最新刊期
卷 44 ， 期 4 ， 2025
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摘要：Developing simple，rapid，sensitive，and accurate approaches for cancer biomarker assay is of great research significance for early diagnosis of cancer. Homogeneous electrochemical sensors are immobilization-free strategies without modifying recognition elements on electrode. Hence，it has outstanding advantages of simple operation，fast response，good reproducibility，and high sensitivity. Under these advantages，homogeneous electrochemical strategies have been widely applied in the area of tumor biomarker detection. This review aims to summarize the recent advances in the design，development，and application of homogeneous electrochemical sensors for cancer biomarker assay. The discussion focuses on the regulation of molecule diffusion and signal transformation based on the strategies including enzyme-assisted nucleic acid digestion，DNA conformational change，different affinity，and stimuli-responsive nanocarriers. This review will promote the rapid development of homogeneous electrochemical biosensors and expand their application fields.关键词：cancer biomarkers;homogeneous electrochemistry;nucleic acid probe;affinity differences;nanocarriers365|135|0更新时间：2025-04-10
Special Topic
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摘要：A liquid chromatography-tandem mass spectrometry（LC-MS/MS） method was developed for the qualitative and quantitative analysis of eight synthetic cannabinoids and seven metabolites in urine and blood. After the urine and blood samples were extracted by a mixture of methanol-acetonitrile （1∶1，volume ratio），the supernatant was extracted by high-speed centrifugation，and the gradient elution was carried out with an aqueous solution containing 0.1% formic acid and acetonitrile as the mobile phase，and the separation was carried out on a C18 chromatography column. The ion source for the tandem mass spectrometry was an electrospray ionization source（ESI+），and the detection was performed in multiple reaction monitoring（MRM） mode. The method can be used for the analysis of 15 targets within 15 min. The results showed that the 15 targets exhibited a good linear relationship in the range of 1-200 ng/mL in urine，the limits of detection（LODs） were 0.01-0.10 ng/mL，and the limits of quantification（LOQs） were 0.03-0.34 ng/mL. The 15 targets exhibited a good linear relationship in the range of 0.50-200 ng/mL in blood，LODs were 0.01-0.20 ng/mL，and LOQs were 0.03-0.66 ng/mL. The recoveries in urine and blood at three different spiked concentrations were 92.2%-105% and 82.2%-117%. The developed method is sensitive，effective in separation，easy to operate，and suitable for the determination analysis of synthetic cannabinoid analogs in urine and blood.关键词：synthetic cannabinoid;metabolites;liquid chromatography-tandem mass spectrometry;blood;urine318|30|0更新时间：2025-04-10 -
摘要：To cope with the rapid screening of common pesticide poisoning cases，a real-time direct analysis tandem mass spectrometry（DART-MS/MS） method for detecting 14 fungicides in whole blood was established. By optimizing the mass spectrometry conditions，pretreatment methods，and DART ion source conditions，the optimal scheme was determined as follows：whole blood samples were subjected to liquid-liquid extraction with ethyl acetate，and the supernatant was taken. Using an automatic sampling device，5 µL of the sample was dipped and scanned in MRM mode under the conditions of positive ion mode，ion source temperature of 300 ℃，grid voltage of 200 V，injection speed of 0.6 mm/s，and ion source to mass spectrometry distance of 1.6 cm. The limit of detection for the 14 fungicides was 0.5-50 ng/mL，and the lower limit of quantification was 1-100 ng/mL； the average recovery was 80.8%-118%，and the average matrix effect was -19%-18%，as well as the intra- and inter-day precision and accuracy of the lower limit of quantification and the low and high concentration quality controls did not exceed 20%，and，except for prochloraz，tetrafluoroimidazole and flubacterazole，the correlation coefficients（r2） were all greater than 0.99. This method was fast，simple，and suitable for the needs of public security business.关键词：fungicides;real-time direct analysis tandem mass spectrometry（DART-MS/MS）;rapid screening;whole blood205|22|0更新时间：2025-04-10 -
摘要：The method for the determination of volatile components in rice was established based on solid-phase microextraction/gas chromatography-mass spectrometry（SPME/GC-MS）. This method was used to detect and analyze the volatile components in 12 kinds of Panjin rice varieties mainly planted in Panjin area and 10 kinds of non-Panjin rice. A total of 23 volatile components were detected，including 4 kinds of alcohols，10 kinds of aldehydes，4 kinds of ketones，1 kind of esters，and 4 other kinds such as alkanes and acid phenols. Area normalization method was used to calculate the relative content of each volatile component and R language was used to dig the data deeply. The linear regression model and random forest model were constructed to study the identification methods of Panjin rice and non-Panjin rice. The results showed that both mathematical models established in this study can complete the identification of Panjin rice with high accuracy and excellent classification effect. The prediction accuracy was 100%. These two mathematical models have their own advantages and support each other，which greatly improve the reliability of Panjin rice identification and provide theoretical support for the study on production area protection of geographical indication product——Panjin rice.关键词：Panjin rice;volatile component;solid-phase microextraction;GC-MS;linear regression;random forest310|50|0更新时间：2025-04-10 -
摘要：This study aims to analyze the differences in volatile components among five types of ginseng products：fresh cultivated ginseng（FCG），white ginseng（WG），dali ginseng（DG），red ginseng（RG），and sugar ginseng（SG）. The analysis employed headspace-gas chromatography-ion mobility spectrometry（HS-GC-IMS） technology，combined with chemometrics and relative odor activity values（ROAV）. The results indicated that a total of 49 volatile compounds，primarily including aldehydes，alkenes，esters，alcohols，ketones，acids，and ethers were identified using HS-GC-IMS. Significant differences were observed in the types and relative contents of volatile components among the different ginseng products. Heptanal，2-pentanone，ethyl hexanoate，butyl acetate，and β-myrcene were identified as the major characteristic flavor compounds of the five different ginseng products，through the orthogonal partial least squares discriminant analysis（OPLS-DA） and ROAV. Therefore，the comparative analysis of volatile components in different ginseng products using HS-GC-IMS provides a scientific basis for the quality identification and optimization of ginseng products.关键词：ginseng products;head space-gas chromatography-ion mobility spectrometry（HS-GC-IMS）;volatile components;chemometrics;relative odor activity values（ROAV）264|60|0更新时间：2025-04-10 -
摘要：A method has been developed for the analysis of sodium distribution of oligonucleotides using matrix-assisted laser desorption ionization time-of-flight mass spectrometry（MALDI-TOF MS）.The single strand oligonucleotide primers（with a length of 20 bp，whose theoretical molecular weight is 6 071.02 Da） were dissolved in pure water and tested by traditional high performance liquid chromatogen-mass spectrometry（HPLC-MS） and MALDI-TOF MS respectively. The sample solution was tested by HPLC-MS and MALDI-TOF MS respectively after sodium acetate and sodium，alcohol precipitation and resolution，and the test mode was positive ion. Before and after sodium addition，HPLC-MS showed only the unsalted single component（corresponding molecular weight 6 069.9 Da and 6 069.8 Da） after deconvolution. MALDI-TOF MS showed a single component（corresponding molecular weight 6 071.09 Da） for the samples before salt addition，while the component distribution of different sodium number molecules was shown for the samples after salt addition：Each component started with no sodium molecules（corresponding molecular weight of about 6 071 Da），and its content showed a trend of first increasing and then decreasing，the number of sodium added ranges from 0-4 to 0-19，and the distribution changed with different salt adding conditions. The results showed that MALDI-TOF MS had the ability to detect the distribution of sodium salt components of oligonucleotides compared with LC-MS，and it also had a wide range of adaptability and sensitivity to detect a range of oligonucleotide molecules with different salt addition degrees. The method can also be used to analyze oligonucleotide sodium salt drugs（antisense oligonucleotide ASO，etc.）. In this paper，the antisense oligonucleotide drug Formivesen sodium was taken as the sample，and the pure product of Formivesen sodium and the animal injection model of Formivesen sodium containing polyethylene glycol and Tween were tested by this method. The results showed that the main sodium addition form of Formivesen sodium ranged from 0 sodium to 3 sodium，the overall content showed a decreasing trend，and did not change before and after adding the matrix. At the same time，the error of Formivesen sodium was also within the range of ±0.5 Da，and the accuracy was not affected by the matrix. In addition，several other components（including polyethylene glycol 300 and Tween-80） of the matrix were also shown independently in the mass spectrum，and there was no interference with the Formivesen sodium component. The method is simple，rapid，and highly sensitive. It is suitable for qualitative identification of a series of oligonucleotide sodium salt distribution，and the actual drug testing is not affected by the drug matrix，which is of great significance for the development and testing of antisense oligonucleotide（ASO） drugs.关键词：MALDI-TOF MS;oligonucleotide;oligonucleotide sodium distribution;qualitative analysis46|47|0更新时间：2025-04-10 -
摘要：Pyrolysis gas chromatography-mass spectrometry（PyGC-MS） was used to determine the average molecular weight of phenolic resin pyrolysis gas. The samples were injected after crushing and sieving. The pyrograms of the samples were obtained at a pyrolysis temperature of 550 ℃. The pyrolysis gas was analyzed quantitatively by area normalization，and the average molecular weight was calculated. The result shows that the error from theoretical value was less than 1%，and the relative standard deviation（RSD，n=6） is 0.79%．The method is simple，convenient and accurate，and it is suitable for the determination of average molecular weight of phenolic resin pyrolysis gas. Verified by ablation tests，it can be used for evaluating the pyrolysis and ablation properties of phenolic resins.关键词：pyrolysis gas chromatography-mass spectrometry;phenolic resin;pyrolysis gas;average molecular weight39|41|0更新时间：2025-04-10 -
摘要：This study aimed to analyze the volatile substances in both virgin and recycled polyethylene terephthalate（PET） using gas chromatography-mass spectrometry（GC-MS）. Based on various chemometric methods，this study also compared the differences between virgin and recycled PET. The ultimate goal was to establish a model that could identify and distinguish between virgin and recycled PET by analyzing characteristic substances and their concentrations. This research collected 26 samples of recycled PET particles and 48 samples of virgin PET particles provided by different plastic chemical companies. Dichloromethane was used as the extraction solvent. The samples were extracted at a temperature of 50 ℃ under ultrasonic conditions with a fixed power of 1000 W for 1 hour. The extracted solutions were analyzed using GC-MS，and a total of 21 volatile organic compounds were detected. The detected compounds were primarily phenolic and fatty substances，with complex sources that were difficult to trace. Subsequently，various chemometric methods were applied to analyze and identify both virgin and recycled PET. These methods included principal component analysis（PCA），orthogonal projections to latent structures discriminant analysis（OPLS-DA），linear discriminant analysis（LDA），artificial neural networks（ANN） and decision trees（DT）. The accuracy of these different models in distinguishing between virgin and recycled PET was compared to determine which method was most effective. The results indicated that the combination of GC-MS with ANN and DT models achieved a classification accuracy of over 96% for recycled PET. This demonstrates that these models are effective in distinguishing between virgin and recycled PET. Therefore，the models can provide technical references for the application and regulation of recycled PET in the market，and will benefit both the industry and environmental sustainability.关键词：recycled plastic;polyethylene terephthalate;chemometrics;gas chromatography-mass spectrometry（GC-MS）;identification273|30|0更新时间：2025-04-10 -
摘要：The chemical component of Lonicerae japonicae Flos and Lonicerae japonicae branches was compared based on the utilizing ultra-high-performance quadrupole-orbitrap high-resolution mass spectrometry（UHPLC-Q-Orbitrap-HRMS） technique. Firstly，the similarity of chemical components between Lonicerae japonicae branches and Lonicerae japonicae flos at different harvesting periods was analysed by high-performance liquid chromatography（HPLC） technique combined with fingerprinting，and the results showed that Lonicerae japonicae branches harvested at the end of October had the highest similarity with honeysuckle，reaching 85%. Then UHPLC-Q-Orbitrap-HRMS technology was used to conduct full scanning and secondary mass spectrometry scanning on the extracts of Lonicerae japonicae flos and Lonicerae japonicae branches at the end of October in positive and negative ionisation modes，and 38 chemical components were identified by comparison with reference substance，online database matching and literature search，among which 35 were common components. The mass spectrometry data of 35 common components were imported into the MetaboAnalyst website，and the projected importance value（VIP） of variables was calculated based on the partial least squares analysis algorithm. As a result，there were eight compounds with VIP>1，indicating that the chemical composition of Lonicerae japonicae branches harvested at the end of October had a high degree of similarity with that of Lonicerae japonicae flos，and the differences were mainly reflected in the contents of some components. The study can provide effective data support for the rational development and utilization of Lonicerae japonicae branches resources.关键词：UHPLC-Q-Orbitrap-HRMS;Lonicerae japonicae flos;Lonicerae japonicae branches;chemical component252|45|0更新时间：2025-04-10 -
摘要：A simultaneous determination method was established of methaqualone，diazepam，perphenazine，thioridazine hydrochloride，chlorpromazine hydrochloride and promethazine hydrochlorine in feeds using mixed cation exchange solid-phase extraction（SPE） by liquid chromatography tandem mass spectrometry（LC-MS/MS）. The samples（compound feed，concentrated feed，additive premixed feed and concentrate supplement） were extracted with 0.5 mol/L hydrochloric acid solution-acetonitrile（1∶9），purified by a mixed cation exchange SPE column and then injected into LC-MS/MS. The chromatographic separation of six sedatives were conducted on a C18 chromatographic column（100 mm×2.1 mm，2.6 μm） utilizing acetonitrile and 0.1% formic acid aqueous solution as mobile phases. Six sedatives were detected by using positive-ion electrospray tandem mass spectrometry via multiple reaction monitoring（MRM） scan mode，and the samples were quantified by external standard method. The results indicated that the calibration curves of six sedatives in different feed matrix showed good linear relationships in the concentration of 0.2-50 μg/L with correlation coefficients（r2） all above 0.98. The limit of detection was 0.05 mg/kg and the limit of quantitation was 0.1 mg/kg. The recoveries of six sedatives in feed ranged from 73.2% to 104% at the spiked levels of 0.1，1.0，100 mg/kg，with relative standard deviations（RSDs） of 1.0% to 11%. The method was sensitive，accurate and suitable for the simultaneous determination of six sedatives in feeds.关键词：liquid chromatography-tandem mass spectrometry（LC-MS/MS）;sedatives;feed;solid-phase extraction70|27|0更新时间：2025-04-10 -
摘要：In this study，silver nanoparticles（AgNPs） were synthesized using trisodium citrate as a protectant，and p-aminothiophenol（PATP） was modified on the surface of AgNPs to establish a method based on the visual detection of carbendazim by PATP-AgNPs. And the concentration of PATP，pH and concentration of buffer solution and reaction time were optimized. The results showed that under the optimal conditions，the limit of detection of carbendazim by the established visualization detection method was 0.052 7 μg/mL，and the concentration of carbendazim showed a good linear relationship in the ranges of 1-3 μg/mL and 3-5 μg/mL. The spiked recoveries of the three actual samples of yam，asparagus and tertiary ginseng were in the range of 91.1%-108% with the relative standard deviations（RSDs） of 1.1%-5.7%. The method has the advantages of rapidity，simplicity and high specificity，and is suitable for the on-site rapid determination of carbendazim in herbs.关键词：carbendazim;silver nanoparticles;visualization;medicinal herbs45|53|0更新时间：2025-04-10 -
摘要：In this study，a quantitative detection assay for bongkrekic acid （BA） based on flow cytometry fluorescence immunoassay was established. Synthesize BA-BSA complete antigen and obtain high titer monoclonal anti-BA antibody by immunization. BA-BSA labeled with phycoerythrin competes with BA in the sample for a limited number of antibody binding sites on the fluorescent microspheres. The average fluorescence intensity on the surface of the microspheres is detected by flow cytometry to achieve accurate quantitative determination of BA in the sample. The results showed that the assay achieved greatlinearity in the linear ranges from 1.01 μg/L to 97.96 μg/L，and the correlation coefficient（r2） was 0.999 8. The limit of detection（LOD）was 0.56 μg/kg. The recoveries in samples ranged from 90.4% to 104%，while the relative standard deviation was between 5.0% and 9.8%. The cross reactivities with ochratoxin A，aflatoxin B1，aflatoxin M1，fumonisin B1，and fumonisin B2 were all less than 0.1%. One positive sample was detected in 18 food samples，with a BA concentration of 6.5 µg/kg，which was consistent with the results obtained by high-performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS） instrument. The flow cytometry fluorescence immunoassay method established in this study is simple，rapid，sensitive，and accurate，and can be extended to the analysis and detection of other fungal toxins in complex matrices such as various foods.关键词：flow cytometry fluorescence immunoassay;bongkrekic acid;antigen;antibody;food safety48|67|0更新时间：2025-04-10
Scientific Papers
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Research on Fully Automated Nucleic Acid Extraction Microsystem and Detection Based on Voice Control
摘要：To solve the problem of high efficiency and precision nucleic acid extraction in microscale environment，an automatic nucleic acid extraction microsystem was proposed in this study. The system integrates nucleic acid extraction chip，air channel，pressure，and vacuum tube，and realizes automatic flow operation of sample solution，washing solution，and eluent through integrated control of microcontroller. Through the control of a smartphone app，users can easily implement the fully automated process of extracting nucleic acids from biological samples，effectively avoiding human interference and significantly reducing the risk of exposure to infection. To verify the success of nucleic acid extraction，diphenylamine reagent was used for preliminary color change detection to quickly determine whether nucleic acid was successfully extracted，and the extraction effect was further verified by solid-state nanopore sensing experiment and nucleic acid sequencing technology to ensure the accuracy and reliability of the extraction results. The experimental results show that the automatic nucleic acid extraction microsystem is not only easy to operate，but also has high efficiency and accuracy.关键词：automatic nucleic acid extraction;microfluidic chip;smartphone control;diphenylamine reagent59|59|0更新时间：2025-04-10 -
摘要：The sensitive and rapid detection of clenbuterol ractopamine（RAC） is of great significance for food safety and human health. However，the traditional RAC analysis methods often involve complex instruments and professional operators，and it is difficult to achieve portable field detection. Using the cation exchange reaction（CER） between cadmium telluride quantum dots（CdTe QDs） and silver ion（Ag+），and the specific recognition properties of aptamer（Apt），combined with enzyme-free hairpin assembly（CHA） of signal amplification，a low-cost，high-sensitivity field quantitative detection method for ractopamine was proposed. The detection limit was as low as 2.3 pmol·L-1，significantly lower than the maximum residue limit（MRL） recommended by the Codex Alimentarius Commission. The key of this method was that the aptamer recognizes RAC to drive cytosine-Ag+-cytosine structure in hairpin DNA to release Ag+，while effectively promoting the occurrence of multiple CERs through CHA and continuously inducing fluorescence quenching of CdTe QDs，which provided a basis for highly sensitive field quantitative analysis of RAC. The practical feasibility of the method was verified，including its stability，repeatability，and performance over non-CHA systems. This method can not only distinguish different contents of RAC with open eyes，but also has universality. It can be used to analyze other target objects only by modifying the identification region in the system. This study is conducive to the advancement of food safety and environmental health，and provides a highly efficient tool for quantitative analysis of RAC and other potentially similar compounds.关键词：clenbuterol;ractopamine;fluorescence visual analysis;quantum dots;cationic exchange39|28|0更新时间：2025-04-10 -
摘要：Plastic products in contact with food are subjected to migration tests using water-based simulants（4% acetic acid solution，10% ethanol solution，20% ethanol solution，50% ethanol solution），oily food simulant（olive oil） and alternative volatile media（95% ethanol solution and isooctane） in accordance with the provisions of GB 31604.1-2023 and GB 5009.156-2016. The obtained soaking solution was analyzed by gas chromatography-mass spectrometry using headspace or liquid direct injection，and quantified by isotope internal standard method. The four target compounds，chlorobenzene，1，2-dichlorobenzene，1，3-dichlorobenzene and 1，4-dichlorobenzene，showed good linear relationships in different food simulants，with a linear range of 0.020-0.50 mg/L（or mg/kg） and correlation coefficients（r2） not less than 0.997 5. The detection limits of four target substances were all 0.01 mg/kg，and the quantification limits were all 0.02 mg/kg. The average spiked recoveries at levels of 0.02，0.05 and 0.10 mg/L（or mg/kg） were 83.0% to 110%，with relative standard deviations（RSDs） ranging from 1.8% to 11%（n=6）. This method is easy to operate，accurate and reliable，and can meet the qualitative and quantitative detection of specific migration amounts of chlorobenzene and dichlorobenzene in plastic products in contact with food.关键词：gas chromatography-mass spectrometry;isotope internal standard;food contact;plastic product;chlorobenzene;dichlorobenzene49|42|0更新时间：2025-04-10 -
摘要：An analytical method was developed to detect the molecular weight of cotton cellulose. This method uses gel permeation chromatography coupled with multi-angle static laser light scattering（GPC-MALS） and adds ionic liquid to dissolve the cotton. The separation of GPC does not require high mobile phase，no gradient drenching，simple experimental operation，good reproducibility，fast test speed，and has many features that other chromatography does not have. MALS measures the light scattering intensity of the sample at each angle. The sample is separated by the column. The RI detector measures the concentration of the eluent. This allows the molecular weights of individual slices to be calculated. By combining GPC and MALS，it not only separates different sets of fractions，but also measures the root-mean-square radius，molecular weights and their distributions of different sets of fractions，and does not require standard samples and standard curves. Therefore，it is widely used in the fields of macromolecular research，biochemistry and reaction kinetics. After the samples were treated with NaOH base，cotton cellulose was dissolved by adding N，N-dimethylacetamide（DMAc） to 1-butyl-3-methylimidazolium acetate（BmimAc） ionic liquid，and then the ionic liquid type test was changed，and after comparing the four ionic liquids methods for dissolving cotton cellulose，it was concluded that BmimAc ionic liquid was the most effective. Various temperatures were also tried to dissolve cotton cellulose，and the dissolved solution was passed through 0.22 μm PTFE filters and then used directly for GPC-MALS to detect its molecular weight. The results showed that cotton cellulose still could not be dissolved at 40 ℃ for a long time； the time needed to dissolve cotton cellulose gradually decreased from 50 ℃ to 80 ℃，and the molecular weight was about 2.2×104，and the inaccuracies were all within 5%，so the results were reliable； the molecular weight of cotton cellulose dissolved at 90 ℃ was 6.634×104，thermal glycosylation at the reducing end is suggested to occur under the neat pyrolysis conditions. The molecular weight distribution of the cellulose was slightly shifted to the high molecular weight region after heat treatment. In summary，the new method for the detection of molecular weight of cotton cellulose by multi-angle laser light scattering coupled with gel permeation chromatography using BmimAc as an additive has the advantages of simple preparation，mild dissolution conditions，high detection precision，fast detection and low consumption，which overcomes the problems of traditional methods，such as the inability to measure absolute molecular weight and the difficulty of finding structurally similar standards.关键词：gel permeation chromatography coupled with multi-angle static laser light scattering;ionic liquid;cellulose;molecular weight and distribution202|41|0更新时间：2025-04-10 -
摘要：In order to achieve rapid，selective identification and quantitative detection of rutin，in this paper，the fluorescent polydopamine organic nanoparticles（FPONs） emitting blue fluorescence were prepared for rutin fluorescence analysis by a simple，green and low-cost method using folic acid and dopamine as precursors. FPONs have excellent water solubility，resistance to photobleaching，salt resistance，relatively high fluorescence quantum yield and good fluorescence stability in a wide pH range. Interestingly，at the excitation wavelength of 360 nm，the fluorescence intensity of FPONs was obviously quenched in the presence of rutin，based on this，a fast and sensitive method for rutin determination was established. The results show that the response time of rutin to FPONs as short as 5 sec，indicating the rapid detection of rutin. With the increase of rutin concentration，the relative fluorescence intensity I0/I showed a good linear relationship with the concentration of rutin with the linear range of 0-50 μmol/L，and the limit of detection（LOD） of 0.016 μmol/L. The mechanism of fluorescence quenching shows that the system may be caused by internal filtration effect and static quenching. Finally，the FPONs were successfully used to detect rutin in actual water samples，with the satisfied recoveries of 95.0%-100%，and the relative standard deviation≤4.1%，implying the feasibility and applicability of the method.关键词：fluorescence sensing;dopamine;folic acid;rutin215|74|0更新时间：2025-04-10 -
摘要：Yao-meat is the traditional food of Zhenjiang. However，the Yao-meat is easy to spoil，thus，it is necessary to monitor its freshness. The traditional monitoring methods including physical and chemical tests have the disadvantages，such as complex operation and time-consuming preparation. Therefore，this paper used hyperspectral imaging as a non-destructive detection method to measure the freshness of Yao-meat. The thiobarbituric acid reactive substance（TBARS） was set as the indicator of freshness，and predicted by the hyperspectral imaging combined with semi-supervised regression. For the dataset，the hyperspectral images and the values of TBARS were assigned as X and y. Meanwhile，the dataset was divided as three parts，including calibration，validation and independent prediction sets. Among them，the calibration set was used to build model and predict samples in validation and prediction sets. In calibration set，the samples with and without y values were called as labeled and unlabeled ones. The samples in validation and independent prediction sets were all labeled ones. The validation set was applied to adjust the parameters of model rather than calibration. Meanwhile，the independent test set was used to test the final results of model rather than calibration and parameters adjustment. In this paper，the sizes of calibration，validation and independent prediction sets were 223，12 and 12，respectively. Among the calibration set，the numbers of labeled and unlabeled samples were 48 and 185，respectively. During calibration，the labeled samples with X and y values were computed to generate model initially. Then the unlabeled samples in calibration set were predicted by the model. At this time，all the samples in calibration set were labeled. Finally，the whole samples in calibration set were applied to build a new model for prediction. The parameters of the two models may be different to each other and were both optimized by validation sets. In this paper，the nonlinear models were executed for calibration，including support vector regression（SVR），Gaussian process regression（GPR），artificial neural network（ANN） and extreme learning machine（ELM）. The results show that compared with different calibration models，the SVR can achieve good results. In the same time，SVR combined with semi-supervised regression can improve prediction accuracy. Moreover，selecting key unlabeled samples based on distances can reduce prediction errors.关键词：Yao-meat;TBARS;semi-supervised regression;hyperspectral imaging;support vector regression（SVR）;Gaussian process regression（GPR）46|36|0更新时间：2025-04-10 -
摘要：A gas chromatography method has been developed for the simultaneous separation and determination of chiral 3-cyclohexene-1-carboxylic acid methyl ester（CHCM） and chiral 3-cyclohexene carboxylic acid（CHCA）. The racemic CHCM serves as a substrate that can be stereoselectively catalyzed by lipase to produce the product chiral CHCA. By employing the orthogonal experimental design，the effects of chromatographic column type，carrier gas linear velocity，initial column temperature and temperature ramp rate on the enantiomeric separation of CHCM and CHCA were investigated. The analysis of variance（ANOVA） indicated that the optimal separation was achieved using an SH-βDEXsm chromatographic column，with a carrier gas linear velocity of 30.0 cm/s，an initial column temperature of 70.0 ℃，and a temperature ramp rate of 1.00 ℃/min. Under these conditions，the separation factor for the enantiomers of CHCM was 2.15，and for CHCA，it was 3.50. The linearity range for（R）- and（S）-CHCM and（R）- and（S）-CHCA were determined to be 3.50-350 mg/L and 15.8-315 mg/L，respectively，with correlation coefficients of 0.999. The limits of detection（LODs） for the four compounds ranged from 0.550 mg/L to 3.16 mg/L，and the limits of quantification（LOQs） ranged from 1.85 mg/L to 9.56 mg/L. The recoveries for（R）- and（S）-CHCM and（R）- and（S）-CHCA at three different concentrations were between 91.4% to 97.1%，91.4% to 95.7%，89.9% to 95.6%，and 88.6% to 96.0%，respectively，with relative standard deviations（RSDs） not more than 4.7%. This method allows for the simultaneous separation of chiral CHCM and CHCA in a single injection.关键词：chiral gas chromatography;3-cyclohexene-1-carboxylic acid methyl ester;3-cyclohexene carboxylic acid;orthogonal test;enantiomers38|21|0更新时间：2025-04-10 -
摘要：A thin-layer electrochemical flow detection system is developed for the analysis of Cd2+ and Pb2+ in water by differential pulse stripping anode stripping voltammetry（DPASV） in ship or buoy applications. The stability and sensitivity of the electroanalytical system are also investigated. After optimized the flow cell structure and applied the modified electrode using multi-wall carbon nanotube，a detection limit of 0.02 μg/L for Cd2+ and 0.17 μg/L for Pb2+ could be obtained，with linear range of 0.2-100 μg/L. The electroanalytical system can be preliminarily applied to the on-line determination of Cd2+ and Pb2+ in water. In order to further improve the detection sensitivity，pyrrole electropolymerized conductive modified electrode was employed，by which thiourea was involved in the polymerization to introduce sulfur groups to increase the adsorption capacity of Pb2+.The detection limit is found to be 0.03 μg/L，and the linear range is 0.1-100 μg/L for Pb2+with recoveries of 93.3%- 110%. The system has been successfully applied to the on-line determination of Pb2+ in water after the optimization of instrumental conditions.关键词：electrochemistry;modified electrode;flow system;Cd2+;Pb2+;analysis287|141|0更新时间：2025-04-10 -
摘要：A method was established for the determination of 8 diaryl phosphates （diphenyl phosphate，dibenzyl phosphate，bis（2-methylphenyl）hydrogen phosphate & bis（4-methylphenyl）hydrogen phosphate，bis（1-chloro-2-propyl）phosphate，bis（1，3-dichloro-2-propyl）phosphate，bis（2-chloroethyl）phosphate，bis（2，3-dibromopropyl）phosphate，bis（butoxyethyl）phosphate） in human urine using high performance liquid chromatography-tandem mass spectrometry. The target compounds were extracted，purified，concentrated and redissolved. Then，the target compounds were separated by a Kinetex C18（100 mm×2.1 mm，2.6 μm） column. 1 mmol/L ammonium acetate aqueous solution and methanol were used as mobile phase and gradient elution was adopted. Quantitative analysis was performed using isotope internal standard under ESI- ion source mode. Under optimal conditions，the target compounds showed good linearity with the correlation coefficients（r2） greater than 0.99 within their respective ranges. The detection limits（LODs） were in the range of 0.05-0.30 μg/L，and the quantification limits（LOQs） were in the range of 0.2-1.0 μg/L. Average recoveries of the target compounds were in the range of 76.8%-115% at three different levels，and the relative standard deviations（RSDs） were between 2.3% and 9.8%. This method is simple，fast，highly sensitive and effective. It has been applied to analyze the levels of metabolites of organophosphate flame retardants in children’s urine in Longhua District，Shenzhen. It provides a scientific basis for the exposure assessment of metabolites of organophosphate flame retardants.关键词：solid-phase extraction;high performance liquid chromatography-tandem mass spectrometry;human urine;metabolites of organophosphate flame retardants67|36|0更新时间：2025-04-10
Experimental Techniques and Methods
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摘要：The color trace material of suspicious documents is an important physical evidence in forensic identification，and the research on the identification methods of color trace material such as written handwriting，seal imprints，printed graphics has always been a hot issue in the field of forensic science，and the real-time analysis，non-destructive appraisal and ambient detection of the identification methods are all of great significance，based on which，the current status of the research on the detection of color traces of documents and its development are analyzed. Currently commonly used document color trace material detection methods such as chromatography，spectroscopy and mass spectrometry have certain specificity and limitations. Ambient ionization mass spectrometry（AIMS） is an emerging analytical technique in recent years，which has the characteristics of real-time and high efficiency，ambient detection，and simple sample pre-treatment，and is gradually becoming an important tool for the detection of document color traces. This review focuses on the principle and research progress of ambient ionization mass spectrometry based on plasma desorption，liquid extraction and laser ionization，summarizes the applications of ambient ionization mass spectrometry in the field of document color trace analysis in recent years，and describes the characteristics of different methods. Finally，the existing problems and future research trends of this technique are summarized and prospected，aiming to provide reference and inspiration for the analysis and detection of document color trace materials.关键词：document color traces;forensic sciences;ambient ionization mass spectrometry;ambient detection263|53|0更新时间：2025-04-10 -
摘要：Mycotoxin contamination is extensive，traceable，synergistic，and difficult to prevent and control，and has become one of the hot spots and focuses of global food safety research. The hazards of mixed contamination with multiple mycotoxins have significant synergistic or additive effects，posing a serious threat to human and animal health. As a result，in comparison to traditional laboratory analysis methods，developing a rapid detection method that is rapid，sensitive，accurate，and capable of detecting a variety of mycotoxins at the same time is of great theoretical significance and application value. Because of its simple operation，strong specificity，fast reaction speed，low cost，and low requirements for operators，immunoassay technology is widely used in the field of rapid detection of mycotoxins. This paper reviews the research progress of mycotoxin multiplexing detection technology based on immunoassay technology in the past five years，and introduces the general situation of typical mycotoxins in food and the principle of immunoassays. This paper summarizes the current situation of eight multiplexing detection methods，analyzes the advantages and disadvantages of each detection method combined with practical application，prospects its future development trend，and provides reference for the multiplexing detection technology of mycotoxins in food.关键词：mycotoxins;food safety;immunoassay;multiple testing253|41|0更新时间：2025-04-10 -
摘要：Due to its environmental toxicity and endurance as a heavy metal，copper ion（Cu2+） has detrimental impacts on both ecosystem and human health. The requirement for expensive and bulky analytical instruments often hinders the application of traditional Cu2+ detection methods in real-time and on-site detection. In recent years，carbon quantum dots（CDs） have been extensively employed in the development of Cu2+ fluorescence sensors across various fields such as agriculture，environment，and medicine due to their inherent advantages including excellent fluorescence stability，resistance to photobleaching，remarkable biocompatibility，negligible toxicity，and facile surface functionalization. This paper provides a comprehensive review on the synthesis method of CDs in recent years and the influence of synthetic regulation on the fluorescence detection performance of CDs.The research progress of CDs in Cu2+ detection is discussed from the detection mechanism of CDs and the types of fluorescence sensors.Finally，the prospect of its development is prospected. In the future，the construction of fast，anti-interference，visualisation and portable fluorescent sensors is still the main research direction for the detection of heavy metal ions such as Cu2+.关键词：carbon quantum dot;fluorescence sensor;copper ion;detection279|70|0更新时间：2025-04-10
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