• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.921-926
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• 2022

Sugar solutions (5%, 10%, 15% and 20%) were tested by seven sensors of Astree E-Tongue for selecting a sensor for sweetness. NMS sensor was chosen as a sensor for sweetness among two sensors (PKS and NMS sensors selected in first stage) by considering precision, linearity and accuracy. Sugar, fructose, glucose and xylitol (5%, 10% and 15%) were tested by E-tongue. The principal component analysis (PCA) result by E-Tongue with seven sensors at 5% concentration level of four sweetners was not satisfactory (Discrimination index was -0.1). On the other hand, the relative NMS sensor response values were derived as 1.08 (fructose), 0.99 (glucose) and 1.00 (xylitol) comparing to sugar. Only the E-Tongue relative glucose response 0.99 was different from 0.5~0.75 of the relative sweetness range reported as the human sensory test results. Considering the excellent precision (%RSD, 1.53~3.64%) of E-Tongue using NMS single sensor for three types of sweeteners compared to sugar in the concentration range of 5% to 15%, replacing sensory test of sweetened beverages by E-Tongue might be possible for new product development and quality control.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.631-636
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• 2022

Alcohol content, which is an important standard for Takju, a traditional multiple parallel fermentation liquor called makgeolli, is a factor that can affect the flavor. For alcohol content analysis, the distillation/hydrometry technique is mainly used. In this study, we analyzed the alcohol content of 14 commercially available Takju by the distillation/hydrometry technique and the improved GC method, respectively, after verifying the reliability of improved GC method. The precision and accuracy of the GC method were satisfactory, and LOQ and LOD were evaluated as 0.5% and 0.1% of ethanol contents, respectively. Among the three Takju exceeding the labelled alcohol content ±1, one Takju was quantitated as alcohol content 9.9% (by GC method) and 10.1% (distillation/hydrometry technique) exceeding labelled 6.0%. It was within the analytical error range of alcohol content for other two Takju, where the alcohol contents were exceeded -1.1%. The average precision (%RSD) of 14 Takju analyzed by the distillation/hydrometry technique (36.2%) and the GC method (12.8%), confirming that the GC method was better than the other. The improved GC method was evaluated to be effective in managing and improving the alcohol content standard of Takju with the wide range of alcohol content.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.343-348
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• 2022

This study was performed to establish an analytical method for the standardization of Angelicae Dahuricae Radix as a functional ingredient. We established six compounds including oxypeucedanin hydrate (1), byakangelcol (2), oxypeucedanin (3), imperatorin (4), phellopterin (5) and isoimperatorin (6) as marker compounds of Angelicae Dahuricae Radix. An analytical method using Ultra Performance Liquid Chromatography (UPLC) was established and validated for marker compounds of Angelicae Dahuricae Radix. The specificity was confirmed by the chromatogram from UPLC and the value of coefficient determination was also higher than 0.999, indicating high linearity. The relative standard deviation (RSD) and recovery of marker compounds were less than 5% and in the range of 90- 110%, respectively, which means that this method has high accuracy and precision. Therefore, this analytical method could be used as basic data for the development of functional ingredients for health functional food of Angelicae Dahuricae Radix.

• Analytical Science and Technology
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• v.36 no.3
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• pp.105-112
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• 2023

Lycopene, a carotenoid hydrocarbon is known to have effects on reducing cardiovascular risk factors, blood lipids, and blood pressure. Thus, a lot of supplementary foods with lycopene in several dosage forms like soft capsule filled with liquid and hard capsule filled with powder are available in a market. Recently, however, our research group found that the lycopene assay in Supplementary Food Code of South Korea is only valid for oily lycopene preparation. Thus, here, we developed a simple method to determine lycopene in solid preparations for Supplementary Food Code of South Korea using saponification and liquid chromatography with an absorbance detector. The method was validated following Ministry of Food and Drug Safety guidelines. All validation parameters observed in this study were within acceptable criteria of the guidelines (selectivity, linearity of r² ≥ 0.991, lower limit of quantification of 0.0149 mg/mL, accuracy as recovery (R) between 92.70 and 97.18 %, repeatability as relative standard deviation (RSD) values of R between 0.85 and 1.59 %, and reproducibility as the RSD value of interlaboratory R of 3.70 %). Additionally, the practical sample applicability of the validated method was confirmed by accuracy between 98.81 and 101.59 % observed from its lycopene certified reference material (CRM) analyses. Therefore, the present method could contribute to fortify the supplementary food safety management system in South Korea.

• Analytical Science and Technology
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• v.19 no.1
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• pp.1-8
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• 2006

The isotope dilution method was used for the determination of Br impurity in $1000{\mu}g/g$ Cl standard solution. Since relatively pure KCl salt was used for the preparation of the Cl standard solution, the Br impurity determination suffers from both spectral and non-spectral interferences due to the presence of a large amount of K and Cl matrices. AG2-X8 anion-exchange resin was employed to separate the Br analyte from the matrices, and RF power was raised to 1500 W and nebulizer gas flow rate was lowered to 0.77 L/min to reduce background from the $ArArH^+$ molecular ions. The Br impurity in the $1000{\mu}g/g$ Cl standard solution was determined to be 43.7 ng/g with the standard addition method. The analytical result was in good agreement with 41.2 ng/g (RSD 1.6%) determined by the isotope dilution method to lower uncertainty from poor reproducibility of the anion-exchange process.

• Analytical Science and Technology
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• v.22 no.2
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• pp.186-190
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• 2009

The oxidation studies of a sulfur to a sulfate ion by various oxyhalide oxidants in organic (thiourea, methionine) and inorganic (sulfate, thiophosphate) compounds were carried out in an acidic solution. The optimized result of the oxidation reaction was obtained when a bromate compound (${BrO_3}^-$) as an oxidant and a 3 M $HNO_3$ solvent were used. The chemical yield for the oxidation of the organic and inorganic sulfur compounds to a sulfate ion was monitored as 80% for thiophosphate, 87% for methionine, and 100% for thiourea and sulfate within 5% RSD. The oxidations of thiourea required at least 1.6 equivalents of the bromate in an acidic solution. In the case of the oxidation of methionine and thiophosphate, the oxidation yields were above 80% if the bromate was used at 20 times higher than that of the substrates. The sulfate ion was quantitatively measured by using a GPC counting of $^{35}S$ followed by precipitates of $BaSO_4$. A quenching correction curve for the $^{35}S$ counting was obtained to use the difference via the precipitate weight result.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.291-298
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• 2023

In this study, a quantitative analysis method was developed using high-performance liquid chromatography (HPLC) to analyze the content of ceramide NP in lotion, cream, and cleanser formulations in cosmetics. The analysis was performed using a C18 column, and the mobile phase was set at a ratio of 70 : 30 for acetonitrile and methanol, the flow rate was set to 0.8 mL/min, and the column temperature was set to 20 ℃. The method was verified by analyzing specificity, linearity, limit of detection, limit of quantitation, accuracy, and precision in accordance with the ICH guidelines. As a result of validating the method, the linearity of the calibration curve was excellent (R² = 0.99984). The accuracy of the lotion, cream, and cleanser formulations was confirmed with a recovery rate ranging from 95.11% to 100.48%. The precision analysis showed a low relative standard deviation (RSD) of less than 0.26%. The limit of detection was 0.902 ㎍/mL, and the limit of quantitation was 2.733 ㎍/mL. Through this quantitative analysis method of ceramide NP applied in cosmetics, it is expected to assist in the quality control of products by enabling measurement even when it is difficult to separate the main peak due to the influence of interfering substances.

• Korean Journal of Veterinary Service
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• v.43 no.3
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• pp.189-196
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• 2020

This study was conducted to analyze feasibility of monitoring of fluoroquinolnes residual through feather analysis in broilers. The calibration curve showed good linearity (r²≥0.99) within the concentration range of 1~100 ㎍/kg. The limit of detection (LOD) and limit of quantification (LOQ) were validated at ≤0.66 and ≤1.99 ㎍/kg in broiler feather, respectively. The recoveries in feather samples ranged from 94.6 to 114.4% (5.1-15.8% RSD) at the 5 to 20 ㎍/kg spiking levels. The proposed new analytical method proved to be suitable and effective for fluoroquinolnes determination. We also monitored fluoroquinolones residue in 36 samples (broiler that were slaughtered in Gyonggi-do) using this method. Among tested feather samples, enrofloxacin and ciprofloxacin were detected in all samples. In muscle samples, enrofloxacin was detected in 20 (55.6%) samples and ciprofloxacin was not detected.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.3923-3927
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• 2011

A noble method for pre-concentration and speciation of ultra trace As (III) and As (V) in urine and whole blood samples based on dispersive liquid-liquid microextraction (DLLME) has been developed. In this method, As (III) was complexed with ammonium pyrrolidine dithiocarbamate at pH = 4 and Then, As (III) was extracted into the ionic liquid (IL). Finally, As (III) was back-extracted from the IL with hydrochloric acid (HCl) and its concentration was determined by flow injection coupled with hydride generation atomic absorption spectrometry (FI-HGAAS). Total amount of arsenic was determined by reducing As (V) to As (III) with potassium iodide (KI) and ascorbic acid in HCl solution and then, As (V) was calculated by the subtracting the total arsenic and As (III) content. Under the optimum conditions, for 5-15 mL of blood and urine samples, the detection limit ($3{\sigma}$) and linear range were achieved 5 ng $L^{-1}$ and 0.02-10 ${\mu}g\;L^{-1}$, respectively. The method was applied successfully to the speciation and determination of As (III) and As (V) in biological samples of multiple sclerosis patients with suitable precision results (RSD < 5%). Validation of the methodology was performed by the standard reference material (CRM).

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1185-1189
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• 2008

Two HPLC methods such as cefadroxil and cefalexin methods were compared in their performance for the quantitative analysis of the content and purity of $\beta$ -lactamic antibiotic, cefradine, for six bulk drug samples. Between the two methods, the cefadroxil method prescribed by the European Pharmacopoeia (EP) for the determination of impurities in cefradoxil was superior to the cefalexin method prescribed by the EP and by the United States Pharmacopeia (USP) for the determination of cefalexin impurity in cefradine in terms of the greater stability of the chromatogram baselines and the higher precision, i.e., the lower % relative standard deviation (RSD). Based on the comparison of the two HPLC methods, the cefadroxil method was recommended to replace the TLC method, which has been prescribed by the EP as the official method for determination of extraneous impurities in cefradine.