• Journal of Environmental Science International
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• v.5 no.5
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• pp.561-567
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• 1996

A method for the simultaneous analysis of 31 residual organic chloride pesticides was studied using gas chromatography. Prepared analytical samples were injected to gas chromatography (HP 5890 Series II plus) on the Ultra-2 column with ECD. The packing materials for column were changed as the following reagents ; florisil and alumina N, The residual solution was loaded to column and was elected pith erection solvents ; ether : benzene (2 : 8) solution, hexane : benzene (1 : 1) solution, dichloromethane, acetone, and methanol. The analytical results showed that 6 kinds of organic chlorides were not detected when florisil (first condition) was used as the column packing material. The nondetected 6 kinds of organic chlorides in the first analytical condition were detected and the recoveries of thrin-pesticides were increased, in particular, captan and captafol, but the recoveries of benzene hexachloride compounds were decreased when dichloromethane and methanol were added as elution solvents (pac'king material was florisil as in the first condition). The recoveries of dichlornuanid, chlorofenvinfos, folpet, and dicofol were increased and that of aldrin was increased, but those of captan and captafol were not good when alumina N was used as the packing material. To detect simultaneously thrin-pesticides, captan, and captafol, florisil and alumina N were used as the packing materials. The elution result showed that captan and captafol were not detected. This was because the column was activated insufficiently. The analytical method was the best (31 kinds of organic chlorides in the residual pesticides were detected sharply and showed high sensitivity) when the column (packing materials were florisil and alumina N: together) was fuliy activated and the impurities were removed using various elution solvents.

• Journal of Plant Biology
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• v.36 no.3
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• pp.297-300
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• 1993

Six flavonoid compounds from the ethyl acetate fraction of Machilus thunbergii leaves were identified by HPLC. Separation by reversed phase chromatography on u-Bondapak C18 column was achieved by isocratic elution. The contents of the major flavonoids, guaijaverin and quercitrin were about 0.48% (w/w) and 0.98% (w/w) for the methanol extract, respectively.

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.264-269
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• 1993

Molecular structural properties of legume starches were investigated. In intrinsic viscosity and degree of Polymerization of amylose and amylopectins, cow pea and mung bean were high, but kidney bean was low. Low molecular weight fractions for kidney bean starch were much eluted by gel chromatography. In the elution profiles of their amylose by Sepharose 2B-CL, molecular weight of kidney bean amylose was smaller than that of other amylose Molecular weights of cow pea and mung bean amyloses were large, but that of kidney bean amylose was small and red bean amylose was medium. The elution profiles by Sephadex G-50 after debranching amylopectins with pullulanase showed similar patterns.

• KSBB Journal
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• v.22 no.2
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• pp.119-122
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• 2007

Since egg white contains various protein, it is important to research the protein distribution of egg white. Specially, lysozyme and ovalbumin important proteins, are used in medicine and food industry. Reversed phase high performance liquid chromatography has been used for separation of egg white, and column of RP-HPLC is available in variety. We have used C4, C8 and C18 columns to obtain chromatograms by varying carbon chain length of stationary phase. Long carbon chain length of stationary phase has good separation of egg white. Also, we have changed the composition of mobile phase (acetonitrile, water, and trifluoroacetic acid) to find optimum chromatograms. Acetonitrile and water composition of 50 : 50 show many peaks from egg white. Isocartic and gradient elution in RP-HPLC were used to compare the chromatography of egg white.

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.32.1-32.12
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• 2020

Objectives: To evaluate the polymerization efficiency of a matrix-modified bulk-fill composite, and compare it to a conventional composite which has a similar filler system. The degree of conversion (DC%) and monomer elution were measured over different storage periods. Additionally, fillers' content was examined. Materials and Methods: Cylindrical specimens were prepared, in bulk and incrementally, from Filtek Bulk Fill (B) and Filtek Supreme XTE (S) composites using a Teflon mold, for each test (n = 6). Using attenuated total reflection method of Fourier transformation infrared spectroscopy, DC% was measured after 24 hours, 7 days, and 30 days. Using high-performance liquid chromatography, elution of hydroxyethyl methacrylate, triethylene glycol dimethacrylate, urethane dimethacrylate, and bisphenol-A glycidyl dimethacrylate was measured after 24 hours, 7 days and 30 days. Filler content was examined by scanning electron microscopy (SEM). Data were analyzed using 2-way mixed-model analysis of variance (α = 0.05). Results: There was no significant difference in DC% over different storage periods between B-bulk and S-incremental. Higher monomer elution was detected significantly from S than B. The elution quantity and rate varied significantly over storage periods and between different monomers. SEM images showed differences in fillers' sizes and agglomeration between both materials. Conclusions: Matrix-modified bulk-fill composites could be packed and cured in bulk with polymerization efficiency similar to conventional composites.

• KSBB Journal
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• v.14 no.4
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• pp.408-413
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• 1999

To separate mixtures analytically and preparatively by LC (Liquid Chormatography), the operating conditions of analytical chromatography should be determined. The HCI program was utilized to find the optimum operating condition accurately and rapidly, and to reduce the number of experiments. In an analytical chromatography, based on the resolution and analysis time, the experimental conditons of deoxyribonucleosides and phopholipids were fixed in terms of taxol was calculated, and the collection time was predicted for the mixture of 5'-IMP and 5'-GMP from the elution profile when and purity wer known.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.408-412
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• 2008

Determining the elution of water-soluble substances from herbal teas is an important factor in their efficient use in terms of taste, perfume, and content of health-related components. The antioxidant activity and content of catechins in commercial Chrysanthemum indicum (gamguk) teas were determined for optimum elution conditions. The water extract of gamguk teas did not differ significantly in yield compared to methanol extracts and showed stronger antioxidant activity. Catechin contents in gamguk teas were 8-18% of the extracts when individual peaks in high-performance liquid chromatography analysis were compared to standard catechin peaks. Gamguk teas exhibited faster release of antioxidants, and the antioxidant activity was positively correlated with the thermal treatments. Gukhwacha (GC) was the best tea for rapid release (30 sec) of antioxidants with the $50^{\circ}C$ treatment, whereas antioxidants in other teas were relatively slower released.

• Korean Journal of Pharmacognosy
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• v.21 no.2
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• pp.148-152
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• 1990

Seven flavonol glycosides from the EtOAc fraction of Ginkgo biloba leaves were identified by high performance liquid chromatography. Separation by reversed phase chromatography on $Lichrosorb^{\circledR}$ RP-18 column was achieved by isocratic elution. The content of the major acylated flavonol glycoside, kaempferol 3-0-[$6'-O-{p}-coumaroyl-{\beta}-_D-glucosyl(1{\rightarrow}2)-{\alpha}-_L-rhamnoside$] was about 8.0% and 0.55% for EtOAc fraction and MeOH extract, respectively.

• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.12-17
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• 2002

The extracellular invertase (EC 3.2.1.26) (Candida utilis) preparation was obtained from the liquid medium after desalting and freeze drying. This prepared enzyme was used for the comparative purification on 4 activated matrices by liquid column affinity chromatography method. In this method there were used controlled porous glass (CPG) silanized covalently activated by keratin, silanized silica gel and silica gel covalently covered by keratin. It was found that the invertase purification process was better using both CPG matrices (silanized CPG and keratin activated CPG) than these with two silica gel supports. Also the elution coefficient of the invertase from the two CPG columns was about 93 to 94%. Two silica gel supports found to be superior in terms of purification efficiency. The invertase purification process was confirmed by PAGE electrophoresis.

• Membrane Journal
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• v.19 no.2
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• pp.113-121
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• 2009

Porous affinity chitosan and chitin membranes with good mechanical strength and high protein binding capacity were prepared by using silica particles as porogen. The maximum binding capacity of affinity chitosan membrane for BSA protein is 21.8mg/mL, and that of affinity chitin membrane for lysozyme enzyme is 26.1mg/mL. Chromatographic separations of BSA and lysozyme proteins using the porous affinity chitosan and chitin membranes were performed with change of the flow rate, loading amount and concentration of protein loading solutions. Protein eluted amount and binding yield were calculated from the filtration chromatograms consisted of loading/washing/elution sequences. Protein binding amount and yield were increased with decreasing of flow rate, increasing of loading amount and concentration of protein loading solutions. Those results suggest that the porous chitosan and chitin membranes prepared by using silica particles as porogen are suitable in affinity filtration chromatography for large scale separation of proteins.