• FOCUS: LIFE SCIENCE
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• no.1
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• pp.12.1-12.6
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• 2024

This document explores the methodologies and considerations for scaling up liquid chromatography (LC) processes from analytical to preparative scales. It provides detailed equations and practical guidance for optimizing parameters such as flow rates, injection volumes, and gradient times while maintaining efficiency and resolution. The paper also includes case studies demonstrating the purification of proteins like α-lactalbumin from milk fractions, highlighting variations in purity across different fractions. With a focus on achieving high reproducibility and maximizing yield, this guide serves as a valuable resource for researchers and industry professionals engaged in preparative chromatography.

• FOCUS: LIFE SCIENCE
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• no.1
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• pp.13.1-13.7
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• 2024

The white paper focuses on the analysis of Per- and Polyfluoroalkyl Substances (PFAS) using the EPA Method 537.1. It highlights the application of VWR® HiPerSolv CHROMANORM® PFAS-grade solvents, specifically 5 mM ammonium acetate, for Liquid Chromatography-Mass Spectrometry (LC-MS). The study compares the performance of CHROMANORM® PFAS-grade solvents against LC-MS-grade alternatives, emphasizing their reliability and suitability for accurate PFAS detection. This method is critical for environmental monitoring and compliance, given the increasing regulatory focus on PFAS contamination. The document underscores the significance of using high-quality solvents in analytical workflows to ensure precise, reproducible results in detecting and quantifying PFAS in water samples.

• Natural Product Sciences
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• v.18 no.3
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• pp.171-176
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• 2012

We previously isolated cordycepin, guanosine and tryptophan from Cordyceps militaris as antiadipogenic constituents. For the quality control of C. militaris for anti-adipogenic activity, simultaneous analytical method using high-performance liquid chromatography (HPLC)-diode array detection (DAD) was developed and validated. Quantitation of these compounds in various Cordyceps samples from different sources and various extraction methods were conducted using developed method. Our study shows that natural Cordyceps and host insect possess higher content than cultured ones and fruiting bodies, respectively. The content of cordycepin showed great difference in different C. militaris samples whereas trytophan content was similar in tested samples. Addition of water to extraction solvent greatly increased the yield of guanosine and tryptophan. High temperature and longer extraction time increased yield of guanosine, whereas the content of trytophan was decreased in high temperature during extraction with water. Extraction using ultrasonic apparatus slightly increased extraction efficiency. Cordycepin, however, has little variation in different extraction method tested. Strong anti-adipogenic activity was observed in the samples that contain all the three constituents. Taken together, quantitation of these compounds using developed analytical method might provide basic requirement for the anti-adipogenic activity of C. militaris.

• Korean Journal of Pharmacognosy
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• v.50 no.2
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• pp.133-140
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• 2019

In our previous study, we found uracil, adenosine, protocatechuic acid, syringin (eleutheroside B) and scoparone (6, 7-dimethoxycoumarin) in the Oplopanax elatus Nakai Stem. High-performance liquid chromatography (HPLC) -UV was used to quality and quantify the internal marker compounds in the O. elatus extract after validation of method with linearity, limit of detection (LOD), limit of quantitation (LOQ), accuracy and precision. The specificity assessment visually confirmed that the substance was detected without the introduction of other substances. The established method showed high linearity of the calibration curve and coefficient of correlation ($R^2$) of over the 0.999. HPLC was reported as five standard compounds equivalent using the following linear equation based on the calibration curve. The accuracy of measurement was 84.34 ~ 119.74% and the relative standard deviation (RSD) value was 0.28 ~ 1.60%. In addition, our established method showed high repeatability. The RSD value was 1.10 ~ 6.81%. So, we found the amount of the internal marker compounds in the O. elatus extract. These results demonstrated that can be used to quality evaluation of the O. elatus.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.67-72
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• 2023

A simple and accurate method was developed for the quantitative analysis of oleanonic acid (OA) from mastic gum. The analysis was carried out using reverse-phase high-performance liquid chromatography combined with a photodiode array detector (HPLC/PDA). Our optimized method was validated by measuring various parameters, using an INNO C18 column fitted with a gradient elution system. The results revealed limits of detection and quantification of 0.34 and 1.042 ㎍/mL, respectively. The OA calibration curve exhibited excellent linearity over the concentration range of 0.0625 to 2.0 mg/mL, with r² =0.9996. Accuracy tests revealed a high recovery rate of 99.44-103.66%, with precision values below 0.15%. These results suggest that the present analytical method can identify and quantify OA in mastic gum with high precision. The HPLC approach developed in this study might be applied to routine analyses and large-scale extraction procedures for OA content quantification.

• Analytical Science and Technology
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• v.25 no.6
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• pp.460-466
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• 2012

An environmentally friendly, so-called green, high performance liquid chromatography method was developed and validated for the determination of trans, trans-muconic acid (t,t-MA) in human urine as a biomarker of benzene exposure. After urinary t,t-MA was extracted and enriched using solid-phase extraction, a MF-Ph1 SG80 ($150mm{\times}2.0mm$ I.D., 5 ${\mu}m$) column with a mobile phase of 10 mM $KH_2PO_4$ containing 0.1% $H_3PO_4$ was used for isocratic separation of t,t-MA with UV detection at 259 nm. The calibration curve was constructed in the range of 0.1-5.0 mg/L with good linearity ($r^2$=0.9992). The intra-day and inter-day precision (as RSD) were 0.9-8.5% and 3.1-4.5%, respectively. The average recovery ranged from 97.5% to 101.7%. The green sample preparation and separation with no organic solvents were successfully achieved. The validated method would be suitable for the routine biological monitoring of benzene exposure in the occupational settings.

• Analytical Science and Technology
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• v.19 no.3
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• pp.239-243
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• 2006

This method is used for the determination of itraconazole in human plasma by liquid-liquid extraction and high performance liquid chromatography. Felodipine was used as an internal standard. After extraction of the plasma with diethyl ether, the centrifuged upper layer was then transferred. The supernantant was evaporated and then reconsituted with mobile phase. The mobile phase was composed of 10 mM ammonium acetate adjusted to pH 7 by phosphoric acid with a flow rate of 0.2 mL/min. A C18 reversed-phase column with a pre-column was used as the analytial column. Linear detection responses were obtained for itraconzole concentration range for 2~1,000 ng/mL. The correlation coefficient of linear regression($R^2$) was 0.9991, limit of quantification (LOQ) was 2 ng/mL, reproducibility was less than 10.8 %, and accuracy was 97.2~108.2%. This method has been successfully applied to the pharmacokinetic study of itraconazole in human plasma.

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1011-1015
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• 2014

Octadecyl-modified graphene (graphene-C18) was fabricated and used as adsorbent in hollow fiber liquid phase microextraction (HF-LPME) for the first time. The extraction performance of graphene-C18 reinforced HF-LPME was evaluated using chlorophenols as model analytes. The factors affecting the extraction efficiency, such as extraction time, pH of the sample solution, agitation rate, the concentration of graphene-C18 and salt addition were optimized. After the graphene-C18 reinforced HF-LPME of the chlorophenols from honey sample, the analytes were separated and determined by high-performance liquid chromatography. The linearity was observed in the range of 5.0-200.0 ng $g^{-1}$ for 2-chlorophenol and 3-chlorophenol, and 2.0-200.0 ng $g^{-1}$ for 2,3-dichlorophenol and 3,4-dichlorophenol, respectively. The limits of detection (S/N = 3) of the method were lower than 1.5 ng $g^{-1}$. The recoveries of the method were between 88% and 108%. The method is simple, sensitive and has been resoundingly applied to analysis of chlorophenols in honey samples.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.2
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• pp.81-86
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• 2015

A simple analytical method to quantify formaldehyde in water at lower levels (${\mu}g/L$) was developed using a high performance liquid chromatography (HPLC) and acetylacetone as a derivative reagent. Unlike conventional methods, no extraction and/or concentration were required. The derivative reagent was added into samples and reacted for 30 minutes at $80^{\circ}C$ prior to the analysis of formaldehyde using HPLC. The method detection limit and the limit of quantification for this method were 1.6 and $5.0{\mu}g/L$, respectively. This method also achieved high precision (0.6-3.0%) and accuracy (91.6-106.3%). The recovery rates for various environmental samples ranged from 92.0 to 115.2%.

• Korean Journal of Veterinary Service
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• v.27 no.1
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• pp.17-29
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• 2004

A multiresidual analysis was performed to determine 12 sulfonamides(sulfacetamide, sulfadiazine, sulfisomidine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfisoxazole, sulfamethoxazole, sulfaquinoxaline, and sulfadimethoxine) in beef and pork simultaneously. The multiresidual analysis for the sulfonamides currently used was able to analyze 5 kinds of sulfonamides at the same time. The method of this 12 sulfonamides multiresidual analysis in this study was matrix solid-phase dispersion(MSPD) by high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC/MS). The recovery rate of the materials was measured by MSPD method with 3 different extraction solvents; Dichloromethane, DCM: Ethylacetate(3:1), DCM:EA(9:1). Also, samples (84 beef and 205 pork samples) which were positive by EEC-4 plate test from 2001 to 2003 were tested to investigate the kinds of sulfonamides using HPLC. The results from the study were as follows; 1. The recovery rate of the materials was measured by MSPD method with 3 different extraction solvents; Dichloromethane, DCM:Ethylacetate(3:1), DCM:EA(9:1). The method of extraction solvent with DCM:ethyl acetate(9:1) was the most excellent(87.7∼99.3%) in separation and reappearance. 2. In the LC/MS analysis. of sulfonamides, signal to noise ratio was showed relatively high in the positive mode and special ion in the quality analysis was determined via [M+H]$\^$+/ and m/z 156. A spectrum of sulfonamides was showed from all 12 sulfonamides. 3. The samples positive by the EEC-4 plate, a screening test method, were categorized by sulfonamides through Charm II and confirmed the kinds of sulfonamides through HPLC. 1) Among 84 beef samples positive by EEC-4 plate, 20 samples were positive by Charm II and identified as 7 sulfamethazine, 9 sulfadimethoxine, 1 sulfamonomethoxine and 3 unknown status. 2) Among 205 pork samples positive by EEC-4 plate, 42 samples were positive by Charm II and identified as 19 sulfamethazine, 1 sulfadimethoxine, 4 sulfamonomethoxine and 5 unknown status.