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Analytical Chemistry

Shuang Wang, Weimin Wang, Hong Li, Yuming Xing, Keyong Hou, Haiyang Li
Illegal drug smugglings and crimes have long been a global concern, and an apparatus which can identify drugs on-the-spot is urgently demanded by law enforcement. A thermal desorption acetone-assisted photoionization miniature ion trap mass spectrometer (TD-AAPI-ITMS) was developed for on-site and rapid identification of illegal drugs at checkpoints. Acetone was chosen for dopant assisted photoionization and the sensitivity of selected drugs was further enhanced with protonated analyte molecular ions [M+H]+...
February 14, 2019: Analytical Chemistry
Muhammad Asif, Ayesha Aziz, Zhengyun Wang, Ghazala Ashraf, Junlei Wang, Hanbo Luo, Xuedong Chen, Fei Xiao, Hongfang Liu
The precise monitoring of H2S has aroused immense research interests in biological and biomedical fields since it is exposed as third endogenous gasotransmitter. Hence, there is an urgent requisite to explore ultrasensitive and economical H2S detection system. Herein, we report a simple strategy to configure extremely sensitive electrochemical sensor with 2D nanosheet-shaped layered double hydroxide (LDH) wrapped carbon nanotubes (CNTs) nanohybrid (CNTs@LDH), where a series of CNTs@CuMn-LDH nanohybrids with varied amount of LDH nanosheets grafted on conductive CNTs backbone has been synthesized via facile co-precipitation approach...
February 14, 2019: Analytical Chemistry
Bin Zhang, Fang Zhang, Ping Zhang, Dazhong Shen, Xuwen Gao, Guizheng Zou
To screen novel toxic-element-free and biocompatible electrochemiluminophores, electrochemluminescence (ECL) of mul-tinary nanocrystals (NCs) was investigated for the first time with Zn-Ag-In-S (ZAIS) NCs as model. Aqueous soluble ZAIS NCs could bring out efficient reductive-oxidation ECL with tri-n-propylamine as co-reactant, while coating the ZAIS NCs with a ZnS shell could reduce the surface defects of ZAIS NCs, and enable 6.7 folds enhanced ECL of ZAIS/ZnS NCs than ZAIS NCs. ECL of ZAIS/ZnS NCs was about 4...
February 14, 2019: Analytical Chemistry
Trisha Tucholski, Samantha Knott, Bifan Chen, Paige Pistono, Ziqing Lin, Ying Ge
Mass spectrometry (MS)-based top-down proteomics provides rich information about proteoforms arising from combinatorial amino acid sequence variations and post-translational modifications (PTMs). Fourier transform ion cyclotron resonance (FT-ICR) MS affords ultra-high resolving power and provides high-accuracy mass measurements, presenting a powerful tool for top-down MS characterization of proteoforms. However, detection and characterization of large proteins from complex mixtures remain challenging due to the exponential decrease in S:N with increasing molecular weight (MW) and co-eluting low-MW proteins; thus, size-based fractionation of complex protein mixtures prior to MS analysis is necessary...
February 13, 2019: Analytical Chemistry
Zhongshan Liu, Ping Jiang, Guang Huang, Xiaowen Yan, Xing-Fang Li
We report a new material of a composite silica monolith nested in sponge (SiMNS) and demonstrate an application in the trace analysis of environmental contaminants in water. SiMNS is prepared through sponge absorption of a hydrolyzed mixture of siloxanes and in situ gel formation within the pores. Images obtained using scanning electron microscopy show that the silica and sponge skeletons are mutually nested in SiMNS. This nested composite structure of SiMNS enhances the mechanical flexibility of the material, allowing for reproducible production of desirable sizes and shapes for solid phase extraction (SPE) cartridges without the need to use frits...
February 13, 2019: Analytical Chemistry
Klaus Koren, Maria Mosshammer, Vincent V Scholz, Sergey M Borisov, Gerhard Holst, Michael Kühl
Luminescence lifetime based imaging is still the most reliable method for generating chemical images using chemical sensor technology. However, only few commercial systems are available that enable imaging lifetimes within the relevant ns to µs range. In this technical note we compare the performance of an older time-domain (TD) based camera systems with a frequency-domain (FD) based camera system regarding their measuring characteristics and applicability for O2 and pH imaging in environmental samples and with different indicator dye systems emitting in the visible and near infrared part of the spectrum...
February 13, 2019: Analytical Chemistry
Surjendu Dutta, Rashmi Shrivastava, Hemant Krishna, Khan Mohammad Khan, Sharad Gupta, Shovan Kumar Majumder
Reliable diagnosis of disease using body fluids requires sensitive and accurate detection of disease-specific analytes present in the fluid. In recent years, there has been increasing interest in using surface-enhanced Raman spectroscopy (SERS) for this purpose. The demonstrable signal enhancement and sensitivity of SERS makes it ideally suited for detection of trace quantity of any analyte. However, lack of reproducibility along with large spatial variability in the measured Raman intensities due to differential (and often random) distribution of surface 'hotspots' limits its routine clinical use...
February 13, 2019: Analytical Chemistry
Sili Fan, Tobias Kind, Tomas Cajka, Stanley L Hazen, W H Wilson Tang, Rima Kaddurah-Daouk, Marguerite R Irvin, Donna K Arnett, Dinesh Kumar Barupal, Oliver Fiehn
Large-scale untargeted lipidomics experiments involve the measurement of hundreds to thousands of samples. Such data sets are usually acquired on one instrument over days or weeks of analysis time. Such extensive data acquisition processes introduce a variety of systematic errors, including batch differences, longitudinal drifts or even instrument-to-instrument variation. Technical data variance can obscure the true biological signal and hinder biological discoveries. To combat this issue, we present a novel normalization approach based on using quality-control pool samples (QC)...
February 13, 2019: Analytical Chemistry
Qingqing Jin, Xinli Fan, Changmai Chen, Lei Huang, Jing Wang, XinJing Tang
Developing new nanomaterials with strong and distinctive Raman vibrations in the biological Raman-silent region (1800-2800 cm -1) were highly desirable for Raman hyper-spectral detection and imaging in living cells and animals. Herein, polymeric nanoparticles with monomers containing alkyne, cyanide, azide and carbon-deuterate were prepared as Raman-active nanomaterials (Raman Beads) for bioimag-ing applications. Intense Raman signals were obtained due to the high density of alkyne, cyanide, azide and carbon-deuterate in single nanoparticles, in absence of metal (such as Au or Ag) as Raman enhancers...
February 13, 2019: Analytical Chemistry
Xiao-Ping Zhao, Fei-Fei Liu, Wen-Chao Hu, Muhammad Rizwan Younis, Chen Wang, Xing-Hua Xia
A biomimetic nanochannel-ionchannel hybrid coupled with electrochemical detector was developed for label-free and ultrasensitive detection of microRNA (miRNA) in cells. Probe single stranded DNA (ssDNA) was first immobilized on the outer surface of the nanochannel-ionchannel hybrid membrane, which can hybridize with the target miRNA in cells. Due to the unique mass transfer property of the hybrid, the DNA-miRNA hybridization kinetics can be sensitively monitored in real-time using the electrochemical technique...
February 13, 2019: Analytical Chemistry
Joanna Xiuzhu Xu, Juan Hu, Dongmao Zhang
No abstract text is available yet for this article.
February 13, 2019: Analytical Chemistry
Alexis Léon, Ronan Cariou, Sébastien Hutinet, Julie Hurel, Yann Guitton, Celine Tixier, Catherine Munschy, Jean-Phillippe Antignac, Gaud Dervilly-Pinel, Bruno Le Bizec
In the present work, we address the issue of non-targeted screening of organohalogenated chemicals in complex matrices. A global strategy aiming to seek halogenated signatures in full scan high resolution mass spectrometry (HRMS) fingerprints was developed. The resulting all-in-one user-friendly application, HaloSeeker 1.0, was developed to promote the accessibility of associated in-house bioinformatics tools to a large audience. The ergonomic web user interface avoids any interactions with the coding component while allowing interactions with the data, including peak detection (features), deconvolution and comprehensive accompanying manual review for chemical formula assignment...
February 13, 2019: Analytical Chemistry
Tomas Skotare, David Nilsson, Shaojun Xiong, Paul Geladi, Johan Trygg
In the present paper we introduce an end-to-end workflow named joint and unique multiblock analysis (JUMBA), which allows multiple sources of data to be analysed simultaneously to better understand how they complement each other. In near infrared (NIR) spectroscopy, calibration models between NIR spectra and responses are used to replace wet chemistry methods, where the models tend to be instrument-specific. Calibration transfer techniques are used for standardization of NIR-instrumentation, enabling the use of one model on several instruments...
February 13, 2019: Analytical Chemistry
Ding Wang, Yaqin Chai, Yali Yuan, Ruo Yuan
In this work, a rigid DNA tetrahedron (TDN) scaffold was synthesized to precisely control the interenzyme distance by randomly anchoring two pairs of horseradish peroxidase (HRP)/glucose oxidase (GOx) at the vertices of TDN, which could not only avoid the drawbacks of poor controllability and biocompatibility from traditional scleroid skeletons, but also overcome the defect of imprecise regulation for interenzyme distance caused by DNA origami. Impressively, by varying the side length of TDN scaffold, the interenzyme distance was precisely regulated, thus, an optimal TDN scaffold with highest catalytic efficiency was acquired and subsequently applied for constructing an ultrasensitive biosensor for DNA detection with a low detection limit of 3 fM...
February 13, 2019: Analytical Chemistry
Jiafu Chang, Xin Wang, Jiao Wang, Haiyin Li, Feng Li
Simultaneous detection of multiple tumor biomarkers is in great demand for early and accurate cancer diagnosis. Homogeneous electrochemical biosensor has been proved to possess high sensitivity, but achieving simultaneous detection of multiple tumor biomarkers is still a challenge. Herein, we develop a novel homogeneous electrochemical biosensor for simultaneous detection of multiple tumor biomarkers based on the functionalized metal-organic frameworks (MOFs). The functionalized MOFs were prepared by using porous UIO-66-NH2 as nanocontainer to load electroactive dyes, and dsDNA as gatekeeper to cap MOFs...
February 13, 2019: Analytical Chemistry
Jonas Henschel, Luca Schwarz, Frank Glorius, Martin Winter, Sascha Nowak
This study illustrates the high complexity of phosphorus-based decomposition products in thermally treated state-of-the-art lithium ion battery (LIB) electrolytes. Liquid chromatographic techniques hyphenated to ion trap time of flight mass spectrometry reveals 118 different organophosphate (OP) and organofluorophosphate (OFP) species, the majority of them not reported in literature so far. The application of hydrophilic interaction liquid chromatography and reversed phase chromatography enables the investigation of the acidic as well as non-acidic spectrum of aging products...
February 12, 2019: Analytical Chemistry
Shi-Yang Tang, Kun Wang, Kai Fan, Zilong Feng, Yuxin Zhang, Qianbin Zhao, Guolin Yun, Dan Yuan, Lianmei Jiang, Ming Li, Weihua Li
Despite that droplet-based microfluidics has been broadly used as a versatile tool in biology, chemistry and nanotechnology, its rather complicated microfabrication process and the requirement of specialized hardware and operating skills hinder researchers to fully unleash the potential of this powerful platform. Here, we develop an integrated microdroplet generator enabled by a spinning conical frustum for the versatile production of near-monodisperse microdroplets in a high-throughput and off-chip manner...
February 12, 2019: Analytical Chemistry
Erika F Dudás, Andrea Bodor
Key questions in folding studies are the protein dimensions and the degree of folding. These properties are best characterized by the self-diffusion coefficients D determining the hydrodynamic dimensions. In our present study we derive empirical variations of D as a function of molecular mass M that distinguish folded, intrinsically disordered and urea-denatured biomolecules. Reliable D values are obtained from diffusion NMR measurements performed under identical conditions using a representative set of proteins/peptides with diverse amino acid sequence and length...
February 11, 2019: Analytical Chemistry
Chiara Deriu, Irene Conticello, Alexander Moiseevich Mebel, Bruce McCord
: An analytical protocol based on surface-enhanced Raman spectroscopy (SERS) and aimed at the detection of toxicologically relevant concentrations of JWH-018 in oral fluid is presented for the first time. A DFT-supported in-depth vibrational characterization of the drug in the solid state and in solution was also performed, providing a body of literature for future spectroscopic works on the compound. A Langmuir adsorption model was used to derive quantitative parameters such as the affinity of JWH-018 for citrate-capped gold nanospheres as well as the LOD...
February 11, 2019: Analytical Chemistry
Yue Lin, Jinpeng Jia, Rui Yang, Daozhen Chen, Jian Wang, Fang Luo, Longhua Guo, Bin Qiu, Zhenyu Lin
DNA tetrahedron nanostructure (DTNs) had the merits of simple synthesis, high yield, structural stability and mechanical rigidity, and its three-dimensional structure provided a satisfactory biosensing interface to the improvement of the binding efficiency of antigenic proteins and antibodies. Electrochemiluminescence (ECL) reagent, tris (4,4'-dicarboxylicacid-2,2'-bipyridyl) ruthenium (Ⅱ) dichloride (Ru(dcbpy)3Cl2), was modified on the electrode through the formation of classical sandwich complex of antibody-antigen-antibody...
February 11, 2019: Analytical Chemistry
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