最新刊期
卷 40 ， 期 8 ， 2021
- 摘要：The compositions of glycerolipids in camellia oil and olive oil were analyzed and compared using a lipidomics method based on ultra performance liquid chromatography－high resolution mass spectrometry（UPLC－HRMS）. The retention behavior of different lipids by liquid chromatography was summarized. The main eluted components were diacylglycerols within 6.5－7.5 min， while within 10.6－12 min， the main eluted components were triacylglycerols. The base peak chromatogram showed that there were no significant differences in the retention time and abundance of glycerolipids between camellia oil and olive oil. The elution of glycerolipids by reversed-phase liquid chromatography was carried out according to the equivalent carbon number. The higher the equivalent carbon number， the longer the retention time. The structures of lipids were calculated according to the neutral lost mass by using the extracted ion chromatogram， primary mass spectrum and secondary mass spectrum. Results showed that 55 glycerolipids were detected in camellia oil and olive oil. All 55 glycerolipids， including 43 triacylglycerols and 12 diacylglycerols were detected in camellia oil. 44 glycerolipids， including 34 triacylglycerols and 10 diacylglycerols were detected in olive oil， while 9 triacylglycerols and 2 diacylglycerols were not detected. TAG 54∶3 was the most important triacylglycerols in camellia oil and olive oil， but its relative content was higher in camellia oil. The relative contents of 9 triacylglycerols and 2 diacylglycerols detected in camellia oil but not in olive oil were all less than 1%. Camellia oil and olive oil have similar major glycerolipids， but they are quite different from other edible oils， such as soybean oil， rapeseed oil and sunflower oil. The peak areas of 55 glycerolipids species were used as the variable for multidimensional statistical analysis. The results of cluster heat map analysis， principal component analysis（PCA） and orthogonal partial least squares－discriminant analysis（OPLS－DA） showed that camellia oil and olive oil had a significant classification trend. Camellia oil and olive oil were aggregated into two different categories in the PCA score plot without any overlap. The contribution rate of the first principal component was 62.7%， while the contribution rate of the second principal component was 18.3%， indicating that there was significant difference in the glyceride abundance between camellia oil and olive oil. With VIP >1.0 and p < 0.01， 3 key glycerolipids were selected from camellia oil and 6 key glycerolipids were selected from olive oil. This study revealed the difference in the molecular composition of glycerolipids between camellia oil and olive oil， providing a basis for analyzing the function and nutrition of camellia oil.关键词：camellia oil;olive oil;glycerolipids;ultra performance liquid chromatography－high resolution mass spectrometry
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发布时间：2023-02-13
Scientific Paper
- 摘要：In this study， metabolic profiles of liver homogenate from hyperlipidemic hamsters were analyzed by liquid chromatography coupled to time-of-flight mass spectrometry， and the potential biomarkers were explored by pattern recognition method to investigate the pathogenesis. Both reversed-phase（RPLC） chromatography and hydrophilic interaction chromatography（HILIC） were used to separate the endogenous metabolites in liver homogenates. Partial least squares discriminant analysis（PLS－DA） was used to analyze the data， and the qualitative analysis of the endogenous components was carried out by comparing the standards， the database or fragmentation analysis. Good separations were observed between the model and normal groups in both HILIC and RPLC separating modes by PLS－DA. Compared with the normal group， 16 potential biomarkers in liver of hyperlipidemic group were identified. The major disturbed metabolic pathways were purine metabolism，phosphatidylcholine metabolism，sphingolipids metabolism and lysine metabolism. Results showed that the abnormal biomarkers and pathways may provide evidences to understand the metabolic mechanism of liver in hyperlipidemic hamsters.关键词：hyperlipidemia;metabolomics;biomarkers;hamsters;liquid chromatography－time-of-flight mass spectrometry
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发布时间：2023-02-13 - 摘要：In this paper， a magnetic molecularly imprinted electrochemical sensor（MNPs－MIP/MCPE） for the detection of oxcarbazepine（OXC） was prepared， using 4-vinylpyridine and methacrylate as raw materials. Firstly， according to the calculation of the density functional theory（DFT/B3LYP/6－31 + G）， the best combination and the best combination ratio of the OXC with functional monomers were successfully screened and constructed. Subsequently， a magnetic molecularly imprinted membrane（MNPs－MIP） capable of recognizing OXC was synthesized based on the precipitation polymerization method， which was coated on the surface of a carbon paste electrode（MCPE） to make a magnetic molecularly imprinted sensor of MNPs－MIP/MCPE. The sensor was used for the determination of different concentrations of OXC solutions with differential pulse voltammetry（DPV）. Results showed that， the current signals of the system had good linear relationship（r > 0.999） with OXC concentrations in the ranges of 5 × 10－8－3 × 10－6 mol/L and 3 × 10－6－1.5 × 10－4 mol/L， and their linear equations were Ip（μA） = 1.755 + 1.097c （μmol/L） and Ip（μA）= 0.131 + 5.177c （μmol/L）， respectively. The detection limit for OXC（LOD = 3S/m） was 2.06 × 10－8 mol/L. The sensor was used for the detection of OXC concentration in the actual samples， with recoveries of 99.4%－101% and relative standard deviations （RSD） of 1.5%－2.5%.关键词：molecularly imprinted membrane;electrochemical sensor;magnetic carbon paste electrode;detection;oxcarbazepine
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发布时间：2023-02-13 - 摘要：An ultra-high performance liquid chromatography－tandem mass spectrometric（UHPLC－MS/MS） method was established for the determination of aerosol content of methacholine chloride for inhalation solution. The sample was separated on an ACQUITY BEH C18（2.1 mm × 100 mm， 1.7 μm） column by gradient elution， using 0.1% formic acid water and acetonitrile as the mobile phases with a flow rate of 0.3 mL/min， an injection volume of 5 μL， an analysis time of 5 min and a column temperature of 40 ℃， and finally determined in multiple-reaction monitoring（MRM） mode. Meanwhile， the specificity， linearity， instrument precision， spiked recovery， extraction recovery and stability were investigated. Methacholine chloride was linear in the range of 10－100 ng/mL（r ＞ 0.999）. The limit of quantitation was 10 ng/mL. The recovery for methacholine chloride in aerosols was 99.2% with a relative standard deviation（RSD） of 0.80%. The extraction efficiency for methacholine chloride was 95.7%. After atomizated for 1 min in the inhalation exposure device， the average content of methacholine chloride in the aerosols was 608.1 mg/m3. RSD of the upper， middle and lower positions was 1.2%. It indicated that the content of methacholine chloride in the aerosols was uniform after 1 min atomization. The method is sensitive and precise， and is suitable for the determination of aerosol content of methacholine chloride powder for inhalation solution， and it also could be used as a reference for the analysis of other aerosol samples for inhalation.关键词：ultra-high performance liquid chromatography－tandem mass spectrometry;methacholine chloride;atomization aerosol;inhalation
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发布时间：2023-02-13 - 摘要：Near-infrared（1 000－2 200 nm） hyperspectral imaging technique was applied to the discrimination of components in formula tobacco， including cut lamina， cut stem， expanded tobacco and reconstituted tobacco. Two approaches， named pixel-wise and object-wise， were investigated to conduct this research. The pixel-wise components discrimination study was based on the spectral data of all pixels of the hyperspectral images of samples. Second derivative coupled with Savitzky－Golay（SG） algorithm was applied as preprocessing method for original spectral data. Through principal component analysis of the pixel data， the feasibility for component discrimination of the pixel hyperspectral data was confirmed. The established support vector machine（SVM） model based on first five components' data showed its excellent character in discriminating cut lamina and cut stem， cut lamina and reconstituted tobacco， obtaining intuitive discrimination results. The K-nearest neighbor and support vector machine discriminant model for the four components of samples was established. The characteristic wavelength was selected by the continuous projection algorithm and the second derivative method， and the band with high discrimination accuracy was selected， with a component discrimination rate reached 86.97%.关键词：formula tobacco;components discrimination;near-infrared hyperspectral imaging;pixel-wise classification;principal component analysis;successive projection algorithm;second derivate method
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发布时间：2023-02-13 - 摘要：In this paper， a fast and efficient method for the detection of volatile pesticides was developed， based on the gold nanofilm as surface enhanced Raman spectroscopy（SERS） substrate， which was prepared by redox reaction on the surface of stainless steel sheet. The volatile pesticides， i.e. fonofos and ferbam were detected by SERS with headspace solid phase extraction（SPE）. Significant Raman signals were obtained by headspace solid phase extraction at 75 ℃ and 55 ℃ for fonofos and ferbam within 15 min， respectively. The limits of detection（LODs） were both 5 × 10－3 mg/L for these two pesticides. There were linear relationships between Raman spectrum intensities of the characteristic peaks（999 cm－1 and 1 381 cm－1） and the pesticdes in a certain mass concentration ranges， with their correlation coefficients（R2） of 0.984 8 and 0.977 8， respectively. The recoveries for fonofos and ferbam in fruit juice were in the range of 93.3%－112% and 92.5%－104%， with relative standard deviations（RSDs） of 4.1%－5.2% and 3.4%－6.5%， respectively. The method is rapid and sensitive， which has a potential application value in the detection of volatile pesticides.关键词：surface-enhanced Raman spectrum;gold nanofilm;headspace solid phase extraction;fonofos;ferbam
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发布时间：2023-02-13 - 摘要：The differences of volatile organic compounds in various cigarette samples were investigated in order to analyze the aromatic characteristics of different tobacco products. Five commercial cigarette brands were selected for the research of volatile organic compounds in cigarette samples using headspace－gas chromatography－ion mobility spectroscopy（HS－GC－IMS）， while the typical aromatic matters were analyzed by relative odor activity value（ROAV）. The HS－GC－IMS analysis results showed that the volatile organic compounds of five selected cigarette samples were almost the same. Nevertheless， the contents of each sample were quite different. ROAV analysis showed that the main volatile organic compounds were aldehydes， ketones， alcohols and esters while the key substances contributing most to the cigarette aroma were 2-furanmethanethiol， 1-octene-3-one， furan alcohol， 3-methylbutyraldehyde， 3-methylbutyl acetate， etc. The different aroma threshold values affect their contribution to the aromatic styles of cigarettes. Based on HS－GC－IMS and ROAV analysis， the typical aromatic matters could be analyzed， which will provide a technical support for the style analysis and quality evaluation of different cigarettes.关键词：headspace－gas chromatography－ion mobility spectroscopy（HS－GC－IMS）;cigarette;relative odor activity value （ROAV）;typical aromatic matters
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发布时间：2023-02-13 - 摘要：In this work， Fe3O4@COF（TpBD） magnetic composites were successfully synthesized through the reaction of Fe3O4 nanoparticles， 1，3，5-trimethylphloroglucinol （Tp） and benzidine （BD） via a solvothermal approach. The fabricated magnetic nanocomposites were applied as the adsorbent for magnetic solid phase extraction （MSPE） of carvedilo （CAR）. Coupled with fluorescence spectrophotometry， a new analytical method of MSPE was developed for the determination of CAR in biological samples. The Fe3O4@COF（TpBD） absorbent was characterized by transmission electron microscopy（TEM）， X-ray diffraction（XRD）， Fourier transform infrared spectrometry（FT－IR）， vibrating sample magnetometry（VSM） and surface area and pore size analyzer. The experimental parameters were optimized， including pH value of solution， amount of adsorbent， adsorption time， the type and volume of desorption solvent and desorption time. The optimum MSPE conditions were as follows： a solution pH value of 6.0， an adsorbent amount of 5 mg， an extraction time of 4 min， and a desorption time of 5 min. Under the optimum conditions， the method exhibited good linearity in the concentration range of 1－100 ng/mL. Moreover， the limits of detection（S/N = 3） and quantification（S/N = 10） were 0.19 and 0.63 ng/mL， respectively. Recoveries at low， medium and high spiked levels were in the range of 95.9%－98.7%. With the advantages of good recovery， high sensitivity and good stability， the proposed method could be applied to the analysis of CAR in plasma and urine samples.关键词：carvedilol;magnetic solid phase extraction;covalent-organic frameworks;fluorescence spectrophotometry;plasma;urine
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发布时间：2023-02-13 - 摘要：An agrose/silica（AG/SiO2） monolithic column was prepared via sol－gel reaction with oxide agrose（AG） and tetramethoxysilane（TMOS） as precursors， and then amide groups were modified through amidation reaction. The structure and morphology of the prepared monolithic column were investigated by X-ray photoelectron spectroscopy（XPS）， Fourier transform infrared spectroscopy（FTIR）， N2/adsorption－desorption and scanning electron microscopy（SEM）. Results indicated that amide groups were successfully modified on the surface of AG/SiO2 monolithic column. The monolith possessed satisfactory permeability and larger specific surface area which could contribute to better extraction and enrichment efficiency. Thereafter， the monolith was used as solid-phase micro-extraction pattern for extraction and enrichment of ractopamine in mutton samples. The pretreatment conditions of real samples were optimized thoroughly， including extraction solvent， pH value， extraction rate， elution rate and elution volume. As a result， the optimized conditions such as an extraction solvent of acetonitrile－water（7∶3）， a pH value of 5.6， an extraction rate of 0.05 mL/min， an elution rate of 0.03 mL/min and an elution volume of 25 μL were used for cleaning up ractopamine from mutton samples. Under the optimized sample pretreatment conditions， coupled with common high performance liquid chromatography with ultraviolet detection（HPLC－UV）， a method for determination of ractopamine was established by using a matrix addition standard curve. The linear range of the method was 1.94－1 170 ng/g with a correlation coefficient（r2） of 0.993 1. The limit of detection（LOD， S/N = 3） was 0.618 ng/g， while the limit of quantitation（LOQ， S/N = 10） was 1.94 ng/g. The recoveries at three spiked levels ranged from 86.6% to 103%， with relative standard deviations（RSD） of 4.8%－7.3% by repeating the same experiment for 5 times. The established method was applicable for detection of trace residue of ractopamine in real mutton samples with the advantages of sensitivity， efficiency， reliability， high recovery and low usage of samples.关键词：high performance liquid chromatography;silica monolithic column;solid-phase micro-extraction;ractopamine;mutton
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发布时间：2023-02-13 - 摘要：A comprehensive two-dimensional gas chromatography quadrupole time-of-flight mass spectrometry（GC × GC－Q－TOF MS） was developed for the rapid and simultaneous determination of 24 organophosphorus and 20 organochlorine pesticides in soil. The impurities and analytes in samples were perfectly intragroup-separated by two-dimensional gas chromatography after soxhlet extraction. 24 organophosphorus and 20 organochlorine pesticides were determined by using the high resolution molecular mass characteristic ions. Results showed that there existed linear relationships for 44 pesticides in the concentration range of 20－3 000 μg/L， with their correlation coefficients（r2） of 0.990 3－0.999 9 and limits of detection（LOD） of 0.3－7.9 μg/L. The average value for fortified recovery was 93.0%， and accordingly the relative standard deviation（RSD， n = 5） was 6.9%. The method could provide a reference for the high-throughput rapid screening of pesticide residues in soil.关键词：comprehensive two-dimensional gas chromatography quadrupole time-of-flight mass spectrometry;organophosphorus pesticides;organochlorine pesticides;soil
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发布时间：2023-02-13 - 摘要：Acrylonitrile－Butadiene－Styrene（ABS）plastic is widely used in toy manufacturing industry. The chemical safety of ABS plastic toys is affected by the residual monomer without polymerization. In order to more accurately evaluate the chemical safety of ABS plastic toys and better protect children's health and safety， a rapid， accurate and sensitive method for the determination of acrylonitrile and styrene residues and migration in ABS plastic toys was established， based on the headspace－gas chromatography－mass spectrometric（HS－GC－MS）technique. Firstly， the headspace equilibrium temperature and equilibrium time of the residue determination method were optimized. Results showed that the optimal equilibrium temperature was 110 ℃ and the optimal equilibrium time was 15 min. Then， the headspace equilibrium temperature， equilibrium time， sampling volume and salting out conditions were optimized by using simulated sweat and simulated saliva as the migration medium. The results showed that the optimal conditions were as follows： equilibrium temperature 70 ℃， equilibrium time 30 min， sampling volume 10 mL and the salt amount 3.5 g. The limits of quantitation（LOQs）for determination of residual acrylonitrile and styrene were 0.4 mg/kg and 1.0 mg/kg， respectively. The correlation coefficients（r2）were greater than 0.999 8 in the linear range of 0.4－2 000 mg/kg. The recoveries were in the range of 93.0%－108% with relative standard deviations（RSDs）not more than 7.2%， while the LOQs for determination of acrylonitrile and styrene in the migration solution were 1.0 μg/L and 0.05 μg/L， respectively. The correlation coefficients（r2）were not less than 0.998 1 in the linear range of 0.05－100 μg/L. The recoveries ranged from 88.4% to 104%， with RSDs not more than 9.5%. Finally， the method was applied to the determination of acrylonitrile and styrene monomer residues and migration in 38 ABS plastic toys. Styrene was detected in all 38 ABS toy samples， and acrylonitrile was not detected in only one of them. The residual amounts of acrylonitrile and styrene were in the ranges of 4.02－58.25 mg/kg and 1.49－1 840.19 mg/kg， respectively. The migration amounts of acrylonitrile in simulated sweat and simulated saliva for 60 min were 0.09－0.58 mg/kg and 0.11－0.67 mg/kg， while those of styrene in simulated sweat and simulated saliva were 0.11－0.88 mg/kg and 0.12－0.92 mg/kg， respectively. The detection results showed that there existed a certain amount of acrylonitrile and styrene in ABS plastic toys， and these residual monomers might migrate from ABS plastic toys under certain conditions， which pose a potential hazard to children. Therefore， the content level and exposure safety of monomers in ABS plastic toys need to be further evaluated. The method is simple， rapid， sensitive and accurate， and it is suitable for the determination of acrylonitrile and styrene residues and migration in ABS plastic toys， which provides a technical support for the safety evaluation on ABS plastic toys.关键词：ABS toys;acrylonitrile;styrene;residues;migration amount
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发布时间：2023-02-13 - 摘要：Graphene quantum dots （GQDs） are a new kind of carbon nanomaterials. GQDs display many merits such as low toxicity， rich surface grafting and have been widely concerned. In this paper， nitrogen and sulfur co-doped graphene quantum dots （N，S－GQDs） were prepared. Compared with undoped GQDs， the electrochemical luminescence （ECL） signal of N，S－GQDs was significantly enhanced. N，S－GQDs were adsorbed on the surface of the working electrode by using chitosan （CS） as a linking agent， and a new type of N，S－GQDs ECL sensor was constructed. Under the action of external voltage， N，S－GQDs transition from the ground state to the excited state， and release light energy in the process of returning to the ground state. After Cu2+ was added， Cu2+ specifically coordinated with groups on the surface of the N，S－GQDs to form aggregates， which reduced the N，S－GQDs that could be excited and manifested as the quenching of ECL signals. The higher the concentration of Cu2+， the greater the quenching degree. The quantitative detection of Cu2+ could be realized by detecting the change of ECL signal. Under the optimal conditions， the change of ECL intensity showed a good linear relationship with Cu2+ concentration from 0.01 to 35 μmol/L and the detection limit was calculated to be 1.7 nmol/L. This research provided a way for the rapid detection of heavy metal ions in actual samples and broadened the application of nanomaterials in the field of ECL sensing.关键词：nitrogen and sulfur co-doped graphene quantum dots（N，S－GQDs）;electrochemiluminescence（ECL）;copper ion;determination
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发布时间：2023-02-13
Scientific Papers
- 摘要：In this paper， a rapid fluorescence assay for the detection of mercury ions was developed using mercury－specific aptamer and PicoGreen， a fluorescent dye embedded in double helix DNA. Mercury ion concentration was determined by fluorescence signal intensity， and the linear relationship between the logarithm of mercury ion concentration and fluorescence intensity was obtained. The linear range of the method was 0.001-100 µg/mL， and the detection limit was 0.38 ng/mL. In the presence of interference ions such as As3+， Pb2+， Cd2+， Cr2+， K+， it has a good specificity. Meanwhile， the irrigation water samples with different concentrations of Hg2+ showed a good recovery of 95.2%－97.9% and the relative standard deviation of 2.3%－4.0%. The method is simple， rapid and sensitive， and is applicable for the determination of mercury ions by using aptamer and fluorescent dye.关键词：aptamer;mercury;rapid detection;fluorescent assay;PicoGreen
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发布时间：2023-02-13 - 摘要：A liquid chromatography－tandem mass spectrometry（LC－MS/MS） was established for the determination of neopentyl glycol in food contact materials and products in this paper. Water， 4% acetic acid（volume fraction）， 10% ethanol， 20% ethanol， 50% ethanol， 95% ethanol and olive oil were used as the food simulants. After soaking in food simulants， different types of soaking solutions were pretreated with appropriate manners. Water， 4% acetic acid and 10% ethanol soaking solutions were directly filtered and injected. For soaking solutions of other ethanol simulants， most of the ethanol was removed by nitrogen blowing in a certain volume， and water was used to replenish to the original volume. For olive oil soaking solution， 10% ethanol was used for extraction. The separation was performed on an ACQUITY UPLC® BEH C18（50 mm × 2.1 mm， 1.7 µm） chromatographic column by gradient elution， with 0.01% formic acid solution and acetonitrile as mobile phases. The detection was performed with electrospray ion source in positive ion（ESI+） multi reaction monitoring（MRM） mode. External standard method was used for quantitative determination. Under the optimized conditions， there was a good linear relationship for neopentyl glycol in the range of 10－100 µg/L（µg/kg）， with its correlation coefficient larger than 0.999. The spiked recoveries for neopentyl glycol at three spiked levels of 10， 20 and 100 µg/L（or µg/kg） ranged from 92.8% to 117%， with relative standard deviations（RSD） of 0.90%－8.6%. The limit of detection（LOD， S/N ≥ 3） was 5 µg/L（or µg/kg）， while the limit of quantitation（LOQ， S/N ≥ 10） was 10 µg/L（or µg/kg）. The method was simple， stable， reliable and sensitive. The food simulants included in the method basically covered the types specified in the regulations and standards. The LOD and LOQ of the method were lower than the specific migration limit（SML） specified in the regulations and standards. The method could not only meet the needs for determination of neopentyl glycol migration in food contact materials and products， but also provide a reliable technical means for related product supervision and quality control.关键词：liquid chromatography-tandem mass spectrometry;food contact material;neopentyl glycol;migration
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发布时间：2023-02-13 - 摘要：In this study，multi-walled carbon nanotubes（MWCNTs） and sodium dodecylbenzene sulfonate（SDBS） were ultrasonically oscillated in water for 1.5 h，and the obtained SDBS－MWCNTs composites were modified onto the surface of glassy carbon electrode（GCE） to construct a SDBS－MWCNTs/GCE electrochemical sensor. The electrochemical behaviors of naphthoacetic acid（NAA） on the electrode surface were investigated by cyclic voltammetry and linear scanning voltammetry. The experimental conditions， including concentration of SDBS， modification dosage of SDBS－MWCNTs and pH value of buffer were optimized. Under the optimal conditions of 0.5 mg/mL SDBS， 5 μL SDBS－MWCNTs and pH 6.0， the sensor was used to detect different concentrations of NAA standard solution by differential pulse voltammetry（DPV）. Result indicated that there was a good linear relationship between the peak oxidation current and NAA in the concentration range of 0.4－45 μmol/L， and the detection limit was 0.07 μmol/L. The sensor was applied to the actual detection of NAA in astragalus with recoveries of 97.8%－102% and RSDs less than 5%. The preparation of the sensor was simple， and the method had high sensitivity， good stability， reproducibility， and anti-interference ability.关键词：naphthoacetic acid（NAA）;modified electrode;electrochemical analysis;multi-walled carbon nanotubes（MWCNTs）
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发布时间：2023-02-13 - 摘要：An all-solid-state self-supported Pb2+-selective miniaturized electrode（Pb2+－ISμE） based on disordered mesoporous carbon was fabricated by filling the disordered mesoporous carbon as the self-supporting material into a capillary glass tube with a tip diameter about 150 μm， and adsorbing the ion-selective polymeric membrane into the porous structure of disordered mesoporous carbon. The electrochemical behaviors of the proposed electrode were characterized by using cyclic voltammetry and electrochemical impedance spectroscopy， and the potentiometric performance of the Pb2+－ISμE was also investigated. Experiments results indicated that the disordered mesoporous carbon-based miniaturized electrode showed a typical "S" cyclic voltammogram and a large double-layer capacitance because of the porous structure， and the proposed Pb2+－ISμE exhibited a Nernstian potentiometric response in the linear range of 1.0 × 10－7－1.0 × 10－4 mol/L with a response slope of （28.9 ± 0.5） mV/dec and a detection limit of 4.0 × 10－8 mol/L. In addition， the proposed electrode showed excellent selectivity， stability and reproducibility， and was successfully applied in the determination of Pb2+ in pore water. This work provides a simple and convenient method for the preparation of the miniaturized electrodes， and is promising for the determination of ions in micro-environments or with micro/small volumes.关键词：polymeric membrane ion-selective electrode;miniaturized electrode;disordered mesoporous carbon;all-solid-state;lead ion
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发布时间：2023-02-13 - 摘要：The electrochemical behavior of coenzyme Q10（CoQ10） on glassy carbon electrode（GCE） was explored by cyclic voltammetry（CV） in this paper. The results revealed the adsorption of CoQ10 on GCE， thus providing an approach to enhance the sensitivity for its detection by pre-enrichment. The experimental conditions including ultrasonic duration for CoQ10 extraction， detection temperature and the ratio of electrolyte solvent （methanol－ethanol） were optimized by Box－Behnken method as 1 min 50 s， 25 ℃ and 1.1∶1，respectively. Under the optimized conditions， after 25 min of adsorption， the CV current linearly responded. to the logarithm of CoQ10 concentration within the range of 0.025－25.0 μmol/L， with a regression equation of I = 2.554 + 1.479lgC（r2 = 0.997）， and a detection limit （LOD）of 19.0 nmol/L. The detection of CoQ10 by using adsorptive CV on GCE could achieve its accurate and high response quantitative analysis.关键词：coenzyme Q10;adsorptive cyclic voltammetry;response surface optimization;quantitative analysis
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发布时间：2023-02-13 - 摘要：A method was developed for the determination of α-chlorotoluene in cosmetics containing benzalkonium chloride. Firstly， the thermal decomposition products of benzalkonium chloride was analyzed by gas chromatography－mass spectrometry（GC－MS）. A phenomenon was confirmed that benzalkonium chloride and similar compounds will decompose into α-chlorotoluene at the inlet of GC－MS. Then， a new analytical method for α-chlorotoluene in cosmetics was developed by a headspace injection mode of gas－liquid equilibrium. The headspace sampling parameters， chromatographic separation and mass spectrometry conditions were optimized. The equilibrium temperature and time for headspace sampler were set at 80 ℃ and 30 min， respectively. The sample was dissolved with 8 mL water and 1.0 g sodium chloride in headspace bottle. The analytes were separated on an HP－INNOWax column（60 m × 0.25 mm × 0.25 μm）， then detected in selectedion monitoring mode and quantified by external standard method. Results showed that the standard curves for α-chlorotoluene were linear over the concentration range of 0.01－5.00 μg/mL with linear correlation coefficients（r） of 0.999. The detection limits and quantification limits of the method were 0.02 μg/g and 0.05 μg/g， respectively. The spiked recoveries ranged from 91.3% to 98.8% with relative standard deviations（RSDs） of 1.5%－4.9%. The method is simple， rapid， high sensitive and specific， and it is suitable for the determination of α-chlorotoluene in cosmetics.关键词：α-chlorotoluene;cosmetics;benzalkonium chloride;thermal degradation;headspace gas chromatography－mass spectrometry （HS－GC－MS）
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发布时间：2023-02-13
Experimental Techniques and Methods
- 摘要：Paper-based microfluidic analytical devices（μPADs）are a kind of technology for sample preparation， reaction， separation， and detection on paper chips， which have been widely used in biomedical， environmental， clinical analysis， chemical and other fields owing to their advantages， such as inexpensive production， simple fabrication， easy recycle， diverse structures， low reagent consumption， environmentally-friendly and biodegradation. In addition， they have the advantage of high sensitivity， which could be used by non-professionals to obtain the test results quickly，so they also exhibit a great practical value and a development potential in the rapid detection of food safety. This review highlights the recent advances on fabrication of paper chips， fluid transportation and control， and signal detection modes from the technical level. Firstly， this paper roughly describes the functional modification methods for paper chips with rich hydroxyl groups and high hydrophilicity， such as lithography， wax techniques， inkjet printing， screen printing， flexographic printing， 3D printing， stamping， polydimethylsiloxane（PDMS）and other methods. Then three immobilization ways of biosensor molecules on paper-based materials， including physical adsorption， embedding and chemical immobilization are described. According to the direction of fluid flow（horizontal direction or vertical horizontal direction）， the methods for preparing the processed paper into two-dimensional（2D）or three-dimensional（3D）paper chips are summarized. Secondly， the transport mechanism of fluid in two stages of incomplete soaking and complete soaking on paper based materials is discussed，incomplete soaking stage refers to the fluid on the paper based materials in the slow penetration of the paper， while complete soaking stage is when the fluid fills the paper based materials and is transported by capillarity. Moreover， this paper comprehensively analyzes the intelligent fluid manipulation technology， which can transport reagents and samples to the corresponding area within the appropriate detection time. Fluid transportation and control methods can be divided into passive device and active device. Passive device is simple and easy to manufacture without additional equipment， while active device relies on external input system and can achieve accurate multi-step fluid flow control. Finally， this review introduces several detection methods that could be combined with paper based microfluidic platform in detail， such as colorimetric， electrochemical， chemiluminescence and electrochemiluminescence， fluorescence， etc. Furthermore， the research progress of paper-based microfluidic technology in food hazardous molecules， foodborne pathogens， heavy metal contamination and other aspects is reviewed， and the challenges and development trends of paper-based microfluidic technology in the food industry are also proposed.关键词：microfluidic paper-based analytical devices(μPADs);food safety;rapid detection;review
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发布时间：2023-02-13 - 摘要：Two-dimensional materials are a new kind of separation material， which have attracted extensive attention of researchers in the field of separation science due to their characteristics of atomic size， excellent mechanical strength， large surface area， abundant surface chemistry and good physical and chemical stability. Graphene is considered as a typical two-dimensional material among the materials. With extensive research of graphene， a variety of emerging two-dimensional materials， such as transition metal dichalcogenides（TMDs）， layered double hydroxides（LDHs）， metal-organic frameworks（MOFs）， covalent organic frameworks（COFs）， transition metal carbides， nitrides and carbonitrides（MXenes） and hexagonal boron nitride（h-BN） have appeared. This review discusses the characteristics and applications of two-dimensional materials and their quantum dots， and focuses on the applications of membrane separation， solid phase extraction/solid phase microextraction， liquid chromatography， gas chromatography， capillary electro chromatography and other fields in separation science. In addition， challenges and application prospect of two-dimensional materials in separation science are also discussed.关键词：two-dimensional materials;quantum dots;separation science
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发布时间：2023-02-13
Reviews
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