• 한국동물위생학회지
• /
• 제38권2호
• /
• pp.127-136
• /
• 2015

A simultaneous determination method was developed for nine preservatives (benzoic acid, sorbic acid, dehydroacetic acid, methyl-, ethyl-, isopropyl-, propyl-, isobutyl- and butyl-parabens) in sausage by liquid chromatography with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). Each parameter was established by multiple reaction monitoring in negative mode. Separation was achieved on a phenyl-hexyl ($2.5{\mu}m$, $2.1{\times}150mm$, Waters) with A-20 mM ammonium acetate containing 0.1% acetic acid in water, B-Acetonitrile as mobile phase with gradient mode at a flow rate of 0.3 mL/min. The developed method was validated for specificity, linearity, accuracy and precision in sausages samples. Linearity was over 0.998 with calibration curve of the mixed standards. The mean recoveries from sausages fortified at the level of 2.0~10.0 mg/L were in range of 98.60~109.16% with RSDs lower than 8.93%. The limits of detection (LOD) and the limits of quantification (LOQ) were in the range between 0.0003~0.085 mg/L and 0.01~0.257 mg/L, respectively. Intra-day precision and inter-day precision were 0.45~6.16% and 2.81~13.33%, respectively. Using presently developed determination method, 33 field sausage samples from Gwangju city in Korea were screened over nine preservatives. As a result, no preservatives were detected in all samples.

• Bulletin of the Korean Chemical Society
• /
• 제30권9호
• /
• pp.2021-2026
• /
• 2009

Toluene, xylene and styrene are volatile organic solvents that are commonly used in mixtures in many industries. Because these solvents are metabolized and then excreted in urine, their urinary metabolites are thought to be biomarkers of occupational exposure to these solvents. Therefore, a simple, rapid, and yet reliable analytical method for determining the metabolites is required for accurate biological monitoring. In the present study, a simple and rapid HPLC-UV method was developed for the simultaneous determination of eight major metabolites of toluene, xylene and styrene: hippuric acid (HA), mandelic acid (MA), o-, m- and p-methylhippuric acids (o-, m- and p-MHAs), and o-, m- and p-cresols. A monolithic column was employed as the stationary phase and several conditions, including flow rate, composition of mobile phase and column temperature, were variables for the optimization of the chromatographic resolution. All eight metabolites were successfully resolved within 5 minutes in 10% aqueous ethanol containing 0.3% acetic acid and 1.6% $\beta$-cyclodextrin, using a flow rate gradient of 1.0 - 5.0 mL/min at 25 ${^{\circ}C}$. The performance of this method was validated by linearity, intra- and inter-day accuracy, and precision. The linearity was observed with correlation coefficients of 0.9998 for HA, 0.9999 for MA, 0.9989 for o-MHA, 0.9998 for m-MHA, 0.9991 for p-MHA, 0.9997 for o-cresol, 0.9998 for m-cresol, and 0.9986 for p-cresol. The intra- and inter-day precision of the method were less than 5.89% (CV) and the accuracy ranged from 92.95 to 106.62%. The validity was further confirmed by analysis of reference samples that were prepared by the inter-laboratory quality assurance program of the Korea Occupational Safety and Health Agency (KOSHA, Seoul, Korea). All measured concentrations of the analytes agreed with the certified values.

• Mass Spectrometry Letters
• /
• 제5권2호
• /
• pp.42-48
• /
• 2014

A specific and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry method (LC-ESI-MS/MS) was developed and validated for the simultaneous quantification of porphyrins (coproporphyrin, pentacarboxylporphyrin, hexacarboxylporphyrin, heptacarboxylporphyrin, and uroporphyrin) in human plasma and urine. Acidified plasma samples and urine samples were prepared by using liquid-liquid extraction using ethyl acetate and protein precipitation with acetonitrile, respectively. The separation was achieved onto a Synergi Fusion RP column ($150mm{\times}2.0mm$, $4{\mu}m$) with a gradient elution of mobile phase A (0.1% formic acid in 2 mmol/L ammonium acetate, v/v) and mobile phase B (20% methanol in acetonitrile, v/v) at a flow rate of $450{\mu}L$/min. Porphyrins and the internal standard (IS), coproporphyrin I-$^{15}N_4$, were detected by a tandem mass spectrometer equipped with an electrospray ion source operating in positive ion mode. Multiple reaction monitoring (MRM) transitions of the protonated precursor ions and the related product ions were optimized to increase selectivity and sensitivity. The proposed method was validated by assessing selectivity, linearity, limit of quantification (LOQ), precision, accuracy, recovery, and stability. The calibration curves were obtained in the range of 0.1-100 nmol/L and the LOQs were estimated as 0.1 nmol/L for all porphyrins. Results obtained from the validation study of porphyrins showed good accuracy, precision, recovery, and stability. Finally, the proposed method was successfully applied to clinical studies on the autism spectrum disorder (ASD) diagnosis of 203 Korean children.

• Journal of Microbiology and Biotechnology
• /
• 제14권1호
• /
• pp.110-115
• /
• 2004

This study was undertaken to develop PCR primers for the simultaneous detection of Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans, using two species-specific reverse primers in combination with a single conserved forward primer. These primers target the variable and conserved regions of the 16S rDNA. The primer specificity was tested against (i) four F. nucleatum and three A. actinomycetemcomitans strains and (ii) seven representatives of the different species of oral bacteria. The primer sensitivity was determined by testing serial dilutions of the purified genomic DNA of F. nucleatum and A. actinomycetemcomitans. The data indicate that species-specific amplicons could be obtained for all the F. nucleatum and A. actinomycetemcomitans strains tested, which were not found in the seven other species. The multiplex PCR could detect as little as 4 fg of chromosomal DNA of F. nucleatum and A. actinomycetemcomitans simultaneously. These findings suggest that these PCR primers are highly sensitive and are suitable for applications in epidemiological studies, diagnosis, and monitoring F. nucleatum and A. actinomycetemcomitans after the treatment of periodontitis.

• Journal of Chest Surgery
• /
• 제54권5호
• /
• pp.377-382
• /
• 2021

Background: Subclavian vein (SV) catheterization is a method for the delivery of fluids, drugs, and blood products, venous blood sampling, and central vein pressure monitoring in cardiac surgery. Catheter occlusion is a serious complication of SV catheterization during cardiac surgery, especially after sternal retractor expansion. Methods: In this observational study, 303 patients who had successful right infraclavicular SV catheterization from September 2019 to April 2020 were enrolled to determine the incidence of catheter occlusion. After catheterization, the lumens of all catheters were checked for the ability to infuse and withdraw blood from the catheter before and after sternal retractor expansion. The patients' characteristics, cannulation approach, on-pump or off-pump technique, occlusion of the catheter and its lumens, and any associated complications were recorded. The data were analyzed using IBM SPSS ver. 22.0 (IBM Corp., Armonk, NY, USA). Results: Of the 303 patients studied, 205 were male (67.7%) and 98 were female (32.3%). Catheter occlusion occurred in 11 patients with on-pump cardiopulmonary bypass (CPB) (227 patients) and 4 patients with off-pump CPB (76 patients) (p=0.863). The incidence of catheter occlusion was 4.95% (15 of 303 patients) with no cases of simultaneous 3-lumen occlusion in a catheter. The most commonly occluded lumen was the distal lumen (57.92%). Simultaneous 2-lumen occlusion occurred in 4 patients. Catheter occlusion was found in 3 of 13 malpositioned catheters (23.07%). Conclusion: The current study showed that malpositioning of the catheter tip was a risk factor for catheter occlusion and that the distal lumen of a triple-lumen catheter was the most commonly occluded lumen.

• 천문학회지
• /
• 제49권6호
• /
• pp.261-288
• /
• 2016

We present the results of simultaneous monitoring observations of $H_2O$ $6_{1,6}-5_{2,3}$ (22GHz) and SiO J=1-0, 2-1, 3-2 maser lines (43, 86, 129GHz) toward five post-AGB (candidate) stars, using the 21-m single-dish telescopes of the Korean VLBI Network. Depending on the target objects, 7 - 11 epochs of data were obtained. We detected both $H_2O$ and SiO maser lines from four sources: OH16.1-0.3, OH38.10-0.13, OH65.5+1.3, and IRAS 19312+1950. We could not detect $H_2O$ maser emission toward OH13.1+5.1 between the late OH/IR and post-AGB stage. The detected $H_2O$ masers show typical double-peaked line profiles. The SiO masers from four sources, except IRAS 19312+1950, show the peaks around the stellar velocity as a single peak, whereas the SiO masers from IRAS 19312+1950 occur above the red peak of the $H_2O$ maser. We analyzed the properties of detected maser lines, and investigated their evolutionary state through comparison with the full widths at zero power. The distribution of observed target sources was also investigated in the IRAS two-color diagram in relation with the evolutionary stage of post-AGB stars. From our analyses, the evolutionary sequence of observed sources is suggested as OH65.5+1.3${\rightarrow}$OH13.1+5.1${\rightarrow}$OH16.1-0.3${\rightarrow}$OH38.10-0.13, except for IRAS 19312+1950. In addition, OH13.1+5.1 from which the $H_2O$ maser has not been detected is suggested to be on the gateway toward the post-AGB stage. With respect to the enigmatic object, IRAS 19312+1950, we could not clearly figure out its nature. To properly explain the unusual phenomena of SiO and $H_2O$ masers, it is essential to establish the relative locations and spatial distributions of two masers using VLBI technique. We also include the $1.2-160{\mu}m$ spectral energy distribution using photometric data from the following surveys: 2MASS, WISE, MSX, IRAS, and AKARI (IRC and FIS). In addition, from the IRAS LRS spectra, we found that the depth of silicate absorption features shows significant variations depending on the evolutionary sequence, associated with the termination of AGB phase mass-loss.

• 한국산학기술학회논문지
• /
• 제19권1호
• /
• pp.654-659
• /
• 2018

본 연구에서는 연안 환경에 대한 대표적인 지상 원격 관측 기기인 Ocean Radar를 이용하여 장기파랑관측을 수행하였다. 지상에 설치한 기기로부터 이루어지는 원격 관측은 소수의 현장 기기 개수로는 관측할 수 없는 넓은 범위의 해역을 통시에 관측할 수 있고 또한 높은 빈도의 지속적인 관측이 가능한 장점이 있다. 장기관측을 위한 Ocean Radar는 과거 지진해일에 의한 피해가 발생하고, 원자력 발전소가 위치한 한국 동해안의 삼척지역에 대해 장기관측을 수행하였으며, 원격관측의 적용성을 검토하기 위해 수압식 파고계를 설치하여 각각의 조사자료를 비교하였다. 원격파랑관측은 연구대상해역 전면에 독일 Helzel사에서 개발된 Array type의 HF-RADAR인 WERA (WavE RAdar)를 2개소에 설치하여 자료를 취득하였으며, 장기간 연속된 관측된 자료의 취득률을 분석해본 결과, Ocean Radar 가 설치된 두 Site의 중심에서 약 24km이며, 약 27km의 범위 내에서는 Wave 자료가 90% 이상 취득되었으며, 시계열로 분석한 결과, 결측된 시간이 전체 계측기간의 1% 미만이다. 직접관측방식인 수압식 파고계와 관측자료를 비교한 결과, RMS 편차는 20cm 이내이며, 상관계수가 0.84 ~ 0.87로 높은 상관관계를 가지는 것으로 분석되었다. 따라서, 금회적용한 Ocean Radar는 기존의 파랑 계측 장비를 대체하여 장기간 면적 파랑관측이 가능할 것으로 생각된다.

• 한국대기환경학회지
• /
• 제28권6호
• /
• pp.697-705
• /
• 2012

Particulate matter (PM) data collected from the Urban Air Monitoring Network in Busan during the period from 2006 through 2010 were statistically examined and analyzed to estimate the probability of exceeding $PM_{2.5}$ 24 hour and annual standard to be implemented from January $1^{st}$, 2015. For Jangrimdong, Yeonsandong, Kijangeup, and Jwadong where simultaneous measurement of $PM_{10}$ and $PM_{2.5}$ was conducted, the probability of exceeding $PM_{2.5}$ standards was estimated using $PM_{2.5}$ data measured on site. For other areas where there were no measured $PM_{2.5}$ data available, the probability of exceeding $PM_{2.5}$ standards was statistically estimated using $PM_{10}$ measured on site and $PM_{2.5}/PM_{10}$ ratios obtained from the four stations where both $PM_{2.5}$ and $PM_{10}$ were monitored simultaneously. At Jangrimdong, Yeonsandong, Kijangeup, and Jwadong, mean value of annual 99 percentile of 24 hr average $PM_{2.5}$ for 5 years from 2006 through 2010 was 99.3, 74.5. 57.0, and $62.5{\mu}g/m^3$, respectively, and the probability of exceeding $PM_{2.5}$ 24 hr standard was estimated at 100%. For areas where there were no measured $PM_{2.5}$ data available, the estimated probability of exceeding $PM_{2.5}$ 24 hr standard was more than 0.82. Mean value of annual average $PM_{2.5}$ from 2008 through 2010 was 31.7 and $27.6{\mu}g/m^3$ for Jangrimdong and Yeonsandong, respectively, which exceeded $PM_{2.5}$ annual standard of $25{\mu}g/m^3$. Mean value of annual average $PM_{2.5}$ during the same period for Kijangeup and Jwadong was 19.2 and $20.7{\mu}g/m^3$, respectively, which satisfied $PM_{2.5}$ annual standard. For other areas where there were no measured $PM_{2.5}$ data available, the probability of exceeding $PM_{2.5}$ annual standard was more than 0.95 except Taejongdae and Kwangahndong. With $PM_{10}$ and $PM_{2.5}$ data measured at 17 Urban Air Monitoring Stations in Busan, the probability of exceeding $PM_{2.5}$ standards was estimated to be very high for almost all areas. This result indicates that proper measures to mitigate $PM_{2.5}$ in Busan should be investigated and established as soon as possible.

• 한국환경과학회지
• /
• 제24권7호
• /
• pp.875-882
• /
• 2015

In 2013, International Agency for Research on Cancer (IARC) concluded that outdoor air pollution is carcinogenic to humans, with the particulate matter component of air pollution most closely associated with sufficient evidence of increased cancer incidence by exposure to particulate matter component of air pollution. Motor vehicles are one of a major emission sources of fine particle ($PM_{2.5}$) in urban areas. A large number of epidemiological studies have reported a positive association of morbidity or mortality with distance from the roadside. We conducted this study to assess the association of $PM_{2.5}$ concentrations measured at roadside hotspots with those at adjacent residential sites using real-time $PM_{2.5}$ monitors. We conducted real-time $PM_{2.5}$ measurements for rush hour periods (08:00~10:00 and 18:00~20:00) at 9 roadside air monitoring Hotspot sites in metropolitan Seoul over 3 weeks from October 1 to 21, 2013. Simultaneous measurements were conducted in residential sites within a 100 m radius from each roadside air monitoring site. A SidePak AM510 was used for the real-time $PM_{2.5}$ measurements. Medians of roadside $PM_{2.5}$ concentrations ranged from $9.8{\mu}g/m^3$ to $38.3{\mu}g/m^3$, while corresponding median values at adjacent residential sites ranged from $4.4{\mu}g/m^3$ to $37.3{\mu}g/m^3$. $PM_{2.5}$ concentrations of residential sites were 0.97 times of hotspot roadside sites. Distributions of $PM_{2.5}$ concentrations in roadside and residential areas were also very similar. Real-time $PM_{2.5}$ concentrations at residential sites, (100 m adjacent), showed similar levels to those at roadside sites. Increasing the distance between roadside and residential sites, if needed, should be considered to protect urban resident populations from $PM_{2.5}$ emitted by traffic related sources.

• Journal of Dairy Science and Biotechnology
• /
• 제33권1호
• /
• pp.27-34
• /
• 2015

본 연구에서는 dispersive-SPE를 사용하여 간편하고, 신속하며, 경제적인 우유 내 19종 잔류농약의 동시 다성분 분석법을 설정하고자 하였다. Liquid-liquid partitioning method와 low-temperature cleanup method를 적용한 추출방법과 PSA 및 PSA + C18의 sorbent가 사용된 dispersive-SPE를 사용한 정제방법을 비교 실험하였으며, GC/MS의 선택이온 검색법(selected ion monitoring, SIM)으로 정량 분석하였다. matrix-matched standards와 matrix-free standards를 사용하여 분석방법의 matrix enhancement effect를 확인하였고, 분석방법 설정을 위한 비교실험의 결과, low-temperature cleanup 방법으로 추출하여 dispersive-SPE(PSA + C18)로 정제하는 방법이 시료 추출물의 간섭물질을 제거하는데 가장 효과적이고, 첨가한 $1{\mu}g/mL$에 대한 개별 농약 성분의 회수율 또한 전체적으로 가장 높은 수준을 나타내었으며, 모든 농약 성분의 RSD(%)가 20% 이하로서 기준에 적합한 재현성을 나타내었다.