90 research outputs found
Influence of pulsed bias on TiO2 thin films prepared on silicon by arc ion plating:Experimental and simulation study
No full textInfluence of pulsed bias on TiO2 thin films prepared on silicon by arc ion plating:Experimental and simulation stud
Heterogeneous cation induced clusters formed at surfaces of micro-droplets
No full textThe surface of a micro-droplet can be treated as a simplified model to study reactions on a cell membrane. A novel group of heterogeneous cations induced clusters (HeteroCICs) that formed at the surface of micro-droplets was discovered by mass spectrometry (MS). This novel category of clusters are produced through two types of cations coinduced self assemblies of thymine molecules. Applying this phenomenon, an on-line derivatization and quantitation method of "ambient MS" style has been established, which can be used to real time monitor fish freshness changes during shelf-life.National Natural Science Foundation of China [20727002, 21075005]; NSFC [21445005]SCI(E)[email protected]; [email protected]
A multichannel rotating electrospray ionization mass spectrometry (MRESI): instrumentation and plume interactions
No full textA multichannel rotating electrospray ionization (MRESI) mass spectrometry method is described. It is carried out by rotating three spray emitters infused with the same or different kinds of solvents or solutions. Rotation effect is shown as a critical factor in equalizing the sampling processes from different channels. The interactions of plumes generated from different spray emitters in MRESI has been systematically studied. Due to electrostatic repulsion, liquid fusion of charged droplets from different channels does not occur, while volatile reagents can induce reactions between sprays by vaporizing into neutral gas phase molecules which then extracted by other droplets. When the method is coupled to a laser desorption technique, the desorbed analytes can be post-ionized by multiple electrosprays concurrently, providing a more informative MS detection of a complex sample.National Natural Science Foundation of China [20727002, 21075005]; NSFC [21445005]SCI(E)[email protected]; [email protected]
Unexpected complexation reaction during analysis of proteins using laser desorption spray post-ionization mass spectrometry
No full textWe describe complexation reactions of insulin and other proteins with metal ions generated from the substrate surface by laser irradiation in laser desorption spray post-ionization mass spectrometry (LDSPI-MS). This particular type of complexation reaction in LDSPI-MS was investigated for the first time, which indicated that the mechanistic process of LDSPI-MS might be much more complicated than that proposed before for similar methods.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000301674600002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, AnalyticalSCI(E)PubMed7ARTICLE81764-176713
Highly sensitive and specific detection of histamine via the formation of a self-assembled magic number cluster with thymine by mass spectrometry
No full textA novel method for the detection of histamine (HIM) via the formation of a self-assembled magic number cluster with thymine (T) by electrospray ionization tandem mass spectrometry (ESI-MS/MS) is described. The formation of the magic number cluster [T-17 + HIM + 2H](2+) shifts the MS signal of histamine to the interference-free higher mass range and the signal intensity is increased by four orders of magnitude. In addition, the formation of [T-17 + HIM + 2H](2+) is highly specific to histamine compared with its metabolite and other similar biogenic amines, which may be attributed to both of its amino and imidazole groups. The linear dynamic range of the method is in the range of 1 nM-20 mu M, and the limit of detection can be as low as 0.1 nM. The feasibility of this method is further demonstrated by the quantitative analysis of histamine in a red wine sample. Since little sample preparation or separation is required before the analysis, this method provides a rapid new way for the sensitive and specific detection of histamine by MS.Chemistry, AnalyticalSCI(E)[email protected]
Targeted Protein Detection Using an All-in-One Mass Spectrometry Cartridge
No full textWe developed a simple 3D printed cartridge for mass spectrometry (MS) targeted detection of plasma proteins, including post-translational modifications (PTMs). The cartridge uses an integrated antibody enrichment column to preconcentrate the protein target as well as a novel built-in substrate to ionize the protein targets for MS detection. We show several examples of using this cartridge to perform rapid detection of clinically significant proteoforms from plasma samples
A label-free double-amplification system for sensitive detection of single-stranded DNA and thrombin by liquid chromatography-mass spectrometry
No full textA label-free double amplification system has been developed by using a ternary DNA probe containing the poly(adenine-thymine) sequence assisted by exonuclease III degradation. The method achieved more than 600-fold signal amplification and allowed sensitive detection of single-stranded DNA and thrombin at the pM level by using liquid chromatography/mass spectrometry.Chemistry, MultidisciplinarySCI(E)[email protected]; [email protected]
Development of a Paper Spray Mass Spectrometry Cartridge with Integrated Solid Phase Extraction for Bioanalysis
No full textA novel paper spray cartridge with
an integrated solid phase extraction
(SPE) column is described. The cartridge performs extraction and pre-concentration,
as well as sample ionization by paper spray, from complex samples
such as plasma. The cartridge allows for selective enrichment of target
molecules from larger sample volumes and removal of the matrix, which
significantly improved the signal intensity of target compounds in
plasma samples by paper spray ionization. Detection limits, quantitative
performance, recovery, ionization suppression, and the effects of
sample volume were evaluated for five drugs: carbamazepine, atenolol,
sulfamethazine, diazepam, and alprazolam. Compared with direct paper
spray analysis of dried plasma spots, paper spray analysis using the
integrated solid phase extraction improved the detection limits significantly
by a factor of 14–70, depending on the drug. The improvement
in detection limits was, in large part, due to the capability of analyzing
larger sample volumes. In addition, ionization suppression was found
to be lower and recovery was higher for paper spray with integrated
SPE, as compared to direct paper spray analysis. By spiking an isotopically
labeled internal standard into the plasma sample, a linear calibration
curve for the drugs was obtained from the limit of detection (LOD)
to 1 μg/mL, indicating that this method can be used for quantitative
analysis. The paper spray cartridge with integrated SPE could prove
valuable for analytes that ionize poorly, in applications where lower
detection limits are required, or on portable mass spectrometers.
The improved performance comes at the cost of requiring a more complex
paper spray cartridge and requiring larger sample volumes than those
used in typical direct paper spray ionization
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