• The Journal of the Korea institute of electronic communication sciences
• /
• v.8 no.9
• /
• pp.1333-1342
• /
• 2013

New & renewable energy becomes a crucial subject to solve the problems inherent in the current energy resources, which results in the fast development of the new & renewable energy industry worldwide. However, not only its base is still weak but the high initial investment for technology development and certain scale of an energy market are required in many cases. For this reason, many countries in the world, including Korea, run the energy policies to foster the new & renewable energy industry such as RSP and FIT. In general, a policy should be established to take various, intertwined interests as well as a number of variables related to economic, social, environmental, and international matters into comprehensive consideration. For new & renewable energy industry, there are many variables to be considered and indexes necessary for evaluation but it is hard to take all of them into account. Even though they were considered, no criteria are available for use in a consistent manner. Therefore, this study plans to develop an evaluation model for the Korean new & renewable energy policy.

• Analytical Science and Technology
• /
• v.17 no.2
• /
• pp.98-107
• /
• 2004

In this study, $^1H$ NMR spectroscopy and HPLC were used to identify the type and quantity of each component in an acrylic coating materials applied for an automotive part. By the $^1H$ NMR analysis, it was found that this acrylic coating contained about 88.40 wt% of poly methyl methacrylate (PMMA), 7.05 wt% of methyl methacrylate (MMA), and 2.36 wt% of allyl methacrylate. Polymer additives such as a benzotriazole light stabilizer (Hisorb 328), an oxanilide light stabilizer, butylated hydroxy toluene (BHT), and dimethyl phthalate (DMP) were also identified and measured quantitatively from the $^1H$ NMR spectra. However, only two light stabilizers were identified by reverse phase (RP) HPLC analysis using Bondapak C18 column, methanol mobile phase, and a PDA (Photodiode array) detector. The contents of two light stabilizers in the acrylic coating were measured by a quantitative analysis through UV-Vis spectroscopy and compared with the NMR data. The analytical informations from $^1H$ NMR spetra were better than those from HPLC-PDA plot.

• Mass Spectrometry Letters
• /
• v.12 no.1
• /
• pp.1-10
• /
• 2021

A simple, specific, and economical LC-MS/MS method was investigated for the screening of 43 prescribed antihypertensive and related drugs in human urine. The urine samples were simply prepared by diluting and mixing with internal standard before directly introduced to the LC-MS/MS system, which is fast, straightforward, and cost-effective. Fractional factorial, Box-Behnken, and I-optimal design were applied to screen and optimize the mass spectrometric and chromatographic factors. The analysis was carried out on a triple quadrupole mass spectrometer system utilizing multiple reaction monitoring with positive and negative electrospray ionization method. Chromatographic separation was performed on a Thermo Scientific Accucore RP-MS column (50 × 3.0 mm ID., 2.6 ㎛) using two separate gradient elution programs established with the same mobile phases. Chromatographic separation was performed within 12 min. The optimal method was validated based on FDA guideline. The results indicated that the assay was specific, reproducible, and sensitive with the limit of detection from 0.1 to 50.0 ㎍/L. The method was linear for all analytes with coefficient of determination ranging from 0.9870 to 0.9981. The intra-assay precision was from 1.44 to 19.87% and the inter-assay precision was between 2.69 and 18.54% with the recovery rate ranges from 84.54 to 119.78% for all drugs measured. All analytes in urine samples were stable for 24 h at 25℃, and for 2 weeks at -60℃. The developed method improves on currently existing methods by including larger number of cardiovascular medications and better sensitivity of 12 analytes.

• Analytical Science and Technology
• /
• v.36 no.1
• /
• pp.32-43
• /
• 2023

This study reports for the first time about a stability indicating RP-HPLC method for qualitative and quantitative determination of acalabrutinib in bulk and dosage form and in presence its impurities 1, 2 and 3. The chromatographic separation was carried on Zorbax XDB-C18 (250×4.6 mm; 5 µ id) as stationary phase, Phosphate buffer pH 6.4 and methanol 80:20 (v/v) as mobile phase at a flow rate of 1.0 mL/min, UV detection was carried at wavelength of 238 nm and the analysis was completed with a run time of 15 min. In these conditions the retention time of acalabrutinib and its impurities 1, 2 and 3 was observed to be 3.50, 4.83, 8.40 and 9.93 min respectively. The method was validated for system suitability, range of analysis, precision, specificity, stability and robustness. Spiked recovery at 50 %, 100 % and 150 % was carried for both standard and impurities and the acceptable % recovery of 98-102 was observed for acalabrutinib and both impurities studied and the % RSD in each spiked level was found to be less than 2. Stability tests were done through exposure of the analyte solution to five different stress conditions i.e expose to 1N hydrochloric acid, 1 N sodium hydroxide, 3 % peroxide, 80 ℃ temperature and UV radiation at 254 nm. In all the degradation condition, standard drug acalabrutinib was detected along with both the impurities studied and the degradation products were successfully separated. In the formulation analysis there is no other chromatographic detection of other impurities and formulation excipients. Hence the developed method was found to be suitable for the quantification of acalabrutinib and can separate and analyse impurities 1 and 2.

• Korean Journal of Food Science and Technology
• /
• v.36 no.4
• /
• pp.531-536
• /
• 2004

Synthesis conditions were optimized using response surface methodology for producing structured lipids (SL) by interesterification of DHA-enriched algae oil derived from microalgae, Schizochytrium sp. and corn oil. Reaction was performed fer 24 hr at $55^{\circ}C$ catalyzed by immobilized lipase from Rhizomucor miehei (RM IM) in shaking water bath. Major fatty acids of SL were palmitic (21.70 mol%), oleic (20.20 mol%), and linoleic (27.34 mol%) acids, and DHA (15.06 mol%). To separate newly synthesized SL-triglycerides (TG) species, HPLC with evaporative light scatting detector (ELSD) was used. Production conditions were optimized using central composite design with reaction temperature $(35-75^{\circ}C,\;X_1)$, reaction time $(2-42\;hr,\;X_2)$, and enzyme concentration $(2-14%,\;X_3)$ as variables. When variables were $70.28^{\circ}C\;(X_1),\;28.74\;hr\;(X_2),\;and\;11.30%\;(X_3)$, maximum content of selected three peaks of synthesized SL-TG species was predicted as 6.97 area%.

• Current Research on Agriculture and Life Sciences
• /
• v.7
• /
• pp.153-163
• /
• 1989

The activity changes and biochemical properties of ${\beta}$-gal in tomato fruits during ripening were investigated. The total activity was increased during ripening and three isoenzymes (${\beta}$-gal I, II and III) were purified through DEAE Sephadex A-50 and Sephadex G-100 column chromatography. The activities of ${\beta}$gal isoenzymes (${\beta}$-gal I, II and III) during ripening were 69.8, 31.8 and 170.0 units in mature green phase, while those were 48.7, 88.4 and 136.8 units in Red phase, respectively. As the ripening proceeded the activities of ${\beta}$-gal I and III were some what decreased but the activity of ${\beta}$-gal II was incresed more than 2.8 fold. The optimum pH of ${\beta}$-gal I, II and III were 3.9, 4.2 and 3.9 and the optimum temperature of those were $60^{\circ}C$, $56^{\circ}C$ and $60^{\circ}C$, respectively. All isoenzymes were stable at pH 3.6~6.0 and lost their activity about 50% when it heated at $55^{\circ}C$ for 5 minute. $Mg^{{+}{+}}$-activated the three isoenzymes but $Ca^{{+}{+}}$ and SDS inhibited about 30~40%. $Hg^{{+}{+}}$ inhibited completely. The km value of ${\beta}$-gal I, II and III was 0.36mM, 0.63mM and 0.45mM, reaction rate was rapidly increased until the concentration of substrate was $6.0{\times}10^{-5}M$.

• Korean Journal of Food Science and Technology
• /
• v.41 no.3
• /
• pp.231-237
• /
• 2009

Trans free margarine stock (TFMS) was produced by lipase-catalyzed synthesis of fully hydrogenated soybean oil (FHSBO), avocado oil (AO) and palm oil (PO). A blend of FHSBO, AO, and PO with a 1:5:4 (30:150:120 g, respectively) ratio was interesterified with lipozyme RM IM(from Rhizomucor miehei) in a 1 L-batch type reactor at 65 for 12 hr, and the physicochemical and melting properties of TFMS were compared with commercial margarine. The solid fat content (%) of the TFMS was analyzed at 25, 30, and $35^{\circ}C$, respectively, while its melting point was $37.8^{\circ}C$. The trans fatty acid content of the TFMS was below 0.1%. It also had acid, saponification, and iodine values of 0.4, 173.9, and 58.6, respectively. In HPLC chromatograms of the TFMS, newly synthesized peaks of triacylglycerol molecules were observed by using reverse-phase HPLC with evaporative light-scattering detection. Normal-phase HPLC with UV detection was used to quantify tocopherols in the TFMS, indicating that its ${\alpha}-$, ${\gamma}-$ and ${\delta}$-tocopherol contents were 5.7, 2.1, and 1.7 mg/100 g, respectively.

• Korean Journal of Food Science and Technology
• /
• v.46 no.3
• /
• pp.315-322
• /
• 2014

Immobilized lipases were prepared by physical adsorption using lipase AK, AY, AH, PS and R on Amberlite$^{(R)}$XAD$^{(R)}$7 HP resin. With the immobilized lipases (10%), structured lipid was synthesized by enzymatic interesterification of canola oil, palmitic ethyl ester, and stearic ethyl ester in order to study the reaction characteristics. Among the lipase, the highest protein content was obtained from lipase AH (11.41%) before immobilization, while the highest levels of bound protein was observed from immobilized lipase AK (63.91%). Immobilized lipase AK had the highest interesterification activity (38.3% of total saturated fatty acid). Lipase AK was also used for a continuous reaction in which the slow flow of reactant resulted in increased reaction rate. Reusability of immobilized AK, AH and PS increased at the second reaction (120-196.5%). However, the activity of immobilized AK, which had the highest bound protein content (63.91%) decreased after the third reaction, while the activity of immobilized AH and PS was maintained until the sixth reaction.

• Journal of the Korean Wood Science and Technology
• /
• v.15 no.3
• /
• pp.44-55
• /
• 1987

In order to study the effect of sawdustboard combined with plastic chips, 0.5mm($T_1$), 1mm($T_2$), 1.4mm($T_3$) thick nylon fiber. polypropylene rope fiber(RP), and 0.23mm thick moth-proof polypropylene net fiber(NP) were cut into 0.5, 1, 2cm long plastic chips. Thereafter, sawdustboard combined with plastic chips prepared as the above and plastic non-combined sawdustboard(control) were manufactured into 3 types of one-, two-, and three layer with 5 or 10% combination level. By the discussions and results at this study, the significant conclusions of mechanical and physical properties were summarized as follows: 1. The MORs were shown in the order of 3 layer> 2 layer> 1 layer among plastic non-combined boards, and $T_3$ < $T_2$ < $T_1$ < RP (NP(5%) < NP(l0%) among plastic combined boards. In 2cm long plastic chip in 1 layer board, the highest strength through all the composition was recognized. 1 layer board showing the lower strength with 0.5cm plastic chip rendered to the bending strength improvement by 2 or 3 layer board composition. On the other hand, 2 or 3 layer combined with 1, 2cm long polypropylene net fiber chips incurred MOR's conspicuous decrease requiring optimum plastic chip combined level and consideration to combined type. 2. MOE in plastic non-combined 3 layer board exhibited sandwich construction effect by higher resin content application to surface layer in the order of 3layer>1layer>2layer with the highest stiffness of the board combined with polypropylene chip, while nylon chip-combined board had little difference from plastic non-combined board. In relevant to length and layer effect, 3 layer board combined with the 0.5cm long polypropylene net fiber chip in 5% and 10% combined level presented 34-43% and 44-76% stiffness increase against plastic non-combined board(control), respectively. Moreover, in 1 layer board, 30% stiffness increase with 10% against 5% combined level in the 1 and 2cm long polypropylene net fiber chip was obtained. 3. Stress at proportional limit(Spl) showing the fiber relationship (r: 0.81-0.97) between MOR presented in the order of 1 layer<2 layer<3 layer in plastic non-combined board. Correspondingly, combined effect by layer and plastic chip length was similar to MOR's. 4. Differently from previous properties(MOR, MOE, Spl). work to maximum load(Wml) of 2 layer board approached to that of 3 layer board. Conforming the above phenomenon. 2 layer combined with 0.5cm long polypropylene net fiber chip kept the greater work than 1 layer. The polypropylene combined board superior to nylon -and plastic non - combined board seemed to have greater anti - failing capacity. 5. Internal bond strength(IB), in contrast to MOR's tendency. showed in the order of T1

• Korean Journal of Food Science and Technology
• /
• v.34 no.2
• /
• pp.174-179
• /
• 2002

A simple and sensitive analysis method based on reverse phase (RP) HPCL with flourescence detector was developed for simultaneous determination of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE), and their degradation products, $BADGE{\cdot}H_2O$, $BADGE{\cdot}2H_2O$, $BFDGE{\cdot}H_2O$, $BFDGE{\cdot}2H_2O$, $BADGE{\cdot}HCl{\cdot}H_2O$, $BADGE{\cdot}HCl$, $BADGE{\cdot}2HCl$, $BFDGE{\cdot}HCl{\cdot}H_2O$, $BFDGE{\cdot}HCl$ and $BFDGE{\cdot}2HCl$, which were hydrolyzed and chlorinated forms of BADGE and BFDGE, in canned foods and food simulants. These compounds were identified by GC/MSD with $MSTFA-NH_4I-DTE$ derivatization. Recovery study was performed at each 100 ng/mL levels of BPA, BPF, BADGE and BFDGE added to canned foods and food simulants. This method was resulted in recovery of $90{\sim}114%$ with relative standard deviation of $4.1{\sim}7.0%$, detection limits of $6{\sim}11$ ng/mL and quantitation limits of $12{\sim}18\;ng/mL$. Calibration curves were linear with correlatin coefficients of 0.997 for BPF, 0.996 for BPA, 0.9987 for BFDGE, and 0.9989 for BADGE.