• Journal of Korean Society for Atmospheric Environment
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• v.34 no.4
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• pp.616-624
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• 2018

In this study, a previous DNPH (2,4-dinitrophenylhydrazine) coupled with high performance liquid chromatography (HPLC) method to measure the concentration of formaldehyde in ambient and source environments has been improved. To improve the disadvantage of the previous HPLC method, an appropriate composition ratio of mobile phase (water: acetonitrile (ACN)) was determined and an isocratic analysis was conducted. Furthermore, limit of detection (LOD), limit of quantitation(LOQ), accuracy, and precision were investigated to verify the reliability of the analytical conditions determined. Finally, samples of exhaust gases from five different industrial facilities were applied to HPLC analytial method proposed to determine their formaldehyde concentrations. The appropriate composition ratio of the mobile phase under the isocratic condition was a mixture of water(40%) and ACN(60%). As the volume fraction of the organic solvent ACN increases, retention time of the formaldehyde peak was reduced. Detection time of formaldehyde peak determined using the proposed isocratic method was reduced from 7 minutes(previous HPLC method) to approximately 3 minutes. LOD, LOQ, accuracy, and precision of the formaldehyde determined using standard solutions were 0.787 ppm, 2.507 ppm, 93.1%, and 0.33%, respectively, all of which are within their recommended ranges. Average concentrations of the formaldehyde in five exhaust gases ranged from 0.054 ppm to 1.159 ppm. The lowest concentration (0.054 ppm) was found at samples from waste gas incinerator in a bisphenol-A manufacturing plant. The highest was observed at samples from the absorption process in manufacturing facilities of chemicals including formaldehyde and hexamine. The analytical time of the formaldehyde in ambient air can be shortened by using the isocratic analytical method under appropriate mobile phase conditions.

• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.723-727
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• 2004

Qualitative and quantitative PCR methods were performed to examine detection and quantitation of epsps inserted into genetically modified soybean (GMS) in processed foods, soy milk, tofu, and biji (soybean curd residue). Using PCR amplification to produce two (121 and 330 bp) epsps in GMS, detection limits of GMS in soy milk, tofu, and biji containing 0.01% GMS were measured. For quantitative detection, test samples containing 1, 3, and 5% GMS were measured by real-time PCR method. Results show real-time PCR method is applicable to detect GMS quantitatively in processed foods.

• Archives of Pharmacal Research
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• v.27 no.6
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• pp.676-681
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• 2004

Acetyl-L-camitine (ALC), a naturally occurring endogenous compound, has been shown to improve the cognitive performance of patients with senile dementia Alzheimer＇s type, and to be involved in cholinergic neurotransmission. Because ALC is an endogenous compound, valida-tion of the analytical methods of ALC in the biological fluids is very important and difficult. This study was presented validation and correction for plasma ALC concentrations and pharmacok-inetics after oral administration of ALC to human volunteers. ALC concentrations in human plasma were corrected by subtracting the concentration of blank plasma from each sample. Precision and accuracy (bias %) for uncorrected ALC concentrations were below 2.6 and 6.5% for intra-days, and 4.0 and 9.4% for inter-days, respectively. Precision and accuracy (bias %)for corrected ALC concentrations were below 10.9 and 6.0% for intra-days, and 10.5 and 16.9% for inter-days, respectively. Quantitation limit was $0.1{\;}\mu\textrm{g}／mL$. After oral administration of a 500 mg ALC tablet to 8 healthy volunteers, the principle pharmacokinetic parameters were 4.2 h of the half-life$ (t_{1/2},{\beta})$, the area under the curve $(AUC_{0{\rightarrow}8){\;}of{\;}9.88{\;}\mu\textrm{g}{\cdot}h/mL$, and 3.1 h of the time ($T_{max}$) to reach $C_{max}$. This study first describes the pharmacokinetic study after oral admin-istration of a single dose of ALC in human volunteers.

• Korean Journal of Veterinary Service
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• v.34 no.4
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• pp.429-439
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• 2011

This article described the comparison of a quick, easy, cheap, effective, rugged and safe (QuEChERS) sample preparation and the classical method established by National Veterinary Research and Quarantine Service (NVRQS) for the determination of pesticide residues in livestock products using GC-tandem mass spectrometry. The classical method by NVRQS used liquid-liquid partioning followed by evaporizing. The modified QuEChERS entailed extraction of 2 g sample with 15 ml acetonitrile containing 1% acetic acid followed by addition of 6 g anhydrous magnesium sulfate and 1.5 g sodium acetate. After centrifugation, 6 ml of the extract underwent a cleanup step (in a technique known as column-based solid phase extraction) using 400 mg each of $C_{18}$ and primary secondary amine sorbents plus 1,200 mg magnesium sulfate. The quantitation of individual pesticides by both methods was based on tissue standard calibration curves with a correlation coefficient in excess of 0.98 for the 24 pesticides. The detection limits by the classical method were ranged 1.3~5.0 ${\mu}g$/kg, with mean recoveries between 76.2% and 114.3% except aldrin (59.3%) and deltamethrin (63.6%). The detection limits by modified QuEChERS were ranged 0.3~6.2 ${\mu}g$/kg, with mean recoveries between 68.0% and 114.3% except dimethipin (152.6%), chlorfenvinphos (138.1%), 4,4-DDT (61.5%), aldrin (60.4%) and chinomethionate (30.3%).

• The Korea Journal of Herbology
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• v.35 no.5
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• pp.23-31
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• 2020

Objectives : This study was conducted to evaluate the anti-hyperlipidemia effect of Scutellariae Radix, Aucklandiae Radix and Bupleuri Radix(SAB). Methods : FL83B cells were mouse liver hepatocytes, and we used this cell line. FL83B cells were treated with 0.5 mM oleic acid(OA) for 24 h, SAB extract was treated. After OA treatment, intracellular triglyceride (TG) and free fatty acid contents were measured with AdiopoRed™ assay and Free Fatty Acid Quantitation assay kit, respectively. Further, we evaluated several lipogenesis and metabolic markers such as sterol regulatory element-binding transcription factor-1c (SREBP-1c), acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), 3-hydroxy3-methyl-glutaryl CoA reductase (HMGCR), hormone-sensitive lipase (HSL), carnitine palmitoyltransferase (CPT-1), peroxisome proliferator activated receptor alpha (PPARα), and cluster of differentiation (CD36) using RT-PCR and Western-blot analysis. Results : OA markedly increased intracellular TG and free fatty acid, which plays a key role in reducing hepatic lipid accumulation, in FL83B cells. These increases were alleviated by SAB extract. The mRNA and protein expression of Fatty acid(FA) oxidation factors (CPT-1, PPARα), lipolysis factor(HSL), FA transporter(CD36), cholesterol synthesis factors (HMGCoA) and Lipodenesis (SREBP-1c, FAS, and ACC-1) were significantly increased by treatment of SAB extract in the OA-induced fatty liver cell model. Conclusions : In summary, the treat of SAB extract showed a significant reduction of the influx of fatty acids into hepatocytes, promoted the oxidation of fatty acids, and regulated fat synthesis-related factors, thereby regulating the accumulation of TG and free fatty acids.

• Biomedical Science Letters
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• v.26 no.2
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• pp.93-100
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• 2020

Xerostomia is a relatively common oral disease that causes various problems such as pain, discomforted, tissue damage, and infection. When the activity of AQPs, which plays an important role in the microbial channel transmembrane activity in tissues, decreases saliva secretion and the oral cavity dryness occurs. In this study, we observed whether there was a change in tissue through the expression level of AQP-5 in the submandibular gland in the 4-DAMP-induced xerostomia model. First, in order to construct a xerostomia model, 4-DAMP (1 mg/kg) and 20% urethane (0.5 mL/kg) were administered intraperitoneal (i.p.) to experimental animals. To observe the changes in the submandibular gland was excised, H&E staining was performed and protein quantitation analysis was performed using the submandibular tissue to observe the changes in AQP5 protein expression involved in changes in saliva secretion. Also, cinnamaldehyde (5, 12.5, 25 and 50 mg/kg) dissolved in 20% DMSO, in distilled water for each concentration, and then orally administered at a dose of 1 mL for biopsy and protein quantitative analysis. As a result, it was observed that the submandibular tissue, a model of xerostomia was wider than the naïve group. And then western blot analysis, the expression level of AQP5 decreased in the 4-DAMP group compared to the naïve group, and the expression increased in the group administered orally with cinnamaldehyde. Therefore, administration of 4-DAMP resulted in histological changes for xerostomia, and cinnamaldehyde would be a material that can be developed by reducing xerostomia.

• YAKHAK HOEJI
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• v.56 no.4
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• pp.211-216
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• 2012

Drug dissolution test has been used for the purpose of both quality control of solid oral dosage forms and predicting in vivo drug release profiles. In this study, the dissolution profiles of buflomedil hydrochloride tablets and ticlopidine hydrochloride tablets were investigated according to the "Guidelines on Specifications of Dissolution tests for Oral dosage forms" of Korean Pharmacopoeia (KP). The analytical method using HPLC was validated. The validation was performed in terms of specificity, linearity, accuracy, precision and limit of quantitation.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.626-632
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• 2011

Phoxim, which is one of veterinary drugs, is a well-known antiparasitic agent in wide use. In this paper, phoxim was extracted from cattle and pig tissue using solid-phase extraction (SPE) employing a silica cartridge with acetonitrile. Liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) for the analysis of phoxim from animal tissue was presented. Phoxim was detected on a $C_{18}$ column ($2.1{\times}100\;mm$, $3.5\;{\mu}m$) using a mobile phase of 0.1% formic acid in water and acetonitrile. A linear correlation observed in the calibration curves for cattle (0.0048~2.0 mg/kg) and pig (0.0055~2.0 mg/kg) showed above $r^2$=0.995. Accuracy measured at concentrations ranging from 0.0048 to 0.2 mg/kg was the range of 68.2~106.9%. Limit of detection (LOD) and limit of quantitation (LOQ) were the range of 0.0014~0.0017 mg/kg and 0.0048~0.0055 mg/kg, respectively. The precision (RSD%) was below 11.2%.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.35-42
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• 2009

Headspace micro solid phase extraction using mulberry paper bag (HS-MPB-$\mu$-SPE) has been developed and validated for the analysis of volatile flavor compounds from five spice by gas chromatography-mass spectrometry (GC/MS). HS-MPB-$\mu$-SPE was performed with adsorbent particles enclosed inside a mulberry paper bag. Four different kinds of adsorbents such as Tenax TA, Porapack Q, dimethylpolysiloxane and polyethylene glycol were tested. The extraction solvents compared were petroleum ether, methylene chloride, and chloroform. Better results were obtained when Tenax TA and petroleum ether were used. The limit of detection (LOD) and the limit of quantitation (LOQ) were in the range of 1.3 ng/mL and 4.3 ng/mL, respectively, for o-cymene as a model compound of monoterpene. Proposed method showed good reproducibility (3.3%, RSD) and good recoveries (94.0%). The HS-MPB- μ-SPE is very simple to use, inexpensive, rapid, requires small sample amounts and solvent consumption. Because the solvent for extraction is reduced to only a very small volume (0.6 mL), there is minimal waste or exposure to toxic organic solvent and no further concentration step. This method allows successful characterization of the headspace in contact with the five spice sample. Strong trans-anethole from star anise or fennel is a characteristic flavor of five spice powders. HS-MPB-$\mu$-SPE combined with GC/MS can be a promising technique for the broad spectrum measurement of volatile aroma compounds from solid spices.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2394-2398
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• 2013

Nicotine is the main component of environmental tobacco smoke, and its presence in indoor air is widely used as a secondhand-smoke indicator. Environmental tobacco smoke is a major source of indoor air pollution, but sufficient investigation of the uncertainty of its measurement, which mirrors the reliability of nicotine measurement, has not been performed. We calculated the uncertainty of measurement of indoor air nicotine concentration at low, medium, and high concentrations of 11.3798, 10.1977, $98.3768{\mu}g/m^3$, respectively, and we employed the Guide to the Expression of Uncertainty in Measurements (GUM), proposed by the International Organization for Standardization (ISO). The factors considered in determining the uncertainty were uncertainty of the calibration curve (calibration curve and repeated measurements), desorption efficiency, extraction volume, and sampling airflow (accuracy and acceptable limits of flowmeter). The measurement uncertainty was highest at low concentrations; the expanded measurement uncertainty is $0.9435{\mu}g/m^3$ and is represented as a relative uncertainty of 63.38%. At medium and high (concentrations, the relative uncertainty was 13.1% and 9.1%, respectively. The uncertainty of the calibration curve was largest for low indoor nicotine concentrations. To increase reliability of measurement in assessing the effect of secondhand smoke, measures such as increasing the sample injection rate ($1{\mu}L$ or more), increasing sampling volume to increase collected nicotine, and using gas chromatography-mass spectrometry (GC/MS) or GC/MS/MS, which has a lower quantitation threshold, rather than gas chromatography with nitrogen phosphorous detector, should be considered.