• Mass Spectrometry Letters
• /
• 제4권4호
• /
• pp.79-82
• /
• 2013

Various types of alkaloids observed in several herbal medicines were analyzed by electrospray ionization tandem mass spectrometry in positive ion mode. In the present study, MS/MS spectralpatterns were investigated for eight-types of alkaloids (aporpine, protoberberine, tetrahydroprotoberberine, benzylisoquinoline, protopine, phthalide, morpine, and bisbenzylisoquinoline). For aporpine- and protoberberine-type alkaloids, main fragmentations occurred at substituted groups on rigid ring structures, not showing ring fusion. Interesting fragmentations due to iminolization and retro-Diels-Alder (RDA) reaction were observed in MS/MS spectra of protopine- and tetrahydroprotobereberine-type alkaloids. Also, several types of fragmentations such as inductive cleavage and ${\alpha}$-cleavage, or bond cleavage between two ring structures were observed depending on their structural characteristics. These fragmentation patterns are expected to allow instant classification of the specific alkaloid type in various MS/MS spectra of alkaloids.

• 한국축산식품학회지
• /
• 제41권5호
• /
• pp.816-825
• /
• 2021

This study aims to validate a fast method of simultaneous analysis of 365 LCamenable and 142 GC-amenable pesticides in hen eggs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS), respectively, operating in multiple reaction monitoring (MRM) acquisition modes. The sample preparation was based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction. Key method performance parameters investigated were specificity, linearity, limit of quantification (LOQ), accuracy, precision and measurement uncertainty. The method was validated at two spiking levels (10 and 50 ㎍/kg), and good recoveries (70%-120%) and relative standard deviations (RSDs) (≤20) were achieved for 92.9% of LC-amenable and 86.6% of GC-amenable pesticide residues. The LOQs were ≤10 ㎍/kg for 94.2% of LC-amenable and 92.3% of GC-amenable pesticides. The validated method was further applied to 100 egg samples from caged hens, and none of the pesticides was quantified.

• Mass Spectrometry Letters
• /
• 제9권1호
• /
• pp.17-23
• /
• 2018

Studies on the interactions of amyloidogenic proteins with trace metals, such as copper, have indicated that the metal ions perform a critical function in the early oligomerization process. Herein, we investigate the effects of Cu(II) ions on the active sequence regions of amyloidogenic proteins using electrospray ionization mass spectrometry (ESI-MS) and collision induced dissociation tandem MS (CID-MS/MS). We chose three amyloidogenic peptides NNQQNY, LYQLEN, and VQIVYK from yeast prion like protein Sup35, insulin chain A, and tau protein, respectively. [Cu-peptide] complexes for all three peptides were observed in the mass spectra. The mass spectra also show that increasing Cu(II) concentrations decrease the population of existing peptide oligomers. The tandem mass spectrum of NNQQNY shows preferential binding for the N-terminal region. All three peptides are likely to appear to be in a Cu-monomer-monomer (Cu-M-M) structure instead of a monomer-Cu-monomer (M-Cu-M) structure.

• Bulletin of the Korean Chemical Society
• /
• 제23권8호
• /
• pp.1097-1102
• /
• 2002

The mass spectrometry using an ion trap tandem mass spectrometer has been investigated to find optimum conditions for the analysis of benzo(a)pyrene (3,4-benzpyrene). The applicability to a real soil sample was also investigated to verify the usef ulness of the MS/MS (or collision induced dissociation, CID) analysis. The optimum CID condition was 1.5 and 0.45 for the RF excitation voltage and the q value, respectively. For comparison, CID and EI were applied to the analysis of a soil sample. CID analysis was more sensitive than EI analysis of the soil sample. The limit of detection (LOD) of benzo(a)pyrene was 3.18 ng mL-1 and 0.85 ng mL,-1 for EI and MS/MS analysis, respectively. The precision at the soil sample for EI and CID showed relative standard deviations of 6.1% and 4.1%, respectively, and the concentrations were 168 ㎍ kg-1 and 162 ㎍ kg-1 , respectively.

• Mass Spectrometry Letters
• /
• 제14권4호
• /
• pp.141-146
• /
• 2023

Liraglutide is a medication prescribed for the management of type 2 diabetes and chronic obesity. A simple, sensitive, and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitative analysis of liraglutide in rat plasma. After a simple protein precipitation step, liraglutide was chromatographically separated using the ACQUITY Premier Peptide BEH C18 Column with mobile phases comprising 50% acetonitrile and 50% methanol, and water with 0.3% FA. Positive ion electrospray ionization in multiple reaction monitoring mode was used to achieve detection. Good linearity was observed in the 5-600 ng/mL concentration range (R² > 0.99). Liraglutide had intra- and inter-day precision values of 2.13%-9.86% and 4.14%-8.36%, respectively. The accuracy ranged from -2.36% to 2.58%. The recovery and matrix effect were within acceptable limits. This selective LC-MS/MS method was used to study the pharmacokinetic properties of liraglutide after subcutaneous administration in rats.

• Mass Spectrometry Letters
• /
• 제2권3호
• /
• pp.69-72
• /
• 2011

Defective synthesis of the steroid hormones by the adrenal cortex has profound effects on human development and homeostasis. Due to the time-consuming chromatography procedure combined with mass spectrometry, the matrix-assisted laser desorption ionization method coupled to the linear ion-trap tandem mass spectrometry (MALDI-LTQ-MS/MS) was developed for quantitative analysis of 10 adrenal steroids in human serum. Although MALDI-MS can be introduced for its applicability as a high-throughput screening method, it has a limitation on reproducibility within and between samples, which renders poor reproducibility for quantification. For quantitative MALDI-MS/MS analysis, the stable-isotope labeled internal standards were used and the conditions of crystallization were tested. The precision and accuracy were 3.1~35.5% and 83.8~138.5%, respectively, when a mixture of 10 mg/mL ${\alpha}$-cyano-4-hydroxycinnamic acid in 0.2% TFA of 70% acetonitrile was used as the MALDI matrix. The limit of quantification ranged from 5 to 340 ng/mL, and the linearity as a correlation coefficient was higher than 0.988 for all analytes in the calibration range. Clinical applications include quantitative analyses of patients with congenital adrenal hyperplasia. The devised MALDI-MS/MS technique could be successfully applied to diagnosis of clinical samples.

• Mass Spectrometry Letters
• /
• 제14권3호
• /
• pp.104-109
• /
• 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).

• Mass Spectrometry Letters
• /
• 제8권4호
• /
• pp.90-97
• /
• 2017

Androgenic anabolic steroids (AASs) are synthetic derivatives of testosterone with a common structure containing cyclopentanoperhydrophenanthrene nucleus. Their use enhances the muscle building capacity and is beneficial during performance. The AASs are one of the most abused group of substances in horse doping. Liquid chromatography tandem mass spectrometry ($LC/MS^n$) has been successfully applied to the detection of anabolic steroids in biological samples. However, the saturated hydroxysteroids viz: nandrolone, $5{\alpha}-estrane-3{\beta}$, $17{\alpha}-diol$ exhibit lower detection responses in electrospray ionisation (ESI) because of their poor ionisation efficiency. To overcome this limitation pre-column chemical derivatization has been introduced to enhance their detection responses in $LC-ESI-MS^n$ analysis. The aim of present study was to develop a sensitive method for identification and confirmation of nandrolone and its metabolite in horse urine incorporating pre-column derivatization using picolinic acid. The method consists of extraction of targeted steroid conjugates by solid phase extraction (SPE). The eluted steroid conjugates were hydrolysed by methanolysis and free steroids were recovered with liquid-liquid extraction. The resulting steroids were derivatized to form picolinoyl esters and identification was done using LC-ESI-MS/MS in positive ionization mode. The picolinated steroid adduct enhanced the detection levels in comparison to underivatized steroids.

• Food Science and Biotechnology
• /
• 제17권3호
• /
• pp.508-513
• /
• 2008

Erythromycin has been used to treat Streptococosis, Edwardsiel1osis, Vibriosis, Bacterial enteritis in the cultured fish. In this study, a rapid and effective erythromycin analysis method with new sample treatment protocol and liquid chromatography/tandem mass spectrometry (LC/MS/MS) system for fish products was developed. For the erythromycin extraction from fish muscle, the solvent mixture composed of 0.2% meta-phosphoric acid and methanol (6:4) showed good recovery rate, and the optimum extraction solvent volume was 20 mL. Erythromycin detection using LC/MS/MS were carried out under electro spray ionization (ESI) positive condition and erythromycin mass value 576.2 and 157.9. And the detection limit of the established method was 0.005 mg/kg in fish products. The recovery rate of the developed method applied to the fish species were as following, olive flounder, $87.6{\pm}5.0%$; black rockfish, $87.2{\pm}6.4%$; eel, $85.2{\pm}4.8%$; and rainbow trout, $86.0{\pm}6.2%$. In the established method in this study, the correlation of coefficient values ($R^2$) of erythromycin calibration curve (n=11) was 0.9998.

• 대한임상약리학회:학술대회논문집
• /
• 대한임상약리학회 2007년도 추계학술대회
• /
• pp.92-93
• /
• 2007

See Full Text