Determination of the Concentration and Isotope Ratio of Uranium in Soil and Water by Thermal Ionization Mass Spectrometry

( Jong Ho Park ),( Sujin Park ),( Kyuseok Song ) 한국질량분석학회 2014 Mass spectrometry letters Vol.5 No.1

Thermal ionization mass spectrometry (TIMS) was used to determine the concentration and isotope ratio of uranium contained in samples of soil and groundwater collected from Korea. Quantification of uranium in ground water samples was performed by isotope dilution mass spectrometry. A series of chemical treatment processes, including chemical separation using extraction chromatography, was applied to the soil samples to extract the uranium. No treatments other than filtration were applied to the groundwater samples. Isotopic analyses by TIMS showed that the isotope ratios of uranium in both the soil and water samples were indistinguishable from those of naturally abundant uranium. The concentration of uranium in the groundwater samples was within the U.S. acceptable standards for drinking water. These results demonstrate the utility of TIMS for monitoring uranium in environmental samples with high analytical reliability.

Differential Protein Quantitation in Mouse Neuronal Cell Lines using Amine- Reactive Isobaric Tagging Reagents with Tandem Mass Spectrometry

( Kun Cho ),( Gun Wook Park ),( Jin Young Kim ),( Sang Kwang Lee ),( Han Bin Oh ),( Jong Shin Yoo ) 한국질량분석학회 2010 Mass spectrometry letters Vol.1 No.1

The high-throughput identification and accurate quantification of proteins are essential strategies for exploring cellular functions and processes in quantitative proteomics. Stable isotope tagging is a key technique in quantitative proteomic research, accompanied by automated tandem mass spectrometry. For the differential proteome analysis of mouse neuronal cell lines, we used a multiplexed isobaric tagging method, in which a four-plex set of amine-reactive isobaric tags are available for peptide derivatization. Using the four-plex set of isobaric tag for relative and absolute quantitation (iTRAQ) reagents, we analyzed the differential proteome in several stroke time pathways (0, 4, and 8 h) after the mouse neuronal cells have been stressed using a glutamate oxidant. In order to obtain a list of the differentially expressed proteins, we selected those proteins which had apparently changed significantly during the stress test. With 95% of the peptides showing only a small variation in quantity before and after the test, we obtained a list of eight up-regulated and four down-regulated proteins for the stroke time pathways. To validate the iTRAQ approach, we studied the use of oxidant stresses for mouse neuronal cell samples that have shown differential proteome in several stroke time pathways (0, 4, and 8 h). Results suggest that histone H1 might be the key protein in the oxidative injury caused by glutamate-induced cytotoxicity in HT22 cells.

Dynamic MRM Measurements of Multi-Biomarker Proteins by Triple- Quadrupole Mass Spectrometry with Nanoflow HPLC-Microfluidics Chip

( Eun Sun Ji ),( Mi Hee Cheon ),( Ju Yeon Lee ),( Jong Shin Yoo ),( Hyun-jin Jung ),( Jin Young Kim ) 한국질량분석학회 2010 Mass spectrometry letters Vol.1 No.1

The development of clinical biomarkers involves discovery, verification, and validation. Recently, multiple reaction monitoring (MRM) coupled with stable isotope dilution mass spectrometry (IDMS) has shown considerable promise for the direct quantification of proteins in clinical samples. In particular, multiple biomarkers have been tracked in a single experiment using MRM-based MS approaches combined with liquid chromatography. We report here a highly reproducible, quantitative, and dynamic MRM system for validating multi-biomarker proteins using Nanoflow HPLC-Microfluidics Chip/Triple-Quadrupole MS. In this system, transitions were acquired only during the retention window of each eluting peptide. Transitions with the highest MRM-MS intensities for the five target peptides from colon cancer biomarker candidates were automatically selected using Optimizer software. Relative to the corresponding non-dynamic system, the dynamic MRM provided significantly improved coefficients of variation in experiments with large numbers of transitions. Linear responses were obtained with concentrations ranging from fmol to pmol for five target peptides.

A Technique to Minimize Impurity Signal from Blank Rhenium Filaments for Highly Accurate TIMS Measurements of Uranium in Ultra-Trace Levels

( Jong-ho Park ),( Inhee Choi ),( Kyuseok Song ) 한국질량분석학회 2010 Mass spectrometry letters Vol.1 No.1

As background significantly affects measurement accuracy and a detection limit in determination of the trace amounts of uranium, it is necessary to minimize the impurities in the filaments used for thermal ionization mass spectrometry (TIMS). We have varied the degassing condition such as the heating currents and duration times to reduce the backgrounds from the filaments prepared with zone-refined rhenium tape. The most efficient degassing condition of the heating current and the duration time was determined as 3.5 A and 60 min, respectively. The TIMS measurement combined with the isotope dilution mass spectrometry IDMS) technique showed that the uranium backgrounds were determined to be in a few fg level from blank rhenium filaments. The background minimized filaments were utilized to measure the uranium isotope ratios of a U030 (NIST) standard sample. The excellent agreement of the measurement with the certified isotope ratios showed that the degassing procedure optimized in this study efficiently reduced the impurity signals of uranium from blank rhenium filaments to a negligible level.

High-Throughput Active Compound Discovery using Correlations between Activity and Mass Profiles

( Kyu Hwan Park ),( Kyo Joong Yoon ),( Kyung-hoon Kwon ),( Hyun Sik Kim ) 한국질량분석학회 2010 Mass spectrometry letters Vol.1 No.1

The active components in a plant extract can be represented as mass profiles. We introduce here a new, multi-compound discovery method known as Scaling of Correlations between Activity and Mass Profiles (SCAMP). In this method, a correlation coefficient is used to quantify similarities between the extract activity and mass profiles. The method was evaluated by first measuring the anti-oxidation activity of eleven fractions of an Astragali Radix extract using DPPH assays. Next, 15 T Fouriertransform ion cyclotron resonance (FT-ICR) MS was employed to generate mass profiles of the eleven fractions. A comparison of correlation coefficients indicated two compounds at m/z 285.076 and 286.076 that were strong antioxidants. Principal component analyses of these profiles yielded the same result. FT-ICR MS, which offers a mass resolving power of 500,000, was used to discern isotopic fine structures and indicated that the molecular formula corresponding to the peak at m/z 285.076 was C16H13O5. SCAMP in combination with high-resolution MS can be applied to any type of mixture to study pharmacological activity and is a powerful tool for active compound discovery in plant extract studies.

Ditopic Binding of Alkali Halide Ions to Trimethylboroxine

( Kyung Hwan Jeong ),( Seung Koo Shin ) 한국질량분석학회 2010 Mass spectrometry letters Vol.1 No.1

Trimethylboroxine (TMB) is a six-membered ring compound containing Lewis acidic boron and Lewis basic oxygen atoms that can bind halide anion and alkali metal cation, respectively. We employed Fourier transform ion cyclotron resonance spectroscopy to study the gas-phase binding of LiBrLi+ and F-(KF)2 to TMB. TMB forms association complexes with both LiBrLi+ and F-(KF)2 at room temperature, providing direct evidence for the ditopic binding. Interestingly, the TMB·F-(KF)2 anion complex is formed 33 times faster than the TMB·Li+BrLi cation complex. To gain insight into the ditopic binding of an ion pair, we examined the structures and energetics of TMB·Li+, TMB·F-, TMB·LiF (the contact ion pair), and Li+·TMB·F- (the separated ion pair) using Hartree-Fock and density functional theory. Theory suggests that F- binds more strongly to TMB than Li+ and the contact ion-pair binding (TMB·LiF) is more stable than the separated ion-pair binding (Li+·TMB·F-).

Collisionally-Activated Dissociation of Peptides with a Disulfide Bond: Confirmation of the Mobile-Proton Model Based Explanation

( Younjin Lee ),( Han Bin Oh ) 한국질량분석학회 2010 Mass spectrometry letters Vol.1 No.1

In the present study, collisionally-activated dissociation (CAD) experiments were performed under low energy collision conditions in six peptides containing a disulfide bond. Fragments produced as a result of the cleavage of a disulfide bond were obtained after CAD in four peptides (bactenecin, TGF-α, cortistantin, and linearly linked peptide, Scheme 1) with basic amino acid residues. In contrast, the CAD analysis of two peptides with no basic residue (oxytocin and tocinoic acid) rarely produced fragments indicative of cleavage of a disulfide bond. These results are consistent with the mobile proton model suggested by the McLuckey and O’Hair groups (ref. 22 and 23); nonmobile protons sequestered at basic amino acid residues appear to promote the cleavage of disulfide bonds.

Brief History of Mass Spectrometry in Korea Related to the Establishment of the Korean Society for Mass Spectrometry

( Hun-young So ) 한국질량분석학회 2010 Mass spectrometry letters Vol.1 No.1

Accurate Quantification of Saccharin Using Isotope Dilution Liquid Chromatography Mass Spectrometry (ID-LC/MS)

( Yunjung Lee ),( Byungjoo Kim ),( Jeongkwon Kim ),( Seonghee Ahn ) 한국질량분석학회 2011 Mass spectrometry letters Vol.2 No.2

Saccharin is a commonly used artificial sweetener in foodstuffs. However, for its carcinogenic dispute, it has been regulated by government bodies. In this study, isotope dilution mass spectrometry (ID-MS) was introduced for the accurate quantification of saccharin. To employ ID-LC/MS, we obtained its isotope analogue, 13C1 .sodium saccharin, by customized synthesis. Samples were spiked with 13C1-sodium saccharin and analyzed with LC/MS in negative mode. Chromatographic conditions were optimized for the adequate chromatographic retention and separation of saccharin with a C18 column. MS was operated with electrospray ionization by the selected ion monitoring (SIM) mode of [M . H]. for saccharin (m/z 182) and [M . Na]. for its isotope analogue (m/z 183). To validate the ID-LC/MS method for accurate measurement, we prepared a batch of a candidate material by sortifying quasi.tea.drinks with saccharin and analyzed samples gravimetrically fortified in various levels of concentration. The repeatability and reproducibility of this method was tested by analyzing the reference material. Result show that ID-LC/MS is a reliable method for the quantitative analysis of saccharin.

Compositional Characterization of Petroleum Heavy Oils Generated fromVacuum Distillation and Catalytic Cracking by Positive-mode APPI FT-ICR Mass Spectrometry

( Eunkyoung Kim ),( Myoung Han No ),( Jaesuk Koh ),( Sungwhan Kim ) 한국질량분석학회 2011 Mass spectrometry letters Vol.2 No.2

Molecular compositions of two types of heavy oil were studied using positive atmospheric pressure photoionization (APPI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Vacuum gas oil (VGO) was generated from vacuum distillation of atmospheric residual oil (AR), and slurry oil (SLO) was generated from catalytic cracking of AR. These heavy oils have similar boiling point ranges in the range of 210-650oC, but they showed different mass ranges and double-bond equivalent (DBE) distributions. Using DBE and carbon number distributions, aromatic ring distributions, and the extent of alkyl side chains were estimated. In addition to the main aromatic hydrocarbon compounds, those containing sulfur, nitrogen, and oxygen heteroatoms were identified using simple sample preparation and ultra-high mass resolution FT-ICR MS analysis. VGO is primarily composed of mono- and di-aromatic hydrocarbons as well as sulfur-containing hydrocarbons, whereas SLO contained mainly polyaromatic hydrocarbons and sulfur-containing hydrocarbons. Both heavy oils contain polyaromatic nitrogen components. SLO inludes shorter aromatic alkyl side chains than VGO. This study demonstrates that APPI FT-ICR MS is useful for molecular composition characterization of petroleum heavy oils obtained from different refining processes.