• Food Science and Preservation
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• v.15 no.1
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• pp.88-93
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• 2008

This paper focused on the detection of the genetically modified soybean (Glycine max L. MERRILL) samples to search for the speedy analysis methods. We have identified the PCR (polymerase chain reaction) assay with a newly developed technique called DHPLC (denaturing high performance liquid chromatography) to screen the GMO in soybean. The DHPLC is i1s ability to directly detection specific sequences of DNA by using column. With these characteristics. the DHPLC assay had the advantage of simplicity, rapidty could obtain result within 20 minutes. Whereas $15{\times}10^{-4}ng/{\mu}L$ concentration could be detected with the PCR analysis, $15{\times}10^{-5}ng/{\mu}L$ concentration could be detected with the DHPLC method. Therefore, DHPLC method was considered to be a simple, fast and sensitivity screening method rather than PCR analysis for GMO detection in soybean.

• 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 Food Science and Technology
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• v.32 no.5
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• pp.1009-1014
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• 2000

In order to detect pantothenic acid (PA), conditions for enzyme-linked immunosorbent assay (ELISA) were established. Anti-PA-BSA antibody was produced from rabbits immunized with PA-bovine serum albumin (BSA) conjugates which were prepared by the bromoacetyl chloride [Bc] method (PA-BSA[Bc]) and by the periodate oxidation [Po] method (PA-BSA[Po]). PA-BSA[Bc] and PA-BSA[Po] was used as a coating antigen for competitive indirect(ci)ELISA. The Anti-PA-BSA[Po] antibody on ciELISA showed no competitive reaction. The detection limit of PA by ciELISA using Anti-PA-BSA[Bc] antibody was 1 ppm. The Anti-PA-BSA[Bc] antibody showed little cross-reactivity to PA derivatives such as pantoyllactone, pantetheine, pantothenyl alcohol, and acetyl CoA. The detection limit of PA by microbiological assay (MBA) was 10 ppb. Assay recoveries of PA in egg, cow's liver, and lettuce by ciELISA were 109, 64, and 344%, respectively, comparing with the MBA results.

• Journal of Radiation Protection and Research
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• v.35 no.3
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• pp.117-123
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• 2010

Plutonium is by far the most important of the transuranic elements which have been released into the environment due to radio-toxicity and long term radiation effects on humans. And Pu isotope ratio ($^{240}Pu/^{239}Pu$) is of great interest because this ratio is used as a fingerprint for different sources. Mass spectrometry has been used as an useful atom counting technique with several advantages over decay counting techniques for the determination of Pu isotopes. It enables a determination of Pu isotope ratio in the environmental samples with a low detection limit and a short determination time. An ICP-MS is the representative mass spectrometry for Pu determination. In this study, the precision of $^{240}Pu/^{239}Pu$ isotope ratio was improved by using 4 multiple ion counters of MC-ICP-MS. The detection limit of $^{239}Pu$ and $^{240}Pu$ were $0.10\;fg\;ml^{-1}$ ($0.24\;{\mu}Bq\;ml^{-1}$), $0.12\;fg\;ml^{-1}$ ($0.97\;{\mu}Bq\;ml^{-1}$), respectively. The relative standard deviation of $^{240}Pu/^{239}Pu$ isotope ratio was less than 1 % in trace level. The various reference materials (seawater, soil and sediment) were analyzed to verify this method and their analytical results were in good agreement with the certified (or recommended value) value.

• The Korean Journal of Pesticide Science
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• v.17 no.2
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• pp.107-116
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• 2013

Polar pesticides like pymetrozine (log $P_{ow}$: -0.18) are known to be difficult to analyze. The analytical method of pymetrozine using hydromatrix included in the official method of KFDA was uncommon and provided ambiguous evidence to confirm both the identity and the quantity. Therefore, precise single residue analytical method was developed in representative crops for using liquid-liquid extraction (LLE). The pymetrozine residue was extracted with methanol from 11 representative crops which comprised apple, blueberry, broccoli, cabbage, cherry, crown daisy, hulled rice, Korean cabbage, potato, rice and watermelon. The extract was purified serially by liquid-liquid extraction (LLE) and silica solid phase extraction (SPE). For rice and hulled rice samples, n-hexane partition was additionally adopted to remove nonpolar interferences, mainly lipids. The residue levels were analyzed by HPLC with DAD, using $C_8$ column. LOQ (limit of quantitation) of pymetroizinie was 1 ng (S/N > 10) and MQL (method quantitation limit) was 0.01 mg/kg. Mean recoveries from 11 crop samples fortified at three levels (MQL, 10 ${\times}$ MQL and 50 ${\times}$ MQL) in triplicate were in the range of 83.1~98.5% with coefficients of variation (CV) of less than 10%, regardless of sample type, which satisfies the criteria of KFDA. The method established in this study could be applied to most of crops as an official and general method for analysis of pymetrozine residue.

• Journal of Life Science
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• v.31 no.1
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• pp.10-16
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• 2021

The consumption of fresh-cut agricultural materials is increasing due to increased public interest in health and the increase of single-person households. Most fresh-cut agricultural materials can be eaten without heating, thus easily exposing the consumer to food-borne pathogens. As a result, food-borne diseases are increasing worldwide. In the analysis of food-borne pathogens, it is important to detect the strains, but this is time consuming and laborious. Alternative detection methods that have been introduced, include polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), which is performed without prior culturing. Samples of fresh-cut agricultural materials, such as vegetables, were analyzed by the culture-based method. In 129 samples, non-pathogenic Escherichia coli (3.9%), Bacillus cereus (31.8%), Clostridium perfringens (5.4%), Yersinia enterocolitica (0.8%), and enterohemorrhagic E. coli (0.8%) were detected. Eight samples contaminated with bacteria were randomly selected, further analyzed by PCR-DGGE, and compared with the culture-based method. Two cases detected non-pathogenic E. coli by PCR-DGGE only, despite a lack of detection by the culture method. It was supposed there was possibility of sample loss during its 10-fold dilution for appropriate cultivation. In the detection of high-risk food-borne pathogens, it was found that the detection limit was lower in PCR-DGGE than in the culture-based method (10 CFU/g). This suggests that PCR-DGGE can be alternatively used to detect strains. On the other hand, low-risk food-borne pathogens seem to have higher detection limits in PCR-DGGE. Consequentially, this study contributes to the improvement of food-borne pathogen detection and the prevention of its related-diseases in fresh-cut agricultural materials.

• Journal of the Korean Chemical Society
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• v.37 no.6
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• pp.590-598
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• 1993

The simultaneous analysis of samples, 16 organic pesticides in water among 129 priority pollutants listed by EPA, was performed by GC-ECD (electron capture detector) and GC/MS-SIM (selected ion monitoring). Two extraction procedures, liquid-liquid extraction (LLE) and solid-phase extraction (SPE), were studied as an extraction and concentration method. Accuracy and precision of the methods were measured by the calculation of mean recovery and mean relative standard deviation. Finally, the detection limits, the experimental limitations, and prospects were discussed.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.272-274
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• 2008

일반적으로 프탈레이트 에스테르의 전처리방법에는 액액추출법(Liquid Liquid Extraction, LLE), 고상추출법(Solid Phase Extraction, SPE), 고상미세추출법(Solid Phase Micro Extraction, SPME) 등의 분석방법이 있다. 그 중에서 본 연구에서는 간편하고 정확성이 높은 SPE를 이용하였으며, 적은 양의 유기용제를 사용하여 전처리함으로써 2차적인 환경 오염을 줄일 수 있다는 점에서 다른 전처리 방법보다 유용하다고 할 수 있다. 또한 프탈레이트 에스테르의 경우는 구조적으로 안정적인 편이나 페놀류의 경우 hydroxy group 때문에 GC/MS 분석시 유도체화 과정이 필수적이나 이번 연구에서는 HPLC를 이용하므로 별도의 유도체화의 번거로움 없이 바로 분석할 수 있는 이점이 있다. 더 많은 연구가 필요하겠지만 앞서서의 결과에서도 알 수 있듯이 전반적으로 검출한계가 0.1$\sim$0.5$\mu$g/L 정도로 높고, 82% 이상의 양호한 회수율을 나타낸 것으로 미루어 보아 극미량 분석이 아닌 이상, 산업체에서 HPLC의 이용이 더욱 유리할 것이라고 사료된다.

• Bulletin of Food Technology
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• v.21 no.2
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• pp.49-54
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• 2008

농산물 중 잔류농약을 보다 쉽고 효율적으로 분석 할 수 있는 다성분 동시분석 방법에 따라서 UPLC-PDA을 이용하여 기기조건에 따른 검출한계 및 정량한계를 식품별 최저 MRL과 비교하여 유효성을 알아보고 회수율을 통하여 방법의 재현성을 조사한 결과 다음과 같다. 41종의 농약에 대한 검량선은 직선성이 우수하였으며 검출한계 $0.005{\sim}0.109mg/kg$으로 나타났으며 정량한계 는 $0.018{\sim}0.363ppm$으로 나타났다. Cycloprothrin 등의 경우처럼 검출기의 감응도가 최저 MRL 기준을 초과하는 농약에 대한 보완으로는 검출감도가보다 우수한 UV 검출기 등의 병행 활용이 필요하다. 회수율에 따른 재현성은 쌀의 경우 첨가 농도 0.4 mg/kg 일때 $62.09{\sim}99.58%$로 편차범위는 $1.03{\sim}13.92%$ 얻을 수 있었다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.4
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• pp.333-340
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• 2019

This study attempted to eatablish a high performance liquid chromatography (HPLC) analysis method for the determination of avicularin, quercitrin as a part of the quality control for the development of functional cosmetic materials from Astilbe chinensis extract. HPLC was performed on a Capcell Pak C₁₈ MGII column with a gradient elution of 0.05% (v/v) trifluoroacetic acid (TFA) and acetonitrile at a flow rate of 1.0 mL/min at 30 ℃. The analyte was detected at 254 nm. The HPLC method was performed in accordance with the international conference on harmonization (ICH) guideline (version 4, 2005) of analytical procedures with respect to specificity, precision, accuracy, and linearity. The limits of detection and quantitation of avicularin and quercitrin were 0.094 and 0.285 mg/mL, 0.031 and 0.095 mg/mL respectively. Calibration curves showed good linearity r² > 0.99990 for avicularin and r² > 0.99994 for quercitrin. Precision of analysis was satisfied with less than 0.59% for avicularin and 0.63% for quercitrin. Recoveries of quantified compounds ranged from 100.97 to 101.77% for avicularin and 100.18 to 100.32% for quercitrin. These result indicated that the established HPLC method is very useful for the determination of marker compounds in A. chinensis extracts.