• Analytical Science and Technology
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• v.29 no.4
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• pp.155-161
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• 2016

Distribution of various illegal or counterfeit drugs of seven approved erectile dysfunction drugs and their analogues has been increased, causing health problems such as cardiovascular disorder, tachycardia, headache, or vision disturbance. We used liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) to determine the erectile dysfunction drugs and their analogues in various counterfeit drugs. Eleven erectile dysfunction drugs and their analogues were detected, with sildenafil and its analogues being the most counterfeited compounds (73.8 %), followed by tadalafil and its analogues (25.4 %). The limits of detection (LOD) and the limits of quantitation (LOQ) of liquid-type and solid-type negative samples ranged from 0.1 to 3.3 ng/mL or ng/g and from 0.3 to 10.0 ng/mL or ng/g, respectively. The recoveries ranged from 84.3 to 112.3 % and 83.2 to 110.2 %, respectively. The contents of sildenafil and tadalafil in the various counterfeit drugs ranged from 21.0 to 947.5 mg/g and from 0.2 to 170.2 mg/g, respectively.

• Analytical Science and Technology
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• v.24 no.3
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• pp.173-182
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• 2011

This research examined prostanozol and its metabolites in urine of women who took the medicine (prostanozol). Prostanozol and its metabolites were successfully separated and detected by using LC/ESI/MS and GC/TOF-MS. Mass spectrum of LC/ESI/MS estimated molecular weight of Prostanozol and its metabolites and that of GC/TOF-MS verified them. For M1, carbon number 17 of Prostanozol substituted to a keto group and it is called 17-keto-Prostanozol. M2 turned out to be hydroxy-17-keto-Prostanozol. It came from substitution of one hydroxyl group of pyrazole nucleus and A-ring of M1. Substitution of one hydroxyl group of B-ring or C-ring became M3, hydroxy-17-keto-Prostanozol. M4 was found to be a hydroxy-17-keto-Prostsnozol transposed from one hydroxyl group to a D-ring. M5 has a hydroxyl group of carbon number 17. One hydroxyl group is substituted from B-ring or C-ring and it is assumed to be hydroxy-17-hydroxy-Prostanozol. M6 was turned out to be dihydroxy-17-keto-Prostanozol transposed from one hydroxyl group to pyrazole nucleus or A-ring and to B-ring or C-ring. Like M6, M7 has a keto group at carbon number 17 and was identified as dihydroxy-17-keto-Prostanozol. M7 has one hydroxyl group at pyrazole nucleus or A-ring and also at D-ring. At last M8 was found to be dihydroxy-17-hydroxy-Prostanozol. Pyrazole nucleus or A-ring has got one hydroxyl group and other rings were substituted to another hydroxyl group. From above, M5, M7 and M8 were verified as new metabolites that were not discovered yet. Prostanozol and all of the 8 metabolites formed glucuronic conjugates as a result of conjugation reaction test in human body. Some of 8 metabolites were excreted without forming conjugates. Particularly M6 and M7 were excreted as sulfate conjugates.

• Korean Journal of Pharmacognosy
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• v.44 no.4
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• pp.350-361
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• 2013

Asarum sieboldii has been used for treatment of fever, pain, common cold, and chronic sinusitis in Korea. In this study, we performed quantification analysis of seven major constituents including aristolochic acid I, aristolochic acid II, ${\alpha}$-asarone, ${\beta}$-asarone, elemicin, methyl eugenol, and safrole in the 70% ethanol extract of Asarum sieboldii and its solvent fractions, n-hexane, ethylacetate, n-butanol, and water ones using a ultra-performance liquid chromatography-electrospray ionization-mass spectrometer(UPLC-ESI-MS) and gas chromatography-mass spectrometer(GC-MS). Regression equations of seven components were acquired with $r^2$ values >0.99. The values of limit of detection(LOD) and quantification(LOQ) were 0.1-3.9 ng/mL and 0.3-11.7 mg/mL, respectively. The amount of the seven compounds in Asarum sieboldii were not detected -143.66 mg/g. The established LC-MS/MS and GC-MS methods will be helpful to improve quality control of Asarum sieboldii.

• Korean Journal of Plant Resources
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• v.31 no.6
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• pp.652-659
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• 2018

In this study, baicalin, as a marker substance of Scutellariae Radix, was quantitatively analyzed by a high performance liquid chromatography-photodiode array detector (HPLC-DAD). We identified wogonoside, baicalein, and wogonin in the Scutellariae Radix by a high performance liquid chromatography-electrospray ionization-mass spectrometer (HPLC-ESI-MS). The baicalin was separated on a Xterra C18 column ($5{\mu}m$, $4.6{\times}250mm$) using mobile phase consisting of 38% acetonitrile in 0.68% phosphoric acid. The baicalin spectrum in the Scutellariae Radix extracts was coincided by comparing with UV-visible spectrum (200-550 nm) of baicalin standard in the library. The amount of baicalin in Scutellariae Radix was 10.46%, which is higher than KFDA's guideline. The marker substances of Scutellariae Radix showed a strong base peak $[M]^+$ in the positive detection mode following as; baicalin (m/z; $271[MH^+-sugar]^+$, $447[M+H]^+$), wogonoside (m/z; $285[MH^+-sugar]^+$, $461[M+H]^+$), baicalein (m/z; $271\;[M+H]^+$), wogonin (m/z; $285[M+H]^+$). These results are consistent with the fragment pattern and molecular weight of standard components from literature.

• Mass Spectrometry Letters
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• v.6 no.4
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• pp.99-104
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• 2015

A liquid chromatography mass spectrometry (LC-MS) system was used to identify and distinguish oligostilbene diastereoisomers. A polyphenolic extract from Neobalanocarpus heimii known to be rich in oligostilbenes of various degrees of condensation was used as test material. Fourteen oligostilbenes were isolated from this extract on a fully automated semi-preparative HPLC system. Out of these, two pairs of dimers, one pair of trimers, two pairs of tetramers and a group of four tetramers with similar skeleton were identified as diastereoisomers. Their structures and configurations were established by spectroscopic methods. All isolated compounds were subjected to an LC-MS/MS to study their fragmentation patterns. The experiments were performed on a liquid chromatography-mass spectrometry (LC-MS) with electrospray-ionization (ESI) interface in positive mode. MS/MS spectra of each pure compound were recorded by direct infusion in identical conditions and their product ion spectra were analysed. Some subtle yet significant differences were observed between the spectra of oligostilbenes from the various diastereoisomeric series.

• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.745-750
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• 2007

An isotope dilution-liquid chromatography/tandem mass spectrometric method was developed as a candidate reference method for the accurate determination of folic acid in infant milk formula. Sample was spiked with 13C5-folic acid and then extracted with phosphate buffer (pH 6) solution. The extract was further cleaned up by deproteinization followed by a C18 solid-phase extraction cartridge. The extract was analyzed by using LC/ ESI/MS/MS with selectively monitoring the collisionally induced dissociation channels of m/z 442 → m/z 295 and m/z 447 → m/z 295, which are the neutral glutamyl loss from the [M+H]+ ions of folic acid and 13C5-folic acid, respectively. LC/MS/MS chromatograms showed substantially reduced background from chemical noises compared to LC/MS chromatograms. Repeatability and reproducibility studies showed that the LC/MS/ MS method is a reliable and reproducible method which can provide less than 1.5 relative percentage of method precision.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.05a
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• pp.18-18
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• 2010

Glucosinolates(GSLs) are major secondary products($\beta$-thioglucoside N-hydroxysulfates) containing sulfates that are found mainly in Cruciferae family such as cabbage, broccoli, radish, turnip, kale, mustard and rapeseed as the important crops in agronomic and economic aspects. Especially, isothiocyanates(ITCs) have been shown to inhibit carcinogenesis with regulation cancer cell development followed by regulating target enzymes, inducing cell cycle arrest and apoptosis against various human cancer cell lines. Total desulfo(DS)-GSLs of nine type in 210 Korean leaf mustard accessions were isolated and confirmed using electrospray ionization mass spectrometric(ESI-MS/MS) method and DS-GSLs powerful library maked from several reference data. The isolated individual DS-GSLs were identified by removed $\beta$-D-glucopyranose residue ($C_6H_{11}O_5$, MW 163) from MS/MS data. Among them sinigrin(41.7%), glucoiberverin(21.7%) and gluconasturtiin(12.6%) were major components, Especially, despite gluconapin was minor component, accession K046197-1 and K046197-2 showed higher content of 4.11 and 3.31 mg/g(DW), respectively. The total GSLs contents in 210 accessions were ranged from 5.3 to 23.2 mg/g(DW) with a mean value of 13.0 mg/g(DW). As a result of principal component analysis(PCA), the individual GSLs loading plots were composed of three groups and components belonged to each group showed correlationship in quantitative pattern.

• Mass Spectrometry Letters
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• v.6 no.4
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• pp.105-111
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• 2015

Sixteen compounds of Neobalanocarpus heimii were successfully identified directly from their plant extract using a triple quadrupole LC-MS/MS system. In order to fulfil the objectives of this work, a series of stilbene oligomers of various degrees of condensation were isolated and their structure are characterized. Out of these, four are resveratrol dimers, three trimers, and nine tetramers. The isolation process was done on a fully automated semi-preparative HPLC system. Their structures were elucidated on the basis of 1D- and 2D-NMR as well as MS data. The mass fragmentation patterns of the compounds were recorded and a retrievable in-house library was built to keep the data. In order to demonstrate the potential of this approach, the polyphenolic crude extract was analysed with the LC-MS/MS system and the MS/MS spectra extracted for each chromatographic peak of interest. The fragmentation patterns were compared with those of anticipated pure compounds that were previously recorded. All compounds were successfully identified. It is therefore believed that the LC-MS/MS potential for dereplication of structurally similar compounds in a crude mixture was thus firmly established.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.1996-2000
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• 2009

Alkali metal salts were introduced to enhance the ionization efficiency of glucose and maltooligoses in electrospray ionization-mass spectrometry (ESI-MS). A mixture of the same moles of glucose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and maltoheptaose was used. Salts of lithium, sodium, potassium, and cesium were employed as the cationizing agent. The ionization efficiency varied with the alkali metal cation types as well as the analyte sizes. Ion abundance distribution of the [M+$cation]^+$ ions of the carbohydrates varied with the fragmentor voltage. The maximum ion abundance at low fragmentor voltage was observed at maltose, while the maximum ion abundance at high fragmentor voltage shifted to maltotriose or maltotetraose for Na, K, and Cs. Variation of the ionization efficiency was explained with the hydrated cation size and the binding energy of the analyte and alkali metal cation.

• Korean Journal of Pharmacognosy
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• v.43 no.2
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• pp.137-146
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• 2012

Dipsaci Radix (Dipsacaceae) has been used as a tonic, an analgesic, anti-inflammatory and anti-complement agents in traditional herbal medicine for the therapy of low back pain, knee pain, rheumatic arthritis, traumatic hematoma, and bone fractures. A high-performance liquid chromatography-electrospray ionization-mass spectrometric method (HPLC-ESI-MS) was developed for the simultaneous quantitation method of the five compounds from the herbal drug: asperosaponin VI and asperosaponin XII (terpene glycosides), sweroside, loganin and dipsacus A(iridoid glycosides). HPLC separation of the analytes was achieved on a C18 column ($150{\times}2.0$ mm i.d., 5 ${\mu}m$) using the aqueous methanol containing 5 mM ammonium acetate with gradient flow of the mobile phase. Detection of the analytes was performed by positive ion electrospray ionization, and selected ion monitoring was used for data acquisition using m/z corresponding molecular adduct ion, $[M+NH_4]^+$ and $[M+H]^+$. Calibration graphs showed good linearity ($r^2$=0.9997) over the wide range of the analytes; intra- and inter-day precisions (RSD, %) were within 9.1% and the accuracy between 94.0-111.0%. Recoveries of the analytes through the assay procedure were in the range of 93.7-110.8%. Analytical results of the herbal drugs of Dipsaci Radix (17 samples) show wide distribution of the five marker compounds and clear difference of the species from Phlomidis Radix (4 samples). The developed method would provide a practical guide for the quality control of the herbal drug.