• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.872-878
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• 2004

Food products selected based on their annual sales and international acrylamide research data were analyzed for quantitation of acrylamide. Samples including raw food, substitute meal, snack, drink, and sauce products were analyzed by LC/MS/MS methods adopted by PDA. Upon comparison, concentrations of acrylamide in these products were similar to those analyzed in other countries.

• Korean Journal of Environmental Agriculture
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• v.39 no.3
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• pp.214-221
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• 2020

BACKGROUND: The demand for pesticide registration has kept increasing for minor crop cultivation in greenhouse since Positive List System (PLS) has been launched. Thus, much study on the evaluation of pesticide residues in minor crops is required to examine the demand. In this study, we evaluated residues of acetamiprid, boscalid, imidacloprid and pyraclostrobin in the minor crop mustard green to provide the potential data for their registration. METHODS AND RESULTS: Pesticide granule formulations of acetamiprid, boscalid, imidacloprid and pyraclostrobin were incorporated into soil and applied onto field soil surface at rates of 3 kg/10a, 6 kg/10a, 3 kg/10a and 6 kg/10a, respectively. The pesticides were also applied at the two times higher than the rates to compare the residues between the application rates. Mustard green seeds were sown 1 day after pesticide application and cultivated under greenhouse conditions. LC/MS/MS analyses coupled with a modified QuEChERs method were employed for determination of the pesticides in plant samples. The method limits of quantitation (LOQ) of the pesticides were 0.01 mg/kg, and the matrix calibration curves of the pesticides showed linearity with coefficient values of determination (r²) greater than 0.995. The average recovery values of the pesticides fortified in control samples at rates of LOQ and 10LOQ ranged from approximately 77.5% to 101.2% with relative standard deviation values lower than 14%. The pesticides in the mustard green samples cultivated for 53 days after sown were determined to be lower than the LOQ level. CONCLUSION: Acetamiprid, boscalid, imidacloprid and pyraclostrobin were found at a level lower than 0.01 mg/kg in the minor crop mustard green. Thus, their residues in mustard green would not violate PLS under greenhouse conditions.

• Korean Journal of Pharmacognosy
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• v.42 no.2
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• pp.144-148
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• 2011

Rhubarb (Rhei Rhizoma) has been used for the various clinical purposes such as purgative, stomach protective and pain relief for a long time. However, rhubarb in current market has a problem of quality control under which many of rhubarb fail to meet the standard specified in Korean Pharmacopoeia. This study was carried out to validate the method for the evaluation of the quality of five rhubarbs and Rumex species; Rheum palmatum, R. officinale, R. tanguticum, R. franzenbachii, R. undulatum, and Rumex species. The content of sennoside A with five anthraquinones (aloe-emodin, rhein, emodin, chrysophanol and physcion) in five rhubarbs and one Rumex has been performed by using HPLC quantitation analysis. In results, only four samples in Palmata sect. were qualified with sennoside A and those samples were R. officinale and R. tanguticum. Samples of R. palmatum did not meet the standard contents of sennoside A. The contents of anthraquinones in Palmata sect. were two times larger than those in Rhapontica sect. Moreover the content variations of anthraquinones were smaller than those of sennoside A. Thus, anthraquinones can be the key characterizing molecules to control quality of rhubarb.

• Toxicological Research
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• v.8 no.2
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• pp.171-177
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• 1992

To investigate a short term screening method for carcinogenic quinone compounds, 8-hydroxydeoxyguanosine (8-OHdG), an oxidative DNA damage, was determined in the kidney and liver DNA isolated from Sprague-Dawley rats after i.p.injection of 7 mg/kg adriamycin (AM), 7mg/kg tetrahydropyranyladriamycin (THP), and 10mg/kg daunomycin (DM) by HPLC-electrochemical detector system. 8-OHdG was also determined from rat hepatocvtes and calf thymus DNA exposed to AM, DM and THP. When rats were treated with DM and THP, 8-OHdG was significantly increased in the kidney compared to control group, and remained at high level (7.9~9.0, 8-OHdG/dG${\times}10^4$)at the end of experiments (48hr after treatment). 8-OHdG level in cultured hepatocyte exposed to AM, DM and THP was 1.5~2 fold higher than control at all time points. (1,2,3,4hr after treatment). From calf thymus DNA exposed to AM, DM and THP, 8-OHdG was 2.5 fold higher than of control. These results suggest that quantitation of 8-OHdG may provide a useful marker for identifying target organ in oxidative chemical carcinogenesis and for short term screening of free radical generating carcinogens.

• Analytical Science and Technology
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• v.13 no.5
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• pp.666-674
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• 2000

The present study describes an analytical method for the determination of polybrominated biphenyls (PBBs) in biota samples by gas chromatography-mass spectrometry (GC/MS). PBBs are extracted twice from 20 g samples with mixture solvent 40mL acetone and 80mL hexane using ultrasonic agitation for 20 min. Lipids in extracts are degraded by concentrated sulfuric acid and then PBBs are purified with Florisil column. The purified extracts are analyzed by GC/MS-selected ion monitoring mode for the quantitation of PBBs in biota sample. The overall recovery yields of PBBs range between 77 and 111% under these experimental conditions.

• Analytical Science and Technology
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• v.30 no.1
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• pp.1-9
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• 2017

Starch is a mixture of amylose (AMY) and amylopectin (AMP) which are different in physical properties such as molar mass (M), rms radius ($R_g$) and hydrodynamic diameter ($d_H$). The rheological and functional properties of starch are influenced by various factors including the molecular size, molar mass distribution (MD) and the concentration ratio of AMY and AMP. It is also important to analyze proteinaceous material in starch as they affect the flavor and texture of food to which starch is added. In this study, asymmetrical flow field-flow fractionation (AF4) was employed for separation and quantitation of AMY and AMP in starches (Amaranth, potato, taros and quinoa). AF4 was coupled with a multi-angle light scattering (MALS) and a refractive index (RI) detector for determination of the absolute M, MD and molecular structure. It was found that AMP has the M and $R_g$ ranging $3.7{\times}10^7{\sim}6.5{\times}10^8g/mol$ and 84 ~ 250 nm, respectively. Also the existence of branch was confirmed in higher M. In addition, proteinaceous material in starch was analyzed by AF4 coupled with a fluorescence detector (FS) after fluorescence-labeling. AF4-FS with fluorescence-labelling showed a potential for investigation on existence of proteinaceous material and the interaction between proteinaceous material and polysaccharide in starch.

• Journal of Pharmaceutical Investigation
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• v.39 no.4
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• pp.309-314
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• 2009

An enzyme immunoassay (EIA) was validated for quantitation of cacitriol in human plasma. Calcitriol was immunoextracted with immunocapsules, which contain monoclonal antibodies to calcitriol linked to solid phase particles in suspension with a vitamin D binding protein inhibitor. Calcitrol was eluated and the eluates were evaporated under a gentle stream of nitrogen gas. The absorbance of analytes was determined using a microplate reader (reference wavelength 650 nm; measurement wavelength 450 nm). The method was specific and sensitive enough to detect as low as 6.5 pmol/L of calcitriol. Linear calibration range was 6.5-491 pmol/L with correlation coefficient greater than 0.99. The overall accuracy was in the range of 83.8 to 111.2% and precision C.V. (%) 0.99 to 8.47%. The recovery was approximately 100% and stability was confirmed during storage and sample preparation. The pharmacokinetic parameters were calculated by baseline subtraction because calcitriol is an endogenous material. Following oral dose of calcitriol, the mean AUC$_{24h}$ was 1038${\pm}$539 pmol/Lhr and C$_{max}$ of 128${\pm}$63.1 pmol/L was reached at 3.50${\pm}$1.07 hr. The mean t$_{1/2}$ of calcitriol was 5.13${\pm}$2.10 hr. The present EIA method was successfully applied to study bioavailability after oral administration of 2 ${\mu}$g of calcitriol in healthy Korean subjects.

• Journal of Pharmaceutical Investigation
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• v.39 no.5
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• pp.321-325
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• 2009

5-HT$_{2C}$ receptors have been considered as therapeutic targets for the treatment of various central nervous system disorders such as depression, anxiety, epilepsy, schizophrenia and sleep disorders. We chemically synthesized KKHQ80114 (K14) and KKHQ80109 (K09), selective 5-HT$_{2C}$ agonists, with the purpose of developing therapeutic agents for the treatment of obesity. The objective of this work is to investigate analytical methods of these compounds in the plasma and urine of rats by gas chromatography/mass spectrometry. In this experiment, K14 was determined in plasma and urine by using K09 as internal standard. Calibration curves give a good linearity in plasma (r$^2$=0.9993) and urine (r$^2$=0.9988). Among hexane, ethyl acetate and diethyl ether, the highest peak was observed in diethyl ether. However, ethyl acetate was used since more interfering peaks were observed with diethyl ether. Inter-day precision and accuracy were determined in the ranges of 50-500 ng/mL for plasma and 10-500 ng/ml for urine. Quantitation limits were 50 ng/mL plasma and 25 ng/ mL urine. These data may be applicable for further studies of these compounds including absorption and metabolism due to no pharmacokinetic or analytical data available.

• Journal of Food Hygiene and Safety
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• v.25 no.1
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• pp.30-35
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• 2010

It has been elucidated desmethylsibutramine in food, that is an analogue of sibutramine used for anti-obesity drug. After separating and purifying in food samples, it was analyzed and identified by the instrument such as HPLC/PDA, HPLC/MS, HPLC/MS/MS and NMR. To analyze sibutamine and desmathylsibutramine in foods, they were analyzed and identified by HPLC/PDA after extracting in dichloromethane, filtering, concentration and diluting in methanol. The overall recoveries were ranged from 87% to 91% and the limit of quantitation was $2.5\;{\mu}g/kg$. As results, sibutramine and desmethylsibutramine was not detected in all the selected 54 food samples.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.521-526
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• 2010

A high-performance liquid chromatography (HPLC) method was established for the determination of fluoroquinolones in milk. Protein was removed by using trichloroacetic acid in order to increase a mean recovery of milk. The extracts were using $Strata^{TM}$-X solid-phase extraction cartridge. The analytes were detected by HPLC on a $C_{18}$ column. HPLC method with fluorescence detection system (Ex: 278 nm, Em: 456 nm) provided a high degree of sensitivity in detecting fluoroquinolones. The limits of quantitation (LOQ) and mean recoveries of fluoroquinolones were 40 ${\mu}g$/kg and 73.6-95.2% (ofloxacin), 10 ${\mu}g$/kg and 77.3-91.9% (norfloxacin), 20 ${\mu}g$/kg and 91.6-94.3% (ciprofloxacin), 10 ${\mu}g$/kg and 81.0-87.8% (enrofloxacin), 10 ${\mu}g$/kg and 71.3-81.0% (sarafloxacin), 10 ${\mu}g$/kg and 89.4-90.8% (orbifloxacin), 2 ${\mu}g$/kg and 69.4-85.5% (danofloxacin).