• 농약과학회지
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• 제19권1호
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• pp.1-4
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• 2015

잔류성 유기오염물질인 과불화합물 중 perfluorooctanesufonic acid (PFOS)와 perfluorooctanoic acid (PFOA)의 잔류분석은 환경부 "잔류성 유기오염물질 공정시험기준"에 따라 hydrophilic-lipophilic balance (HLB) solid phase extraction (SPE) 전처리 후 LC-$MS^n$를 이용해 정량 분석하고 있다. 본 연구에서는 환경부 설정 공정시험법에 따라 농업용수 전처리 후, 시험법에서 제거하지 못한 미지의 불순물을 Envi-Carb$^{TM}$을 통해 회수율에 영향을 주지 않고 손쉽게 제거하였다. 또한, 과불화합물 분석에 사용되는 LC-$MS^n$ 중 quadrupole-time-of-flight mass spectrometry (qTOFMS)에서 측정된 PFCs의 정량한계를 평가한 결과, 시험에 사용된 장비간 정량한계 편차가 크게 관찰되었으나, 시험대상 장비 모두 농업용수 중 ng/L 수준으로 잔류하는 과불화합물의 정밀 잔류분석에 사용가능 한 것으로 확인되었다.

• 한국환경과학회지
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• 제24권12호
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• pp.1569-1582
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• 2015

The analytical method for 16 organophosphorus pesticides was developed in this study. The 16 organophosphorus pesticides were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS) using on-line solid phase extraction (on-line SPE) with PLRP- S cartridge. Analysis of all analytes in the MS/MS was processed in the electrospray ioni-zation (ESI) positive mode. They are Azinphos ethyl, Chlorfenvinphos, Ethion, Famphur, Phosmet, Phosphamidon, Terbufos, Aspon, Chlorpyrifos-methyl, Crotoxyphos, Dichlofenthi-on, Dicrotophos, Fonofos, Thionazin, Dimethoate and Iprobenfos. Limits of detection (LODs) and Limits of quantification(LOQs) were obtained as 0.8~2.0 ng/L and 2.6~6.4 ng/L, respectively. All compounds were not detected at the 8 sampling points of the raw water and clean water.

• Bulletin of the Korean Chemical Society
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• 제26권5호
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• pp.740-746
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• 2005

In this article, we report the tandem mass spectrometry investigations for the electron capture efficiencies of the protons belonging to the different locations (generations) in a poly(propylene imine) dendrimer with three layers of a repeat unit (named as the third generation dendrimer). The employed tandem mass spectrometry methods include SORI-CAD (sustained off-resonance irradiation collisional activation dissociation) and ECD(electron capture dissociation) mass spectrometry. We obtained SORI-CAD spectra for the dendrimer ions in the different charge states, ranging from 2+ to 4+. The analysis of fragmentation sites provides the information as to where the protons are distributed among various generations of the dendrimer. Based upon this, a new strategy to study the electron capture efficiencies of the protons is utilized to examine a new type of triplycharged ions by SORI-CAD, i.e., the 3+ ions generated from the charge reduction of the native 4+ ions by ECD: (M+4H)$^{4+}\;+\;e^-\;{\rightarrow}$ (M+4H)$^{3+\bullet}$ ${\rightarrow}\;({H^{\bullet}}_{ejected}$) + (M+3H)$^{3+}\;\rightarrow$ CAD. Interestingly, comparison of these four SORICAD spectra indicates that the proton distribution in the charge-reduced 3+ ions is very close to that in the native 4+ ions. It further suggests that in this synthetic polymer ($\sim$1.7 kDa) with an artificial architecture, the electron capture efficiencies of the protons are actually insensitive to where they are located in the molecule. This is somewhat contradictory to common expectations that the protons in the inner generations may not be well exposed to the incoming electron irradiation as much as the outer ones are, thus may be less efficient for electron capture. This finding may carry some implications for the case of medium sized peptide ions with similar masses, which are known to show no obvious site-specific fragmentations in ECD MS.

• Mass Spectrometry Letters
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• 제5권2호
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• pp.52-56
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• 2014

Glycated hemoglobin (HbA1c) is used as an index of mean glycemia over prolonged periods. This study describes an optimization of enzyme digestion conditions for quantification of non-glycated hemoglobin (HbA0) and HbA1c as diagnostic markers of diabetes mellitus. Both HbA0 and HbA1c were quantitatively determined followed by enzyme digestion using isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) with synthesized N-terminal hexapeptides as standards and synthesized isotope labeled hexapeptides as internal standards. Prior to quantification, each peptide was additionally quantified by amino acid composition analysis using ID-LC-MS/MS via acid hydrolysis. Each parameter was considered strictly as a means to improve digestion efficiency and repeatability. Digestion of hemoglobin was optimized when using 100 mM ammonium acetate (pH 4.2) and a Glu-C-to-HbA1c ratio of 1:50 at $37^{\circ}C$ for 20 h. Quantification was satisfactorily reproducible with a 2.6% relative standard deviation. These conditions were recommended for a primary reference method of HbA1c quantification and for the certification of HbA1c reference material.

• KSBB Journal
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• 제22권4호
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• pp.234-238
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• 2007

본 연구에서는 전극분무 이온화-이온 포획 질량 분석기를 이용하여 인체 IgG의 N-연결 글라이칸 중 이중촉각 구조를 가지면서 비환원 말단의 갈락토오즈 개수가 0, 1, 2 개인 서로 다른 세 가지 글라이칸의 단일 쪼개짐 (MS/MS) 및 다중 쪼개짐 현상을 관찰하고 이를 구조 분석에 이용하였다. MS/MS 분석에서는 퓨코오즈가 결합된 환원 말단의 N-아세틸 글루코사민의 0,2-고리 쪼개짐으로 파생되는 조각 피크가 가장 높은 세기로 나타나는 것을 관찰할 수 있었고, 전구체 피크와 별개로 연속적인 당 단위체의 쪼개짐이 일어나는 것을 알 수 있었다. 또한 G1 글라이칸의 경우에서만 비환원 말단의 갈락토오즈와 N-아세틸글루코사민이 결합된 채 쪼개지는 현상이 일어나는 것을 관찰할 수 있었다. 다중 쪼개짐 질량 분석 기법을 이용하여 MS/MS 스펙트럼에서 나타나는 조각 피크들의 구조를 재확인할 수 있었고, 이를 트리 구조로 정리할 수 있었다. 또한 추가적인 2,4-고리 쪼개짐 현상이 환원 말단 하나 바깥쪽의 N-아세틸 글루코사민에서 공통적으로 일어나는 것을 관찰할 수 있었다. 이와 같은 다중 쪼개짐 질량 분석기법을 이용하여 보다 복잡한 구조의 글라이칸 구조 분석에 이용될 수 있을 것으로 기대된다.

• Mass Spectrometry Letters
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• 제5권4호
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• pp.115-119
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• 2014

The Brazil nut (Bertholletia excelsa - Lecythidaceae) is considered a product with high economic value, being a food widely appreciated for its nutritional qualities. Although previous studies have reported the biochemical composition of Brazil nut oil, the knowledge regarding the phospholipid composition exhibits a disagreement: the composition of fatty acids present in the structures of phospholipids is reported as being different from the composition of the free fatty acids present in the oil. In this work, solid phase extraction (SPE) was employed to provide a fast extraction of the phospholipids from Brazil nuts, in order to compare the phospholipid profile of the in nature nuts and their fatty acids precursor present in the oil. The major phospholipids were characterized by mass spectrometry approach. Their fragmentation pattern through direct infusion electrospray ionization ion-trap tandem mass spectrometry ($ESI-IT-MS^2$) proved to be useful to unequivocal characterization of these substances. High resolution (HR) experiments through ESI using a quadruple time of flight mass spectrometry (QTOF) system were performed to reinforce the identifications.

• Mass Spectrometry Letters
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• 제13권4호
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• pp.158-165
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• 2022

Many therapeutic class drugs such as beta-blocker, corticosteroids, NSAIDs, etc are prohibited substances in the horse racing industry. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology makes it possible to isolate drugs from interference, enables various drug analyses in complex biological samples due to its sensitive sensitivity, and has been successfully applied to doping control. In this paper, we describe a rapid and sensitive method based on solid-phase extraction (SPE) using solid phase cartridge and LC-MS/MS to screen for different class's 35 drug targets in equine plasma. Plasma samples were pretreated by SPE with the NEXUS cartridge consisted non-polar carbon resin and minimum buffer solvent. Chromatographic separation of the analytes was performed on ACQUITY HSS C18 column (2.1 × 150 mm, 1.8 ㎛). The elution gradient was conducted with 5 mM ammonium formate (pH 3.0) in distilled water and 0.1% formic acid in acetonitrile at a flow rate of 0.25 mL/min. The selected reaction monitoring (SRM) mode was used for drug screening with multiple transitions in the positive ionization mode. The specificity, limit of detection, recovery, and stability was evaluated for validation. The method was found to be sensitive and reproducible for drug screening. The method was applied to plasma sample analysis for the proficiency test from the Association of Racing Chemist.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.251.2-251.2
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• 2002

2-Methylaminoethyl- 4,4' -dimethoxy- 5, 5',6,6' -dimethylenedioxybiphenyl- 2' -carboxy- 2-carboxylate (DDB-S) is a synthetic compound derived from DDB. which is protects liver against carbon tetrachloride-, D-galactosamine-, thioacetamine-, and prednisolone- induced hepatic injury in experimental animals. We assessed the use of liquid chromatography/electrospray iontrap tandem mass spectrometry (LC/MS/MS) method to identify and quantify in vivo metabolites and to measure excretion. (omitted)

• Mass Spectrometry Letters
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• 제5권2호
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• pp.42-48
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• 2014

A specific and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry method (LC-ESI-MS/MS) was developed and validated for the simultaneous quantification of porphyrins (coproporphyrin, pentacarboxylporphyrin, hexacarboxylporphyrin, heptacarboxylporphyrin, and uroporphyrin) in human plasma and urine. Acidified plasma samples and urine samples were prepared by using liquid-liquid extraction using ethyl acetate and protein precipitation with acetonitrile, respectively. The separation was achieved onto a Synergi Fusion RP column ($150mm{\times}2.0mm$, $4{\mu}m$) with a gradient elution of mobile phase A (0.1% formic acid in 2 mmol/L ammonium acetate, v/v) and mobile phase B (20% methanol in acetonitrile, v/v) at a flow rate of $450{\mu}L$/min. Porphyrins and the internal standard (IS), coproporphyrin I-$^{15}N_4$, were detected by a tandem mass spectrometer equipped with an electrospray ion source operating in positive ion mode. Multiple reaction monitoring (MRM) transitions of the protonated precursor ions and the related product ions were optimized to increase selectivity and sensitivity. The proposed method was validated by assessing selectivity, linearity, limit of quantification (LOQ), precision, accuracy, recovery, and stability. The calibration curves were obtained in the range of 0.1-100 nmol/L and the LOQs were estimated as 0.1 nmol/L for all porphyrins. Results obtained from the validation study of porphyrins showed good accuracy, precision, recovery, and stability. Finally, the proposed method was successfully applied to clinical studies on the autism spectrum disorder (ASD) diagnosis of 203 Korean children.

• Mass Spectrometry Letters
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• 제13권4호
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• pp.95-105
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• 2022

Amatoxin-induced mushroom poisoning starts with nonspecific symptoms of toxicity but hepatic damage may follow, resulting in the rapid development of liver insufficiency and, ultimately, coma and death. Accurate detection of amatoxins, such as α-, β-, and γ-amanitin, within the first few hours after presentation is necessary to improve the therapeutic outcomes of patients. Therefore, analytical methods for the identification and quantification of α-, β-, and γ-amanitin in biological samples are necessary for clinical and forensic toxicology. This study presents a literature review of the analytical techniques available for amatoxin detection in biological matrices, and established an inventory of liquid chromatography (LC) techniques with mass spectrometry (MS), ultraviolet (UV) detection, and electrochemical detection (ECD). LC-MS methods using quadrupole tandem mass spectrometry, time-of-flight mass spectrometry, and orbitrap MS are powerful analytical techniques for the identification and determination of amatoxins in plasma, urine, serum, and tissue samples, with high sensitivity, specificity, and reproducibility compared to LC with UV and ECD, enzyme-linked immunoassay, and capillary electrophoresis methods.