by the isotope dilution（ID） internal standard method．The results showed that the calibration curves were linear（r2 > 0.995） in the range of 0.05－20 ng/mL for ALD，and 0.02－20 ng/mL for the other analytes．The detection of limit（LOD） and quantitation of limit（LQQ） of ALD wase 20， 50 pg/mL，respectively，the LODs and LOQs of the other analytes were 10， 20 pg/mL，respectively．The absolute extraction recoveries for four corticosteroids were between 55.5% and 90.8%．The method recoveries ranged from 91.0% to 101%，with intra-day relation deviation standards（intra-RSDs） and inter-day RSDs（inter-RSDs） not more than 13% and 18%，respectively．Meanwhile，the matrix effects were in the range of 85.9%－108%．The pretreatment method could purify serum samples significantly and increase the reliability of the detection results．It was easy to realize high-throughput processing without derivatization and complex steps．This method was accurate，rapid，stable and reproducible，and was suitable for the detection of serum endogenous corticosteroids in complex matrices．关键词：corticosteroids;ultra-performance liquid chromatography－tandem mass spectrometry（UPLC－MS/MS）;isotope dilution（ID）;protein precipitation（PPT）;liquid－liquid extraction（LLE）
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发布时间：2022-07-01 - 摘要：In this paper，an analytical method of ultra-high performance liquid chromatography with a polymer monolithic column microextraction（PMME/UPLC） was established for the extraction and separation of sulfadiazine（SDZ），sulfamethazine（SMZ），sulfapyridine（SPD）and sulfathiazole（STZ） in honey．The polymer monolithic column was prepared by the thermally initiated in-situ polymerization in pretreated glass capillaries，using 4-vinylbenzoic acid（VBA）and 4-vinylphenylboric acid（VPBA） as mixed functional monomers， methanol and toluene as the porogenic solvent and azobisisobutyronitrile（AIBN）as the initiator to copolymerize with divinylbenzene（DVB）. The poly（VBA-DVB-VPBA）monolithic column was used to extract sulfonamides（SAs） in honey in micro-extraction，and the target components were separated on a ZORBAX Eclipse Plus C18 column（2.1 mm × 50 mm i.d.，1.8 μm），then detected by diode array detection（DAD）．The extraction performance of the monolithic column was evaluated by peak area of chromatography．The properties of the monolithic column were characterized by infrared spectroscopy（IR），scanning electron microscopy（SEM） and energy dispersive spectroscopy（EDX）. With rich functional groups，uniform porosity，good permeability and stability，the column could adsorb sulfonamides by ion exchange，hydrophobic interaction，hydrogen bonding and B－N coordination，etc．The extraction conditions were optimized as follows：sample volume：3 mL，pH value：4，NaCl concentration：60 g/L，and elution volume：200 μL．The method was used for the extraction and separation of SDZ，SMZ，SPD and STZ in the actual samples. Under the optimized conditions，there were good linear relationships for the four target substances in corresponding mass concentration ranges，i.e. 40－200 ng/mL for SDZ，and 60－200 ng/mL for SPD，SMZ and STZ，with their correlation coefficients（r2） higher than 0.99．The enrichment factor of the monolithic column was between 10.97 and 12.82，while its extraction rate for four SAs ranged from 73.1% to 85.5%．The limits of detection and the limits of quantitation were in the ranges of 8.32－16.2 ng/mL and 27.5－53.9 ng/mL，respectively．The method was applied to the analysis of four SAs drugs in honey，and no target was detected in the actual samples．The average recoveries for those compounds at two spiked levels of 60.0 ng/mL and 100 ng/mL ranged from 89.8% to 105%，with relative standard deviations（RSD） of 2.0%－7.2%．With the advantages of low reagent consumption，short time and simple operation，the method could meet the requirements for extraction and separation of SAs in honey，and provide a simple and reliable approach for the actual monitoring of low-concentration antibiotics in food．关键词：polymer monolithic column microextraction;ultra-high performance liquid chromatography;sulfonamides;honey
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发布时间：2022-07-01 - 摘要：There are many kinds of additives in cosmetics．Addition of these substances could improve the use effect and shelf life of cosmetics，but excessive use may result adverse effects on human health．In this study，a rapid method for analysis of additives in cosmetics was established by antireflection surfaces laser desorption ionization mass spectrometry（AR－LDI MS）．The detection limits for 3-benzylidene camphor，4-methylbenzylidene camphor，p-hydroxyacetophenone and cyclopyridone in cosmetics were 4， 6， 40 and 10 mg/kg，respectively．The quantitative analysis of camphor derivatives including 3-benzylidene camphor and 4-methylbenzylidene camphor in cosmetics could also be realized by adding the internal standard，within linear range of 60－140 mg/kg．With simple pretreatment process，short analysis time（not more than 5 min），good sensitivity and accuracy，the method has a broad application prospect in the in-situ rapid detection of cosmetics．关键词：antireflection surface laser desorption ionization mass spectrometry（AR－LDI MS）;additives;cosmetics;rapid analysis
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发布时间：2022-07-01 - 摘要：A new method was developed for the determination of γ-hydroxybutyric acid（GHB） in human blood by gas chromatography－tandem mass spectrometry（GC－MS/MS） with a kind of purification column（MPFC－QuEChERS）．Effects of sample pretreatment conditions and analytical instrument conditions on the test results were investigated in the round，and the optimal experimental conditions were determined. First of all，GHB－D6 was spiked into 0.1 mL blood sample as the internal standard，and then the analyte was extracted using ethyl acetate efficiently．After that，the supernatant was allowed to flow through the MPFC－QuEChERS purification column and evaporated to dryness．Finally，the dried residue was derivated with trifluoroacetamide（BSTFA） and analyzed in multi-reaction monitoring（MRM） mode．Experimental results showed that there were linear relationships for the spiked human blood samples in the range of 0－1 000 ng/mL（r2 > 0.995 1）．The limits of detection（LOD） and limits of quantitation（LOQ） of the method were 0.2 ng/mL and 0.5 ng/mL，respectively．The inter-day relative standard deviations（RSD） and intra-day RSD were both less than 15%．An extraction recovery of 80.1%－84.7% was obtained for the spiked human blood samples．The matrix effect ranged from 87.4% to 94.4%．The results indicated that the developed method was improved and optimized by traditional liquid－liquid extraction method，it could be applied to the rapid and effective determination of GHB in human blood samples of actual cases with its good stability and high sensitivity.关键词：γ-hydroxybutyric acid;MPFC－QuEChERS;gas chromatography-tandem mass spectrometry;blood
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发布时间：2022-07-01 - 摘要：The colorants in toothpastes are mainly synthetic colorants，which may cause varying degrees of harm to the human body with long-term or excessive use．However，there is a lack of research on effective methods for detection of colorants in toothpastes．In this study，a high performance liquid chromatographic（HPLC） method was established for the simultaneous determination of 19 synthetic colorants in toothpastes．The samples were dispersed using 4 mL water with a vortex mixer，then defoamed with 1.0 mL of methanol，and finally added water to 9 mL．The ultrasonic extraction was performed for 10 min．The solution was added water to volume of 10 mL，centrifuged at 10 000 r/min for 5 min，and filtered through 0.45 μm hydrophobic microporous poly tetra fluoroethylene（PTFE）．Chromatographic separation was achieved on an Agilent eclipse XDB－C18 column（4.6 mm × 150 mm，5 μm） by gradient elution，using acetonitrile－20 mmol/L ammonium acetate（pH 6.0） as mobile phase at a flow rate of 0.7 mL/min and a column temperature of 35 ℃．The multi-wavelength analysis was carried out by means of a diode array detector，and the external standard method was used for quantification．The results showed that the 19 synthetic colorants had good linearities in the range of 1－50 mg/L，with correlation coefficients（r） greater than 0.999．The detection limits of the method were in the range of 0.3－2.6 μg/g and the quantitation limits were 0.9－8.6 μg/g．At two spiked levels of 25 μg/g and 400 μg/g，the average recoveries for the 19 colorants were in the range of 95.2%－103%，with relative standard deviations（RSD，n = 6） less than 5%．This method was used for the determination of 19 colorants in 25 batches of toothpastes on the market．As a result，Food Blue 2 was detected in 7 batches of samples with content of 1.1 - 17.8 μg/g. Food Yellow 4 was detected in 4 batches of samples with content of 4.8 - 31.1 μg/g．Food Yellow 3 was detected in 4 batches with content of 2.6－25.5 μg/g．Food Yellow 4，Food Blue 2 and Food Yellow 3 were detected simultaneously in one batch of samples．Food Red 12，Food Green 3 and Acid Red 92 were detected in three batchs of samples，respectively，with contents of 4.5、1.1、55.3 μg/g，respectively，The other colorants were not detected．The results indicated that the method was simple，rapid，accurate and reliable，and was suitable for the qualitative and quantitative detection of 19 synthetic colorants in toothpastes.关键词：synthetic colorant;toothpaste;simultaneous determination;high performance liquid chromatography（HPLC）
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发布时间：2022-07-01 - 摘要：Spectral analysis technology has been widely used in the qualitative and quantitative analysis of complex systems due to its simple，fast，speed and non-destructive．However，spectra often contain hundreds or thousands of wavelengths（variables）．Some of them may not be related to the research object，which will lead to a large amount of calculation and reduce the prediction accuracy of model．Therefore，it is necessary to select the variables before establishing the model．The least absolute shrinkage and selection operator（LASSO） could be used to shrink the regression coefficients to zero，so as to achieve the purpose of variable selection．In this study，LASSO was used to select the variables for near infrared（NIR） spectra of ternary blend oil and Raman spectra of bio-fluid samples．The contents of sesame oil and sarcosine were quantitatively analyzed by building partial least squares（PLS） and multiple linear regression（MLR） models．The methods are compared with the three variable selection methods，i.e. uninformative variable elimination－PLS（UVE－PLS），Monte Carlo uninformative variable elimination－PLS（MCUVE－PLS） and random test－PLS（RT－PLS）．The result shows that the variable selection methods based on LASSO retain the least variable numbers and the fastest calculation speed．LASSO－PLS shows the highest prediction accuracy for ternary blend oil samples，while LASSO－MLR shows the highest prediction accuracy for bio-fluid samples．Therefore，the variable selection methods based on LASSO are expected to be well applied in the field of spectral analysis.关键词：multivariate calibration;variable selection;least absolute shrinkage and selection operator （LASSO）;spectral analysis
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发布时间：2022-07-01 - 摘要：A method was established for the simultaneous determination of 5 amide herbicides，i.e. acetochlor，alachlor，metolachlor，butachlor and pretilachlor，as well as their metabolites including 2-ethyl-6-methylaniline（MEA） and 2， 6-diethylaniline and（DEA） in aquatic products by gas chromatography－mass spectrometry（GC－MS）．Based on previous studies，the pretreatment conditions and chromatographic conditions were optimized in this paper．The appropriate characteristic ions were selected to achieve the chromatographic separation and determination for five amide herbicides and their metabolites in aquatic products．In the sample pretreatment，the mixing parameters for the extractant were optimized，the appropriate eluent and elution volume were selected，and the heating program for the chromatographic column was optimized to make the separation effect better．Specific method and process were as following：the sample was firstly extracted with dichloromethane－ethyl acetate（3∶2，by volume），then concentrated with nitrogen blowing，purified by HLB solid phase extraction，eluted with 3 mL n-hexane，and finally quantified by GC－MS detection．Results showed that，after optimizing the detection conditions，there were good linear response values in the mass concentration range of 1.0－25 μg/L for MEA，DEA and metolachlor，and 2.0－50 μg/L for the other four herbicides．Meanwhile，the correlation coefficients（r2） were greater than 0.998 8．The spiked recoveries for Mactraveneriformis at low，medium and high levels ranged from 69.7% to 111%，with the relative standard deviations（RSDs） of 0.40%－7.6%．The recoveries for Sebastes schlegelii ranged from 65.3% to 118%，with the RSDs of 1.7%－9.3%．The recoveries for Portunustrituberculatus ranged from 61.4% to 113%，with the RSDs of 0.90%－7.1%．The limits of detection（LODs） and limits of quantification（LOQs） for MEA，DEA and metolachlor were 0.5 μg/kg and 1.5 μg/kg，respectively．The LODs and LOQs for the remaining four herbicides were 1.0 μg/kg and 3.0 μg/kg，respectively．This method was used to detect Mactraveneriformis，Scophthalmus maximus，Fenneropenaeuschinensis and Cynoglossussemilaevis samples in the coastal waters of Shandong Province．The metabolite MEA was detected in one of the Mactraveneriformis samples with a detection rate of 2.5%．The sensitivity and precision of this method could meet the requirements for pesticide residue detection，and was suitable for the detection on 5 kinds of amide herbicides and their metabolites in aquatic products．关键词：gas chromatography－mass spectrometry（GC－MS）;amide herbicides;aquatic products;pesticide residues
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发布时间：2022-07-01
Experimental Techniques and Methods
- 摘要：Food safety problems caused by the migration of hazardous substances have become an important focus of society．The intentionally or non-intentionally added substances are characterized with complex types and strong unpredictability，which has make many technical challenges in the identification，quantitative determination and safety assessment of them．The key to the safety research and management of food contact materials is to develop rapid，accurate and sensitive techniques for the detection of food contact materials so as to realize the accurate and quantitative detection of migrants with high concern．This paper briefly introduces the new progress on detection techniques for food contact materials in recent years，including analysis methods for substances of very high concern and non-intentionally added substances，research progress of green packaging materials，and the development trend in analysis techniques for food contact materials，in order to provide a reference for the further development of detection techniques in the field of food contact materials.关键词：food contact materials;substances of very high concern;non-intentionally added substances;green packaging materials
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发布时间：2022-07-01 - 摘要：Magnetic micro－nano materials（MMNPs） are iron，cobalt，and nickel-based materials containing at least one-dimensional size ranging from nano to micron，with surface effects，unique superparamagnetic and nanoenzyme-like activities．Recently，MMNPs have been widely used in the analysis of mycotoxins and have made much progress，which provides a new means for the study on mycotoxins and their prevention and control．However，the comprehensive research progress on analysis and detection of mycotoxins based on MMNPs has not been systematically reported．Thus，the applications of MMNPs in analysis and detection of mycotoxins are summarized in the paper．Specifically，the principles，advantages and disadvantages and the latest research progress of MMNPs as fixed carrier，signal tags，modified interface and hybrid application are mainly described，respectively. Furthermore，their future directions and the potential applications are prospected，anticipating to provide a reference for the further research and application of mycotoxins.关键词：magnetic micro－nano material;mycotoxin;national standard method;sensing method
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发布时间：2022-07-01 - 摘要：Organophosphorus pesticides（OPs） residues have posed a great threat to natural ecosystem and human health by enrichment through the food chain．Traditional analytical methods for OPs detection，including high performance liquid chromatography（HPLC） and gas chromatography（GC） have some inevitable limitations，such as long response times，high cost，and requirements for complicated detection procedure and highly qualified operators. In recent years，biosensors have been effectively used in the field of quantitative analysis chemistry due to their strong specificity，high speed and high accuracy．The biosensors using acetylcholinesterase（AChE） as an identification element and catalytic element have opened up a bright prospect for the rapid and practical determination of OPs residues in real samples．In this review，the latest sensing strategies and devices based on AChE inhibition with different reaction mechanisms are summarized，especially the sensing devices combined with new generation detection technologies. The challenges and deficiencies for the current detection of OPs based on AChE inhibition are also summarized，and the future research direction is prospected.关键词：organophosphorus pesticides（OPs）;acetylcholinesterase（AChE）;biosensors;enzyme inhibition
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发布时间：2022-07-01 - 摘要：As an important additive in food industry，gelatin mainly comes from the bones and skins of pigs，cattle and other animals．However，in the Islamic religious belief，it is forbidden to eat products containing pig-derived ingredients，so the detection of pig-derived ingredients in gelatin is very important．In this paper，the methods for detecting pig DNA or protein components in gelatin at home and abroad in recent years，as well as their advantages and disadvantages are expounded and analyzed，and the development trend of detection methods in the future is prospected．In addition，it is particularly important to conduct sample pretreatment due to the degradation of DNA and protein in the process of food processing．And finally，the sample pretreatment methods are sorted out to some extent．关键词：gelatin;porcine derived components;detection methods;research progress
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发布时间：2022-07-01
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