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

• Analytical Science and Technology
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• v.26 no.5
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• pp.307-314
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• 2013

Selenium exists in various forms of chemical species. The activity and bioavailability is strongly dependent on its chemical form and concentration. Consequently the information on each selenium species and its concentration must be exactly determined for the food we take in. In this study, selenium species in seafood were separated and quantified by RP (reversed phase) HPLC (high performance liquid chromatography) coupled with ICP-MS (inductively coupled plasma mass spectrometry) using post-column isotope dilution. $^{79}Br$, which interferes on $^{80}Se$, has mostly been removed by solid phase extraction and then mathematical correction has been applied for the more accurate correction. The experimental result for CRM (certified reference material) DOLT-4 agreed well with the certified value but each selenium species could not be compared. SeCys (selenocysteine) and SeMet (selenomethionine) were the major species detected in seafood such as belt fish, spanish mackerel, and squid that have been serving as Korean diet. The concentrations found in Korean sea food for SeCys and SeMet were in the range of 0-661.6 mg/kg and 137.3-462.7 mg/kg, respectively.

• Analytical Science and Technology
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• v.10 no.5
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• pp.343-349
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• 1997

Analytical method using the reversed phase ion-pair chromatography (RP-IPC) for the determination of kasugamycin(5-amino-2-methyl-6-(2,3,4,5,6-pentahydroxy cyclohexyloxy)tetrahydropyran-3-yl-amino-${\alpha}$-imino acetic acid), pesticide as fungicide bactercide has been established. The retention behavior of kasugamycin in the RP-IPC was examined with respect to the effect of concentrations of organic modifiers, pH of eluent and types and concentrations of the counter ions as ion-pair reagent. This method developed by the optimum factors, can be used for the application of the quality control in the crude product and its formulation.

• Korean Journal of Pharmacognosy
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• v.24 no.4
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• pp.309-312
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• 1993

A new method for separation and quantitative determination of isoflavone glucosides in rhizomes of Belamcanda chinensis (Iridaceae) by high performance liquid chromatography was elaborated. A reverse-phase system with a Spheri-5 RP-18 column using MeOH:HOAc:$H_2O$(24 : 5 : 71) as a mobile phase was developed. The isoflavonoids were detected at 268 nm and the analysis was successfully carried out within 15 min.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.544-547
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• 2003

Fusion $ferritin(F_H+F_L),$ an iron-binding protein, was purified from recombinant E. coli by gel filtration chromatography after two-step sonications. Unfolded ferritin was refolded by GFC with various refolding enhancing additives. 50 mM Tris-HCI(pH 7.4) buffers containing 2 M urea and additive was used in GFC. Objective was to characterize the structure change at various conditions. Molecular weight was determined using GF-HPLC and RP-HPLC was used to quantify the unfolded and refolded proteins. Activity was confirmed by iron-uptake reaction.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.480-483
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• 2003

Fusion ferritin$(F_H+F_L)$, an iron-binding protein, was purified from recombinant E. coli by two-step sonications with urea. Unfolded ferritin was refolded by gel filtration chromatography with various concentration of urea. 50 mM Tris-HCl(pH 8.0) buffers with 1 M to 4 M urea were used in GFC. Objective was to characterize the structure change with urea concentration. Molecular weight was determined using GF-HPLC and RP-HPLC was used to quantify the unfolded and refolded proteins.

• Korean Journal of Pharmacognosy
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• v.30 no.2
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• pp.163-167
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• 1999

A method for isolation and qantitative determination of anemarsaponin B from the rhizomes of Anemarrhena asphodeloides has been developed. Isolation of anemarsaponin B was achieved by silica gel and RP-18 column chromatography. The HPLC method for quantitative determination of anemarsaponin B provided a method for standardization of the crude drug. It suggested that the content of anemarsaponin B in Anemarrhena asphodeloides is about 0.12-1.48%.

• Applied Biological Chemistry
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• v.36 no.1
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• pp.33-37
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• 1993

Oxidations products of ${\alpha}-tocopherol$, ${\gamma}-tocopherol$ and ${\gamma}-tocotrienol$ in lipophilic reaction media were studied. ${\alpha}-Tocopherylquinone$, ${\gamma}-tocopherylquinone$ and ${\gamma}-tocotrienylquinone$ were fractionated using micro column, isolated and identified by HPLC and MS.

• Korean Journal of Clinical Pharmacy
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• v.5 no.2
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• pp.71-74
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• 1995

A high performance liquid chromatographic method has been developed for the simultaneous analysis of non-steroidal anti-inflammatory drugs in plasma. The simultaneous determination of ibuprofen, fenoprofen and ketoprofen is performed by RP-HPLC with UV detection. The chromatographic system consisted of Spherisorb octyl column$(5{\mu}m)$ ; the mobile phase was $acetonitrile\;-\;0.5\%$ phosphoric acid(55 : 45, v/v) and the detection wavelength was 230nm. Tolmetin was employed as an internal standard. The method described is rapid and simple with sensitivity limits of $2.0{\mu}g/ml$ ibuprofen, $0.5{\mu}g/ml$ fenoprofen and $0.3{\mu}g/ml$ ketoprofen and is suitable for routine clinical and pharmacokinetic studies.

• Archives of Pharmacal Research
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• v.17 no.1
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• pp.48-50
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• 1994

Three p-coumaroylamino acids (p-CAAs) were isolated from the yeast-elicited Ephedra distachya cultures by consecutive purification using XAD_2, silicagel and RP-HPLC. Retention times on HPLC as well as their UV, IR, NMR and MS spectral data indicated that the yeast-induced p-CAAs wre p-coumaroyl--D-valine, p-coumaroyl-D-serine and p-coumarouyl-D-threonine, respectively. The structures of p-CAAs were confirmed by the comparison of their physico-chemical properties 3with those of synthetic ones. They were isolated and identified for the first time from natural products and supposed to be accumulated as phytoalexins of Ephedra.