• 분석과학
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• 제22권2호
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• pp.152-158
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• 2009

본 연구에서는 유기화합물의 효과적인 소프트 이온화를 위하여 기존의 SPI장치를 개선한 새로운 형태의 방전 장치를 제작하였다. 새로 제작된 소프트 플라스마 이온화 장치는 반 원통 형태의 메쉬 음극과 속빈 원통 형태의 양극으로 구성하였다. 이온화원으로 사용하기에 앞서, 특정압력에서 전극간격에 따른 전압 전류 특성곡선을 조사하여 장치의 구성을 최적화 하였으며, 그 결과 넓은 전압 전류 영역에서 안정한 플라스마를 생성하는 조건을 결정하여 다양한 이온화 패턴을 기대 할 수 있게 하였다. 최적화된 이온화장치를 사중극자 질량분석기와 연결하여 디클로로메탄의 질량 스펙트럼을 관찰하였고, 분석결과 디클로로메탄은 전자충격이온화에 의한 분리 패턴과 비슷하게 나타나는 것을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1221-1227
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• 2011

Ethyl pyruvate (EP) is known as a scavenger of reactive oxygen species (ROS) in the body through its role in the donation of diketone groups to metals to form an EP-metal complex. In order to develop a method for the quantification of EP in biological media, a sensitive and specific, high-performance liquid chromatographyelectrospray ionization-mass spectrometry (HPLC-ESI/MS) method is used to determine the EP-alkali metal ion binding species. The analyte was separated on a ZORBOX SB-C8 ($3.5{\mu}m$, $30mm{\times}2.1mm$ I.D.) column and analyzed in selected ion monitoring (SIM) mode with a positive ESI interface using the m/z 255 $[2M + Na]^+$ ion. The method was validated over the concentration range of $0.5-60.0\;{\mu}g$/mL under 1/9 (v/v) of acetonitrile/methanol solvent system with flow rate 0.05 mL/min. The limit of quantification (LOQ) was $0.5{\mu}g$/mL.

• Mass Spectrometry Letters
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• 제2권3호
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• pp.65-68
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• 2011

The effects of column length and particle size on the efficiency of separation and characterization of phospholipids (PLs) are investigated using nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry (nLC-ESI-MS-MS). Since PLs are associated with cell proliferation, apoptosis, and signal transduction, it is of increasing interests in lipidomics to establish reliable analytical methods for the qualitative and quantitative profiling of PLs related to biomarker development in adult diseases. Due to the complexity of PLs, the preliminary separation of PLs is necessary prior to MS analysis. In this study, length of capillary column and the particle size of reversed phase ($C_{18}$) packing materials are varied to find a reliable condition for the high speed and high resolution separation using 8 PL standard mixtures. From experiments, it was found that a capillary column of nLC-ESI-MS-MS analysis for PL mixtures can be minimized to a 5 cm long pulled tip column packed with 3 ${\mu}m$ $C_{18}$ particles without losing resolution.

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.2143-2147
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• 2013

Matrix assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is a very effective method for lipid mass fingerprinting. However, MALDI MS suffered from spectral complexities, differential ionization efficiencies, and poor reproducibility when analyzing complex lipid mixtures without prior separation steps. Here, we aimed to find optimal MALDI sample preparation methods which enable selective or class-wide mass fingerprinting of two totally different lipid classes. In order to achieve this, various matrices with additives were tested against the mixture of phosphatidylcholine (PC) and cerebrosides (Cers) which are abundant in animal brain tissues and also of great interests in disease biology. Our results showed that, from complex lipid mixtures, 2,4,6-trihydroxyacetophenone (THAP) with $NaNO_3$ was a useful MALDI matrix for the class-wide fingerprinting of PC and Cers. In contrast, THAP efficiently generated PC-focused profiles and graphene oxide (GO) with $NaNO_3$ provided Cer-only profiles with reduced spectral complexity.

• Mass Spectrometry Letters
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• 제11권3호
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• pp.41-51
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• 2020

Microbes influence many aspects of human life from the environment to health, yet evaluating their biological processes at the chemical level can be problematic. Mass spectrometry imaging (MSI) enables direct evaluation of microbial chemical processes at the atomic to molecular levels without destruction of valuable two-dimensional information. MSI is a label-free method that allows multiplex spatiotemporal visualization of atomic- or molecular-level information of microbial and microberelated samples. As a result, microbial MSI has become an important field for both mass spectrometrists and microbiologists. In this review, basic techniques for microbial MSI, such as ionization methods and analyzers, are explored. In addition, we discuss practical applications of microbial MSI and various data-processing techniques.

• Mass Spectrometry Letters
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• 제9권3호
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• pp.77-80
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• 2018

The focus of this paper is to present techniques to overcome certain difficulties in quantitative analysis with a time-of-flight mass spectrometer (TOF-MS). The method is based on conventional solid-phase extraction, followed by reversed-phase ultra high performance liquid chromatography of the extract, and mass spectrometric analysis. The target compounds included atenolol, atrazine, caffeine, carbamazepine, diclofenac, estrone, ibuprofen, naproxen, simazine, sucralose, sulfamethoxazole, and triclosan. The matrix effects caused by high concentrations of organic compounds in wastewater are especially significant in electrospray ionization mass spectroscopy. Internal-standard calibration with isotopically labeled standards corrects the results for many matrix effects, but some peculiarities were observed. The problems encountered in quantitation of carbamazepine and triclosan, due to nonlinear calibration were solved by changing the internal standard and using a narrower mass window. With simazine, the use of a quadratic calibration curve was the best solution.

• 대한임상검사과학회지
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• 제55권4호
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• pp.244-252
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• 2023

검사 결과의 적시성과 정확성은 임상의가 특히 생명을 위협하는 감염이나 시력과 같은 중요한 장기 및 기능이 위험에 처한 경우, 효과적이고 표적화된 항균 요법을 결정하고 즉시 시행하는데 중요한 요소이다. 가능한 한 최단 시간 내에 정확하고 신뢰할 수 있는 결과를 얻기 위해 matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) 질량분석기기반 분석을 개선하고 최적화하기 위한 추가 연구 노력이 이루어져야 할 것이다. MALDI-TOF 질량분석기기반 세균 식별은 주로 임상 시료에서 병원체를 분리 및 정제하는 기술, 스펙트럼 라이브러리 확장 및 소프트웨어의 업그레이드에 중점을 둔다. 기술이 발전함에 따라 많은 MALDI-TOF 기반 미생물 동정 데이터베이스 및 시스템이 허가되어 임상에 사용되고 있다. 그럼에도 불구하고, 포괄적인 임상미생물의 특성화를 위해서는 MALDI-TOF 질량분석기 기반 항균제 내성 분석을 개발하는 것이 여전히 필요하다. 특정 적용 범주, 일반적인 분석물질, 주요 수행방법, 한계 및 해결점을 포함하여 임상 연구에서 MALDI-TOF의 적용이 중요하다. 임상 미생물 검사실에서 업무 활용을 위해 임상병리사들의 교육 및 훈련을 통한 전문성 확보가 필수적이며, 데이터베이스 구축과 경험을 극대화하여야 할 것이다. 향후 더 강력한 데이터베이스의 활용으로 다양한 분야에서 MALDI-TOF 질량분석기가 적용될 것으로 보인다.

• Mass Spectrometry Letters
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• 제14권3호
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• pp.104-109
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• 2023

Anabolic-androgenic steroids (AAS) are used illegally to enhance muscle development and increase strength and power. In this study, a reliable, and sensitive quantitative method was developed and validated using heptafluorobutyric acid anhydride (HFPA) derivatives for the simultaneous detection of prohibited AAS (testosterone [TS], boldenone [BD], 5α-estrane-3β,17α-diol [EAD]) using gas chromatography-tandem mass spectrometry (GC-MS/MS). For processing the samples, solid phase extraction, methanolic hydrolysis, and liquid-liquid extraction were used. For detection using mass spectrometry, the multiple reaction monitoring (MRM) mode was used with the electron ionization (EI) positive mode. The method was evaluated for selectivity, linearity, lower limit of quantification, intra- and inter-day precision, accuracy, and stability. The results showed that the method was accurate and reproducible for the quantitation of the three steroids. The developed method was finally applied to the analysis of a suspect gelding urine sample received from the Asian Quality Assurance Program (AQAP).

• 세라미스트
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• 제21권3호
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• pp.249-269
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• 2018

In conventional MALDI-TOF mass spectrometry, analyte molecules are known to be ionized by mixing with organic matrix molecules. As the organic matrix molecules are made into small fragments, they generate unreproducible mass peaks such that MALDI-TOF mass spectrometry is nearly impossible in the low mass-to-charge (m/z) range (< 1000). Additionally, the dried sample mixed with matrix were made as inhomogeneous crystal on metal plate. When the laser radiation was made on the sample crystal, the amount of generated sample ion was observed to be quite different according to the radiation point. Therefore, the quantitative analysis was very difficult even for the sample spots at the same concentration for the conventional MALDI-TOF mass spectrometry. In this work, we present laser desorption/ionization (LDI) mass spectrometry based on solid-matrices for the quantitative analysis of small molecules in the low m/z range by using MALDI-TOF mass spectrometry: (1) Carbon based nanostructures; (2) Semiconductor based nanomaterials; (3) Metal based nanostructures.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2383-2385
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• 2010