• Food Science and Biotechnology
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• 제18권2호
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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.

• Mass Spectrometry Letters
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• 제2권1호
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• pp.12-15
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• 2011

The Korean government has regulated emission of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in waste water of manufacturing facilities producing chlorinated compounds since 2009. As this regulation is expected to be reinforced in 2013 to 50 pg I-TEQ/L, a large sample volume is required for the analysis of trace amounts of PCDD/Fs in waste water. Liquid-liquid extraction (LLE) is used to extract PCDD/Fs from aqueous samples; however, its low efficiency makes it inadequate for analyzing large sample volumes. Herein, we present a disk-type solid-phase extraction (SPE) method for the analysis of dioxin at a part per quadrillion level in waste water. This SPE system contains airtight glass covers with a decompression pump, which enables continuous semi-automated extraction. Small (0.5 L) and large (7 L) samples were extracted using LLE and SPE methods, respectively. The method detection limits (MDLs) were 0.001.0.25 and 0.015.4.1 pg I-TEQ/L for the SPE and LLE methods, respectively. The concentrations of detected congeners with both methods were similar. However, the concentrations of several congeners that were not detected with the LLE method were quantified using the SPE method.

• 농약과학회지
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• 제17권2호
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• pp.107-116
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• 2013

액-액 분배법을 이용한 pymetrozine의 잔류분석방법을 다양한 작물에 적용이 가능하도록 작물의 특성과 대상농약의 물리화학적 특성을 고려하여 간섭물질을 최소화한 방법을 확립하였다. 확립된 분석법의 validation을 진행하였으며 정확성 및 정밀성, 검출한계, 정량한계, 직선성(표준물질의 검량선)을 기준으로 진행하였다. 대표 농산물로 쌀, 현미, 감자, 고추, 배추, 브로콜리, 수박, 쑥갓, 블루베리, 사과 및 체리를 선정하였으며, 농산물 시료에 borax 완충용액과 1N-NaOH 수용액을 가하여 pH를 조절하고 methanol로 추출된 pymetrozine 잔류분은 dichloromethane 액-액 분배법과 silica SPE cartridge를 이용한 silica 흡착크로마토그래피법으로 정제하여 분석대상 시료로 하였다. Pymetrozine의 정량적 분석을 위한 최적 HPLC 분석 조건을 확립하였고, $C_8$ 칼럼을 이용한 HPLC 분석 시 불순물의 간섭은 없었으며, 11종의 대표 농산물 중 pymetrozine의 분석정량한계(MQL)는 0.01 mg/kg이었다. 전체 농산물에 대한 회수율은 83.1~98.5%였으며, 농산물 시료 및 처리수준에 관계없이 반복 간 분석오차는 10% 미만을 나타내어 잔류분석 기준이내를 만족하였다. 검출한계, 회수율 및 분석오차 면에서 국제적 분석기준을 충분히 만족하였으므로, 본 연구에서 확립된 분석법은 기존의 hydromatrix 분배법을 대체하여 농산물 중 pymetrozine의 잔류분석법으로 사용이 가능할 것으로 판단된다.

• Mass Spectrometry Letters
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• 제13권4호
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• pp.146-151
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• 2022

Rotigotine (RTG) is a non-ergot dopamine agonist used to manage the early stage of Parkinson's disease (PD) as transdermal patch. However, the poor medication compliance of PD patients and skin issues related with repeated applications of RTG patches lead to the search for alternative formulations and it also requires appropriate analytical methods for their in vivo evaluation. Thus, here, a sensitive, efficient, and cost-effective method to determine RTG in rat plasma using liquid-liquid extraction (LLE) and multiple reaction monitoring was developed. The use of 20 µL of rat plasma for sample treatment, 8-OH-DPAT as the internal standard, and methyl tert-butyl ether as the LLE solvent in the present method gives it advantages over previous methods for the analysis of RTG in biological samples. The good analytical performance of the developed method was confirmed in specificity, linearity (the coefficient of determination ≥0.999 within 0.1-100 ng/mL), sensitivity (the lower limit of quantitation at 0.1 ng/mL), accuracy (81.00-115.05%), precision (≤10.75%), and recovery (81.00-104.48%) by following the FDA guidelines. Finally, the applicability test of the validated method to the in vivo evaluation of a RTG formulation showed that the present method is the only method which can be accurately applied to that longer than 24 hours, critical for the development of formulations with reduced dosing frequencies. Therefore, the present method could contribute to the development of new RTG formulations helpful to people suffering from PD.

• Asian-Australasian Journal of Animal Sciences
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• 제14권10호
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• pp.1465-1469
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• 2001

A sensitive high-performance liquid chromatographic method was developed to determine the content of cholesterol in milk and dairy products. To optimize separation of cholesterol, mobile phases including acetonitrile:2-propanol (8:1, v/v), acetonitrile:methanol (3:1, v/v), and acetonitrile:methanoI:2-propanol (7:3: I, v/v/v) were compared. Acetonitrile/methanol/2-propanol was superior to the other mobile phase systems for separating cholesterol. Liquid-liquid extraction (LLE) of cholesterol was simplified using a non-polar solvent, hexane, to remove interfering compounds, and had an excellent recovery $(100{\pm}1.0%)$ of cholesterol. A solid phase extraction (SPE) method using Sep-pak $C_{18}$ was developed and compared with LLE. The SPE method was rapid and highly reproducible. Both extraction methods were useful when used in combination with saponification of esterified cholesterol to facilitate total cholesterol determination. The detection limit of cholesterol was $0.01{\mu}g$. The newly developed HPLC method was rapid, simple, and accurate, and has advantages over the many methods commonly used.

• 대한화학회지
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• 제47권6호
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• pp.559-568
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• 2003

LLE-GC/MS법을 사용하여 내분비계 교란물질로 추정되는 항 산화제 및 살충제를 동시에 분석할 수 있는 방법을 고안하였다. 본 연구에서 사용한 항 산화제는 butylated hydroxy anisole(BHA) 및 butylated hydroxy toluene (BHT)이고, 살충제는 allethrin 및 fenvalerate이었다. 표준시료에 대한 분석결과에서 검출한계(LOD)는 0.071~0.159 ng/ml이었으며, 이 때 상대표준편차는(%RSD)는 1.41~5.34이었다. 한강, 금강, 낙동강 및 섬진강 수계 중에서 이들 화합물들은 검출되지 않았다. 합성한 시료의 경우, 검출한계(LOD)는 0.051~0.132 ng/ml이었으며, 이 때 상대표준편차(%RSD)는 6.39~13.4% 이었다.

• 대한화학회지
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• 제43권6호
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• pp.663-669
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• 1999

HPLC/UV 및 GC/FPD 법을 사용하여 환경수에 존재하는 Diazinon, EPN, Fenitrothion, Phosalon 및 Phosmet 등 5종의 유기인계 잔류농약을 분석하였다. 전처리 과정으로 고체상추출법(SPE)과 용매추출법(LLE)을 각각 적용한 결과, 회수율과 재현성에 있어, HPLC/UV에서는 용매추출법(LLE)보다 고체상추출법(SPE)이 더 우수하였고, GC/FPD에서는 고체상추출법(SPE)보다 용매추출법(LLE)이 더 우수하였다. 또 수돗물 및 하천수(와룡천)에 일정량의 유기인계 농약을 가하여 만든 합성시료중 각 성분을 분석한 결과, SPE-HPLC/UV 법에서는 회수율이 101%, % RSD는 4.3∼8.7이었고, LLE-GC/FPD 법에서는 회수율이 100%, % RSD는 3.2∼9.5이었다. 이 결과는 두 방법 모두 유기인계 잔류농약 분석에 이용할 수 있는 우수한 방법임을 제시하고 있다.

• Mass Spectrometry Letters
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• 제8권1호
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• pp.18-22
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• 2017

Products containing any one or more of 26 fragrance allergens likely to cause contact allergies, are required under the 2008 domestic cosmetic law to be labeled when their concentrations exceed a certain range. This study focuses on the comparison and development of analytical methods based on headspace-solid phase micro extraction (HS-SPME) and liquid-liquid extraction (LLE) methods followed by GC-MS/MS for 24 of the fragrance allergens excepting for two natural materials in water samples. Using the developed HS-SPME method, 15 of the 24 fragrance allergens were analyzed and 9 compounds which have relatively low $logK_{OW}$ values (below about 2.5) were not extracted, and the correlation coefficient ($r^2$) of the calibration curve for quantification showed linearity of 0.9969 or more, and the method detection limits (MDL) and the limits of quantification (LOQ) were $0.078{\sim}0.582{\mu}g/L$ and $0.261{\sim}1.940{\mu}g/L$, respectively. In the case of using the optimized LLE method, all 24 fragrance allergens were analyzed, and the correlation coefficient ($r^2$) of the calibration curve for quantification showed linearity of 0.9957 or more, MDL and LOQ were $0.020{\sim}0.138{\mu}g/L$ and $0.065{\sim}0.440{\mu}g/L$, respectively.

• 분석과학
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• 제22권1호
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• pp.65-74
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• 2009

옻나무는 아시아지역 전역에 주로 분포하며 예로부터 도료 및 약용 식물로 많이 사용되어져 왔었다. 특히 우리나라에서 재배되는 옻나무가 그 기능이 더욱 우수하다고 알려져 있는데 그 원인은 명확히 밝혀진 바가 없다. 우선 옻나무에서 우루시올의 추출을 위하여 나무는 soxhlet의 방법으로, 옻나무 추출물은 liquid-liquid extraction (LLE)의 방법을 이용하여 각각의 우루시올을 추출하였으며, 추출한 각 성분들은 high performance liquid chromatography/ultraviolet & visible detector system (HPLC/UV-Vis)에 먼저 적용하여 분리의 최적 조건을 찾았다. 그리고 각 성분에 대한 정확한 분석을 위하여 reverse phase liquid chromatography on-line electro spray ionization mass spectrometer (LC-MS/MS)를 이용하였으며 이를 바탕으로 분자량에 따른 성분 확인과 함량을 연구하였다. 이동상의 조건으로는 methanol : 0.1% formic acid : DDW를 929 : 1 : 70의 부피비로 사용하여 최적의 분리 조건을 얻었다. 이러한 LC의 조건으로 다시 LC-MS/MS에 적용하여 MRM의 방식으로 각각의 함량을 구할 수 있었다. 분자량에 따라 총 4종류의 우루시올 동종체들이 존재를 확인하였다. 본 연구를 통하여 한국산 옻나무 추출물의 경우 외국산 옻나무의 것 보다 곁사슬에 이중결합이 많은 우루시올 동종체의 함량이 많이 존재하며 그 전체적 비율이 높은 것으로 밝혀졌다.

• Journal of the Korean Wood Science and Technology
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• 제41권5호
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• pp.447-455
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• 2013

Hemicellulose extract obtained by pre-pulping extraction of woodchips, is very diluted acidic in nature. The major component responsible for this weak acidity is acetic acid, present in levels up to 5~10 g/L. Here, we report an exploratory study on the extract upgrading by reactive solvent extraction of acetic acid as well as ASPEN simulation. In this study, liquid-liquid equilibria for the ternary systems (water + acetic acid + ethyl acetate) were measured at the temperature of 298.15 K and 10 (pH = 2.02), 5 (pH = 2.17), and 1 (pH = 2.48) percent of acetic acid samples were used to carry out liquid-liquid extraction studies using ethyl acetate. In a one-stage batch experiment, 96.0% of acetic acid could be extracted for the solvent when the ratio of organic-to-aqueous phases is 4:1. For simulation results, they were used to estimate the interaction parameters between each of the three compounds of the systems studied for the NRTL and UNIQUAC models. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the two models.