• Journal of Food Hygiene and Safety
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• v.8 no.4
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• pp.251-254
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• 1993

Extraction and Clean-up procedures coupled with quantitation by high performance liquid chromatography(HPLC) was evaluated for the detection of 4 aflatoxins, B1, B2, G1 and G2, in peanut butter. The Sep-pak clean-up method showed poorer separation and repeatability than did the modified DeVries' and an immunoaffinity column clean-up methods. No significant difference of detected aflatoxins between the affinity column clean-up and modified DeVries' method. The coefficients of variation for the 4 aflatoxins were ranging from 6.3∼32.3 by the modified DeVries' method and 5.3∼9.8 by the affinity column clean-up.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.1
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• pp.120-143
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• 2018

The analytical methods and their ambient levels of organic nitrogenous compounds such as nitrosamines, nitramines (nitroamines), imines, amides and nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) in the atmosphere are summarized and discussed. Sampling for the analysis of organic nitrogenous compounds was mostly conducted using high volume air sampler. The direct liquid extraction (DLE) using sonification and the pressurized liquid extraction (PLE) using the accelerated solvent extraction (ASE) have been frequently employed for the extraction of organic nitrogenous compounds in the atmospheric samples. After extraction, clean-up via filtration and the solid phase extraction (SPE) and concentrations using nitrogen and rotary evaporator have been generally conducted but in some studies the clean-up and concentration steps have been omitted to prevent the loss of analyte and improve the recovery rate of the analytical procedure. Instrumental analysis was mainly carried out using gas chromatography (GC) or the high performance liquid chromatography (HPLC) coupled with the single quadrupole mass spectrometer or tandem mass spectrometer in the electron ionization (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI) mode and analysis sensitivity of nitrosamines and nitramines were higher in NCI mode. Desirable sampling and analysis methods for analyzing particulate organic nitrogenous compounds are suggested.

• Journal of Soil and Groundwater Environment
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• v.17 no.4
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• pp.63-72
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• 2012

The main objective of this study is to assess the compatibility between Korean ministry of environment (KME) standard and ISO (KS I ISO) standard for the determination of BTEX and TPH content in soil. We carried out comparison analysis for both methods using CRM and matrix spiked samples. In case of GC-MS analysis for BTEX, we got statistically (significance level: 0.05) the same results from KME standard (ES 07600.1) and ISO standard (KS I ISO 15009). However, it showed statistically (significance level: 0.05) different results when TPH was analyzed by KME standard (ES 07552.1) and ISO standard (KS I ISO 16703). To clarify the reason why both methods produced different results for TPH content, we also did some additional experiments in terms of differences in extraction, clean-up and target hydrocarbon range. Extraction with polar and non-polar compounds mixed solvent (acetone+n-heptane) of KS I ISO 16703 showed higher extraction efficiency than with only non polar solvent (dichloromethane) extraction of ES 07552.1 by about 9%. While column type clean-up of KS I ISO 16703 showed the reduction in TPH content between before and after clean-up, batch type of clean-up of ES 07552.1 did not show any changes in TPH content through clean-up process. The target hydrocarbon range of ES 07552.1 and KS I ISO 16703 is $C_8{\sim}C_{40}$ and $C_{10}{\sim}C_{40}$, respectively. From this point of view, kerosene and JP-8 contaminated soil showed higher RPD (relative producibility deviation) values between results by both method than that of lubricant or diesel contaminated soil. The higher content of hydrocarbon ($C_8{\sim}C_{10}$) in kerosene and JP-8 played an important role in increasing RPD values in addition to the effects caused by different solvents and clean-up method. Consequently, it was concluded that both methods (ES 07552.1 and KS I ISO 16703) were not compatible.

• Journal of Korean Society on Water Environment
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• v.32 no.6
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• pp.600-627
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• 2016

Korea is one of the countries with a large veterinary antibiotics market, although antimicrobial resistance in bacteria is becoming a serious issue in many countries. The Korean government started to take interest in estimating the effects of livestock manure on rivers and agricultural soils and in monitoring of heavy metals, organic pollutants and antibiotics in the ambient water and soil. In this paper, pre-treatment methods to separate the selected antibiotics from solid samples were reviewed. It is essential to select an efficient and appropriate procedure for pre-treatment due to the high proportion of proteins and organics in biosolid samples. Pre-treatment consists of extraction followed by clean-up. Initially, homogenized samples were extracted by sonication, mechanical agitation or pressurized liquid extraction with methanol/acetonitrile/water mixture under acidic/basic conditions depending on the compound. However, aminoglycosides and colistin were extracted with 5% trichloroacetic acid and HCl, respectively. Since the ${\beta}-lactams$ are easily decomposed in acidic and basic conditions, they were extracted in neutral pH. Filtration with a membrane (pore size, $0.2{\mu}m$) or solid phase extraction with HLB and methanol, as eluents, was normally applied for the clean-up. At least, three different pre-treatment procedures should be adopted to screen all the selected antibiotics in solid samples.

• Advances in materials Research
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• v.9 no.4
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• pp.251-263
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• 2020

α-mangostin imprinted polymers have been synthesized by a non-covalent imprinting approach with α-mangostin as a template molecule. The α-mangostin molecularly imprinted polymers (MIPs) prepared by radical polymerization using methacrylic acid, ethlylene glycol dimethacrylate, benzoyl peroxide, and acetonitrile, as a monomer, crosslinker, initiator, and porogen, respectively. The template was removed by using methanol:acetic acid 90:10 (v/v). The physical characteristics of the polymers were investigated by Fourier Transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The rebinding studies were carried out by batch methods. The results exhibited that the MIPs was able to adsorb the α-mangostin at pH 2 and the contact time of 180 min. The kinetic adsorption data of α-mangostin performed the pseudo-second order model and followed the Langmuir isotherm model with the adsorption capacity of 16.19 mg·g-1. MIPs applied as a sorbent material in solid-phase extraction, namely molecularly imprinted solid-phase extraction (MISPE) and it shows the ability for enrichment and clean-up of α-mangostin from the complex matrix in medicinal herbal product and crude extract of mangosteen (Garcinia mangostana L.) pericarp. Both samples, respectively, which were spiked with α-mangostin gives recovery more than 90% after through by MISPE in all concentration ranges.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.879-886
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• 2006

The analytical methods of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) for water sample with extremely low concentration was developed to extract large volume and to improve fast chromatography for clean up. Semi-automated solid phase extraction (SPE) system and column coupling chromatography using elution pump was optimized and applied to each processes of treatment plant. Results of disk type SPE indicated that this system was applicable below 40 L of aqueous sample with a flow rate of 0.08 ~ 0.2 L/min. Average recoveries of SPE using labeled sampling spike of $^{37}Cl$-2,3,7,8-TCDD was 97%. Column coupling method resulted in reduced clean up time, solvent volume, increased average recoveries with constant elution rate. The combined methods were applied to the monitoring of drinking water treatment plant. Limits of detection (LOD) of each process were calculated. For example, LOD of raw and treated water ranged 0.094~0.968 pg/L and 0.028~0.364 pg/L, respectively. Combined methods of extraction and cleanup techniques provided fast analysis of PCDD/Fs with high accuracy and low LODs for water samples.

• 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.

• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.219-229
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• 2005

The analytical methods for dioxins in water sample from wastewater to tap water were reviewed. For extraction method, liquid-liquid extraction (LLE) has been widely used, however, this process needs too much time and man power. New approach including solid phase extraction (SPE) is now applicable to large volume of water sample with high extraction efficiency. Column clean up in classical analytical methods were very complex and time consuming procedures during decade. Modifications were tried to decrease solvent and reagents volume. Moreover, use of column connection method has been demonstrated in the environmental matrices. Instrumental configurations also have been improved, in which GC/MS/MS with large volume injection approach can analyze picogram levels. Absolute sensitivities of HRMS increased compared to old versions of double focusing sector type mass spectrometers. Based on these analytical evolutions during last 10 years, we tried to optimize the analytical method for dioxins in water sample from sample extraction to instrumental analysis.

• Journal of the Korean Society of Tobacco Science
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• v.36 no.1
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• pp.26-33
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• 2014

Simultaneous determination of crop protection agents(CPAs) in food are done with multi-residue methods, which are composed of sample clean-up, concentration, chromatographic separation and detection. Stir Bar Sorptive Extraction(SBSE) technique is used for sample preparation of various analytes in several fields. The aim of this study was to develop a sensitive and fast method based on SBSE followed by thermal desorption - gas chromatography - mass spectrometry(TD - GC/MS) to determine CPAs in tobacco sample. For the analysis of tobacco sample prior to the SBSE method, solvent extraction or ultrasound-assisted solvent extraction was performed. methanol was used as the extraction solvent. The extract was then diluted with water. Finally, the sample was subjected to SBSE. A method for fast screening of crop protection agents in tobacco using SBSE-TD - GC/MS has been developed. About 17 CPAs including organochlorine, organophosphorous and others were identified and quantified. This method showed good linearity and high sensitivity for most of the target CPAs. The method was applied to the determination of CPAs at ng/mL levels in tobacco sample. This method is simple, rapid and may be applied in detection of other components.

• Analytical Science and Technology
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• v.15 no.3
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• pp.300-316
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• 2002

The extraction methods of PBBs from environmental samples by soxhlet extraction for solid phase and liquid-liquid extraction for liquid phase were compared. After extraction, silicagel and florisil as column clean up methods were used for the comparison of cleanup efficiency with different solvent system. Also, the analytical instruments were used GC/MSD. The 22 kinds of PBBs standards were used to establish the analytical methods to perform the experiments of recoveries and detection limits in water and soil. The detection limits of PBBs represented 5~10 ng/L for water and 0.5~3.5 ng/g for soil samples, respectively. The recoveries of water samples represented 96~107% in n-hexane, dichloromethane and toluene for water, and 60~80% in combined solvent with n-hexane and acetone. The recoveries of soil sample were surveyed 67~97% in soxhlet extraction and 64~76% in ultrasonic extraction with selected solvents.