• 제목/요약/키워드: mobile phase

검색결과 1,241건 처리시간 0.023초

가공식품 중 아크릴아마이드 분석 (Determination of acrylamide in food products)

  • 정형욱;박성국;최동미
    • 분석과학
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    • 제20권2호
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    • pp.164-169
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    • 2007
  • 고속액체크로마토그라피/질량분석기를 이용하여 가공 식품 중 아크릴아마이드를 분석하였다. 대상 식품은 감자칩 (6종), 프렌치후라이 (11종)으로 총 17종이었다. 시료를 균질화하여 3차 증류수로 추출하고 C18 및 혼합이온교환수지 카트리지를 이용하여 정제한 후 LC/MS/MS으로 분석하였다. 이동상으로는 0.1% 초산과 0.5% 메탄올을 함유하는 수용액을 사용하였으며, 대상물질의 특이이온을 ESI 질량분석기로 확인 및 정량하였다. 평균 회수율은 91~101%이었으며, 정량한계는 $10{\mu}g/kg$이었다. 대상식품의 유형에 따라 검출 수준에 차이를 나타냈으며, 평균 검출수준은 감자칩은 0.71 mg/kg, 프렌치후라이는 0.34 mg/kg이었다.

올리브유 중 벤조피렌 분석 (Determination of benzo(a)pyrene in olive oils)

  • 허수정;우건조;최동미
    • 분석과학
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    • 제20권2호
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    • pp.170-175
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    • 2007
  • 올리브유중 벤조피렌을 분석하기 위하여 고속액체크로마토그래피/형광검출기를 이용하였다. 시료의 지방성분을 헥산으로 제거한 후 N,N-DMF 수용액을 다시 헥산으로 추출하여 후로리실 SPE 카트리지로 정제한 후 기기분석하였다. 이동상으로는 아세토니트릴과 물의 혼합용액(8:2)을 사용하였으며 형광검출기의 여기파장은 294 nm이었고 형광파장은 404 nm이었다. 평균 회수율은 95%이었으며, 정량한계는 $0.9{\mu}g/kg$이었다. 대상 식품인 올리브유 중 벤조피렌의 검출수준은 불검출~$1.9\mu}g/kg$이었으나, 식품공전의 기준인 올리브유중 벤조피렌의 최대수준 $2.0{\mu}g/kg$이하이었다.

동위원소희석 액체크로마토그래피/질량분석법에 의한 혈청 내 콜레스테롤의 정량 (Quantification of cholesterol in human serum by isotope dilution liquid chromatography/mass spectrometry)

  • 신혜선;이화심;이계호
    • 분석과학
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    • 제21권6호
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    • pp.502-509
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    • 2008
  • 혈청 내 콜레스테롤을 정량분석하기 위한 일차분석법으로 동위원소희석 액체크로마토그래피/질량분석법(isotope dilution liquid chromatography/mass spectrometry)을 사용하였다. 콜레스테롤은 Thermo ODS hypersil $C^{18}$ 칼럼을 사용하여 분리하였고, 이동상은 100% 메탄올, 유속은 0.3 mL/min으로 하였다. 콜레스테롤과 콜레스테롤-$3,4-13C_2$$[M-H_2O+H]^+$이온에 해당하는 m/z 369.4와 371.3에서 모니터링하여 정량에 합당한 크로마토그램을 얻을 수 있었다. 방법의 유효성을 증명하기 위해서 NIST SRM 909b를 분석한 결과 인증값과 불확도 범위 내에서 일치하는 것을 확인하였다. 이 방법을 바탕으로 혈청 인증표준 물질 4 종류를 제조하여 인증을 실시하였다. 인증 결과, 반복성의 상대표준오차는 0.1~0.8%, 재현성의 경우 0.24%이하, 확장 불확도는 95% 신뢰도구간에서 약 1.43%로 나타났다.

Worker Safety in Modular Construction: Investigating Accident Trends, Safety Risk Factors, and Potential Role of Smart Technologies

  • Khan, Muhammad;Mccrary, Evan;Nnaji, Chukwuma;Awolusi, Ibukun
    • 국제학술발표논문집
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    • The 9th International Conference on Construction Engineering and Project Management
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    • pp.579-586
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    • 2022
  • Modular building is a fast-growing construction method, mainly due to its ability to drastically reduce the amount of time it takes to construct a building and produce higher-quality buildings at a more consistent rate. However, while modular construction is relatively safer than traditional construction methods, workers are still exposed to hazards that lead to injuries and fatalities, and these hazards could be controlled using emerging smart technologies. Currently, limited information is available at the intersection of modular construction, safety risk, and smart safety technologies. This paper aims to investigate what aspects of modular construction are most dangerous for its workers, highlight specific risks in its processes, and propose ways to utilize smart technologies to mitigate these safety risks. Findings from the archival analysis of accident reports in Occupational Safety and Health Administration (OSHA) Fatality and Catastrophe Investigation Summaries indicate that 114 significant injuries were reported between 2002 and 2021, of which 67 were fatalities. About 72% of fatalities occurred during the installation phase, while 57% were caused by crushing and 85% of crash-related incidents were caused by jack failure/slippage. IoT-enabled wearable sensing devices, computer vision, smart safety harness, and Augment and Virtual Reality were identified as potential solutions for mitigating identified safety risks. The present study contributes to knowledge by identifying important safety trends, critical safety risk factors and proposing practical emerging methods for controlling these risks.

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Structural evaluation of degradation products of Loteprednol using LC-MS/MS: Development of an HPLC method for analyzing process-related impurities of Loteprednol

  • Rajesh Varma Bhupatiraju;Bikshal Babu Kasimala;Lavanya Nagamalla;Fathima Sayed
    • 분석과학
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    • 제37권2호
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    • pp.98-113
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    • 2024
  • The current investigation entails the characterization of five degradation products (DPs) formed under different stress conditions of loteprednol using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition, this study developed a stable high-performance liquid chromatography (HPLC) method for evaluating loteprednol along with impurities. The method conditions were meticulously fine-tuned which involved the exploration of the appropriate solvent, pH, flow of the mobile phase, columns, and wavelength. The method conditions were carefully chosen to successfully resolve the impurities of loteprednol and were employed in subsequent validation procedures. The stability profile of loteprednol was exposed to stress degradation experiments conducted under five conditions, and DPs were structurally characterized by employing LC-MS/MS. The chromatographic resolution of loteprednol and its impurities along with DPs was effectively achieved using a Phenomenex Luna 250 mm C18 column using 0.1 % phosphoric acid, methanol, and acetonitrile in 45:25:30 (v/v) pumped isocratically at 0.8 mL/min with 243 nm wavelength. The method produces an accurate fit calibration curve in 50-300 ㎍/mL for loteprednol and LOQ (0.05 ㎍/mL) - 0.30 ㎍/mL for its impurities with acceptable precision, accuracy, and recovery. The stress-induced degradation study revealed the degradation of loteprednol under basic, acidic, and photolytic conditions, resulting in the formation of seven distinct DPs. The efficacy of this method was validated through LC-MS/MS, which allowed for the verification of the chemical structures of the newly generated DPs of loteprednol. This method was appropriate for assessing the impurities of loteprednol and can also be appropriate for structural and quantitative assessment of its degradation products.

계피 에탄올 추출물의 유효성분 분석 및 항산화 효능 평가 (Antioxidant Potential of Cinnamomum cassia Ethanolic Extract: Identification Of Compounds)

  • 허지웅;손재동;양예진;김민정;양주혜;박광일
    • 대한한의학방제학회지
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    • 제32권3호
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    • pp.223-233
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    • 2024
  • Objectives : Natural products containing bioactive compounds with high antioxidant activity are potentially important sources that can contribute to the improvement of various diseases. Therefore, the aim of this study was to investigate phenolic compounds of Cinnamomum cassia (C. cassia) ethanolic extract (CCEE). And then we evaluated the antioxidant effect. Methods : We used liquid chromatography with tandem mass spectrometry (LC-MS/MS) to identify the compounds in CCEE. LC-MS/MS was performed in positive ion mode using Shimadzu, Nexera HPLC system and IDA TOF mass system. Solvent A was distilled water and solvent B was acetonitrile as mobile phase. The analysis was performed at a flow rate of 0.5 ml/min, column temperature of 35 ℃ and wavelength of 284 nm. The antioxidant effect of CCEE was analyzed using DPPH (2,2-diphenyl-2-picrylhydrazyl free radical) and ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)). In addition, total phenolics and total flavonoids contents were measured to determine antioxidant effects. Results : Analysis using LC-MS/MS identified four compounds: Coumarin, Trans-cinnamaldehyde, Trans-cinnamic acid, and 2-Methoxycinnamaldehyde. Free radicals decreased in a concentration-dependent manner starting from 10 ㎍/ml of CCEE, and decreased to a level similar to Ascorbic acid (AA) from a concentration of 60 ㎍/ml onwards. Conclusions : Based on the findings, CCEE exhibits strong antioxidant activity as evidenced by the presence of Coumarin, Trans-cinnamaldehyde, Trans-cinnamic acid, and 2-Methoxycinnamaldehyde. Consequently, this study suggests that CCEE can serve as an important source of natural antioxidants and can be efficiently used in the management of oxidative stress diseases.

식품 중 인공감미료의 분석법에 관한 연구 (A Study on the Analytical Method of Artificial Sweeteners in Foods)

  • 김희연;윤혜정;홍기형;이창희;박성관;최장덕;최우정;박선영;김지혜;이철원
    • 한국식품과학회지
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    • 제36권1호
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    • pp.14-18
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    • 2004
  • 본 연구는 인공감미료의 사용확대에 따른 실태 파악 및 실제 섭취량 조사를 통해 현행 사용기준의 안전수준에 대한 안전성을 확보하는 연구의 기초자료로서 우리나라에서 식품첨가물로 허용되어 있는 인공감미료인 삭카린나트륨, 아스파탐, 아세설팜칼륨 및 수크랄로스에 대한 식품 중 분석법을 확립하였으며 결과는 다음과 같다. 먼저 투석이나 정제과정 없이 보다 간편하고 짧은 시간에 효율적으로 시료를 전처리할 수 있는 방법을 시료의 성상에 따라 확립하였다. 고속액체크로마토그래프(HPLC)의 최적 분석조건을 검토한 결과, 삭카린나트륨, 아스파탐 및 아세설팜칼륨의 3종 인공감미료의 분석에 컬럼은 Symmetry $C_{18}(3.9mm\;i.d{\times}150mm,\;5{\mu}m)$, 이동상은 0.005M tetrapropylammonium hydroxide가 함유된 0.01M $KH_{2}PO_{4}$: acetonitrile(9:1, pH 3.5). 측정파장은 210mm로 설정하였다. 수크랄로스의 분석조건은 컬럼은 Symmetry $C_{18}(3.9mm\;i.d{\times}150mm,\;5{\mu}m)$, 이동상은 water: methanol(7:3)을 사용하였고 검출기는 굴절율 검출기(RI), sensitivity=16호 설정하였다. 검출한계는 삭카린나트륨, 아스파탐 및 아세설팜칼륨은 각각 0.1ppm, 수크랄로스는 25ppm으로 측정되었다. 이와 같이 결정된 인공감미료의 최적 분석조건으로 회수율을 측정한 결과 아스파탐 92.5%, 아세설팜칼륨 97.3%, 삭카린나트륨 96.5%, 수크랄로스 93.4%로 양호한 결과를 얻었다. 시중에서 유통되고 있는 제품 중 총 17종 151품목을 다상으로 4종의 인공감미료 함량을 정량한 결과, 아스파탐은 탄산음료 2품목에서 $180.8{\mu}g/g$, 발효음료 4품목에서 $65.3{\mu}g/g$, 껌 2품목에서 $232.5{\mu}g/g$, 사탕 1품목에서 $1,672.0{\mu}g/g$, 혼합제제식품첨가물 2품목에서 $5,259.0{\mu}g/g$이 검출되었으며 아세설팜칼륨은 탄산음료 2품목에서 $110.8{\mu}g/g$, 껌 3품목에서 $250.3{\mu}g/g$, 혼합제제식품첨가물 1품목에서 $2,362.1{\mu}g/g$, 삭카린나트륨은 어묵 1품목에서 $42.3{\mu}g/g$, 수크랄로스는 껌 1품목에서 $120.1{\mu}g/g$이 검출되었으며 검출된 인공감미료는 표시사항과 일치하였다.

고성능액체크로마토그래피-유도결합플라즈마 질량분석기를 이용한 어류 중 메틸수은 분석법 확립 (Establishment of Analytical Method for Methylmercury in Fish by Using HPLC-ICP/MS)

  • 유경열;반경녀;김은정;김양선;명정은;윤혜성;김미혜
    • 한국환경농학회지
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    • 제30권3호
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    • pp.288-294
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    • 2011
  • 최근에는 전처리가 단순하며 정량 시 방해물질의 영향을 최소화하기 위해 액체크로마토그래피를 이용하여 메틸수은을 분리한 후 유도결합플라즈마/질량분석기로 part per billion 수준까지 정량하는 방법들의 연구가 활발하다. 하지만 대부분의 액체크로마토그래피-유도결합플라즈마/질량분석기는 메틸수은 분리 시 전처리 용액의 pH를 조절하지 않으면 피크깨짐 등의 문제가 발생하여 pH를 조절하고 있다. 본 연구에서는 어류에 잔류하는 메틸수은을 신속하고 정확하게 분석하기 위하여 마이크로웨이브를 이용한 전처리 방법, HPLCICP/MS 조건, 시험법 검증의 실험을 통하여 효율적인 분석법을 확립하였다. 전처리 방법은 추출용매 1% L-cysteine HCl로 추출온도 $60^{\circ}C$에서 추출시간 120분 동안 추출하는 최적 조건을 확립하였다. 기기조건 중 HPLC에서는 시료주 입량 $50{\mu}L$, 컬럼온도는 $25^{\circ}C$에서 0.1% L-cysteine HCl + 0.1% L-cysteine 이동상으로 메틸수은을 분리 한 후, ICP-MS에서 분자량 202의 분석물질을 정량하는 조건을 확립하였다. 직선성에 대한 상관계수 값은 0.9998 이였으며, 검출한계 및 정량한계는 각각 0.15, $0.45{\mu}g/kg$ 이었다. 확립된 전처리 및 기기조건을 통하여 시료별 회수율을 구한 결과 95~99%였다. 전처리 용매와 이동상에 L-cysteine이 존재함으로써 수은에 대한 안정성, Memory effect 및 피크 끌림 등의 문제를 해결할 수 있었다. 확립된 HPLC-ICP/MS 방법에 대해 표준인증물질을 이용하여 검증한 결과, 회수율 및 상대표준편차가 각각 93~96%, 1~3%였다. 확립된 방법은 추출과정 후 별도의 전처리 과정 없이 바로 HPLC-ICP/MS를 이용하여 검출할 수 있어 메틸수은을 분석하기에 매우 적합한 것으로 판단된다.

식품 중 감초추출물 및 에리스리톨 분석법에 관한 연구 (Studies on the Determination Method of Natural Sweeteners in Foods - Licorice Extract and Erythritol)

  • 홍기형;이달수;장영미;박성관;박성국;권용관;장선영;한윤정;원혜진;황혜신;김병섭;김은정;김명철
    • 한국식품위생안전성학회지
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    • 제20권4호
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    • pp.258-266
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    • 2005
  • 현재 우리나라에서 허용된 식품첨가물인 감초추출물 및 에리스리톨의 경우 천연감미료로서 식품의 제조$\cdot$가공시 다양하게 사용되고 있으나 유통식품 중 식품 중 이들 첨가물의 함유여부 및 함유량을 파악할 수 있는 분석방법이 확립되어 있지 않은 실정이다. 따라서, 본 연구에서는 식품 중 감초추출물 및 에리스리톨의 분석방법을 확립하고, 이를 적용하여 국내유통식품 중 감초추출물 및 에리스리틀의 사용실태를 파악하고자 하였다. 식품 중 감초추출물 및 에리스리톨의 분석방법에 대한 최근 국내의 문헌 및 연구논문 등 기초 자료를 참고로 감초추출물 TLC및 HPLC분석방법과 에리스리톨 HPLC 분석방법을 비교$\cdot$검토하였다. 그 결과 감초추출물은 실리카겔 TLC판을 이용하였으며 TLC 최적용매조건은 부틸알콜 : 4N 암모니아용액 : 에틸알콜 50:20:10)이었다. HPLC 분석은 글리실리진산 (glycyrrhizic acid)을 표준물질로 하여 역상계 컬럼인 Capcell pak $C_{18}$ UG120을 사용하였으며 이동상, UV파장, 컬럼온도는 각각 아세토니트릴 : 물 (38:62), 254 nm 및 $40^{\circ}C$이었다. 에리스리톨의 HPLC 분석은 에리스리톨(meso- erythritol을 표준물질로 하여 역상계 컬럼인 Shodex Asahipak NH2P-50 4E 및 RI 검출기를 사용하였으며 이동상, 컬럼온도는 각각 아세토니트릴 : 물 (75:25), $30^{\circ}C$이었다. 글리실리진산은 서울,부산 등 11개 도시에서 구매한 국내 유통 가공식품 중 장류 18품목, 소스류 12품목, 건강기능식품류 15품목, 음료류 26품목, 주류 8품목, 과자류 23품목, 절임류 3품목 등 총 7종 105품목을 대상품목으로 하였으며 이 중 장류, 소스류, 건강기능식품, 음료류, 주류에서 각각 ND$\∼$48.7 ppm, ND$\∼$5.3 ppm, ND$\∼$988.9 ppm, ND$\∼$180.7 ppm, ND$\∼$2.6 ppm의 글리실리진산이 검출되었고, 나머지 품목은 모두 불검출이었다. 에리스리틀의 경우 껌류 13품목, 캔디류 15품목, 음료류 12품목, 건강기능식품류 12품목등 총 4종 52품목을 대상품목으로 하었으며, 껌류 및 건강기능식품에서 각각 ND$\∼$155.62 ppm, ND$\∼$398.14 ppm의 에리스리톨이 검출되었으며, 나머지 품목은 모두 불검출이었다. 본 연구결과는 식품 중 천연감미료인 감초추출물 및 에리스리톨의 분석방법 확립함으로써 국내유통식품의 감초추출물 및 에리스리톨 사용실태파악 및 사후 식품의 품질관리에 기여할 수 있을 것으로 사료된다.

U-마켓에서의 사용자 정보보호를 위한 매장 추천방법 (A Store Recommendation Procedure in Ubiquitous Market for User Privacy)

  • 김재경;채경희;구자철
    • Asia pacific journal of information systems
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    • 제18권3호
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    • pp.123-145
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    • 2008
  • Recently, as the information communication technology develops, the discussion regarding the ubiquitous environment is occurring in diverse perspectives. Ubiquitous environment is an environment that could transfer data through networks regardless of the physical space, virtual space, time or location. In order to realize the ubiquitous environment, the Pervasive Sensing technology that enables the recognition of users' data without the border between physical and virtual space is required. In addition, the latest and diversified technologies such as Context-Awareness technology are necessary to construct the context around the user by sharing the data accessed through the Pervasive Sensing technology and linkage technology that is to prevent information loss through the wired, wireless networking and database. Especially, Pervasive Sensing technology is taken as an essential technology that enables user oriented services by recognizing the needs of the users even before the users inquire. There are lots of characteristics of ubiquitous environment through the technologies mentioned above such as ubiquity, abundance of data, mutuality, high information density, individualization and customization. Among them, information density directs the accessible amount and quality of the information and it is stored in bulk with ensured quality through Pervasive Sensing technology. Using this, in the companies, the personalized contents(or information) providing became possible for a target customer. Most of all, there are an increasing number of researches with respect to recommender systems that provide what customers need even when the customers do not explicitly ask something for their needs. Recommender systems are well renowned for its affirmative effect that enlarges the selling opportunities and reduces the searching cost of customers since it finds and provides information according to the customers' traits and preference in advance, in a commerce environment. Recommender systems have proved its usability through several methodologies and experiments conducted upon many different fields from the mid-1990s. Most of the researches related with the recommender systems until now take the products or information of internet or mobile context as its object, but there is not enough research concerned with recommending adequate store to customers in a ubiquitous environment. It is possible to track customers' behaviors in a ubiquitous environment, the same way it is implemented in an online market space even when customers are purchasing in an offline marketplace. Unlike existing internet space, in ubiquitous environment, the interest toward the stores is increasing that provides information according to the traffic line of the customers. In other words, the same product can be purchased in several different stores and the preferred store can be different from the customers by personal preference such as traffic line between stores, location, atmosphere, quality, and price. Krulwich(1997) has developed Lifestyle Finder which recommends a product and a store by using the demographical information and purchasing information generated in the internet commerce. Also, Fano(1998) has created a Shopper's Eye which is an information proving system. The information regarding the closest store from the customers' present location is shown when the customer has sent a to-buy list, Sadeh(2003) developed MyCampus that recommends appropriate information and a store in accordance with the schedule saved in a customers' mobile. Moreover, Keegan and O'Hare(2004) came up with EasiShop that provides the suitable tore information including price, after service, and accessibility after analyzing the to-buy list and the current location of customers. However, Krulwich(1997) does not indicate the characteristics of physical space based on the online commerce context and Keegan and O'Hare(2004) only provides information about store related to a product, while Fano(1998) does not fully consider the relationship between the preference toward the stores and the store itself. The most recent research by Sedah(2003), experimented on campus by suggesting recommender systems that reflect situation and preference information besides the characteristics of the physical space. Yet, there is a potential problem since the researches are based on location and preference information of customers which is connected to the invasion of privacy. The primary beginning point of controversy is an invasion of privacy and individual information in a ubiquitous environment according to researches conducted by Al-Muhtadi(2002), Beresford and Stajano(2003), and Ren(2006). Additionally, individuals want to be left anonymous to protect their own personal information, mentioned in Srivastava(2000). Therefore, in this paper, we suggest a methodology to recommend stores in U-market on the basis of ubiquitous environment not using personal information in order to protect individual information and privacy. The main idea behind our suggested methodology is based on Feature Matrices model (FM model, Shahabi and Banaei-Kashani, 2003) that uses clusters of customers' similar transaction data, which is similar to the Collaborative Filtering. However unlike Collaborative Filtering, this methodology overcomes the problems of personal information and privacy since it is not aware of the customer, exactly who they are, The methodology is compared with single trait model(vector model) such as visitor logs, while looking at the actual improvements of the recommendation when the context information is used. It is not easy to find real U-market data, so we experimented with factual data from a real department store with context information. The recommendation procedure of U-market proposed in this paper is divided into four major phases. First phase is collecting and preprocessing data for analysis of shopping patterns of customers. The traits of shopping patterns are expressed as feature matrices of N dimension. On second phase, the similar shopping patterns are grouped into clusters and the representative pattern of each cluster is derived. The distance between shopping patterns is calculated by Projected Pure Euclidean Distance (Shahabi and Banaei-Kashani, 2003). Third phase finds a representative pattern that is similar to a target customer, and at the same time, the shopping information of the customer is traced and saved dynamically. Fourth, the next store is recommended based on the physical distance between stores of representative patterns and the present location of target customer. In this research, we have evaluated the accuracy of recommendation method based on a factual data derived from a department store. There are technological difficulties of tracking on a real-time basis so we extracted purchasing related information and we added on context information on each transaction. As a result, recommendation based on FM model that applies purchasing and context information is more stable and accurate compared to that of vector model. Additionally, we could find more precise recommendation result as more shopping information is accumulated. Realistically, because of the limitation of ubiquitous environment realization, we were not able to reflect on all different kinds of context but more explicit analysis is expected to be attainable in the future after practical system is embodied.