最新刊期
卷 43 ， 期 5 ， 2024
- 摘要：A new method for the simultaneous and rapid determination of 67 indicative components from plant extracts in cosmetics by ultra high performance liquid chromatography-tandem mass spectrometry（UHPLC-MS/MS） was established. The cosmetic samples were dispersed with methanol（1% formic acid） and ultrasonic extraction. The filtrate was analyzed by a Agilent RRHD Eclipse Plus Zorbax C18 chromatographic column（3.0 mm×100 mm，1.8 μm） with mobile phase consisted of 0.1% formic acid aqueous solution and acetonitrile. 67 indicative components from plant extracts were analyzed in the electrospray ionization source，including positive ion scanning with multiple reaction monitoring mode（MRM） and negative ion scanning with dynamic multiple reaction monitoring mode（DMRM） respectively. Creams and lotions were choosed as the representative matrix. The 67 indicative components showed good linearity with the correlation coefficients（r2） greater than 0.99 in their respective mass concentration ranges. The detection limits（LODs） of 67 indicative components were in the range of 0.002 6-1.7 μg/g，and the quantitation limits（LOQs） were in the range of 0.008 0-5.0 μg/g. For cream and lotion samples，the average recoveries of 67 indicative components at three different concentration levels ranged of 85.6%-117% and 82.7%-116%，respectively； with relative standard deviations（RSDs，n=6） ranged of 1.0%-12% and 0.90%-12%. The established method is simple，rapid，effective，high sensitive，and is suitable for the qualitative identification and content determination of 67 indicative components from plant extracts in cosmetics.关键词：UHPLC-MS/MS;cosmetics;plant extracts;indicative components
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发布时间：2024-08-16 - 摘要：α-Glucosidase is an indispensable enzyme in the glucose metabolism pathway of organisms. The development of simple，sensitive and accurate detection methods for α-glucosidase activity and inhibitors screening are of great significance for the treatment and prevention of diabetes. In this work，a novel fluorescent "on-off-on" method for detection of α-glucosidase activity and its inhibitors screening was developed based on N-doped Ti3C2 MXene quantum dots（N-Ti3C2 MQDs） and internal filtration effect（IFE）. The prepared N-Ti3C2 MQDs emitted blue fluorescence（λem = 440 nm） with a fluorescence quantum yield of 15.7%. α-Glucosidase can hydrolyze substrate p-nitrophenyl-α-D-glucopyranoside to produce p-nitrophenol，which causes fluorescence quenching of the N-Ti3C2 MQDs through IFE. After adding the acarbose inhibitor，the activity of α-glucosidase is inhibited and the produced p-nitrophenol by hydrolysis is reduced，resulting in fluorescence recovery of N-Ti3C2 MQDs. Fluorescent intensity of N-Ti3C2 MQDs probe is proportional to α-glucosidase concentration in the range of 5-300 U/L，with a detection limit of 2.5 U/L（S/N = 3）. The half-maximal inhibitory concentration of inhibitor（IC50） value is calculated to be 178.5 μmol/L for acarbose. This proposed method has the advantages of low cost，simple operation，high sensitivity，and good selectivity，which has been successfully used for determination of α-glucosidase activity in human serum.关键词：α-glucosidase;N-doped Ti3C2 MXene;quantum dots;fluorescent probe
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发布时间：2024-08-16 - 摘要：In this study，zeolitic imidazolate framework-8（ZIF-8） based on effervescent tablet-assisted dispersive solid-phase extraction method（ET-DSPE） was developed and coupled with high performance liquid chromatography tandem mass spectrometry（HPLC-MS/MS） for the determination of five benzodiazepines（BZDs） in human urine samples，including estazolam，alprazolam，diazepam，triazolam and lorazepam. The prepared ZIF-8 sorbent was characterized by Fourier transform infrared spectroscopy，X-ray powder diffractometry，scanning electron microscopy，automatic specific surface area and pore analyzer，and the results showed that ZIF-8 nanoparticles with rhombohedral dodecahedral structure were successfully synthesized. The extraction parameters of the adsorption and elution processes were optimized in detail，involving amount of ZIF-8 sorbent and Na2CO3，adsorption time，pH and ionic strength of solution，urine dilution ratio，elution solvent，elution volume and time. The optimal conditions were shown as follows：ZIF-8 amount，35 mg；Na2CO3 amount，20 mg；adsorption time，4 min；pH and ionic strength of the solution，no adjustment；urine dilution ratio，no dilution；elution，1.0 mL of methanol；elution time，30 min. Under the optimized conditions，the proposed method provided the linear ranges of 0.002-100 ng/mL for estazolam and 0.001-100 ng/mL for the other four analytes（r≥0.999）. The limits of detection（S/N=3） and the limits of quantification（S/N=10） of five BZDs were in the ranges of 0.000 3-0.000 6 ng/mL and 0.001-0.002 ng/mL，respectively. Besides，the recoveries for spiked urine samples with three concentration levels varied from 81.6% to 108% with the intra-day relative standard deviations（RSDs） and inter-day RSDs of 1.4%-5.6% and 1.4%-9.9% separately. Compared with the previous pretreatment methods for BZDs in urine samples，ZIF-8 based effervescent tablet-assisted dispersive solid-phase extraction method allowed direct loading of crude urine samples without any filtration or dilution step. Besides，the effervescent tablet-assistance facilitated a well dispersion and an adequate adsorption，offering the enhancement factor of 40.8-54.0. The developed method achieved a strategy for the accurate，convenient and sensitive determination of five BZDs in human urine samples.关键词：urine;benzodiazepines;effervescent tablet-assisted dispersive solid-phase extraction;high performance liquid chromatography tandem mass spectrometry（HPLC-MS/MS）
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发布时间：2024-08-16 - 摘要：As a dual-use substance，nitrogen mustard is not only on a list of the Convention on the Prohibition of Chemical Weapons，but its derivatives are traditional clinical chemotherapy drugs. In this paper，the adducts formed by incubation of three typical nitrogen mustards（HN1，HN2 and HN3） with 4 bases，4 deoxyribonucleosides，4 deoxyribonucleotides and salmon DNA respectively，were analyzed and identified by high-performance liquid chromatography-quadrupole electrostatic field orbitrap high-resolution mass spectrometry. The HN-DNA adducts in all 39 incubation systems were chromatographically separated and the data were collected by Full MS/dd-MS2 mode to obtain their mass spectrometry characteristics. The results showed that the mono-adducts formed by three kinds of nitrogen mustard with guanine，adenine and cytosine could be identified in each incubation system and the di-adducts formed by nitrogen mustard with guanine or adenine could be identified. Although the mono-adducts formed by three kinds of nitrogen mustard with thymine were detected in the base incubation system，they were not detected in the salmon DNA incubation system，indicating that adducts formed by HNs with thymine base were not primary adducts for DNA. By exploring the mass spectrometry characteristic fragments of each adduct，the specific ion pairs of series of DNA adducts for the multi-reaction monitoring mode of mass spectrometry have been summarized，which lays a foundation for the establishment of a method for structural analysis，accurate traceability and rapid quantification of nitrogen mustard-DNA adducts in complex biological samples.关键词：nitrogen mustard;DNA adducts;characteristic fragments;high performance liquid chromatography-quadrupole electrostatic field orbitrap high-resolution mass spectrometry
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发布时间：2024-08-16 - 摘要：A highly sensitive and selective pre-column derivatization coupled with high performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS） assay was developed for the determination of the D，L configurations of 26 free chiral amino acids in industrial products. The samples were dissolved and extracted in 0.1 mol/L HCl solution，and then derivatized by Marfey reagent under alkaline condition at 37 ℃ for 16 hours. Baseline separation of the derivatives was achieved on a Phenomenex Kinetex F5（250 mm ×5 mm，4.6 μm） column. The mobile phase consisted of 10 mmol/L ammonium acetate and acetonitrile by gradient elution. Reverse phase chromatographic resolution of the enantiomers was obtained within 27 min. The derived analytes were sensitively detected using an electrospray ionization source in negative ion mode（ESI-） and multiple reaction monitoring（MRM） mode. The results showed that the derivatized products of 26 chiral amino acids could be effectively separated. The mass concentrations of 26 chiral amino acids showed a good linear relationship with their corresponding peak areas in a corresponding range. The limits of quantification were determined to be 0.5-12.5 ng/mL and correlation coefficients（r2） not less than 0.994 0. The extraction recoveries for all analysts were in the ranges of 80.3%-118% and the relative standard deviations were in the ranges of 0.47%-9.8%. The method was applied to determine chiral amino acids in 180 industrial samples. The results indicated that D-amino acids were detected in L-type pure amino acid reagent，L-type stable isotope-labeled amino acid internal standard reagent，single L-amino acid raw material，and composite amino acid raw material powder. It is the first time to evaluate the quality of chiral amino acids in relevant industrial products in China，and it was found that the monitoring and management of chiral configurations need to be strengthened for amino acid complex powders. It also thoroughly investigates the potential impact on the accuracy of test results in the food，environmental，chemical，and pharmaceutical industries sectors when the amino acid purity reagents are used as standards or isotopic internal standards for the detection of relevant samples. With the advantages of rapid，accurate，high sensitivity，and simple sample pretreatment，this method can be an effective technical tool for quality management and health assessment in the fields of research reagents，biopharmaceuticals，chemical food and nutritional health.关键词：chiral amino acids;chiral derivatization;HPLC-MS/MS;industrial products
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发布时间：2024-08-16 - 摘要：The aim of this study is to establish a new colorimetric method for the detection of bovine pregnancy associated glycoprotein 9（bPAG9） based on the metal-organic framework Fe-MIL-101 and double aptamer sandwich principle. In a typical experimental procedure，biotinylated aptamer1 was immobilized onto microplate to act as capture probes. Fe-MIL-101 functionalized aptamer 2 act as a signal probe. In the presence of bPAG9，aptamer 1 and aptamer 2 bind with bPAG9 and forma double aptamer sandwich structure on solid phase carrier. Fe-MIL-101 coupled to aptamer 2 enable to catalyze the colorless peroxidase substrate to yield a colorimetric output signal. Thus，the qualitative and quantitative analysis of bPAG9 could be realized by the change of colorimetric signal. The results showed that under the optimal conditions，the linear detection range were 0.5-50 ng/mL for bPAG9 in buffered solution，with a limit of detection（LOD） of 0.13 ng/mL. The average recoveries of bPAG9 in blank serum samples were in the range of 89.4%-104%，and the relative standard deviations were less than 10%. Subsequently，the serum samples from Holstein cows at 28 days after insemination were analyzed by the developed assay. The test results were confirmed with ultrasonography and compared with PAG-ELISA test kit. The diagnostic sensitivity，specificity，and accuracy of the developed assay were 92.5%，90.0% and 91.5%，respectively.The developed assay has such advantages as simple，noninvasive，and economical. It has a good application prospect in the field of cow early pregnancy detection.关键词：pregnancy associated glycoprotein;aptamer;metal organic framework;pregnancy diagnosis;cow
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发布时间：2024-08-16 - 摘要：This study established an online solid phase extraction（OSPE）/ultrahigh performance liquid chromatography tandem mass spectrometry（UPLC-MS/MS） method for the determination of 90 pharmaceutical and personal care products（PPCPs） in surface water. After filtration，the water sample was directly injected into the OSPE column for purification and enrichment，and the target substances were transferred to the analysis column for further separation and analysis through valve switching. Using a Waters HSS T3 C18（100 mm×2.1 mm，1.8 μm） chromatographic column for separation，with 0.1% formic acid aqueous solution and acetonitrile as the mobile phase for elution. The analytes were detected in multiple reaction monitoring（MRM） mode through positive and negative electrospray ionization（ESI），and quantified with internal standard method. Under optimized chromatography-mass spectrometry conditions，90 PPCPs showed good linear relationships with the correlation coefficients（r2） more than 0.99. The detection limits reached 0.06-10.00 ng/L，and the quantitation limits reached 0.24-40.00 ng/L. The recoveries in actual samples analyzed at spiked concentrations of 10，20，and 100 ng/L were between 81.2% and 120%，with relative standard deviations（n=7） of most compounds less than 10%. This method has high analysis efficiency，sensitivity，and stable operation，and could be used as a monitoring method for analyzing PPCPs in surface water samples.关键词：pharmaceutical and personal care products（PPCPs）;online solid phase extraction（OSPE）;UPLC-MS/MS;surface water
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发布时间：2024-08-16 - 摘要：Synthetic musks（SMs） are widely utilized as flavor additives in everyday washing，and prolonged exposure to SMs may present potential health risks to humans. This study employs silicone bracelet as passive sampler for the collection of daily exposure to SMs among college students. After extraction with ethyl acetate solution，the samples were concentrated with solid phase extraction（SPE）. The concentration of SMs in individual samples was detected by gas chromatography-mass spectrometry（GC-MS） and internal standard method，while the health risks associated with SMs exposure were assessed by hazard quotient（HQ）. The findings demonstrate that the galaxolide（HHCB） and tonalide（AHTN） were linear in the range of 5-500 µg/L，with linear correlation coefficients（r2） more than 0.999. The limits of detection for the analytes were 1.2-6.6 µg/L and the limits of quantitation were 4.10-21.9 µg/L. The recoveries of HHCB and AHTN ranged from 91.6% to 113% and from 92.7% to 118%，with relative standard deviations（RSDs） ranging from 1.9% to 15% and from 0.81% to 11%，respectively. The average daily exposure to HHCB and AHTN was found to be 2.60 μg/（kg·d） and 0.23 μg/（kg·d），respectively，among the college student population. The HQ of SMs dermal exposure is below 1，indicating no significant human health risk to the college student population. The study results confirm the silicone bracelet's potential as a new passive sampling device for researching human compound exposure，offering valuable data and research methods for investigating chemical exposure and assessing human health risks.关键词：silicone bracelet;passive sampling;synthetic musks;gas chromatography-mass spectrometry;health risks
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发布时间：2024-08-16 - 摘要：The dispersion liquid-liquid microextraction assisted by pasteurized dropper（PTD-DLLME） combined with ultra-high performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） method was established for the simultaneous determination of 7 neonicotinoid pesticides in environmental water. In the experiment，a pasteurized dropper was used as the extractor，acetonitrile with low density and low toxicity was used as the extractant，and acetone was used as the dispersant for the first time. The separation was performed on a BEH C18 column（2.1 mm×50 mm，1.7 μm） by gradient elution，with 0.01% formic acid aqueous solution（containing 2 mmol/L ammonium formate） and 0.01% formic acid acetonitrile solution（containing 2 mmol/L ammonium formate） as the mobile phases. After optimization of the gradient elution procedures and mass spectrometric conditions，chromatographic separation and feature recognition of the 7 neonicotinoid pesticides were obtained. Moreover，the optimal extraction conditions were determined as follows：sampling volume was 10 mL，extraction salt was 1 g NaCl and 4 g MgSO4，extractant was acetonitrile（800 μL），and dispersant was acetone（400 μL），which was confirmed by the best extraction efficiency in the sample pretreatment. Analytes were scanned in positive ion mode by electrospray ionization source（ESI） under multiple reaction monitoring（MRM） mode，qualitated by retention time and characteristic ion，and quantitated by external standard method. Under the optimal conditions，the linear relationship of target compounds were good in the range of 0.05-100 μg/L with the correlation coefficients（r2） not less than 0.996. The limits of detection（LOD） were in the range of 0.02-0.1 μg/L，while the limits of quantitation（LOQ） were in the range of 0.05-0.2 μg/L，and the enrichment ratio was 10 times. At the spiked levels of 1，2 and 10 times LOQ，the recoveries of the analytes ranged from 75.3% to116%，and the relative standard deviations of intraday（Intra-RSDs，n=6） were 2.7%-8.2% and that of interday（Inter-RSDs，n=3） were 3.1%-10% . The matrix effects of the 7 neonicotinoid pesticides ranged from -0.18% to 6.66%. The established method was applied to 20 batches of environmental water samples，in which imidacloprid and thiacloprid were detected in one river water sample，but their concentrations were below LOQ. This study indicated that PTD-DLLME combined with UPLC-MS/MS is an effective analytical method to detect 7 neonicotinoid pesticides in environmental water. The method is easy to operate，has a good enrichment effect，and offers stable recovery，environment friendly，and low cost，providing a new solution for the detection of neonicotinoid pesticides in environmental water samples.关键词：environmental water;pasteurized dropper;DLLME;UPLC-MS/MS;neonicotinoid pesticides
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发布时间：2024-08-16 - 摘要：An online monitoring system of near infrared spectrum（NIR） and ultraviolet-visible spectroscopy（UV-Vis） is constructed using small optical fiber spectrometers，and the spectra are online collected with the system. After a spectrum collection，the sample is sent back into the extraction container to avoid the loss of the extraction liquid，and the pipeline is cleaned with the backward flow to prevent the pipeline from clogging. The extraction process is monitored by the dual-spectrum system to improve the acquisition of spectral information. Sampling error profile analysis（SEPA） and stability competitive adaptive reweighted sampling（SCARS） and other chemometric methods are used for the spectral process and model establishment. The analytical performances of NIR spectroscopy，UV-Vis spectroscopy and dual-spectrum fusion models are compared. The results show that the NIR spectral model of luteolin and the UV-Vis model of chlorogenic acid are better. The predicted root-mean-square error（RMSEP） of luteolin model is 0.010 7 μg·mL-1，and that of chlorogenic acid model is 0.029 5 mg·mL-1. The system developed in this study is simple，rapid and has high model accuracy，which provides a new strategy for online monitoring of Chinese medicine extraction.关键词：dual-spectrum monitoring;NIR;UV-Vis;online monitoring;Chinese medicine;Dracocephalum tanguticum Maxim;luteolin;chlorogenic acid
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发布时间：2024-08-16 - 摘要：The development of detection techniques for the accurate determination of sulfadimethoxine（SDM） is crucial in food safety. In this study，nickel-zinc bimetallic microflowers（Ni-Zn MFs） with excellent electrochemical activity were utilized as an electrochemical sensing platform，while reduced graphene oxide（rGO） modified with Aurum-Manganese nanoparticles（AuMn NPs） was introduced as an electrical signal hindering molecule（AuMn/rGO，AMG）. On this basis，a highly sensitive biosensor for the determination of SDM was developed. When SDM is present，it can specifically bind to the binding Aptamer（Apt）-labeled AMG（AMG-Apt），which carries the electrical signal hindering molecules away from the electrode surface and amplifies the electrochemical signal of the redox probe ［Fe（CN）6］3-/4-. The proposed aptasensor for the detection of SDM showed good linearity in the range of 1 pg/mL-100 ng/mL with a low limit of detection（LOD） of 0.26 pg/mL. Notably，this biosensor also showed satisfactory results in milk samples，which is expected to be applied in food safety analysis.关键词：electrochemical detection;bimetals;aptasensor;sulfadimethoxine（SDM）
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发布时间：2024-08-16 - 摘要：An ultra-high performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） method was developed for the determination of 12 common antioxidants in pediatric antitussive oral liquid and its packaging material（oral liquid medicinal composite film）. The chromatographic column used was Shim-pack GIST C18（100 mm×2.1 mm，2 μm），with methanol（containing 0.01 mol/L formic acid and ammonium formate） and water（containing 0.01 mol/L formic acid and ammonium formate） as the mobile phase by gradient elution. Electrospray ionization（ESI） and multiple reaction monitoring（MRM） in positive ion mode were employed for qualitative and quantitative analysis. The results showed good linearity for the 12 antioxidants in the concentration ranges of 10 ng/mL to 400 ng/mL，with correlation coefficients（r） not less than 0.996 3. The detection limits of extraction and migration were in ranges of 0.40-13.25 ng/g and 1.01-33.13 ng/mL，and the quantitative limits were in ranges of 1.35-44.17 ng/g and 3.37-110.42 ng/mL，respectively. The recoveries ranged from 80.1% to 114%，and the relative standard deviations（RSDs，n=3） were between 1.5% and 7.2%. Migration of antioxidants 1010 and 168 was detected in the medicinal solution，but their levels were below their respective permitted daily exposure（PDE），posing minimal impact on the safety risk of the medication. The method is highly efficient，sensitive，accurate，reliable，and easy to operate，making it suitable for the determination of 12 common antioxidants in pediatric antitussive oral liquid and its packaging material.关键词：UPLC-MS/MS;antioxidants;pediatric antitussive oral liquid;medicinal composite film
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发布时间：2024-08-16
Scientific Papers
- 摘要：As an important marine equipment，underwater mass spectrometry has the advantages of good consistency，strong directivity，and simultaneous detection of multiple substances，and has been widely used in the field of deep-sea exploration. However，the sampling efficiency（membrane permeation efficiency） of underwater mass spectrometry is highly susceptible to the influence of ambient temperature，which increases the difficulty of dissolved gas concentration inversion and reduces the accuracy of detection results. This article focuses on the deep sea environment（temperature change range：4-35 ℃） and conducts research on the impact of temperature on membrane permeability efficiency. The results show that in this temperature range，the membrane permeation efficiency of dissolved gas increases approximately three times. At the same time，the temperature rise and fall experimental results show that the membrane permeation efficiency is not only related to the temperature at the current moment，but also affected by the historical temperature. That is，the influence of temperature on the membrane permeation efficiency has a hysteresis effect. This study quantifies the effect of temperature on membrane permeation efficiency，reveals the phenomenon of temperature lag in membrane sampling technology，and provides a method reference for accurate inversion of dissolved gas concentration.关键词：underwater mass spectrometer;membrane mermeation efficiency;dissolved gases;membrane injection mass spectrometry;temperature
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发布时间：2024-08-16 - 摘要：Magnesium（Mg） represents one of the important nutritional components in milk. However，its detection methods require cumbersome sample pretreatment，which is inadequate for the high-throughput online analysis of trace elements. In this regard，this work developed a novel methodology that was named as ultrasonic spraying laser-induced breakdown spectroscopy（US-LIBS）. In the US-LIBS，the techniques of ultrasonic spraying and ultra-short focus laser-induced breakdown spectroscopy were combined to avoid the plasma quenching，thus enhancing the stability and intensity of the signal greatly. Benefiting from the instantaneous phase transition technology，US-LIBS can achieve in situ analysis of trace elements in milk samples within seconds without any pretreatment of the milk samples. This enables the intelligent assessment of dairy product quality and safety in an efficient way. In order to improve the detection accuracy of US-LIBS，the algorithm of reweighted-characteristic spectrum algorithm（RCSA） was also developed to extract the spectral bands of Mg element from the complicated and fluctuant matrix interference. Moreover，the RCSA algorithm utilizes its flexible weighting distribution to guarantee the integrity of spectral information，thus preventing the loss of crucial information bands. As a result，the RCSA algorithm exhibits a notably superior quantitative accuracy and reliability than those of other variable selection algorithms. In the validation samples，the limit of detection and r2 of Mg were 0.3 mg/kg and 0.97，respectively. The results reveal that the US-LIBS is a promising online analysis tool for smart manufacturing of dairy products，which may well extend to any other liquid systems as well.关键词：ultrasonic spraying laser-induced breakdown spectroscopy;reweighted characteristic spectrum algorithm（RCSA）;liquid milk;magnesium element;trace element;in-situ online detection
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发布时间：2024-08-16 - 摘要：Metal ions may have specific interactions with various analytical samples of different structures，so chromatography stationary phase modified by metal ions usually have specific separation selectivity. In this paper，polystyrene-divinylbenzene microspheres were used with uniform particle size，large specific surface area and uniform pore size. The phenyl groups in the crosslinked microspheres were sulphonated by concentrated sulfuric acid to provide cation exchange function. Furthermore，Ag+ modified polymer stationary phase with specific separation selectivity was prepared by exchanging H+ with Ag+ by using ion exchange method，and were also packed in solid phase extraction（SPE） columns to investigate their stability，running conditions and separation performance. The prepared Ag+ modified stationary phase owned the characteristics of simple preparation，good stability，strong ion adsorption ability and good separation selectivity，which could be packed into SPE columns and met the needs of complex practical sample pretreatment with corresponding sample loading and elution methods.关键词：chromatographic packing material;ion exchange;metal ion;solid phase extraction;polystyrene-divinylbenzene microspheres
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发布时间：2024-08-16 - 摘要：An ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） method for the determination of apramycin residue in pig kidney was established. The pig kidney samples were extracted with KH2PO4 solution and purified by HLB solid phase extraction. The separation was performed by CAPCELL PAK MG ⅡC18（2.0 mm×150 mm，5 µm） column by gradient elution，with 0.1% formic acid aqueous solution and methanol as mobile phases. The compound was analyzed in electrospray ion source positive ion mode under multi-reaction monitoring（MRM） mode. The matrix-matched isotope internal standard method was used for quantification. Apramycin showed good linearity in the concentration range of 20-200 µg/L with a correlation coefficient（r2） of 0.999 3. The limit of quantification was 10.0 µg/kg. The average recoveries at spiked levels of 10，20，100 µg/kg were 85.5%-94.6% with relative standard deviations（RSDs） not greater than 5.9%. Based on HLB solid phase extraction column purification and quantification by matrix-matched isotope internal standard method，this method has the characteristics of simple operation，accurate qualitative and high sensitivity. It is suitable for the determination of ampramycin residue in pig kidney.关键词：ultra performance liquid chromatography-tandem mass spectrometry;apramycin;pig kidney;matrix-match;isotopic internal standard
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发布时间：2024-08-16 - 摘要：To address the issue of spectral drift，this study proposes a quantitative model approach for near infrared spectroscopy based on reverse proportional analytical method. The research focuses on tobacco leaf near infrared spectra and nicotine content，with the data being divided into training and test sets. By calculating the correlation between the spectra in these sets and sorting them accordingly，select the top 20% of spectra for constraint programming calculation to estimate the spectra in the test set. The results demonstrate that the reverse proportional analytical method yields an average absolute error of 0.346 6，a predicted standard deviation of 0.425 2，and a correlation coefficient of 0.793 2，indicating its strong performance compared to PLS models. This highlights how the reverse spectral proportional analytical method effectively addresses spectral drift while accurately predicting nicotine content in tobacco，providing valuable insights for nicotine measurement.关键词：inverse proportion;near infrared spectroscopy;correlation;fit coefficient;weighted
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发布时间：2024-08-16
Experimental Techniques and Methods
- 摘要：Stroke is a class of diseases caused by a sudden decrease or interruption in cerebral blood supply，resulting in brain tissue damage. It is characterized by high prevalence，high mortality，and high disability rates. Recently，mass spectrometry has demonstrated immense potential in the discovery of disease biomarkers，owing to its high sensitivity and specificity. Notably，from the period before the clinical determination of stroke to recovery，significant changes in metabolites and proteins occur in the body of the patient，which may provide opportunities for mass spectrometry-based diagnosis before clinical determination，pre-hospital emergency care，and prognosis assessment. This article primarily reviews the representative works in the discovery of metabolic and protein biomarkers using mass spectrometry over the past decade. In the realm of metabolic biomarkers，we compile those associated with energy metabolites，amino acids，and lipids relevant to stroke. Regarding protein biomarkers，we discuss stroke-related matrix metalloproteinases，metalloproteins，and fibrinogen，among others. This review is significant in revealing the pathophysiological mechanisms of stroke and advancing the application of mass spectrometry for stroke diagnosis in clinical setting.关键词：stroke;mass spectrometry;biomarkers;metabolomics;proteomics
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发布时间：2024-08-16
Review
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