Determination of manganese(II) in powdered barnacle shells by electron paramagnetic resonance

A rapid precise method of determining Mn(II) (as opposed to total manganese) in powdered barnacle shells by e.p.r. is described. The method is based on the linear relationships between the intensity of the first-derivative e.p.r. signal and the weight and Mn(II) concentration in the sample. Atomic absorption was used as a reference method. For eleven samples, the difference between the a.a.s. and e.p.r. methods was, on average, within 3 %; the detection limit was 20 p.p.b. A good correlation between the Mn(II) content of the shell and the position of the animal in an inter-tidal zone was found.     

Research progress of rapid detection of typical environmental pollutants based on chromatographic technologiesEI北大核心CSCD

对复杂环境介质中的典型污染物进行快速、精准甚至远程连续自动的检测,是控制环境污染、确保环境和生态安全的重要前提。近年来,基于色谱技术的典型环境污染物快速检测方法发展迅猛,主要包括样品快速制备和目标物快速检测两方面。辅助萃取、快速液相萃取、QuEChERS等样品前处理方法具有萃取效率高、溶剂消耗少、操作简便快速等优点。快速检测技术可在几秒到半小时内提供检测结果,主要包括实验室和现场检测。本文综述了2019年以来基于色谱技术的典型环境污染物快速检测研究新进展。介绍了萃取技术和基于试验设计的样品快速制备,实验室快速检测、便携仪器现场检测及遥感技术远程检测,提出了色谱技术快速检测环境污染物的挑战和展望。     

Studies on metal carboxylates: XI. Reactions of rhenium carbonyl with picolinic acid and of the tungsten(I) complex [W(CO)3(pic)]n with monodentate tertiary phosphines

The reactions of the tungsten(I) complex of picolinic acid [W(CO)₃(pic)]_n with certain monodentate tertiary phosphines affords a convenient route to complexes of the types W(CO)₃(PR₃)₃ and HW(CO)₂(PR₃)₂(pic). The latter hydrido complexes of tungsten(II) have been characterized by infrared and NMR spectroscopy. The reactions of Re₂(CO)₁₀ with picolinic acid have also been investigated and the new series of rhenium(I) derivatives of the types Re(CO)₃(L)(pic), where L = py, 4-Ph-py, PPh₃ or dppe, and Re(CO)₂(L')₂(pic), where L' = PPh₃ or $\text{1}\text{2}$dppe, have been isolated and characterized.     

Novel biosensor for microRNA-141 analysis based on lanthanide coordination polymer immobilized methylene blue as a signal label and 3D DNA walking machineEI北大核心CSCD

MicroRNA-141 is of great significance in the early diagnosis and treatment of related cancers. A biosensor was developed for the detection of microRNA-141 based on lanthanide coordination polymer immobilized methylene blue as a signal label and three-dimensional 3D DNA walking machine. First lanthanide coordination polymerCe-COPwith straw-sheaf like structure was successfully prepared with a large scale via a simplemild and rapid solution phase method at room temperature. The Ce-COP had a large specific surface area and can immobilize a large number of gold nanoparticles and methylene blue MB signal molecules. Thena 3D DNA walking machine was designed and introduced to the biosensor system for converting trace target microRNA-141 to a larger number of intermediate DNA and achieving significant signal amplification. The sensing platform exhibited recommendable stability and good selectivity. MicroRNA-141 could be accurately quantified with a linear range of 100 amol/L-100 nmol/L with the detection limit of 33 amol/L. This method provides a certain reference to high-sensitive detection for various cancer markers. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Recent advances in nucleic acid amplification-based optical biosensors for disease diagnosisEI北大核心CSCD

Optical biosensors have been widely used in the detection of biomarkers due to their advantages of simple operationquick responsehigh sensitivity and visualization. When constructing optical biosensors nucleic acid amplification technology can be used to improve the analytical performance of optical biosensor which can further realize the highly sensitive detection of biomarkers and provide more accurate information for disease diagnosis. In this reviewrecent advances in nucleic acid amplification-based optical biosensors for disease diagnosis were reviewed the possible problems may exist in practical applications and future development trends were proposed. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Determination of digoxin and its metabolites in biological samples by solidphase supported liquid-liquid extraction-liquid chromatography-tandem mass spectrometryEI北大核心CSCD

采用固相支撑液液萃取-超高效液相色谱-串联质谱（SLE-UPLC-MS/MS）技术建立了生物样本血液、尿液和肝组织中地高辛（DG）及其3种代谢物的分析方法。生物样本经匀浆、蛋白沉淀后,通过含有硅藻土的固相支撑液液萃取（SLE）柱净化富集,经洗脱、定容后进行LC-MS/MS分析。结果表明,血液基质中,地高辛在0.1～100 ng/mL浓度范围内线性关系良好;肝脏和尿液基质中,地高辛在0.2～100 ng/mL浓度范围内线性关系良好,地高辛的3种代谢物在0.5～100 ng/mL浓度范围内线性关系良好,3个浓度水平（10, 50和100 ng/mL）的加标回收率为60.5%～95.6%,基质效应80.7%～113.6%,日内、日间相对标准偏差（RSD）均小于13%,检出限为0.1～0.5 ng/mL。所建立的方法可用于生物样本中地高辛及其代谢物的定性定量分析。     

Detection of bleomycin based on N and S co-doped graphene quantum dots as a fluorescence probeEI北大核心CSCD

N and S co-doped graphene quantum dotsNS-GQDswith excellent fluorescence properties were synthesized by hydrothermal method using citrate and thiourea as ingredientsand were characterized. The fluorescence signal was notably reduced in the presence of single stranded DNAssDNAsince ssDNA can adsorb on the surface of NS-GQDs through p-p stacking interaction. Whereas a significantly restored fluorescence signal was observed in the presence of bleomycinowing to the irreversible cleavage of ssDNA by bleomycin with Fe2+ as cofactor. Thusa fluorescence sensor for bleomycin detection was developed. The linear range was from 1.8 to 1200 nmol/L and the detection limit was 0.25 nmol/L. The method was used to detect bleomycin content in human serum samples with satisfactory results. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

分子印迹技术在黄曲霉毒素检测中的最新研究进展EI北大核心CSCD

黄曲霉毒素(AFT)是由黄曲霉和寄生曲霉等某些菌株产生的一类真菌毒素,主要包括B1,B2,G1,G2,M1,M2,GM,P1,Q1,毒醇等,其中B1的毒性最大,致癌性最强,其广泛存在土壤、动植物、各种坚果、谷物,奶,食用油及其制品中,因此,食品中超痕量及痕量的黄曲霉毒素的检测方法受到高度关注。由于农产品样品基质复杂,而黄曲霉毒素含量和限量极低,高效特异性样品前处理技术是高灵敏精准检测黄曲霉毒素的关键之重。近年来分子印迹技术在样品前处理和核心识别元件等方面发展迅猛,在黄曲霉毒素痕量检测方面凸显出一定优势。综述了近几年来分子印迹技术在黄曲霉毒素前处理及快速检测等方面最新研究进展,并展望了分子印迹技术在黄曲霉检测应用的发展前景。     

The extraction of niobium (V) and Tantalum (V) by Octylarsinic acid in chloroform

Dioctylarsinic acid (HDOAA) in chloroform solution extracts Nb(V) and Ta(V) efficiently from solutions containing oxalate and oxalic acid at hydrochloric acid concentrations greater than 1M.The extraction coefficients are 92.5 at 7M hydrochloric acid and 251 at 6M hydrochloric acid for niobium and tantalum, respectively. These metals can be extracted even more efficiently from sulfuric acid solutions. The results of the reagent- and pH-dependence studies suggested that a trimeric, monobasic oxoacid of niobium, associated with ten HDOAA molecules, is extracted. Tantalum appears to be present in the organic phase as (H₂DOAA)⁺ [Ta(C₂O₄)₃ (HDOAA_n] (n=l or 2).     

Detection of H2O2 by quenching fluorometry of bovine serum albumin-silver nanoclustersEI北大核心CSCD

Bovine serum albuminBSAas protective agent and NaBH4 as reducing agentthe fluorescent silver nanoclustersBSA-AgNCswere prepared at room temperature by wet chemistry. Based on the fluorescence quenching effect of H2O2 to BSA-AgNCsa quantitative detection method of H2O2 was established. The results showed that the fluorescence quenching intensity of BSA-AgNCs was linear to the concentration of H2O2 in the range of 50-400 nmol/Lwhere the regression equation wasF0-F/F0 =0.0005cH2O2 +0.0543 with the coefficientr2of 0.997 and the detection limit of 1.51 nmol/L. This method could be used for the determination of glucose content in human blood. The linear range of glucose was 2-24 mmol/Lwhile the linear regression equation wasF0-F/F0 = 0.00152c+0.06569and the recoveries were 96.1%-101.2%with the r2 of 0.993. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

ICP-MS分析马莲花中的10种元素

目的 对马莲花中的微量元素进行分析.方法 采用微波消解法处理样品,利用电感耦合等离子体质谱法（ICP-MS）对马莲花中钾、钠、钙、镁、铜、铁、锌、锰、钼、镍等10种元素进行测定.所测元素校准方程的相关系数均大于0.999 0,回收率范围为90.2％ ～107.0％,相对标准偏差为1.54％～7.57％.结果 马莲花中含有丰富的钾、钙、镁等元素.结论 该法简便、快速、准确,灵敏度高,可用于马莲花中10种元素的同时测定.     

A fluorescence enhanced probe for sulfur dioxide detection and fluorescence imaging in living cellsEI北大核心CSCD

基于香豆素和苯并吡啶基团,构建了用于二氧化硫(SO_(2))高效检测的荧光探针P1,其化学结构通过核磁氢谱(^(1)H NMR)、碳谱(^(13)C NMR)和高分辨质谱(HR-MS)确证。在缓冲溶液体系中,单独的探针P1具有微弱的荧光,识别SO_(2)后荧光发射强度明显增强,能够实现对SO_(2)的专一性裸眼识别,检出限为126 nmol/L。生物应用实验结果表明,该探针具有较低的细胞毒性,可用于生物活细胞中外源性SO_(2)的荧光成像。     

Effect of clay surface on aldehyde-diol equilibrium

The effect of clay surface on the equilibrium between aldehyde and diol was examined by using 4-formyl-1-methylpyridin-1-ium chloride (MPy⁺) as a substrate. MPy⁺ exists as diol (DHMPy⁺) and aldehyde (FMPy⁺) in water and acetonitrile, respectively. It was turned out that FMPy⁺ was clearly observed in the presence of clay nanosheet even in water. This indicates that clay nanosheet surface acts as unique chemical reaction field, affecting the potential energy surface between FMPy⁺ and DHMPy⁺.     

On-line determination of trace-level Cr (VI) by carbon dots-immobilized fluorescent capillary sensorEI北大核心CSCD

A new carbon dots-immobilized fluorescent capillary sensor (CDs-FCAS) was developed by immobilizing CDs on the inner surface of glass capillary through cross-linking with KH550. CDs-FCAS was used for on-line detection of Cr (VI) based on fluorescence quenching reaction between CDs and Cr (VI). After reaction, the sensor was simply cleaned with PBS to recover its fluorescence. Therefore, the reuse of CDs-FCAS was realized. The fluorescence stability of the sensor was good (RSD © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Robust regression techniques A useful alternative for the detection of outlier data in chemical analysis

The validation of an analytical procedure means the evaluation of some performance criteria such as accuracy, sensitivity, linear range, capability of detection, selectivity, calibration curve, etc. This implies the use of different statistical methodologies, some of them related with statistical regression techniques, which may be robust or not. The presence of outlier data has a significant effect on the determination of sensitivity, linear range or capability of detection amongst others, when these figures of merit are evaluated with non-robust methodologies.In this paper some of the robust methods used for calibration in analytical chemistry are reviewed: the Huber M-estimator; the Andrews, Tukey and Welsh GM-estimators; the fuzzy estimators; the constrained M-estimators, CM; the least trimmed squares, LTS. The paper also shows that the mathematical properties of the least median squares (LMS) regression can be of great interest in the detection of outlier data in chemical analysis. A comparative analysis is made of the results obtained by applying these regression methods to synthetic and real data. There is also a review of some applications where this robust regression works in a suitable and simple way that proves very useful to secure an objective detection of outliers. The use of a robust regression is recommended in ISO 5725-5.     

Qualitative classification of COVID-19 by Raman spectra based on convolution neural networkEI北大核心CSCD

Taking the Raman spectra data of healthy people and sick people as experimental samplesa classification method of COVID-19 by Raman spectra based on convolution neural networkCNNwas proposed. In the training processit only needs to simply expand the sample data without complex preprocessing work. The training efficiency is higher than that of the traditional machine learning algorithms which depend on complex data preprocessing. Compared with K nearest neighborlogistic regression and support vector machinethe CNN has the highest classification accuracy of 96.77%. It's a new method for the detection of COVID-19. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

用于谷胱甘肽检测的新型罗丹明衍生物荧光探针EI北大核心CSCD

合成了一种反应型近红外荧光探针N-Rh-GSH,该探针以罗丹明衍生物为荧光母体,通过与谷胱甘肽(GSH)作用触发螺环的开关来实现信号的响应,其开环释放的荧光产物具有760 nm的近红外发射波长。细胞实验表明,该探针可实现对活细胞中GSH的成像。     

Application of split aptamers-based sensors for the detection of small moleculesEI北大核心CSCD

The split aptamers (SPAs)-based sensors is a novel kind of biosensors, assembled by two or more oligonucleotides in the presence of specific targets. To be successfully assembled, the sensor has to be induced by a specific target, which can aviod false-positive results and thus has a high degree of specificity and sensitivity. SPAs are suitable for the detection of various targets and show great advantages and potential in the development of aptasensors, especially for the detection of small molecules. However, the development and application of SPA-based sensors still remain challenging. Currently, the major difficulty is how to improve the stability of SPA-target complexes. Herein, this review summarizes the SPAs, strategies of splitting aptamers, and their applications in the detection of small molecules, aiming to provide new ideas for the development of novel, sensitive, and specific aptasensors. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Research progress of the retrospective detection of organophosphorus nerve agent exposure using point-of-care testing techniqueEI北大核心CSCD

有机磷神经性毒剂(OPNA)是一类速杀性化学战剂,人员中毒后通过溯源检测来确定OPNA种类和剂量对于毒剂使用指证和人员救治非常重要。当前大部分溯源检测方法灵敏度高、特异性好,但因依赖大型设备限于实验室,不便于现场检测。随着现场快速检测(POCT)技术的发展和新识别分子的开发,大量OPNA中毒溯源现场检测技术被建立和应用。本文主要基于胆碱酯酶活性抑制、特异性识别和直接生化反应原理从3方面分析总结了OPNA中毒溯源POCT技术的研究进展和应用,展望了其未来发展趋势。