• Korean Journal of Environmental Agriculture
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• v.42 no.3
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• pp.203-210
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• 2023

Ferimzone Z is a fungicide for effectively controlling rice blast. Under light irradiation conditions, it undergoes a rapid conversion to its E-stereoisomer. Given the importance of isomers in risk assessments of residues in crops, an analytical method was developed for individual isomer quantification. A comparative analysis performed using two columns in HPLC-MS/MS demonstrated that the isomers were successfully separated using the Cadenza column. For the brown rice sample preparation, 5 g of the homogenized sample was saturated with 7 mL of water. The sample was then extracted with a 10 mL mixed solvent of acetonitrile and ethyl acetate (1:1, v/v) that contained 0.1% formic acid, and it was subsequently partitioned with magnesium sulfate and sodium chloride. The upper layer was purified using dSPE containing C₁₈ and PSA sorbents. The established method was subjected to method validation, and it showed recovery rates of 90.6-98.8% (RSD ≤ 3.9%) at concentrations of 0.01, 0.1, 2 mg/kg, with a soft matrix effect (%ME) ranging from -3.1% to +6.5%. This method can be employed in monitoring studies of brown rice to determine the conversion ratio from the Z isomers to the E isomers.

• Journal of Korean Society on Water Environment
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• v.32 no.6
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• pp.628-648
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• 2016

Increased attention has been paid to the presence of veterinary antibiotics in various environmental matrices due to their toxicological behavior in the ecosystem and development of antibiotic-resistant strains of pathogenic bacteria. In the this review, 37 target antimicrobials were selected based on annual sales of antibiotics for livestock in South Korea 2014. Also, extraction and clean-up methods for the determination of the antibiotic residues in liquid samples including water, milk, and honey were comprehensively reviewed in the literature. Solid-phase extraction (SPE) was commonly used as a pre-treatment method for the samples. Most of the analytes were extracted in acidic conditions (2.5~4.0) except for aminoglycosides, which were extracted in neutral conditions (7.0~8.0). ${\beta}-Lactams$ showed the highest recoveries in neutral pH due to their degradation characteristics in acidic media. Starta-X, Oasis HLB, and Oasis MCX were frequently applied as an SPE cartridge and Oasis HLB showed the highest recoveries for the majority of antibiotic classes. The homogenized honey and milk were extracted by mixing with acids for deproteinization. Solids and other interfering substances in the extract were eliminated by centrifugation followed by membrane filtration or SPE before injection into HPLC.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.397.1-397.1
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• 2002

A human immune globulin preparation (histobulin\ulcorner) are made to bind a small amount of histamine (0.15 $\mu$g) to the protein (12 mg) to increase the resistance of histamine susceptibility in the treatment of allergic diseases. Strict control of histamine content of the drug are required since intake of histamine might result in hypo- or hypertension. headache. or anaphylactic shock syndromes. HPLC analytical method with pre-column fluorescent derivatizalion after clean-up by solid-phase extraction (SPE) was developed. (omitted)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4927-4935
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• 2012

Turmeric is a medicinal herb with various pharmacological activities. Curcumin, demethoxycurcumin(DMC) and bisdemethoxycurcumin(BDMC) were extracted from turmeric by dipping and ultrasonic wave method. And extraction efficiency was identified using solid phase extraction(SPE). The extracted sample were simultaneously separated and analyzed from three kinds of commercial $C_{18}$ reversed-phase high performance liquid chromatography using water and acetonitrile as mobile phase with isocratic elution mode. Flow rate 1.0mL/min, injection volume $10{\mu}L$ and column oven temperature $40^{\circ}C$ at 425nm wavelength has been conducted. From the experimental results, the optimum mobile phase composition of water/acetonitrile 50/50vol% using RS tech column. It is evident that the amount of curcuminoids extracted(extraction time 4h) by 100% MeOH was higher than any aqueous MeOH composition. Finally, in 100% water extraction, the amount(mAU${\times}$mim) of curcuminoids extracted by SPE was 14.3 and 24.5 times respectively higher than ultrasonic wave and dipping method. The shown results can be applied as sources for pharmaceuticals and functional material.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.287-291
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• 2010

In this study, a simple and rapid pre-treatment method based on liquid extraction was applied for the simultaneous determination of three macrolides (spiramycin, tylosin, and tilmicosin) residues. In these studies, the stock farm products was used as a matrix sample. When the liquid extraction method was compared with the solid phase extraction (SPE) method, the former showed higher recovery percentages and simpler steps than the latter. The macrolids were separated using a reverse-phase C18 ($250\;mm{\times}4.6\;mm$, $5\;{\mu}m$) column and a gradient elution with mobile phases consisting of phosphate buffer (pH 2.5) and acetonitrile. Tylosin and tilmicosin were detected at 288 nm and spiramycin was detected at 232 nm. The average recovery percentage ranged between 83.0-90.2% for samples spiked with the three macrolids at 50 and 100 ng/g The validation results showed that the limit of detection (7 (spiramycin), 12 (tilmiconsin), 12 (tylosin) ng/g)) was under the regulatory tolerances and the linearity from calibration curves was satisfactory for determining the multi-residue of three macrolids in farm products. Monitoring samples were collected at the main cities in Korea as Seoul, Busan, Deajeon, Incheon, Deagu, and Gwangju. Microlide antibiotics were not detected in most samples.

• KSBB Journal
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• v.22 no.5
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• pp.356-361
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• 2007

Cyanobacteria are a very old group of prokaryotic organisms that produce very diverse secondary metabolites, especially non-ribosomal peptide and polyketide structures. Although some cyanobacteria produce lethal toxins such as microcystins and anatoxins, some may be useful either for development into commercial drugs or as biochemical tools. Detection of unknown secondary metabolites was carried in the present study by a screening of 98 cyanobacterial strains from Cyanobiotech GmbH in order to establish a screening process, isolate pure substances and determine their bioactivities. A degenerated polymerase chain reaction technique as molecular approaches has been used for general screening of NRPS gene and PKS gene in cyanobacteria. A putative PKS gene was detected by DKF/DKR primer in 38 strains (38.8%) and PCR amplicons resulted from a presence of NRPS gene were showed by MTF2/MTR2 primer in 30 strains (30.6%), respectively. A screening of interesting strains was performed by comparing PCR screening results with HPLC analyses of extracts. HPLC analysis for a detection of natural products was performed in extracts from biomass. 5 strains were screened for further scale-up processing. 7 pure substances were isolated from the scale-up cultures and tested for bioactivities under consideration to purity, amount and molecular weight of substances. One substance isolated from CBT 635 showed cytotoxic activity. This substance may be regarded as Microcystin LR.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.84-93
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• 2013

BACKGROUND: This study was carried out to investigate the residual characteristics of insecticides used for Oriental Tobacco Budworm control and to establish the recommended pre-harvest residue limit leading to contribution in safety of paprika production. METHODS AND RESULTS: The recommended Pre-Harvest Residue Limits (PHRLs) of insecticides during cultivation of paprika were calculated from residue analyses of insecticides in fruits 1, 3, 5, 7, 10, 12, 15, 18 and 21 days after treatment. Paprika samples were extracted with QuEChERS method and cleaned-up with amino propyl SPE cartridge and PSA, and insecticide residues were analyzed either by HPLC/DAD or GLC/ECD. The limits of detection were 0.01 mg/kg for 5 insecticides. Average recoveries were $81.3{\pm}1.62%$-$98.3{\pm}1.58%$ of 5 insecticides at fortification levels of 0.1 and 0.5 mg/kg. The biological half-lives of the insecticides were 8.5 days for bifenthrin, 11.8 days for chlorantraniliprole, 16.8 days for chlorfenapyr, 7.1 days for lamda-cyhalothrin and 31.3 days for methoxyfenozide at recommended dosage, respectively. CONCLUSION(S): The pre-harvest residue limits for 10 days before harvest were recommended 1.05 mg/kg, 1.41 mg/kg, 0.93 mg/kg, 2.06 mg/kg and 1.08 mg/kg as bifenthrin, chlorantraniliprole, chlorfenapyr, lamda-cyhalothrin and methoxyfenozide, respectively. This study can provide good practical measures to produce safe paprika fruit by prevention of products from exceeding of MRLs at pre-harvest stage.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.361-369
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• 2015

This study investigated residual characteristics of bistrifluron and fluopicolide in Korean cabbage, and suggested the pre-harvest residue limits (PHRLs) based on their dissipation patterns and biological half-lives. The pesticides were sprayed on Korean cabbage in two different region under greenhouse conditions at the recommended dose, respectively. The samples for residue analysis were harvested at 0 (2 hr), 1, 2, 4, 6, 8 and 10 days after treatment, and analyzed by HPLC after clean-up with Florisil SPE. The limit of quantification (LOQ) was $0.03mg\;kg^{-1}$ for bistrifluron and fluopicolide, and the recoveries ranged from 87.2-110.6% with below 5% of RSD. The biological half-lives of field I and field II were 3.9 and 4.2 days for bistrifluron and 4.9 and 4.2 days for fluopicolide, respectively. The PHRL of bistrifluron and fluopicolide were recommended as 3.83 and $3.23mg\;kg^{-1}$ for 10 days before harvest, respectively.

• Korean Journal of Medicinal Crop Science
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• v.16 no.6
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• pp.446-454
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• 2008

An advanced extraction method by ultrasonic extraction with applied solid phase extraction (SPE) has been developed for the determination of simultaneous eight major ginsenosides, namely ginsenosides Rg1, Re, Rf, Rb1, Rg2, Rc, Rb2, and Rd in the root of Panax ginseng. Four extraction methods including n-BuOH reflux extraction (Method A), 70% EtOH reflux extraction (Method B), 50% MeOH reflux extraction with SPE (Method C), and 50% MeOH ultrasonication with SPE clean-up process (Method D) were investigated for the determination of eight major ginsenosides. Total contents of ginsenosides were highest by extraction of Method C as $2.408{\pm}0.011%$. However, Method D was evaluated as relatively simpler and more efficient method due to short extraction time, small solvent consumption and less expensive, compared to conservative reflux method. Ginsenosides were also satisfactorily separated with good resolution and the accuracy range was between 1.05 and 4.06% as relative standard deviation (RSD) by Method D. SPE condition and HPLC condition were further optimized for determination of eight major ginsenosides by the ultrasonic extraction method. Conclusively, ultrasonic extraction of 2 g sample of ginseng using ultrasonic bath and 1 loading for SPE was evaluated as proper condition for extraction of ginseng.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.148-153
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• 1993

Composition and structure of synthetic glucitol fatty acid polyesters (GPE)-a potential fat substitute-were investigated. Also degree of substitution (D.S) of GPE was determined according to the relative ester distribution within it to evaluate the feasibility of GPE using as a fat substitute. The GPE was separated into single ester group by a normal-phase HPLC and D.S of it was identified to be 6. Absorption band at $1747\;cm^{-1}$ in the IR spectrum of GPE indicated that there were ester bonds within GPE molecules. which link fatty acid moiety to glucitol. Disappearance of the hydroxyl proton signals of glucitol in the H-NMR spectrum of GPE implied that most of hydroxyl groups in glucitol participated in the formation of ester bonds with fatty acids. In addition the D.S estimated from the quantitative proton integration of GPE coincided well with the D.S of GPE determined by hydroxyl value measurement. In conclusion, the GPE synthesized in this study was found to be a glucitol fatty acid hexaester so that it is expected to be used as a fat substitute in the near future.