（1）
Chinese Journal of Analytical ChemistryVolume 49, Issue 4, April 2021, Pages 483-495
Advance in Novel Methods for Enrichment and Precise Analysis of Circulating Tumor Cells
SHEN Cong-Cong1, WU Cheng-Ke1, CHEN Yue-Hua1, WANG Jian-Xiu2, YANG Ming-Hui2,*, ZHANG Hua1,*
1 College of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
2 College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
Highlights
本文对近年来循环肿瘤细胞(CTC)的传统、新型和联合富集分离及精准分析技术的研究进展进行了评述，基于当前CTC常规及新型的分离富集方法及精准分析检测策略，探讨了现有方法的优缺点，总结了CTC检测分析面临的挑战以及未来发展趋势，为进一步开发和优化CTC富集和检测技术以及扩展其在基础研究及临床中的应用提供参考。
AbstractThe dissemination of circulating tumor cells (CTCs) in peripheral blood is an important intermediate step for cancer metastasis. It has become one of the most promising targets of “liquid biopsy”, on account of providing complete information of cell biology. However, due to the extremely rarity, complex environment and strong heterogeneity of CTC in peripheral blood, the development of efficient enrichment and separation methods are the key in the accurate detection of CTC. Currently reported CTC enrichment and analysis techniques are mainly based on the physical or biological characteristics of CTC. They are commonly combined with the traditional techniques including density gradient centrifugation, superfine membrane filtration and immunomagnetic separation, the novel methods such as microfluidic chip separation and two-dimensional electrophoresis-field separation, and the analysis techniques such as reverse transcription-polymerase chain reaction, flow cytometry, immunocytochemistry, photoacoustic imaging, surface-enhancement Raman scattering and electrochemistry to realize accurate detection of CTC. In this review, we summarized the recent processes on enrichment and novel detection methods of CTC and discussed the challenges and their clinical application status, which could provide reference for the further improvement of the technology of enrichment, accurate counting and molecular phenotype analysis for CTC, as well as the application in scientific research and clinical practice.
Graphical abstractCirculating tumor cells (CTCs) entering into peripheral blood through blood circulation are the source of tumor metastasis. Tumor microenvironment promotes CTCs to produce epithelial mesenchymal transition (EMT) and mesenchymal epithelial transition (MET) to further emerge metastatic tumor. The morphological and quantitative changes of CTCs are closely related to tumor metastasis. Due to the extremely low content and strong heterogeneity of CTCs, the efficient CTCs enrichment and accurate analysis methods is significance for the early diagnosis and metastasis of cancer.
（2）
Chinese Journal of Analytical ChemistryVolume 49, Issue 4, April 2021, Pages 496-503
Chemiluminescence Sensor Based on Composite Functional Nucleic Acid for Detection of Ochratoxin A in Wine
YANG Cheng1,*, ZHANG Ya-Qi1, LIN Dai-QIN2,*, LIU Yang3, SUN Bing-Bing1
1 State Key Laboratory of Fine Chemicals, School of Chemistry, College of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
2 Jiangxi Product Quality Supervision Testing Institute, Nanchang 330052, China
3 Key Laboratory of Life Organophosphorus Chemistry and Chemical Biology of Ministry of Education, Tsinghua University, Beijing 100084, China
Highlights
构建了以赭曲霉毒素A(OTA)核酸适配体为“裂开型”核酶激活“开关”的化学发光传感器，用于葡萄酒中OTA的高灵敏度检测。OTA可诱导核酸适配体形成反平行G四链体结构，从而拉近“裂开型”核酶的两段核酸序列，使其可与血红素复合，生成具有明显的类过氧化物酶活性的核酶。基于此，以鲁米诺为底物通过化学发光法，实现了葡萄酒中OTA 的高灵敏度检测。
AbstractA chemiluminescence (CL) sensor, using ochratoxin A (OTA) aptamer as the activation switch of the split DNAzyme, was established to achieve high-sensitivity detection of OTA in wine. A guanine-rich oligonucleotide could fold into a parallel G-quadruplex in K+ solution. Hemin as a ligand could bind to parallel G-quadruplexes precisely. Hemin-G-quadruplex complexes displayed peroxidase-like activity, named as DNAzyme. The activity of the DNAzyme could be measured by CL via the H2O2 mediated-oxidation with luminol. Guanine-rich oligonucleotide split into two fragments; when they were near each other, they could reform DNAzyme. OTA aptamer as a switch was inserted into the nucleic acid sequence of DNAzyme. In the absence of OTA, the unfolded OTA aptamer inhibited the split DNAzyme effective self-assemble to form a structure with enzymatic activity. In the presence of OTA, OTA induced the aptamer to form an antiparallel G-quadruplex and drew the tail of the aptamer closer so that the two fragments of split DNAzyme refolded and compound with hemin. The folding degree of the aptamer would directly affect the activity of DNAzyme and high-sensitivity detection of OTA could be obtained by monitoring the enhanced ratio of CL intensity. The linear range of this method was 0.10‒2.00 nmol/L, and the limit of detection was 0.10 nmol/L.
Graphical abstract
OTA aptamer as a switch is inserted into the nucleic acid sequence of DNAzyme. OTA induces the aptamer to form an antiparallel G-quadruplex and draws the split DNAzyme refold and compound with hemin. The folding degree of the aptamer will directly affect the activity of DNAzyme and high-sensitivity detection of OTA can be obtained by monitoring the enhanced ratio of chemiluminescence intensity.
（3）
Chinese Journal of Analytical ChemistryVolume 49, Issue 4, April 2021, Pages 520-527
Determination of Polybrominated Diphenyl Ethers and Hydroxylated Analogues in Serum Using High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry with Online Solid Phase Extraction
JIN Jin1,2, SONG Shan-Jun2,*, PENG Zi-Juan2, GUO Feng3,*, LI Peng-Hui1
1 Tianjin University of Technology, Tianjin 300384, China
2 National Institute of Metrology, Beijing 100029, China
3 National Research Center for Geoanalysis, Beijing 100037, China
Highlights
建立了在线固相萃取-高效液相色谱和电感耦合等离子体质谱（Online SPE-HPLC-ICP-MS）法同时分析检测对多溴二苯醚及其羟基代谢产物。此方法可有效解决微量样品中痕量目标物的分析检测,其灵敏度及精密度满足微量血清样品中痕量目标物的分析需求。将本方法应用于30个实际血清样品的分析检测,共检出4种多溴二苯醚和2种羟基多溴二苯醚,其赋存特征与已有报道一致。本方法可应用于大批量实际样品的分析检测,具有较强的实用价值。
AbstractOnline solid phase extraction-high performance liquid chromatography-inductively coupled plasma mass spectrometry (Online SPE-HPLC-ICP-MS) technique was developed for simultaneous determination of 6 kinds of polybrominated diphenyl ethers and 5 kinds of hydroxyl metabolites in serum. A serum sample (200 μL) was directly analyzed after protein precipitation and dilution. The target analytes were automatically enriched on a solid phase extraction column, and then separated and analyzed by liquid chromatography-inductively coupled plasma mass spectrometry with methanol/acetonitrile/water as mobile phase. The main parameters such as loading rate, elution time and elution solvent were optimized. As a result, Oasis HLB was selected as the SPE column, the loading solvent was pure water at a rate of 3.0 mL/min, the elution solvent was methanol-acetonitrile-water (54:26:20, V/V), the elution flow rate was 1.0 mL/min, and the liquid chromatography column was ZORBAX Eclipse Plus C18. The limits of quantification (LOQ) of the method were 0.14–0.74 ng/L, the recoveries were 61.8%‒77.7%, and the relative standard deviations (RSDs) of the results were 3.7%‒10.1% (n = 3). The established method was successfully applied to the analysis of 30 serum samples. A total of 4 kinds of polybrominated diphenyl ethers and 2 kinds of hydroxy polybrominated diphenyl ethers were detected, and their occurrence characteristics were consistent with previous reports. The results showed that this method could be applied to analyze actual samples in large quantities, which was of great practical value.
Graphical abstractA method for simultaneous analysis of polybrominated diphenyl ethers and hydroxyl metabolites in minute serum samples based on online solid phase extraction-high performance liquid chromatography inductively coupled plasma mass spectrometry (Online SPE-HPLC-ICP-MS) was developed. The field samples analysis approved the practicability of the developed method.
（4）
Chinese Journal of Analytical ChemistryVolume 49, Issue 4, April 2021, Pages 581-592
Nanozymes and Their Application Progress in Biomedical Detection
WEI Feng, HAN Xiao-Jun*
State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
Highlights
本文根据材料组分概述了三类主流纳米酶以及其他新兴的纳米酶的研究进展，并详细介绍了不同种类纳米酶的反应过程及催化路径，总结了纳米酶在生物医学检测领域中对不同目标检测物的检测机理和检测限，展望了纳米酶实时检测的应用前景及未来发展方向。
AbstractAs a kind of biocatalyst with high specificity, natural enzymes can be applied in recognition and detection by selective catalysis. However, the high cost and easy inactivation limit their practical applications. Nanozyme is a kind of nanomaterial which can mimic enzyme-like properties via the instinct ability and has the advantages of low cost, stable performance and wide applications. The biomedical detection based on nanozymes with high sensitivity, excellent specificity and low limit of detection is promising. In this paper, several main types of nanozymes were summarized, followed by the introduction of their research progress in biomedical detection. The outlook of nanozymes in biomedical detection was also proposed at the end of this paper.
Graphical abstractNanozymes, composed of noble metals, metal oxides and carbon-based materials, possess enzyme-like properties with the advantages such as low cost and stable performance, which show great potentials in biomedical detection (small molecules, ions, nucleic acid and proteins) with high sensitivity, excellent selectivity and low limit of detection.
（5）
Chinese Journal of Analytical ChemistryVolume 49, Issue 4, April 2021, Pages 593-601
Multivariate Optical Computing and Next-generation Spectrometer
DUAN Chao-Shu1, CAI Wen-Sheng1,2, SHAO Xue-Guang1,2,3,*
1 Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, China
2 Tianjin Key Laboratory of Biosensing and Molecular Recognition, Tianjin 300071, China
3 State Key Laboratory of Medicinal Chemical Biology, Tianjin 300071, China
Highlights
多元光学计算（MOC）是一种新的光谱测量方式。基于MOC的光谱仪是化学计量学和仪器设计的完美结合,被称为“下一代光谱仪”。本文阐述了MOC方法的发展历史、MOC光谱仪的原理和近年来的主要研究进展,总结了滤波器的设计方法、滤波器的光学器件的MOC光谱仪的应用,探讨了基于MOC的光谱仪在滤波器的设计及光学实现、系统集成等方面面临的挑战。
AbstractMultivariate optical computing (MOC) is a technique that uses optical filters to modulate the light to achieve calculation and obtain qualitative or quantitative results directly by detection of a single-point detector. Therefore, the complicated instrument design and cumbersome data processing are no longer needed for the MOC-based analytical instrument. The key technique for MOC is the design of the filter to achieve the detection that directly reflects the result for different purposes. In recent years, more efforts have been made for designation and optimization of the filters to enhance the performance. MOC-based spectrometer is a perfect combination of chemometrics and instrument design, and thus it is praised as the next-generation spectrometer. In this paper, the history, principle and the recent advances of MOC related techniques were summarized, with an emphasis on the filter design, filter optics and applications, and the challenges in the design and the optical implementation of the filters, as well as the integration of the instrument system.
Graphical abstractMultivariate optical computation (MOC) is a new technique for spectral measurement and analysis. The technique employs a single detector to sense the information of multi-wavelength and achieves the complex calculation in optical domain through an optimized optical filter.
（6）
Chinese Journal of Analytical ChemistryVolume 49, Issue 4, April 2021, Pages e21039-e21045
Kinetics Analysis of Reaction between Molybdenum and Nitrogen Trifluoride
NIU Yong-Sheng1,2,3,#, SUN Li-Xin1,2,#, HU Cong-Wei1,2, ZHOU Jin-Hao1,2, DOU Qiang1,2,*, LI Qing-Nuan1,2,*
1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
2 Center of Excellence TMSR Energy Systerm, Chinese Academy of Sciences, Shanghai 201800, China
3 University of Chinese Academy of Sciences, Beijing 100049, China
Highlights
基于NF3氟化剂反应性对温度的敏感性特点，利用在线红外光谱监测分析方法结合热力学计算，开展了Mo粉与NF3氟化反应及动力学研究。结果表明，Mo通过MoF3中间产物转化为最终产物MoF6；温度显著影响Mo与NF3反应速率和NF3的利用率，当反应温度从500 K升至700 K时，Mo粉平均氟化反应速率由1.04×10-2 mol/h 增加到2.40×10-2 mol/h，与此同时，NF3气体利用率由21.2% 提高至49.0%。Mo粉与NF3的有效反应温度较NF3与UF4之间的反应温度约低200 K。
AbstractThe fluorination behavior of molybdenum (Mo) powder with NF3, such as temperature dependence of reactivity, reaction mechanism and kinetics were investigated on a homemade fluoride volatility process (FVP) research device. The in-situ Fourier transform infrared (FTIR) spectroscopy was applied to determine the beginning and the end of reaction. The research demonstrated that near 500 K or lower, the reaction between Mo power and NF3 occurred, meanwhile, the temperature had an important influence on the average reaction rate and the utilization of NF3. When the temperature increased from 500 K to 700 K, the average rate increased from 1.04 × 10–2 mol/h to 2.40 × 10–2 mol/h and the utilization of NF3 increased from 21.2% to 49.0%. The in-situ FTIR and XRD analysis assisted by thermodynamic calculation indicated that Mo power was converted to MoF6 through an intermediate product MoF3: 2NF3 (g) + 2Mo (s) = 2MoF3 (s) + N2 (g), then 2MoF3 (s) + 2NF3 (g) = 2MoF6 (g) + N2 (g). Based on a mathematical model with unreacted shrinking core, the calculated reaction rate constant increased from 1.77 × 10–2 min–1 to 3.48 × 10–2 min–1 in the temperature range of 500–700 K, and the activation energy was 10.13 kJ/mol.
Graphical abstractBased on the sensitivity of NF3 reactivity to temperature, the fluorination reaction and the reaction kinetics between Mo power and NF3 were studied using the in-situ FTIR spectrometer assisted by thermodynamic calculation. The results demonstrated that Mo power was converted to MoF6 through an intermediate product MoF3, and the temperature had a significant effect on the reaction rate and utilization of NF3.
（7）
Chinese Journal of Analytical ChemistryVolume 49, Issue 4, April 2021, Pages e21046-e21054
Investigation of Quantitative Structure Activity Relationship of Isatin-based Oxadiazole Derivatives as Thymidine Phosphorylase Inhibitors
TONG Jian-Bo1,2,*, FENG Yi1,2, WANG Tian-Hao1,2, LUO Ding1,2
1 College of Chemistry and Chemical Engineering, Shaanxi University of Science & Technology, Xi’an 710021, China
2 Shaanxi Key Laboratory of Chemical Additives for Industry, Shaanxi University of Science and Technology, Xi’an 710021, China
Highlights
本研究通过对30种TP抑制剂的QSAR研究，确定了可使此类化合物活性提升的基团。然后基于ZINC数据库以及建模结果进行了新化合物的设计，设计出的化合物活性更高，与大蛋白之间的结合更具优势，此项研究为血管抑制剂类抗癌药物的研发提供了理论基础。
AbstractTo obtain a better understanding of chemical biological interaction of isatin-based oxadiazole derivatives as a thymidine phosphorylase (TP) inhibitor, 30 kinds of quantitative structure activity relationship (QSAR) models of isatin-based oxadiazole derivatives were established using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA), respectively. Among them, the r2 and q2 of the best CoMFA model were 0.920 and 0.697, and the best CoMSIA model gave r2 = 0.912 and q2 = 0.692, respectively. Docking studies were used to find the actual conformations of chemicals in active sites of TP protease, as well as the binding pattern to the binding site in protease enzyme. The information provided by 3D-QSAR model and molecular docking offered useful references for the structural requirements of the 30 kinds of isatin-based oxadiazole derivatives and helped to design potential anti-tumor drugs of vascular inhibitors.
Graphical abstractBased on the 3D-QSAR model research and analysis of TP inhibitors, new TP inhibitors with higher activity were designed. Finally, molecular docking was used to verify the binding mode.
（8）
Chinese Journal of Analytical ChemistryVolume 49, Issue 4, April 2021, Pages e21055-e21064
Scanning Electrochemical Cell Microscope Study of Individual H2 Gas Bubble Nucleation on Platinum: Effect of Surfactants
JIN Cheng, LIU Yu-Long, SHAN Yun, CHEN Qian-Jin*
College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China
Highlights
界面表面的气泡现象广泛存在与许多电化学工业中，然而针对这些微纳米尺度气泡的分析研究相对较少。本研究采用了先进的扫描电化学池显微镜技术在Pt电极表面实现了单个氢微米气泡的电化学成核，并探究了表面活性剂的存在对电极表面气泡行为的影响机制。
AbstractAdsorption of gas bubbles on the electrode surface is one of important issues responsible for the reduced efficiency of water electrolysis. Understanding the bubble phenomena can benefit the management of gas bubbles. In this study, we carried out a single-entity electrochemical study of individual gas bubbles on the Pt electrode using scanning electrochemical cell microscopy. Different from conventional ensemble methods, the bubble nucleation behaviour and the effect of surfactants (perfluorooctanoic acid (PFOA), hexadecyl trimethyl ammonium bromide (CTAB) and siloxane defoamer) on the electrode surface were investigated at microscale resolution. Statistical analysis of individual nucleation event showed the stochastic characteristic and the addition of surfactant could significantly improve the stability of gas bubbles especially those formed in small nanopipets. A correlation between the critical supersaturation (or Faradic current) for bubble nucleation and surface tension was observed, which was consistent with classic nucleation theory. However, chronoamperometry study showed that the water electrolysis efficiency after surfactant addition was not significantly improved. This study provided unique insights into understanding of nucleation event at single-entity.
Graphical abstractA single-entity electrochemical study of individual gas bubbles using the scanning electrochemical cell microscopy was reported. It was found that the electrochemical nucleation and stability of single H2 bubble from proton reduction at Pt film confined in a micropipet could be readily tuned through interfacial surface tension as illustrated with three different surfactants: PFOA, CTAB and siloxane.
文章来源：“分析化学”公众号
《分析化学》创刊于1972年，由中国科学院长春应用化学研究所和中国化学会共同主办，报道我国分析化学创新性研究成果，反映国内外分析化学学科的前沿和进展。主要栏目包括特约来稿、研究快报、研究报告、仪器装置与实验技术、评述与进展等。现任名誉主编汪尔康院士，主编杨秀荣院士。《分析化学》期刊于1999年被SCI-E收录，2006年被Scopus收录, 2016年被EI收录。《分析化学》始终致力于打造国际知名学术期刊，以创办中文精品期刊为目标；同时，《分析化学》与国际著名科技出版商Elsevier公司合作，发行本刊的英文电子版（www.sciencedirect.com/journal/chinese-journal-of-analytical-chemistry, eISSN 1872-2040）。
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