• Mass Spectrometry Letters
• /
• v.6 no.1
• /
• pp.13-16
• /
• 2015

This study demonstrated the stabilizing role of a cyclodextrin on Keggin $[PW_{12}O_{40}]^{3-}$ via hydrogen bonding complexation unveiled by ESI-MS. The distinctive fragmentation pathways of the $\{PW_{12}\}/{\gamma}$-CD complexes from that of discrete $[PW_{12}O_{40}]^{3-}$ showed that the so-called "weak" non-covalent interactions can effectively change the dissociation chemistry of POM in the gas phase. The influence of different types of solvents and organic additives such as ${\gamma}$-CD on the stability of Keggin $[PW_{12}O_{40}]^{3-}$ was also addressed firstly by ESI-MS.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.6
• /
• pp.959-967
• /
• 2010

Down syndrome (DS) is an abnormality of the 21st chromosome that commonly occurs in children born to older women. Thus, amniotic fluid (AF) is usually collected from such women for prenatal diagnosis. This study analyzed human AF supernatants (AFS) using a mass spectrometric (MS) approach to search for candidate biomarkers of a DS pregnancy. The AFS were collected from older pregnant women at weeks 16-18 of their gestation by amniocentesis for cytogenetic analysis. The AFS from the pregnancies carrying DS (n=4) or chromosomally normal (n=6) fetuses, as revealed by the cytogenetic analysis, were then subjected to global protein profiling based on liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Affinity chromatography was also applied prior to the LC-ESI-MS/MS to minimize the masking effect of highly abundant albumin and immunoglobulin and thereby increase the diversity of the identified proteins. As a result, at least 30 new AFS proteins were identified and 44 AFS proteins were found to be differentially expressed between the DS and normal cases, where 6 of the proteins were unique to the DS cases and 11 were unique to the chromosomally normal cases. In addition, in the DS cases, 19 AFS proteins were downregulated and 8 were upregulated to varying degrees. A Western blot analysis confirmed the LC-ESI-MS/MS data, indicating that the combined detection of apolipoprotein A-II (apoA-II) and alpha-fetoprotein (AFP) could be a potential tool for diagnosing DS cases.

• Mass Spectrometry Letters
• /
• v.12 no.3
• /
• pp.93-105
• /
• 2021

Exosomes have gained the attention of the scientific community because of their role in facilitating intercellular communication, which is critical in disease monitoring and drug delivery research. Exosome research has grown significantly in recent decades, with a focus on the development of various technologies for isolating and characterizing exosomes. Among these efforts is the use of matrix-assisted laser desorption ionization (MALDI) mass spectrometry (MS), which offers high-throughput direct analysis while also being cost and time effective. MALDI is used less frequently in exosome research than electrospray ionization due to the diverse population of extracellular vesicles and the impurity of isolated products, both of which necessitate chromatographic separation prior to MS analysis. However, MALDI-MS is a more appropriate instrument for the analytical approach to patient therapy, given it allows for fast and label-free analysis. There is a huge drive to explore MALDI-MS in exosome research because the technology holds great potential, most notably in biomarker discovery. With methods such as fingerprint analysis, OMICs profiling, and statistical analysis, the search for biomarkers could be much more efficient. In this review, we highlight the potential of MALDI-MS as a tool for investigating exosomes and some of the possible strategies that can be implemented based on prior research.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.5
• /
• pp.840-842
• /
• 2007

• Mass Spectrometry Letters
• /
• v.6 no.4
• /
• pp.99-104
• /
• 2015

A liquid chromatography mass spectrometry (LC-MS) system was used to identify and distinguish oligostilbene diastereoisomers. A polyphenolic extract from Neobalanocarpus heimii known to be rich in oligostilbenes of various degrees of condensation was used as test material. Fourteen oligostilbenes were isolated from this extract on a fully automated semi-preparative HPLC system. Out of these, two pairs of dimers, one pair of trimers, two pairs of tetramers and a group of four tetramers with similar skeleton were identified as diastereoisomers. Their structures and configurations were established by spectroscopic methods. All isolated compounds were subjected to an LC-MS/MS to study their fragmentation patterns. The experiments were performed on a liquid chromatography-mass spectrometry (LC-MS) with electrospray-ionization (ESI) interface in positive mode. MS/MS spectra of each pure compound were recorded by direct infusion in identical conditions and their product ion spectra were analysed. Some subtle yet significant differences were observed between the spectra of oligostilbenes from the various diastereoisomeric series.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.9
• /
• pp.1347-1353
• /
• 2005

Sets of sialic acid-containing trisaccharides having different internal and terminal linkages have been synthesized to develop a sensitive method for analysis of the reducing terminal linkage positions. The trisaccharides, sialyl($\alpha$ 2-3)Gal($\beta$ 1-3)GalNAc and sialyl($\alpha$ 2-3)Gal($\beta$ 1-X)GlcNAc where X=3, 4 and 6, were synthesized and examined using electrospray ionization (ESI)-collision induced dissociation (CID) tandem mass spectrometry (MS/MS). The compounds chosen for this study are related to terminal groups likely to be found on polylactosamine-like glycoproteins and glycolipids which occur on the surface of mammalian cells. The purpose of this study is to develop tandem mass spectrometral methods to determine detailed carbohydrate structures on permethylated or partially methylated oligosaccharides for future applications on biologically active glycoconjugates and to exploit a faster method of synthesizing a series of structural isomeric oligosaccharides to be used for further mass spectrometry and instrumental analysis.

• Mass Spectrometry Letters
• /
• v.14 no.3
• /
• pp.110-115
• /
• 2023

The reaction of (COD)PdCl₂ with new C₃-symmetric tridentate L (COD = 1,5-cyclooctadien; L = 1,3,5-tris(picolinoyloxyethyl)cyanurate) in a mixture of acetone and dichloromethane produces single crystals consisting of unprecedented monometallacyclic [PdCl₂(L)]. This cyclic compound arises from trans-chelation of two of three donating pyridyl groups of L, while the third pyridyl group remains uncoordinated. Electrospray ionization mass spectrometry (ESI-MS) data on L exhibited the major peak corresponding to [C₂₇H₂₄N₆O₉ + H⁺]⁺. Fast atom bombardment mass spectrometry (FABMS) data on [PdCl₂(L)], however, showed the mass peak corresponding to the L instead of the present palladium(II) compound species, due to the insolubility and dissociation in solution. The physicochemical properties of the present palladium(II) compound were fully characterized by means of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, thermal analysis, single-crystal X-ray diffraction (SC-XRD) measurement.

• Food Science and Biotechnology
• /
• v.18 no.1
• /
• pp.113-117
• /
• 2009

A method was developed using enhanced liquid chromatography coupled with electrospray ionization mass spectrometry for the analysis and quantitation of 2 main potato glycoalkaloids, $\alpha$-chaconine, and $\alpha$-solanine, without any pre-concentration or derivatisation steps. Calibration curves generated by this technique exhibited a linear dynamic range from 0.025 to $50{\mu}g/mL$ and from 0.05 to $50{\mu}g/mL$ for $\alpha$-chaconine and $\alpha$-solanine, respectively. Matrix effects were evaluated by comparing calibration curves measured in matrix-matched and solvent-based systems. Ion suppression due to matrix effects was weak and extraction recoveries of 88 to 114% were obtained in different sample matrices spiked with analyte concentrations ranging from 15 to $35{\mu}g/mL$. Potatoes that had been genetically modified to tolerate glufosinate contained the same glycoalkaloid levels as their non-transgenic counterpart. We suggest complementing compositional comparison assessment strategy by validating quantitative analytical methods for the toxic glycoalkaloids in potato plants.

• Mass Spectrometry Letters
• /
• v.3 no.3
• /
• pp.68-73
• /
• 2012

Fat malabsorption is an important cause of poor growth in infancy and childhood. Steatorrhea tests have been developed using various methods. Traditional measurements of stool fat, however, require large samples and it often takes as a week to complete the analysis. In this paper, a liquid chromatography-electrospray ionization/mass spectrometry (LC-ESI/MS) method was developed for simultaneous quantitative analysis of triacylglycerols, triolein, diolein and monoolein, in mouse feces. Moreover, the procedure was rapid, simple as well as compatible with LC-ESI/MS. Chloroform-isopropyl alcohol solution was used for fat-soluble sample extraction. After centrifugation and filtration, an analytical solution was prepared. Triolein, diolein and monoolein were separated using non-aqueous reversed-phase column with the mobile phase consisting of A (methanol) and B (acetone-isopropyl alcohol). The precision (% CV) and accuracy (% bias) of the assay were 3.8-14.7% and 85.2-114.9%, respectively. This method has been successfully applied to simultaneous determination of triolein, diolein and monoolein in feces from 30 mice. This method can therefore be applied to measure triacylglycerols in mouse feces accurately and precisely by LC-ESI/MS, thereby helping to predictive biomarker in fat malabsorption and diagnostic research.

• Fibers and Polymers
• /
• v.3 no.4
• /
• pp.140-146
• /
• 2002

Non-genotoxic diamines 2,2'-dimethyl-5,5'-dipropoxybenzidine and 5,5'-dipropoxy-benzidine were employed as potential alternatives to benzidine in the synthesis and evaluation of new direct dyes for cotton. Assessment of the resultant dyes indicated that both diamines can be used to prepare new direct dyes having colors and fastness properties that make them comparable to commercial direct dyes, and that the structures of the new direct dyes can be confirmed by negative ion electrospray mass spectrometry (ESMS). The mutagenic properties of new direct dyes were established using the standard Ames Salmonella mammalian mutagenicity assay.