• Mass Spectrometry Letters
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• v.4 no.1
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• pp.21-23
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• 2013

The effects of trifluoroacetic acid (TFA) were evaluated on the generation of multiply charged ions of cytochrome c in a 2-nitrophloroglucinol (2-NPG) matrix in high-vacuum, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The presence of 1% TFA in the 2-NPG matrix solution was more effective in generating multiply charged protein ions than matrix solutions containing 0.1% or 0% TFA. Regarding the matrix itself, with 1% TFA, 2-NPG was significantly more effective in generating multiply charged ions than 2,5-dihydroxybenzoic acid (2,5-DHB). The maximum charge state of cytochrome c was +8 when using a 2-NPG matrix containing 1% TFA.

• Mass Spectrometry Letters
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• v.3 no.3
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• pp.63-67
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• 2012

The need of heavy and unconventional crude oil as an energy source is increasing day by day, so does the importance of petroleomics: the pursuit of detailed knowledge of heavy crude oil. Crude oil needs techniques with ultra-high resolving capabilities to resolve its complex characteristics. Therefore, ultra-high resolution mass spectrometry represented by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has been successfully applied to the study of heavy and unconventional crude oils. The analysis of crude oil with high resolution mass spectrometry (FT-ICR MS) has pushed analysis to the limits of instrumental and methodological capabilities. Each high-resolution mass spectrum of crude oil may routinely contain over 50,000 peaks. To visualize and effectively study the large amount of data sets is not trivial. Therefore, data processing and visualization methods such as Kendrick mass defect and van Krevelen analyses and statistical analyses have played an important role. In this regard, it will not be an overstatement to say that the success of FT-ICR MS to the study of crude oil has been critically dependent on data processing methods. Therefore, this review offers introduction to peotroleomic data interpretation methods.

• Mass Spectrometry Letters
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• v.9 no.1
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• pp.1-16
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• 2018

Microfluidic technologies hold high promise and emerge as a potential molecular tool to facilitate the progress of fundamental and applied biomedical researches by enabling miniaturization and upgrading current biological research tools. In this review, we summarize the state of the art of existing microfluidic technologies and its' application for characterizing biophysical properties of individual cells. Microfluidic devices offer significant advantages and ability to handle in integrating sample processes, minimizing sample and reagent volumes, and increased analysis speed. Therefore, we first present the basic concepts and summarize several achievements in new coupling between microfluidic devices and mass spectrometers. Secondly, we discuss the recent applications of microfluidic chips in various biological research field including cellular and molecular level. Finally, we present the current challenge of microfluidic technologies and future perspective in this study field.

• Bulletin of the Korean Chemical Society
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• v.16 no.7
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• pp.578-582
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• 1995

The resonance ionization mass spectrometry (RIMS) system with angular reflectron type time-of-flight mass spectrometer (AREF-TOFMS) has been developed and characterized. The system is applied for the ultratrace determination of Pb element. The 2-color 3-photon laser ionization scheme is adopted for the study and the mass resolution of the system is determined as T/ΔT=1680. The calibration curve for Pb is obtained in the range of 100 ppb to 0.01 ppb by using standard solutions. The minimal amount of detection for the present RIMS system is determined as less than 100 femtograms (10-13 gram).

• Mass Spectrometry Letters
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• v.4 no.2
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• pp.38-40
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• 2013

Glycans released from ovalbumin by PNGase F were analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry using three different dihydroxybenzoic acid (DHB) matrix systems: 2,5-DHB, 2,6-DHB, and a 2,5-DHB/2,6-DHB binary matrix. Relative to the results obtained with the single-component matrices (2,5-DHB or 2,6-DHB), the 2,5-DHB/2,6-DHB binary matrix boasted lower background noise and higher sensitivity. A total of 16 glycan peaks were observed using the 2,5-DHB/2,6-DHB binary matrix, while only 10 and 9 glycan peaks were observed using the 2,5-DHB and 2,6-DHB matrices, respectively.

• Mass Spectrometry Letters
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• v.9 no.2
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• pp.56-60
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• 2018

In this study, matrix-assisted laser desorption/ionization (MALDI) was applied to the TEMPO-assisted FRIPS for the first time. We found that 3-HPA is the optimal matrix for the analysis of p-TEMPO-Bz-Sc-peptides, which gives minimal precursor fragmentations. MALDI-TOF/TOF experiments on p-TEMPO-Bz-Sc-peptides yielded mainly $[a_n+H]^+$, $[z_n+H]^+$, and $[y_n]^+-type$ products, indicating that radical-driven peptide fragmentation occurs in MALDI-TOF/TOF-MS.

• Mass Spectrometry Letters
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• v.10 no.3
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• pp.71-78
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• 2019

For several decades, cancer has been the primary cause of mortality worldwide. New diagnosis and regimens have been developed to improve the chemotherapeutic efficacy and the quality of life of the patients. However, cancer tissues are complex and difficult to assess. Understanding the various properties of the tumor and its environment is crucial for cancer and pharmaceutical research. Several analytical techniques have been providing new insights into cancer research. Recently, matrix-assisted laser desorption ionization (MALDI)-mass spectrometry imaging (MSI), an advanced analytical technique, has been applied to translational research. Proteomic and lipidomic profiling obtained by MALDI-MSI has been critical for biomarker discovery and for monitoring heterogenous tumor tissues. In this review, we discuss technical approaches, benefits and recent applications of MALDI-MSI as a valuable tool in cancer research, namely for diagnosis, therapy, prognosis.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.4
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• pp.244-252
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• 2023

The timeliness and accuracy of test results are crucial factors for clinicians to decide and promptly administer effective and targeted antimicrobial therapy, especially in life-threatening infections or when vital organs and functions, such as sight, are at risk. Further research is needed to refine and optimize matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based assays to obtain accurate and reliable results in the shortest time possible. MALDI-TOF MS-based bacterial identification focuses primarily on techniques for isolating and purifying pathogens from clinical samples, the expansion of spectral libraries, and the upgrading of software. As technology advances, many MALDI-based microbial identification databases and systems have been licensed and put into clinical use. Nevertheless, it is still necessary to develop MALDI-TOF MS-based antimicrobial-resistance analysis for comprehensive clinical microbiology characterization. The important applications of MALDI-TOF MS in clinical research include specific application categories, common analytes, main methods, limitations, and solutions. In order to utilize clinical microbiology laboratories, it is essential to secure expertise through education and training of clinical laboratory scientists, and database construction and experience must be maximized. In the future, MALDI-TOF mass spectrometry is expected to be applied in various fields through the use of more powerful databases.

• Mass Spectrometry Letters
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• v.2 no.2
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• pp.53-56
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• 2011

[ $C_8$ ]functionalized magnetic nanoparticles were synthesized by coating magnetic $Fe_3O_4$ nanoparticles with silicaamine groups using 3-aminopropyltriethoxysilane and by subsequently modifying the amine groups with chloro(dimethyl)octylsilane to produce octyl groups on the surface of the MNPs. The $C_8$-functionalized MNPs were used to enrich peptides from tryptic protein digests of myoglobin and ${\alpha}$-casein. The enriched peptides were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). MALDI-MS was also used to investigate desalting of the $C_8$-functionalized MNPs. Sample solutions were prepared in 1.0 M NaCl, and the successful removal of salt was observed. Enrichment with $C_8$-functionalized MNPs was very effective for separating and concentrating tryptic peptides.

• Analytical Science and Technology
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• v.15 no.1
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• pp.7-14
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• 2002

Laser ablation ion trap mass spectrometry (LAITMS) was developed for the analysis of metal and ceramic samples. For this study, XeCl excimer laser (308 nm) was used for ablating the samples and ITMS was used as a detector. Samples were introduced from outside of a ring electrode and this way of sample introduction was very effective for solid samples when laser ablation was employed. Helium gas was used as a buffer gas, and its effect on sensitivity and some parameters (buffer gas pressure, ion storage time, and cut-off RF voltage) were studied. The optimized conditions were $1{\times}10^{-4}$ Torr of buffer gas pressure, 100 ms of ion storage time and $1150V_{p-p}$ of cut-off RF voltage. From that results, copper (Cu) and molybdenum (Mo) metals were tested with LAITMS and the mass spectra of these pure metals were compared with the natural abundance of isotope ratio. We also examined ceramic samples ($Al_2O_3$, $ZrO_2$) and represented the result of elemental analysis.