POLYMER TESTING
·
2015
·
IF 2.24
Xinchao Bian,Lidong Feng,Gao Li,Zhiming Chen,Xuesi Chen
An analytical method has been developed to quantitatively determine the residual lactide monomer in polylactide (PLA) using an internal standard method of gas chromatography (GC). The experimental results showed that diphenyl ether (DPE) was an appropriate internal standard for quantitative analysis of residual lactide in PLA. PLA and DPE were dissolved in dichloromethane and precipitated in hexane . At the same time, the residual lactide in PLA and DPE as an internal standard were extracted to hexane from the polymer solution . The resulting solution could be directly injected into a GC system. Therefore, the residual lactide was determined quantitatively using an internal standard method of GC. This method is practical for measuring the residual lactide content in PLA. When the lactide content is 5.0%, the relative standard deviation ( RSD ) of the measurements is 1.7%, while RSD is 6.9% at the low level of 0.4%, which indicates that the method is sufficiently precise.
研究领域:
分析化学
·
材料科学
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产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL CHEMISTRY
·
2022
·Vol. 77
·期 3
·361-368
·
IF 1.237
Xue Liming,Xu Jiale,Feng Chao,Lu Dasheng,Zhou Zhijun
Abstract It is a challenge to perform target screening of metabolites on a large scale in metabolomics study using gas chromatography with mass spectrometry ( GC-MS ). Some metabolites can hardly be detected and identified in biosamples due to their low MS response or poor specificity. Moreover, synthesis and degradation of derivatized metabolites in samples made it difficult to achieve fine method stability. Our method screens 475 metabolites in a single run using GC-MS/MS in MRM mode, and both internal standard and quality control-based normalization strategies were used to correct the peak intensity. A total of 91 and 161 metabolites were detected in plasma and urine, respectively. The method was validated to have fine linearity range and intra-day and inter-day stability. The method was applied to a pilot study, and this study investigated the metabolic perturbation in rats after fluorochloridone ( FLC ) administration. 18 metabolites exhibited statistical significance in rat urine, and they were confirmed to be associated with FLC treatment, where the upregulation of glucose, lactose, and galactose is potentially linked to oxidative stress reaction. This study has proved its value in large-scale detection of metabolites in biosamples using GC-MS/MS with high sensitivity, specificity, and stability. We hope that our study can promote the GC-MS-based metabolomics studies.
研究领域:
分析化学
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代谢组学
·
生物医学
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产品关联
DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 3
·421
·
IF 5.719
Rongyuan Cai,Lijun Yin,Qian Huang,Ruiyun You,Shangyuan Feng,Yudong Lu
In this work, we developed a new type of SERS probe, which was composed of glass-SiO2[email protected]@Ag nanoparticles (NPs) three-dimensional Surface-enhanced Raman spectroscopy (SERS) substrate. When the laser passed through the quartz glass sheet, on the one hand, the SiO2NPs supporting the[email protected]@Ag NPs increase the roughness of the substrate surface, resulting in a large number of hot spots among nanoparticles. On the other hand, based on the focusing effect of silicon dioxide nanospheres, the laser can better focus on the surface of nanoparticles in the inverted SERS probe, thus showing better SERS enhancement. Furthermore, the[email protected]@Ag NPs core-shell structure was used with 4-mercaptobenzoonitrile (MBN) as an internal standard molecule, and the quantitative determination of tyrosine and urea was realized by internal standard correction method. The standard working curves of the two had good linear correlation with R2above 0.9555. The detection limits of tyrosine and urea were in the range of 2.85 × 10−10M~7.54 × 10−6M, which confirms that this design can be used for quantitative and specific detection of biological molecules, demonstrating great practical significance for the research of diseases such as skin lesions and endocrine disorders.Keywords:SERS;endoscope;internal standard;tyrosine;urea;sweat
研究领域:
分析化学
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生物医学工程
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材料科学
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产品关联
DOI
PubMed
高影响因子
Energies
·
2017
·Vol. 10
·期 7
·967
·
IF 2.262
Fu Wan,Lingling Du,Weigen Chen,Pinyi Wang,Jianxin Wang,Haiyang Shi
Analyzing the concentration of low molecular acids dissolved in oil is vital in the oil-paper insulation aging diagnostic procedure of power transformers. The existing methods cannot distinguish between different acid types and their strengths. In this study, an improved solution Raman detection platform is fabricated. The direct measurement of dissolved acetic acid, a kind of low molecular acids, is observed in transformer oil without extraction. The Raman shift line of oil-dissolved acetic acid at 891 cm−1corresponding to H–C–H symmetrical swing and O–H swing modes is taken as its characteristic value. Taking Raman shift line of pure oil at 932 cm−1as an internal standard, a linear regression curve for quantitative analysis is obtained with a slope of 0.19. The best platform parameter of accumulation number is 300, which is determined by Allan deviation analysis. The current concentration detection limit and accuracy for oil-dissolved acetic acid are obtained at about 0.68 mg/mL and 91.66%, separately. The results show that Raman spectroscopy could be a useful alternative method for evaluation insulation aging state of an operating power transformer in the future.Keywords:power transformer;oil-paper insulation aging state;acetic acid;Raman spectroscopy;internal standard
研究领域:
电气工程
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分析化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
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2020
·
IF 3.721
Caiyun Zhang,Jiaxiong Zeng,Wenguang Xiong,Zhenling Zeng
A rapid, simple and reliable method using amoxicillin-D4 as internal standard (IS) for determination of amoxicillin (AMO) in porcine tissues was developed. The analytical methodology used a phosphate buffer (0.01 M, pH = 6.3) with trichloroacetic acid (50 mg/mL) for extraction and Oasis® HLB cartridges for clean-up followed by UPLC-MS/MS analysis. The optimized method was validated according to EU guideline 2002/657/EC and FDA guideline. The LOQ in muscle, fat, liver and kidney were set to 10 μg/kg which was below the maximum residue limits, while the LOD were set to 5 μg/kg. Results showed that using AMO-D4 as IS can effectively eliminate relative matrix interference and improve the recovery and precision. A good linearity was observed at the range of 10−500 μg/kg with a correlation coefficients (R 2 ) larger than 0.99. The mean recoveries were higher than 87.0 %, and the RSDs were lower than 11.2 %. This method could be applied to conveniently analysis the residue of AMO in different porcine tissues.
研究领域:
兽医学
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分析化学
·
食品安全
✓ 已验证
DOI
高影响因子
TALANTA
·
2024
·
IF 5.6
Xiaoming Li,Jiaqi Hu,De Zhang,Xiubin Zhang,Zhetao Wang,Yufeng Wang,Qiang Chen,Pei Liang
Surface-enhanced Raman spectroscopy (SERS) can quickly identify molecular fingerprints and has been widely used in the field of rapid detection. However, the non-uniformity inherent in SERS substrate signals, coupled with the finite nature of the detection object, significantly hampers the advancement of SERS. Nowadays, the existing mature immunochromatographic assay (ICA) method is usually combined with SERS technology to address the defects of SERS detection. Nevertheless, the porous structure of the strip will also affect the signal uniformity during detection. Obviously, a method using SERS-ICA is needed to effectively solve signal fluctuations, improve detection accuracy, and has certain versatility. This paper introduces an internal standard method combining deep learning to predict and process Raman data. Based on the signal fluctuation of single-antigen SERS-ICA test strip, the double-antigen SERS-ICA test strip was constructed. The full spectrum Raman data of double-antigen SERS-ICA test strip was normalized by the sum of two characteristic peaks of internal standard molecules, and then processed by deep learning algorithm. The Relative Standard Deviation (RSD) of Raman data of bisphenol A was compared before and after internal standard normalization of double-antigen SERS-ICA test strip. The RSD processed by this method was increased by 3.8 times. After normalization, the prediction accuracy of Root Mean Square Error (RMSE) is improved by 2.66 times, and the prediction accuracy of R-square (R 2 ) is increased from 0.961 to 0.994. The results showed that RMSE and R 2 were used to comprehensively predict the collected data of double-antigen SERS-ICA test strip, which could effectively improve the prediction accuracy. The internal standard algorithm can effectively solve the challenges of uneven hot spots and poor signal reproducibility on the test strip to a certain extent, so as to improve the semi-quantitative accuracy.
研究领域:
分析化学
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生物医学工程
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产品关联
DOI
PubMed
高影响因子
CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS
·
2018
·
IF 2.701
Xue-Qin Zhang,Sheng-Xian Li,Zeng-Ping Chen,Yao Chen,Ru-Qin Yu
Due to the practical impossibility in controlling the number and distribution of "hot spots" on or close to the surfaces of enhancing substrates, internal standards are generally used to improve the accuracy and precision of quantitative surface-enhanced Raman spectroscopy (SERS). Traditional internal standard methods based on either univariate ratiometric models or conventional multivariate calibration models can use the information of only one characteristic SERS peak of only one internal standard, which weakens the efficiency of traditional internal standard methods in improving the quantitative results of SERS assays. In this contribution, the concept of using multiple internal standards was introduced for the first time to quantitative SERS assays by incorporating a unique spectral shape deformation (SSD) quantitative theory with multiple-internal-standard embedded core-shell nanoparticles . The quantification of phosmet residues on apple skins by SERS technique with Au-core/Ag-shell nanoparticles embedded with both 2-MB and PATP as enhancing substrate was used to illustrate the applicability of the proposed strategy. Experimental results demonstrated that the proposed multiple-internal-standard strategy based on SSD achieved much more accurate and precise concentration predictions for phosmet residues on apple skin than traditional single-internal-standard methods based on either univariate ratiometric calibration models or conventional multivariate calibration models. The SERS quantitative results of the multiple-internal-standard strategy were comparable to those obtained by LC-MS/MS. The average relative deviation between the quantitative results of the proposed method and those of ICP-MS was about 8%. The good accuracy of the proposed method makes it a promising alternative for quantitative SERS assays.
研究领域:
分析化学
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食品科学
·
纳米技术
✓ 已验证
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2022
·
IF 8.008
Sheng Chen,Jiayi Fan,Mengya Lv,Chenfeng Hua,Gaolin Liang,Shusheng Zhang
Hydrogen sulfide (H2S), as the third endogenous gasotransmitter, is closely associated with various physiological and pathological processes, whereas many aspects of its functions remain unclear. Effective tools for the accurate detection of H2S in living organisms are urgently needed. We herein reported an internal standard assisted surface-enhanced Raman scattering (SERS) nanoprobe for ratiometric detection of H2S in vitro and in living cells based on the reduction of nitros with H2S. This nanoprobe consists of an internal standard (4-mercaptobenzonitrile, MPBN) embedded core-molecule-shell Au nanoflower (Au@MPBN@Au) as the high plasmonic active SERS substrate and the 4-nitrothiophenol (4-NTP) molecule immobilized on the surface as the H2S recognition unit. With the addition of H2S, the nitros peak (1329 cm–1) decreased. Meanwhile, three obvious new peaks appeared at 1139, 1387, and 1433 cm–1, which were related to the vibration of the dimerized product 4,4′-dimercaptoazobisbenzene (DMAB) of 4-aminothiophenol (4-ATP). However, the peak intensity at 2223 cm–1 derived from MPBN was not influenced by the outer environment. Thus, the H2S level was able to be determined based on the ratio of two peak intensities (I1139/I2223) with a detection limit as low as 0.24 μM. Notably, we have proved that SERS nanoprobe Au@MPBN@Au@4-NTP could ratiometrically image both the endogenous and exogenous H2S in living cells. We anticipate that Au@MPBN@Au@4-NTP could be applied for the study of H2S-related physiological function in the future.
研究领域:
分析化学
·
生物医学工程
·
分子生物学
·
生物成像
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产品关联
DOI
PubMed
高影响因子
Surfaces and Interfaces
·
2024
·
IF 5.7
Xiaoming Li,De Zhang,Yufeng Wang,Jie Huang,Qianmin Dong,Shangzhong Jin,Pei Liang
This work proposes the application of multi-residue Surface-enhanced Raman spectroscopy (SERS) detection based on an internal standard and aptamer-functionalized gold nanofilms. First, two types of complementary DNA (cDNA) are fixed on the self-assembled monolayer of a halide ion-regulated nano-membrane through gold-sulfur bonds. Then, two signal probe molecules are prepared and modified. The aptamer specifically binds to cDNA, generating SERS signals. Detection of the target analytes is achieved by measuring the Raman intensity and using the internal standard method. The results show that the concentrations of thiamethoxam and dichlorodiphenyltrichloroethane (DDT) at 10 -12 M can be effectively measured under optimal experimental conditions. The Raman intensity exhibits a linear relationship at the shifts of 1085 cm -1 for 4-mercaptopyridine (4-MPY) and 1583 cm -1 and 2223 cm -1 for 4-mercaptobenzoic acid (4-MBN). When applied to the detection of thiacloprid in actual lake water samples, the results show no significant difference compared to the standard.
研究领域:
分析化学
·
纳米技术
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 46
·34261-34269
·
IF 3.9
Min Xie,Jun Xu,Dan Fei,Ye-Lan Guang,Yao-Min Zhou,Fan Li,Li-Zhen Hu
An improved QuEChERS method combined with Multi-Plug Filtration Cleanup (m-PFC) clean-up procedure was developed for the simultaneous determination of 16 different sulfonamides in forage grasses using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The forage grass sample was extracted with 0.1 mol L−1 Na2EDTA-Mcllvaine buffer and acetonitrile solution, purified by the Navo U-QuE column tube, separated by Agilent ZORBAX Eclipse Plus C18 column, and analyzed by MRM (multiple reaction monitoring) mode and the internal standard method was utilized for quantification. The 16 different sulfonamides display good linearity within the range of 0.5–50 μg L−1 (R2 > 0.9967), the limit of detection was 0.02–0.5 μg kg−1, and the limit of quantification was 0.05–1.0 μg kg−1. Under the additive amounts of 1, 2, and 10 μg kg−1, the recoveries were in the range of 72.3–116.9%, and the relative standard deviation was between 1.4% and 10.3%. The presented method showed the advantages of simple operation, excellent selectivity and high sensitivity. It was well-suited for both qualitative and quantitative analyses of sulfonamides in forage grass. Overall, this method provided a scientific basis for risk assessment, enforcement of quality and safety standards, and detection of sulfonamide residues in forage grass for import and export.
研究领域:
分析化学
·
兽医学
·
食品安全
·
药物分析
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）