• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.321-329
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• 2014

This experiment was conducted to establish an analytical method for residues of amisulbrom, as recently developed an oomycete-specific fungicide showing inhibition of fungal respiration, in crops using HPLC-UVD/MS. Amisulbrom residue was extracted with acetonitrile from representative samples of five raw products which comprised apple, green pepper, kimchi cabbage, potato and hulled rice. The extract was diluted with 50 mL of saline water and directly partitioned into dichloromethane to remove polar co-extractives in the aqueous phase. For the hulled rice sample, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. On an octadecylsilyl column in HPLC, amisulbrom was successfully separated from sample co-extractives and sensitively quantitated by ultraviolet absorption at 255 nm with no interference. Accuracy and precision of the proposed method was validated by the recovery test on every crop samples fortified with amisulbrom at 3 concentration levels per crop in each triplication. Mean recoveries ranged from 85.3% to 105.6% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of amisulbrom was 0.04 mg/kg as verified by the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring technique was also provided to clearly identify the suspected residue. The proposed method was sensitive, reproducible and easy-to-operate enough to routinely determine the residue of amisulbrom in agricultural commodities.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.639-648
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• 2010

The optimal conditions for the analysis of BPA by HPLC-MS/MS was investigated and the ultrasound degradation capacity of the BPA, with the goal to establish the proper directions for analyzing infinitesimal quantities of BPA by HPLC-MS/MS was examined. The MDL and LOQ of BPA analyzed by HPLC-MS/MS were measured 0.13 nM and 1.3 nM respectively, its sensitivity about 620 and 32 times greater than HPLC-UV (MDL: 81.1 nM, LOQ: 811 nM) and FLD (MDL: 4.6 nM, LOQ: 46 nM). In other words, the new method enables the analysis of BPA with the accuracy up to one 1,180th of the amount specified in U.S. EPA guideline for drinking water. Degradation rate of BPA by ultrasound measured over 95% under 580 kHz and 1000 kHz frequency within 30 minutes of treatment, whereas the rate showed some decrease at 28 kHz frequency. At 580 kHz of ultrasound has proven to be the most effective among others at degradation rate and $k_1$ value, so we concluded that this frequency of ultrasound creates hospitable condition for the combined process of degradation by pyrolysis and oxidization. With the addition of 0.01 mM of $CCl_4$, BPA with the initial concentration of 1 ${\mu}M$ was degraded by more than 98% within 30 minutes, the $k_1$ value measured 5 minutes and 30 minutes into the experiment both showed increases by 1.4 and 1.1 times, respectively, compared with BPA without $CCl_4$. It is also found that the main degradation mechanism of BPA by ultrasound is oxidization process by OH radical, based on the fact that the addition of 10 mM of t-BuOH decreased the rate of BPA degradation by around 60%. However, 33% of BPA degradation rate obtained with the addition of t-BuOH implies further degradation done by pyrolysis or other sorts of radical beside OH radical.

• Journal of Ginseng Research
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• v.32 no.4
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• pp.390-396
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• 2008

For evaluating the quality of ginseng, simple and fast analysis methods are needed to determine the ginsenoside content of the ginseng products. The aim of this study was therefore to optimize conditions for fast analysis of the ginsenosides, the active ingredients in extracts of Korean red ginseng. When tandem HPLC mass spectrometry (HPLC-MS/MS) was used, four forms of ginsenoside, Rb1, Rb2, Rc, and Re, were readily separated in seven minutes using a gradient mobile phase (acetonitrile and water containing acetic acid). This is the shortest separation time reported among the studies of major ginsenoside analysis. When gradient HPLC with UV detection was used, the detection limit was high, but separation of these four ginsenosides required 25 minutes using acetonitrile and water containing formic acid as a mobile phase. HPLC-MS/MS was able to separate ginsenoside Rg1 easily regardless of the mobile phase condition, but the HPLC-UV could not separate Rg1 because acetonitrile concentration in the mobile phase had to be maintained below 20%. Ginsenoside peaks were clearer and had more sensitive detection limits when Korean red ginseng extract was analyzed by the HPLC-MS/MS, but the UV detection was useful for chromatographic fingerprinting of all four major ginsenosides of the extract: Rb1, Rb2, Rc, and Re. Extracts were found to contain 2.17 mg, 1.51 mg, 1.29 mg, and 0.46 mg of ginsenoside Rb1, Rb2, Rc, Re, respectively, per gram weight. The ratios of each ginsenoside in the extracts were 1.0 : 0.7 : 0.6 : 0.2, respectively. Taken together, the results indicate that HPLC-MS/MS spectrometry could be the most useful method for rapid analysis of even small amounts of major ginsenosides, while HPLC with UV detection could also be used for rapid analysis of major ginsenosides and for quality control of ginseng products.

• Archives of Pharmacal Research
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• v.28 no.5
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• pp.592-597
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• 2005

An HPLC/Esl/MS method has been developed to identify and quantify the spirostanol glycosides in the rhizomes of five Polygonatum species. The relative distribution of two steroidal saponins in each extract was established using the selective ion monitoring (SIM) mode via an electrospray ionization (ESI) source. It was found that there were significant differences in the amount of spirostanol glycosides among the Polygonatum Species. The results showed that this method could be used to identify the steroidal saponins in the extracts and differentiate Polygonatum species with high sensitivity and reproducibility in a short time. Fragmentation patterns of the two reference compounds were also discussed with the electrospray ionization multi-stage tandem mass spectroscopy (ESI-MS$^n$).

• Korean Journal of Food Science and Technology
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• v.40 no.3
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• pp.354-359
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• 2008

A survey for zearalenone contamination was conducted on 27 soy bean samples, 27 red bean samples, 16 black bean samples, 19 seoritae samples, 14 seomoktae samples, for a total of 127 commercial Korean samples. Zearalenone was quantified by the immunoaffinity column clean-up method with high performance liquid chromatography-fluorescence detection (HPLC-FLD), and was confirmed by liquid chromatography tandem mass spectrometry(LC-MS/MS). The limits of detection and quantification were $2.0{\mu}g/kg$ and $6.0{\mu}g/kg$, respectively. The recovery in the beans ranged from 82.2 to 98.4%. According to HPLC-FLD, zearalenone was detected in 13 samples (10.2% incidence), including 1 soybean and 12 red bean samples. The zearalenone contamination levels were in the range of 8.01${\sim}38.98{\mu}g/kg$. Finally, LC-MS/MS analysis was conducted in the contaminated samples to verify the results of HPLC-FLD. The LC-MS/MS results confirmed the presence of zearalenone in all 13 samples. The contamination level was lower than that of EU, which is below $100{\mu}g/kg$ for raw grains.

• Analytical Science and Technology
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• v.15 no.6
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• pp.574-579
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• 2002

A sensitive and easy high performance liquid chromatograph (HPLC) / electrospray ionization (ESI)-mass spectrometric (MS) method has been developed for the quantitative and qualitative analyses of acarbose and its metabolites. After plasma samples were simply filtered with a syringe filter, the filtered plasma was analyzed by LC/MS. The standard calibration curve for acarbose was linear ($r^2=0.9963$) over the concentration range $0.1{\sim}10{\mu}g/m{\ell}$ in plasma. The metabolite component-I and II, which were metabolized by the ${\alpha}$-amylase and ${\beta}$-amylase, were found also by in vitro incubation. The developed method can be utilized to study acarbose and the other carbohydrates.

• Journal of Life Science
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• v.32 no.11
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• pp.841-846
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• 2022

The purpose of this study was to evaluate the antioxidant properties of Rosa rugosa extract and to identify which of its components are responsible for these properties. Reactive oxygen species play an important role in diseases such as cancer, arteriosclerosis, and heart disease as a consequence of increased metabolic rates, gene mutations, and relative hypoxia. Therefore, the antioxidant effect of R. rugosa extract was confirmed by HPLC, HPLC-MS/MS, the total polyphenol content, the total flavonoid content, and the radical scavenging activity. HPLC and HPLC-MS/MS analyses were conducted to identify and quantify the main components of the R. rugosa extract. Gallic acid and epigallocatechin gallate were identified as the main components, with 17.4 and 4.35 mg/g dry matter (DM), respectively. The antioxidant activity of R. rugosa extract was evaluated based on its total polyphenol content, total flavonoid content, and radical scavenging activity, which were 72.3 mg gallic acid equivalent/g DM, 11.2 mg quercetin equivalent/g DM, and 87.9%, respectively. The radical scavenging activities of the main components, gallic acid and epigallocatechin gallate, were 80.5% and 89.7%, respectively. Therefore, R. rugosa has a high polyphenol content and antioxidant activity, and it can be used as a natural antioxidant in food, cosmetics, and pharmaceuticals.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.326-333
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• 2020

In this work, we developed an analytical method for determining 11 illicit compounds in dietary supplements using high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry. Eleven target compounds, including those meant for weight loss (7-keto-dihydroepiandrosterone, buformin, metformin, phenformin, salbutamol, and tolbutamide), sexual enhancement (dihydroepiandrosterone), and relaxation (asarone, kavain, magnoflorine, and picamilon) were screened and confirmed in dietary supplements. Method validation was performed by evaluating the selectivity, linearity, limit of quantification (LOQ), accuracy, and precision according to the Association of Official Analytical Chemists guidelines. The linearity was > 0.993 for all analytes. The LOQs were ranged in 2.1-9.9 ㎍/mL (HPLC-DAD) and 0.002-0.008 ㎍/mL (LC-MS/MS). The accuracies (expressed as recovery) were 90.0-106% (HPLC-DAD) and 83.0-114% (LC-MS/MS). The precision (expressed as the relative standard deviation) was below 10% using HPLC and LC-MS/MS. The proposed method can be used for the surveillance of illicit compounds in dietary supplements.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1163-1168
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• 2003

The structures of molecular species of galactolipids, such as monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG), isolated from wheat flour have been investigated using negative-ion electrospray ionization (ESI) mass spectrometry interfaced with high performance liquid chromatography (HPLC). According to the result of HPLC analysis, MGDG and DGDG were found to consist of mixtures of five and four molecular species, respectively. The galactolipids have been also analyzed to determine their fatty acid compositions, using HPLC/ESI-MS combined with in-source (or cone voltage) fragmentation. HPLC/ ESI-MS is very useful for one-step analysis of mixtures of galactolipids with a small sample quantity. Especially, the carboxylate anions produced in in-source fragmentations of the negative-ion of each component separated by HPLC provide valuable information on the composition of its fatty acyl chains.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.3
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• pp.353-358
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• 2006

Flavonoid and limonoid compounds were determined by HPLC on the methanol and ethanol extracts from citron seeds. The quantities of the compounds in these categories were higher in the ethanol extract than methanol extract. The types of these compounds were detected in larger numbers in the ethanol extract. The content of limonin was the largest in both methanol and ethanol extract among the detectable compounds ; 140.34 mg/100g and 170.98 mg/100g, respectively, and the contents of other compounds, caffeic acid, naringin, lutin, nomilin, were found in large amount in this order. The molecular weights of forty two compounds in ethanol extract were determined with mass spectrums and extracted ion current chromatograms by HPLC/MS.