• Analytical Science and Technology
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• v.20 no.4
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• pp.347-354
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• 2007

A simple and rapid high-performance liquid chromatography assay for the determination of residual novobiocin levels in bovine, porcine, chicken, flatfish and japanese eel muscle has been developed and validated. The separation condition for HPLC/UV was optimized with phenyl hexyl ($4.6{\times}150mm$, $5{\mu}m$) column with 10 mM monobasic sodium phosphate buffer (pH 2.5)/acetonitrile (50/50, v/v) as the mobile phase at a flow rate of 1.0 mL/min and detection wavelength was set at 254 nm. Residues were extracted from tissue by blending with methanol and lipid materials were removed with n-hexane. Then, the methanol extract was evaporated to dryness under a nitrogen stream, reconstituted in the mobile phase. Aliquot of the organic extract was decanted and filtered through $0.45{\mu}m$ syringe filter. The $20{\mu}L$ of the resulting solution was injected into the HPLC system. The calibration ranges were $0.5{\sim}5{\mu}g/g$ and calibration curves were linear with coefficients of correlation better than 0.95. The limits of quantification were $0.5{\mu}g/g$ for all muscles. The recoveries of bovine, porcine, chicken, flatfish and japaneseel muscles were 99.8%, 102.4%, 91.0%, 104.0% and 93.0%, respectively. The procedures were validated according to the CODEX guideline, determining specificity, linearity, accuracy, precision, quantitation limit and recovery.

• Journal of Life Science
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• v.23 no.8
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• pp.1025-1031
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• 2013

From a 95% ethanolic extract of H. diffusa, four marker compounds (HD1~HD4) were isolated, which were relatively unique and exist in comparably high contents. The structures of marker compounds were identified as digitolutein (1), 2-hydroxy-3-methylanthraquinone (2), (E/Z)-6-O-p-coumaroyl scandoside methyl ester (4:1 mixture) (3), and (E/Z)-6-O-p-methoxycinnamoyl scandoside methyl ester (4:1 mixture) (4), respectively, on the basis of $^{13}C$ and $^1H$-NMR analyses. The calibration curves of marker compounds showed high linearity, as their correlation coefficient ($R^2$) were in the range of 0.9991~0.9999. In addition, the limit of detection (LOD) and the limit of quantification (LOQ) were $0.03{\sim}0.07{\mu}g/ml$ and $0.099{\sim}0.231{\mu}g/ml$, respectively. The intra-day/inter-day precision and accuracy were 0.23~2.00%/0.25~1.16% and 94.60~108.44%/94.73-110.23%, respectively. The optimal HPLC conditions for the simultaneous quantification of HD1~HD4 were as follows: stationary phase; Merck Chromolith RP-18e ($100{\times}4.6mm$, $5{\mu}m$), column temp.; room temperature, UV detection at 280 nm, flow rate; 2.0 ml/min, injection volume; $10{\mu}l$, mobile phase; start with the mixture of 80% solvent A ($H_2O$ containing 0.5% acetic acid) and 20% solvent B (methanol containing 0.5% acetic acid) and gradually decrease solvent A to 40% in 9 min., then retain this condition to 18 min. Under the HPLC condition, the four marker compounds 1~4 were successfully separated without any interference of other constituents. The results obtained in this study are expected to be helpful for the development of nutraceutics and natural medicines and for the quality control of this plant.

• Journal of Food Hygiene and Safety
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• v.36 no.4
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• pp.298-309
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• 2021

In this study we sought to develop a simultaneous analysis method for cis-bixin and cis-norbixin, the main components, to detect annatto pigment in food. To establish the optimal test method, the HPLC analysis methods of the European Food Safety Authority (EFSA), Japan's Ministry of Health, Labor and Welfare (MHLW), and National Institute of Food and Drug Safety Evaluation (NIFDS) were compared and reviewed. In addition, a new pretreatment method applicable to various foods was developed after selecting conditions for simultaneous high-performance liquid chromatography (HPLC) analysis in consideration of linearity, limit of detection (LOD), limit of quantification (LOQ), and analysis time. The HPLC analysis method of NIFDS showed the best linearity (R² ≥ 0.999), exhibiting low detection and quantification limits for cis-norbixin and cis-bixin as 0.03, 0.05 ㎍/mL, and 0.097, 0.16 ㎍/mL, respectively. All previously reported pretreatment methods had limitations in various food applications. However, the new pretreatment method showed a high recovery rate for all three main food groups of fish meat and meat products, processed cheese and beverages. This method showed an excellent simultaneous recovery rate of 98% or more for cis-bixin and cis-norbixin. The HPLC analysis method with a new pretreatment method showed high linearity with a coefficient of determination (R²) of 1 for both substances, and the accuracy (recovery rate) and precision (%RSD) were 98% and between 0.4-7.9, respectively. From this result, the optimized analytical method was considered to be very suitable for the simultaneous analysis of cis-bixin and cis-norbixin, two main components of annatto pigment in food.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.1062-1067
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• 2014

In the present study, a new analytical method was devised for the simultaneous determination of soluble carbohydrates in soybean seeds using high performance liquid chromatography/evaporative light scattering detection (HPLC/ELSD). The limit of quantification (LOQ) for soybean soluble carbohydrates ranged from 5.6~7.6 mg/kg using the HPLC/ELSD method and from 16.2~33.9 mg/kg using the high performance liquid chromatography/refractive index detection (HPLC/RID) method. Therefore, the HPLC/ELSD method was more sensitive than HPLC/RID. The precision values for retention time and peak area of the HPLC/ELSD method were evaluated by inter-day (n=5) and intra-day (n=10) assays using a standard solution. All precision values (CV<2.5%) for soybean soluble carbohydrates were acceptable and fulfilled international acceptance criteria. All linear calibration curves were obtained with a correlation coefficient of $R^2$ >0.999. The contents of soluble carbohydrates for the "Shingikong" (yellow soybean) and "Cheongjakong 3" (black soybean) samples were analyzed using the HPLC/RID and HPLC/ELSD methods. The difference in carbohydrate contents between the two detection methods was significant. Carbohydrate contents in the HPLC/ELSD method were higher than those in the HPLC/RID method. Overall, the HPLC/ELSD method showed satisfactory resolution with a favorable LOQ and reproducibility. Therefore, these results indicate that the HPLC/ELSD method may be applied to determine the contents of soluble carbohydrates in soybean seeds and related food stuffs.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2235-2241
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• 2010

A reverse-phase HPLC method with detection by mass spectrometry is described for the simultaneous determination of doxifluridine and its two active metabolites, 5-fluorouracil (5-FU) and 5-fluorouridine (5-FUrd), in beagle dog plasma. The optimal chromatographic separation was achieved on a Waters $Xterra^{(R)}$ $C_{18}$ column ($4.6{\times}250\;mm$ i.d., $5\;{\mu}m$ particle size) with a mobile phase of 0.1% formic acid in a mixture of 99% methanol and purified water (99:1, v/v). The developed method was validated in beagle dog plasma with a lowest limit of quantification of $0.05\;{\mu}g/mL$ for both doxifluridine and 5-FU, and $0.2\;{\mu}g/mL$ for 5-FUrd. Doxifluridine and its two metabolites were stable under the analysis conditions, and intra- and inter-day accuracies exceeded 92.87%, with a precision variability ${\leq}11.34%$ for each analyte. Additionally, the method for quantifying doxifluridine and its two metabolites, 5-FU and 5-FUrd, in beagle dog plasma was applied successfully to the analysis of pharmacokinetic samples.

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.377-382
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• 2018

An HPLC method was developed to quantitate a marker, oxyresveratrol (ORT), for the standardization of mulberry branch extracts (MBE) as a functional ingredient. HPLC was performed on a $C_{18}$ column with a gradient elution using 0.05% $H_3PO_4$ and acetonitrile at a flow rate of 0.8 mL/min, and detected at 320 nm. The HPLC method was validated according to Korea Food and Drug Administration (KFDA) guideline of analytical procedures with respect to specificity, linearity, accuracy and precision. Calibration curve of ORT showed high linearity ($R^2=1$), and limits of detection and quantification were 0.3 and $1.0{\mu}g/mL$, respectively. Relative standard deviation values from intra-and inter-day precision were less than 3.52 and 4.70%, respectively. Recovery rate ranged from 97.64% to 103.69%, and ORT content in MBE was approximately 3.78%. These results suggest that the HPLC method developed for the analysis of ORT in MBE is simple, efficient, and could contribute to the quality control of MBE.

• Korean Journal of Medicinal Crop Science
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• v.21 no.6
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• pp.486-492
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• 2013

This study has been conducted to establish the optimal extraction process and HPLC analysis method for the determination of marker compounds as a part of the materials standardization for the development of health functional food materials from Astragali radix. Five extraction conditions including the shaking extraction at room temperature and the reflux extraction at $85^{\circ}C$ with 30%, 50% and 95% ethanol were evaluated. Reflux extraction with 50% ethanol showed the highest extraction yield as $27.27{\pm}2.27%$, while the extraction under reflux with 95% ethanol showed significantly the lowest yield of $10.55{\pm}0.24%$. The quantitative determination methods of calycosin-7-O-${\beta}$-D-glucoside and calycosin as marker compounds of Astragali radix extracts were optimized by HPLC analysis using a Thermo Hypersil column ($4.6{\times}250mm$, $5{\mu}m$) with the gradient elution of water and acetonitrile as the mobile phase at the flow rate of $0.8mLmin^{-1}$ and a detection wavelength of 230nm. The HPLC/UV method was applied successfully to the quantification of two marker compounds in Astragali radix extracts after validation of the method with the linearity, accuracy and precision. The contents of calycosin-7-O-${\beta}$-D-glucoside and calycosin in 50% ethanol extracts by reflux extraction were significantly higher as $1,700.3{\pm}30.4$ and $443.6{\pm}8.4{\mu}g-1$, respectively, comparing with those in other extracts. The results indicate that the reflux extraction with 50% ethanol at $85^{\circ}C$ is optimal for the extraction of Astragali radix, and the established HPLC method are very useful for the evaluation of marker compounds in Astragali radix extracts to develop the health functional material from Astragali radix.

• Korean Journal of Food Science and Technology
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• v.51 no.5
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• pp.420-424
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• 2019

An HPLC analysis method was developed and standardized for the detection of dieckol as a functional food ingredient in Ecklonia cava extracts. HPLC was performed using a Capcell Pak C18 column ($250{\times}4.6mm$, $5{\mu}m$) with a gradient elution of water and acetonitrile, both containing 0.1% (v/v) trifluoroacetic acid, at a flow rate of 1.0 mL/min at $25^{\circ}C$. The eluate was detected at 230 nm. For validation, the specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ) of dieckol were measured. The calibration curve for the detection of dieckol had high linearity ($R^2=0.9994$), with LOD and LOQ values of 0.38 and $1.16{\mu}g/mL$, respectively. Recovery of the quantified compound ranged from 99.61 to 100.71%. The relative standard deviation values of the intra-day and inter-day precisions were less than 1.7 and 1.25%, respectively. These results indicate that the reported HPLC method is simple, reliable, and reproducible for the detection of dieckol in Ecklonia cava extracts.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.565-569
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• 2009

This study was conducted to evaluate the effects of different preparation methods on the recovery and quantification of ginsenosides in raw Korean ginseng (Panax ginseng C.A. Meyer). Eight major ginsenosides ($Rb_1$, $Rb_2$, $Rb_3$, Rc, Rd, Re, Rf, and $Rg_1$) were analyzed by high performance liquid chromatography (HPLC), after which the recovery and repeatability of the extraction of those ginsenosides using 3 different preparation methods were compared [A. direct extraction (DE) method, hot MeOH extraction/evaporation/direct dissolution; B. solid phase extraction (SPE) method, hot MeOH extraction/evaporation/dissolution/$C_{18}$ cartridge adsorption/MeOH elution; C. liquid-liquid extraction (LLE) method, hot MeOH extraction/evaporation/dissolution/n-BuOH fractionation]. Use of the DE method resulted in a significantly higher recovery of total ginsenosides than other methods and a relatively clear peak resolution. Use of the SPE and LLE methods resulted in clearer peak resolution, but lower ginsenoside recovery than the DE method. The LLE method showed the lowest ginsenoside recovery and repeatability among the 3 methods. Given that the DE method employed only extraction, evaporation, and a dissolution step (avoiding complicate and time consuming purification), this technique may be an effective method for the preparation and quantification of ginsenosides from raw Korean ginseng.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.24-27
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• 2006

A simple HPLC quantification method was developed for genistein, genistin, daidzein, and daidzin in soybeans and soybean products. The procedure used a $4.6{\times}100\;mm$ $Chromolith^{(R)}$ RP-18e column with a mobile phase of 1% HOAc in 20% MeOH to 1% HOAc in 80% MeOH for 10 min. The injection volume was $2\;{\mu}L$ at a flow rate of 2 mL/min. Detection was carried out under UV at 254 nm. Under these conditions, the major isoflavones daidzein, daidzin, genistein, and genistin in soybean and soybean pastes were eluted within 7 min with baseline separation. Optimal extraction of the above four major isoflavones was achieved when 40 g of soybean or soybean paste was refluxed in 100 mL of 95% ethanol for 2 hr. Ten different soybean cultivars and nine commercial soybean pastes were analyzed by this method. The total isoflavone content was highest in the cultivar Somyung ($2,497\;{\mu}g/g$ dry weight). The isoflavone content in soybean pastes varied widely from manufacturer to manufacturer (an almost five-fold difference between the highest and lowest values). Such variations were presumably due to differences in fermentation conditions, type of soybeans used, and levels of such additives as starch and salt.