• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.1109-1112
• /
• 2003

Information technology has enabled mass standards calibration to be performed through internet. For this, an automatic weight handler was manufactured. During the operation the images of weight operation and the system are provided via the measurement system and a web server. The measurement system consists of a balance, a weight handler, instruments for environment measurement and a PC. The weight handler automatically loads and unloads weights on and from the weighing pan. The weight handler allows 6 series weights to be operated for weight calibration of 100-50-20-20-10-10 gram series weight. This capability could be used for "remote training" for series weight calibration.

• Mass Spectrometry Letters
• /
• 제4권4호
• /
• pp.83-86
• /
• 2013

A new interface for coupling CIEF and MS using a four-way cross has been developed in a single mechanical system. This new interface could be operated without the electric discontinuity and reinstallation of lines. Additionally, a bare fused silica capillary was facilitated as a spray needle to produce electrospray and to guide catholyte or sheath liquid. Focusing for CIEF was completed in a hanging droplet at the end of spray needle. This capillary spray needle also provided stable spray, enhanced the ionization efficiency and increased sensitivity. Results with carbonic anhydrase I showed that focusing and spraying were well completed with the new interface and the new spray needle.

• 한국유전체학회:학술대회논문집
• /
• 한국유전체학회 2005년도 The 14th Korea Genome Conference
• /
• pp.71-71
• /
• 2005

• Bulletin of the Korean Chemical Society
• /
• 제35권10호
• /
• pp.3103-3106
• /
• 2014

• Mass Spectrometry Letters
• /
• 제1권1호
• /
• pp.1-4
• /
• 2010

• 분석과학
• /
• 제16권1호
• /
• pp.82-89
• /
• 2003

Isotope dilution mass spectrometry (IDMS) was applied to the determination of Ni, Cr, Mo in low alloy steel reference materials. The Mo isotope ratio measurement was performed by dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP/MS) using ammonia as a reaction cell gas. In the case of Ni and Cr measurement, all data were obtained at medium resolution mode (m/${\Delta}m=3000$) of double focusing sector field high resolution inductively coupled plasma mass spectrometry (HR-ICP/MS). For the method validation of the technique was assessed using the certified reference materials such as NIST SRM 361, NIST SRM 362, NIST SRM 363, NIST SRM 364, NIST SRM 36b. This method was applied to the determination of Ni, Cr and Mo in low alloy steel sample (CCQM-P25) provided by NMIJ for international comparison study.

• Mass Spectrometry Letters
• /
• 제2권2호
• /
• pp.37-40
• /
• 2011

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, $^{13}C_1$-sodium saccharin, by customized synthesis. Samples were spiked with $^{13}C_1$-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 $C_{18}$ 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.

• Bulletin of the Korean Chemical Society
• /
• 제34권1호
• /
• pp.207-210
• /
• 2013

We report the construction of a MALDI imaging mass spectrometer equipped with a specially designed laser focusing lens, a compact aspherical singlet lens, that obtains a high-lateral imaging resolution in the microprobe mode. The lens is specially designed to focus the ionization laser (${\lambda}$ = 355 nm) down to a $1{\mu}m$ diameter with a long working distance of 34.5 mm. With the lens being perpendicular to the sample surface and sharing the optical axis with the ion path, the imaging mass spectrometer achieved an imaging resolution of as good as $5{\mu}m$ along with a high detection sensitivity of 100 fmol for peptides. The mass resolution was about 900 (m/${\Delta}m$) in the linear TOF mode. The high-resolution capability of this instrument will provide a new research opportunity for label-free imaging studies of various samples including tissues and biochips, even for the study at a single cell level in the future.

• Mass Spectrometry Letters
• /
• 제5권2호
• /
• pp.57-61
• /
• 2014

A gravimetric standard addition method combined with internal standard calibration has been successfully developed for the accurate analysis of total arsenic in a laver candidate reference material. A model equation for the gravimetric standard addition approach using an internal standard was derived to determine arsenic content in samples. Handlings of samples, As standard and internal standard were carried out gravimetrically to avoid larger uncertainty and variability involved in the volumetric preparation. Germanium was selected as the internal standard because of its close mass to the arsenic to minimize mass-dependent bias in mass spectrometer. The ion signal ratios of $^{75}As^+$ to $^{72}Ge^+$ (or $^{73}Ge^+$) were measured in high resolution mode ($R{\geq}10,000$) to separate potential isobaric interferences by high resolution ICP/MS. For method validation, the developed method was applied to the analysis of arsenic content in the NMIJ 7402-a codfish certified reference material (CRM) and the result was $37.07mg{\cdot}kg^{-1}{\pm}0.45mg{\cdot}kg^{-1}$ which is in good agreement with the certified value, $36.7mg{\cdot}kg^{-1}{\pm}1.8mg{\cdot}kg^{-1}$. Finally, the certified value of the total arsenic in the candidate laver CRM was determined to be $47.15mg{\cdot}kg^{-1}{\pm}1.32mg{\cdot}kg^{-1}$ (k = 2.8 for 95% confidence level) which is an excellent result for arsenic measurement with only 2.8 % of relative expanded uncertainty.

• 대한방사선방어학회:학술대회논문집
• /
• 대한방사선방어학회 2009년도 춘계 학술발표
• /
• pp.234-235
• /
• 2009