• Journal of the Society of Cosmetic Scientists of Korea
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• v.19 no.1
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• pp.20-30
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• 1993

Liquid Chromatographic behavior of Pd(II) in Isonitosoethylacetoacetate imine IEAA-NR: R=H, CH3, C2H5, n-C3H7, n-C4H9, C6H5-CH2) Chelates were investigated by reversed phase high performance 1iquid chromatography on Micropak MCH-5 Column using Methanol /water as mobile phase. The optimum condition for the separation of Pd-Isonitrosoethylacetoacetate imine chelates were examined with respect to the flow rate, mobile phase strength. It was found that Pd(IEAA-NR)2 chelates were eluted in an acceptable range of the capacity factor value (0 $\leq$ log k' $\leq$ 1), The dependence of the logarithm of capacity factor(k') on the volume fraction of water in mixture with in the binary mobile phase was examined. Also, the dependence of k'on the liquid-liquid extraction distribution constant in methanol-water / n-alkane extraction system was on system was invert tigated for Pd(IEAA-NR)2. Both kinds of dependence are linear, which suggests that the retention of the electroneutral metal chelates be largely due to the solvophobic effect.

• Journal of Applied Biological Chemistry
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• v.55 no.4
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• pp.263-266
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• 2012

Isolation of iron and calcium-binding peptides derived from cottonseed meal protein (CMP) hydrolysates was investigated. The degree of hydrolysis of CMP by Flavourzyme was monitored using trinitrobenzenesulfonic acid method and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Enzymatic hydrolysis of CMP for 12 h was sufficient for the preparation of CMP hydrolysates, and the hydrolysates were membrane-filtered under 3 kDa as a molecular weight. The filtered solution was fractionated using Q-Sepharose fast flow, Sephadex G-15, and reversed phase-high performance liquid chromatography for iron and calcium-binding peptides. As a result, F51 fraction was obtained as the best candidate for calcium and iron chelation, and the isolated iron and calcium-binding peptides can be used as functional food additives, similar to iron and calcium supplements.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.720-724
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• 1991

Simultaneous determination of chloragenic acid (CA), 3,4-o-dicafeoyl quinic acid(3,4-DCQA), 4,5-o-dicaffeoyl quinic acid (4,5-DCQA) and linarin in Chrysanthemum sibiricum Fisher was newly established by a reversed-phase high performance liquid chromatography (HPLC). Sample was extracted with 20 ml methanol for 4 hrs. The extract was cleaned up by using Sep-Pak $C_18$ cartridge and 4 ml methanol-$H_2$O(1 : 1) as eluent. Their determination was performed by means of RP-HPLC with Bondapak $C_18$ column (30 cm ${\times}$ 3.9 mm i.d., 10 ${\mu}m$ and gradient elution mode as methanol-5 mM $H_3PO_4$ solution (30 : 70). The established method was applied to various samples purchased. As a result, their content ranges showed to be 0.35~0.55% for CA, 0.46~0.76% for 3,5-DCQA, 0.077~0.23% for 4,5-DCQA and 0.16~2.72% for linarin, respectively.

• Journal of Pharmaceutical Investigation
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• v.39 no.3
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• pp.177-183
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• 2009

A rapid and sensitive reversed-phase high performance liquid chromatography (HPLC) method was developed for the determination of piroxicam in the rabbit plasma. After a treatment of plasma sample by liquid-liquid extraction, the drug was analyzed on an HPLC system with ultraviolet detection at 330 nm. HPLC was carried out using reversed-phase isocratic elution with a C18 column, a mobile phase of a mixture of acetonitril, doubly deionized water and acetic acid 43.74:56.00:0.26 v/v%) at a flow rate of 1.1 mL/min. The chromatograms showed good resolution and sensitivity and no interference of plasma. The calibration curve for the drug in plasma sample was linear over the concentration range of 0.01-2.0 ${\mu}$g/mL. The intra- and inter-day assay accuracies of this method ranged from 86.82% to 108.33% of normal values and the precision did not exceed 13% of relative standard deviation. The plasma concentration of piroxicam decreased to below the quantifiable limit at 12 hr after the i.v. bolus administration to rabbits following dose of 0.375 mg/kg yielding a apparen t plasma half life of 1.38 hr. The transdermal route prolongs plasma levels of piroxicam. The bioavailability, calculated from the dose-adjusted ratio of the $AUC_{transdermal}$ to the $AUC_{i.v.}$, was 7.44%. The plasma concentration of piroxicam was detected by 48 hr after the transdermal administration of patch at a dose of 32 mg/kg. This method was suitable for cutaneous absorption studies of piroxicam in the rabbit after transdermal administration of different types of dosages of the drug.

• Toxicological Research
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• v.12 no.2
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• pp.163-169
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• 1996

The focus of this study was to investigate the suitable analytical methods for measurement of sulfamerazine and its metabolite in shrimp hepatopancreas and tail tissue, in addition to the methods for the optimization of solid-phase extraction cartridge conditions and the elucidation of sulfamerazine concentrations in aqueous buffer using HPLC with UV and EC detectors. Compared with UV detector the EC detector appears to be 10 times more sensitive than that of the UV detector. After the shrimp was exposed to 10 ppm sulfamerazine, the accumulation levels of sulfamerazine and its metabolite in tail tissue, which is edible portion, were considerably lower than 0.1 ppm. The data indicate that sulfamerazine continues to be a candidate for use at levels of sulfamerazine concentration used in aquaculture of shrimp.

• Analytical Science and Technology
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• v.19 no.6
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• pp.455-459
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• 2006

The extraction and separation of glabridin from licorice root by HPLC was performed in this work. First, by investigating the different extraction solvents, extraction methods and extraction times, a one-hour ultrasonic extraction procedure with ethyl acetate as the extraction solvent was optimized. Then the ethyl acetate extraction was applied to RP-HPLC for separation of glabridin. The column efficiencies and resolutions were experimentally investigated with different mobile phase compositions. Baseline separation of glabridin was obtained under the mobile phase composition of 50/50 vol.% (ACN/water). The retention time of glabridin was 20.3 min. The peak of glabridin was collected from the HPLC elution for several times and identified by LC/MS. Under the optimum extraction and HPLC separation methods, 1.26 g of glabridin per kg licorice root could be extracted.

• 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.

• Analytical Science and Technology
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• v.7 no.1
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• pp.103-114
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• 1994

The elution behaviors of Ni(II), Cu(II), Co(II), and Cr(II) in 1-phenyl-3-methyl-4(2-hydroxy-5-X-phenylazo)-5-pyrazolone, [Pm(2-OH)(5-X)PaPz](X=H, $CH_3$, $NO_2$, Cl) chelates have been studied by reversed phase HPLC. Thirteen metal-[Pm(2-OH)(5-X)PaPz] chelates were prepared and characterized by UV, IR, MS, and ICP spectroscopic methods. These metal-2-hydroxyarylazopyrazolone chelates were successfully separated on Novapak-$C_{18}$ column using methanol/water mixtures as a mobile phases. It was found that the chelates were eluted properly in an acceptable range of the capacity factor value($0{\leq}log\;k^{\prime}{\leq}1$). The dependence of the capacity factor(log k') on the volume fraction of water in the binary mobile phase showed a good linearity. Also, there was a good linear dependence of the capacity factor on the liquid-liquid extraction distribution ratio($D_c$) in methanol-water/n-pentadecane extraction system by the batch method. It suggested that the retention of the chelates in the reverse phase liquid chromatographic system be largely due to the solvophobic effect.

• FOCUS: LIFE SCIENCE
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• no.1
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• pp.1.1-1.4
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• 2024

This article provides comprehensive guidance on the maintenance, cleaning, regeneration, and storage of silica-based HPLC (High-Performance Liquid Chromatography) columns. The general considerations emphasize the importance of using in-line filters and guard cartridges to protect columns from blockage and irreversible sample adsorption. While these measures help, contamination by strongly adsorbed sample components can still occur over time, leading to an increase in back pressure, loss of efficiency, and other issues. To maximize column lifetime, especially with UHPLC (Ultra-High Performance Liquid Chromatography) columns, it is advisable to use ultra-pure solvents, freshly prepared aqueous mobile phases, and to filter all samples, standards, and mobile phases. Additionally, an in-line filter system and sample clean-up on dirty samples are recommended. However, in cases of irreversible compound adsorption or column voiding, regeneration may not be possible. The document also provides specific recommendations for column cleaning procedures, including the flushing procedures for various types of columns such as reversed phase, unbonded silica, bonded normal phase, anion exchange, cation exchange, and size exclusion columns for proteins. The flushing procedures involve using specific solvents in a series to clean and regenerate the columns. It is emphasized that the flow rate during flushing should not exceed the specified limit for the particular column, and the last solvent used should be compatible with the mobile phase. Furthermore, the article outlines the storage conditions for silica based HPLC columns, highlighting the impact of storage conditions on the column's lifetime. It is recommended to flush all buffers, salts, and ion-pairing reagents from the column before storage. The storage solvent should ideally match the one used in the initial column test chromatogram provided by the manufacturer, and column end plugs should be fitted to prevent solvent evaporation and drying out of the packing bed.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.486-490
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• 1997

A stereospecific HPLC method has been developed for the resolution of the enantiomers of salbutamol in human urine. After solid-phase extraction and derivatization with (S)-(-)-${\alpha}$-methyl-benzyl isocyanate, the diastereomeric derivatives were resolved $(R_s=1.59)$ on $5{\mu}M$ octadecylsilan column using 47% methanol as a mobile phase with fluorescence detection. The detection limit of each enantiomer was 10 ng/ml (S/N=3).