Dong il Shimadzu Corporation
Dong il Shimadzu Corporation
Kim W.-G.,Hanyang University |
Yong S.-D.,Hanyang University |
Yook S.-J.,Hanyang University |
Ji J.H.,EcoPictures Co. |
And 4 more authors.
Carbon | Year: 2017
Elemental carbon (EC) can cause lung cancer or inflammation. Therefore, the objective of this study is to identify the possibility of real-time estimation of the EC concentration of multi-walled carbon nanotubes (MWCNTs) for workplace emission assessment. MWCNT aerosol particles were generated at a relatively constant rate over a period of 24 h, and the aerosolized MWCNTs were generally smaller than 1 μm. On-line measurement was performed by using an aethalometer and a scanning mobility particle sizer (SMPS) to determine black carbon (BC) concentration and particle mass concentration of the MWCNTs, respectively. Off-line analysis was conducted according to the National Institute for Occupational Safety and Health (NIOSH) method 5040 to obtain EC concentration of the MWCNTs. Then, correlations among the BC concentration, particle mass concentration, and EC concentration were investigated for the MWCNT particles. The particle number concentration converted from the SMPS measurement data and the BC concentration measured by the aethalometer were found to be in linear relation with the filter-sampling-based EC concentration, when the EC concentration of the MWCNTs was determined by the NIOSH method 5040. It is therefore anticipated that the use of the aethalometer and the SMPS can be of great help to the MWCNT emission assessment. © 2017 Elsevier Ltd
Park K.M.,Seoul National University |
Moon J.H.,Korea Research Institute of Bioscience and Biotechnology |
Kim J.H.,Dong il Shimadzu Corporation |
Song U.T.,Dong il Shimadzu Corporation |
And 3 more authors.
Rapid Communications in Mass Spectrometry | Year: 2016
Rationale In analyte profiling by matrix-assisted laser desorption/ionization (MALDI), drawing a quantitative profile map is an outstanding problem. Recently, we developed a method to quantify an analyte by MALDI, which is needed to solve the problem. Another requirement for quantitative profiling is the quantitative sample-to-matrix analyte transfer, which is investigated in this work. Methods MALDI-time-of-flight (TOF) spectra were acquired for samples produced by two methods. In one, a sample solution containing a matrix and an analyte was loaded with a pipet and dried. In the other, a sample was prepared by a consecutive process, i.e., loading-drying of an analyte solution followed by that of a matrix solution. Two different micro-spotters were used in the second method. Various mixtures of organic solvents with water were used to prepare matrix solutions. Results The organic solvent, matrix, and analyte used in the study did not affect the analyte transfer efficiency, whereas it improved as the water content in the solvent increased. It also improved as the liquid droplet emitted by a micro-spotter got larger. Use of a more polar solvent or a larger droplet increases the contact time between a solution droplet and the sample surface, which seems to be responsible for the improvement in the transfer efficiency. Conclusions Sample-to-matrix analyte transfer occurred efficiently when polar solvents and/or large liquid droplets were used to produce solid samples for MALDI profiling with a micro-spotter. A long contact time between the sample surface and a matrix solution droplet is one of the requirements for quantitative profiling. Copyright © 2015 John Wiley & Sons, Ltd.
Shin S.,Chungnam National University |
Yang H.-J.,Chungnam National University |
Kim J.-H.,Dong il Shimadzu Corporation |
Kim J.,Chungnam National University |
And 3 more authors.
Journal of Mass Spectrometry | Year: 2012
A peptide peak at m/z 1634 in the mass spectrum of tryptically digested cytochrome c has been ambiguously assigned to either a peptide IFVQKCAQCHTVEK or a peptide CAQCHTVEK combined with a heme group (CAQCHTVEK + heme (Fe(III))). A comprehensive investigation was performed to clearly identify the origin of the peak. Tryptic digests of cytochrome c were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), liquid chromatography-tandem MS (LC-MS/MS), LC-ultraviolet (LC-UV), and MALDI Fourier transform-ion cyclotron resonance (FT-ICR) MS. The use of instruments with extremely high mass accuracy revealed the mass difference between the IFVQKCAQCHTVEK and the (CAQCHTVEK + heme (Fe(III))) ions. Fragmentation of the peptide associated with the unknown peak yielded a heme ion and other fragment ions originating from a (CAQCHTVEK + heme (Fe(III))) ion. Furthermore, an absorption peak at 395 nm confirmed the presence of a heme group in the unknown peptide. High mass accuracy analyses of MS and MS/MS spectra, in addition to three-dimensional UV contour mapping, showed that the peak at m/z 1634 is due to a (CAQCHTVEK + heme (Fe(III))) ion and not from protonated IFVQKCAQCHTVEK. © 2012 John Wiley & Sons, Ltd.
Kim B.,Korea Research Institute of Standards and Science |
Park S.,Korea Research Institute of Standards and Science |
Park S.,CJ Corporation |
Lee I.,Korea Research Institute of Standards and Science |
And 4 more authors.
Analytical and Bioanalytical Chemistry | Year: 2010
A certified reference material (CRM), KRISS CRM 108-10-003, has been developed for analysis of acrylamide in potato chips, as a representative of carbohydrate-rich food cooked in high-temperature oil. The material was prepared by grinding commercially available potato chips to a paste which was then homogenized, bottled in 15-g units, and stored at -70 °C. Certification, homogeneity and stability testing, were carried out by liquid chromatography-isotope-dilution mass spectrometry (ID-LC-MS). A single ID-LC-MS measurement was performed for each of 10 selected units for certification and homogeneity assessment. The mean measurement result for the 10 bottles, 0.455∈±∈0.012 mg∈kg-1, was assigned as the certified value of the CRM. The between-bottle homogeneity was 0.8% of the certified value. The within-bottle homogeneity, tested by measuring three replicate sub-samples from each of three randomly selected bottles, was similar to the between-bottle homogeneity. The stability of the CRM under storage conditions (-70 °C) was tested for 21 months and no change in the acrylamide content was observed within the measurement uncertainty. Stability of the CRM at -20 °C (storage at user's site) and room temperature (for regular use and transportation) was also tested. Also presented is the newly designed procedure for evaluating the uncertainty of the certified value for the characterization scheme used in this study. [Figure not available: see fulltext.] © 2010 Springer-Verlag.
Sajjad R.U.,Myongji University |
Kim K.J.,Dong il Shimadzu Corporation |
Memon S.,Myongji University |
Sukhbaatar C.,Myongji University |
And 3 more authors.
Water Environment Research | Year: 2015
The monitoring of stormwater runoff from Light Rail Transit (LRT) facilities is insufficient in many regions around the world. In this study, runoff quality and quantity were monitored during operational and non-operational LRT phases during 2010-2013. The event mean concentration (EMC) of pollutants showed little statistical variability during both phases. The antecedent dry day (ADD) showed a strong to moderate positive correlation with most pollutant EMCs during the non-operational phase. The existence and magnitude of the first flush from LRT runoff was found to be similar to those from other transportation land uses. The comparison of LRT runoff data with an adjacent road bridge site showed that the pollutant EMC and unit load were 2 to 9 times higher from the road bridge. It was suggested that LRT automated operation and the elevated track makes this transportation mode a viable option for the management of non-point source pollution.
Hong Y.,Dongil SHIMADZU Corporation |
Lee S.,Dongil SHIMADZU Corporation |
Kim H.-A.,Catholic University of Korea |
Hwang Y.-K.,Catholic University of Korea
Journal of Applied Biological Chemistry | Year: 2010
This paper describes a simultaneous method for the determination of two aminoglycosides (neomy-cin and gentamicin) using solid phase extraction followed by liquid chromatograph-mass spectrom-etry. The extract was applied to an WCX and HLB solid phase extraction cartridge. The cartridges were washed with water and methanol, and analytes were eluted with TCA buffer-acetonitrile mixture. The aminoglycosides were separated by ion-pairing reversed phase mode prior to ESI-LC/ MS. Under the conditions applied neomycin was almost separated from all the gentamicin compounds. No interfering peaks from endogenous compounds of matrix were noted at the elution position of the analytes. Recoveries of neomycin fortified at levels of 0.25, 0.5, 1.0 and 2.0 mg/kg seafood samples ranged from 92 to 115%. Recoveries of gentamycin fortified at levels of 0.05, 0.1, 0.2, 0.4 mg/kg seafood samples ranged from 99 to 116%. Method detection limits in four seafood sample matrices were between 0.002 and 0.033 mg/kg.
PubMed | Dong il Shimadzu Corporation and Korea Institute of Science and Technology
Type: Journal Article | Journal: Analytical chemistry | Year: 2016
Sulfated steroids can act as a latent form of active free steroids, coexisting with them in biological specimens. To evaluate the metabolic significance of free and sulfated steroid species, a simultaneous analysis of eight free steroids [cholesterol, pregnenolone, 17-hydroxypregnenolone, progesterone, 17-hydroxyprogesterone, dehydroepiandrosterone (DHEA), testosterone, and 17-estradiol] and four biologically relevant sulfated steroids was developed and validated, using selected-ion and multiple-reaction monitoring modes coupled to polarity-switching liquid chromatography/mass spectrometry (LC/MS). All steroids were separated on a reversed-phase phenyl column (50 mm 2 mm, 3 m) at a flow rate of 0.5 mL/min. The limits of quantification ranged from 0.1 to 50 ng/mL at extraction recoveries of 94.1-105.5%, while the precision and accuracy were 2.5-9.3% and 92.4-105.9%, respectively. Quantitative results obtained for samples from obese girls showed that the serum levels of DHEA sulfate were significantly increased (P = 0.004), along with the metabolic ratio representing DHEA sulfotransferase (P < 0.02). The developed novel LC/MS method can quantitatively profile both free and sulfated steroids in a single analytical run.
PubMed | Korea University, Eulji University, Duksung Womens University, Konkuk University and 2 more.
Type: Journal Article | Journal: Viruses | Year: 2016
Influenza is a serious public health concern worldwide, as it causes significant morbidity and mortality. The emergence of drug-resistant viral strains requires new approaches for the treatment of influenza. In this study, Rubus coreanus seed (RCS) that is left over from the production of wine or juice was found to show antiviral activities against influenza type A and B viruses. Using the time-of-addition plaque assay, viral replication was almost completely abolished by simultaneous treatment with the RCS fraction of less than a 1-kDa molecular weight (RCSF1). One of the polyphenols derived from RCSF1, gallic acid (GA), identified by liquid chromatography-tandem mass spectrometry, showed inhibitory effects against both influenza type A and B viruses, albeit at relatively high concentrations. RCSF1 was bound to hemagglutinin protein, inhibited hemagglutination significantly and disrupted viral particles, whereas GA was found to only disrupt the viral particles by using transmission electron microscopy. In BALB/c mice infected with influenza virus, oral administration of RCSF1 significantly improved the survival rate and reduced the viral titers in the lungs. Our results demonstrate that RCSF1 and GA show potent and broad antiviral activity against influenza A and B type viruses and are promising sources of agents that target virus particles.
PubMed | Dong il Shimadzu Corporation, Korea Research Institute of Bioscience and Biotechnology and Seoul National University
Type: Journal Article | Journal: Rapid communications in mass spectrometry : RCM | Year: 2016
In analyte profiling by matrix-assisted laser desorption/ionization (MALDI), drawing a quantitative profile map is an outstanding problem. Recently, we developed a method to quantify an analyte by MALDI, which is needed to solve the problem. Another requirement for quantitative profiling is the quantitative sample-to-matrix analyte transfer, which is investigated in this work.MALDI-time-of-flight (TOF) spectra were acquired for samples produced by two methods. In one, a sample solution containing a matrix and an analyte was loaded with a pipet and dried. In the other, a sample was prepared by a consecutive process, i.e., loading-drying of an analyte solution followed by that of a matrix solution. Two different micro-spotters were used in the second method. Various mixtures of organic solvents with water were used to prepare matrix solutions.The organic solvent, matrix, and analyte used in the study did not affect the analyte transfer efficiency, whereas it improved as the water content in the solvent increased. It also improved as the liquid droplet emitted by a micro-spotter got larger. Use of a more polar solvent or a larger droplet increases the contact time between a solution droplet and the sample surface, which seems to be responsible for the improvement in the transfer efficiency.Sample-to-matrix analyte transfer occurred efficiently when polar solvents and/or large liquid droplets were used to produce solid samples for MALDI profiling with a micro-spotter. A long contact time between the sample surface and a matrix solution droplet is one of the requirements for quantitative profiling. Copyright 2015 John Wiley & Sons, Ltd.