• Journal of Environmental Science International
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• v.17 no.10
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• pp.1155-1167
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• 2008

Chlorophyll a (chl a) has been used as an indicator for phytoplankton biomass in pelagic ecosystems due to the relative ease of measurement and selectivity for autotrophs in mixed plankton assemblages. However, the use of chi a as an indicator for phytoplankton biomass is restricted due to its inability to resolve taxonomic differences of phytoplankton and the highly variable relationship of chi a with phytoplankton. Here, we describe the analysis of High-Performance Liquid Chromatography (HPLC) photosynthetic pigment data using CHEMTAX, which is a matrix factorization program that uses chemical taxonomic indices (phytoplankton carotenoids) to quantify the abundance of phytoplankton groups. Compared to direct microscopic counting that can distinguish species within broad groups, the resolution of taxonomic groups by CHEMTAX is generally coarse. It can only distinguish between diatoms, dinoflagellates, cryptophytes, cyanobacteria, chlorophytes, prasinophytes, and haptophytes. However, CHEMTAX analysis is much faster and less expensive than microscopic counting methods. HPLC pigment observations were taken in the spring, summer, fall, and winter in$ 2005\sim2006$ within Gamak Bay, South Korea. CHEMTAX results revealed that diatoms were the dominant taxonomic group in Gamak Bay. In inner Gamak Bay, the ratio between diatoms and cryptophytes was $75\sim80%$, and the ratio between dinoflagellates and cryptophytes was $10\sim15%$. In outer Gamak Bay, the ratio between diatoms and cryptophytes was $85\sim90%$, and the ratio between dinflagellates and cryptophytes was only $1\sim5%$. The population structure was seasonal. Relative diatom populations were less in the summer than the winter season.

• Korean Journal of Veterinary Service
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• v.32 no.3
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• pp.281-286
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• 2009

Fluoroquinolones in muscle and egg were separated by liquid extraction and determined. The analysis was carried out using following conditions; C18 column ($150{\times}4.6mm$, $5{\mu}m$), mobile phase composed of D.W. (containing 0.4% triethylamine and phosphoric acid) : methanol : acetonitrile (780:100:120, v/v/v), quarternary pump at a flow rate of 0.9ml/min and $20{\mu}l$ of injection volume, fluorescence detector with EX 278nm/Em 456nm. The calibration range of seven fluoroquinolones showed linearity ($r^2{\geq}0.999$) at concentration range of $0.025{\sim}0.8{\mu}g/ml$. The recoveries in fortified muscle and egg represented more than 81.3%. The detection limits for ofloxacin, norfloxacin, ciprofloxacin, enrofloxacin, danofloxacin, saraloxacin and orbifloxacin were 3.1, 2.5, 3.6, 1.7, 0.9, 2.5 and $2.1{\mu}g/kg$, respectively. We also monitored fluoroquinolones residue in the sample (chicken muscle 182, cattle muscle 140, pig muscle 139, egg 212) using EEC-plate (E. coli ATCC 11303) screening and HPLC confirmation methods. The screening test results, fluoroquinolones, antibacterial substances were all negative.

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.529-536
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• 2005

Measurement of toxicologically relevant polychlorinated biphenyl (PCB) congeners such as non-ortho(IUPAC#) 77, 81, 126, 169 and mono-ortho 105, 114, 118, 123, 156, 157, 189 and di-ortho 170, 180 and polybrominated diphenyl ethers (PBDEs) such as 47, 66, 85, 99, 100, 138, 153, 154 in environmental samples become almost mandatory in several countries now. However, most of the available methods involve expensive instrumentations such as HRGC-HRMS or ECNI-LRMS, apart from expensive extraction and clean-up (with large volume of solvents) steps. A method has been devised combining the analytical separation power of PYE [2-(1-pyrenyl)ethyldimethysilylated silica] column HPLC and high-resolution gas chromatographic techniques including micro-electron capture detection (ECD) and two dimensional gas chromatograpy-ECD techniques to determine these eco-toxic substances at parts-per-trillion (ppt) levels. This combination resolves co-elution of congeners that occur in disproportionate ratios (e.g. CB-110 and -77) and allows accurate congener-specific determination of target compounds. This method is cost effective as it requires only hexane, that in small quantities (10 mL) and GC-ECD. The elution and analysis time are optimized to less man hours. This method is effectively utilized in the analysis of co-planar PCBs and PBDEs from archived solvent extracts of samples previously analyzed for pesticides and PCBs. Structure based separation of contaminant classes improves GCECD determination at ppt levels.

• Journal of Pharmacopuncture
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• v.9 no.2
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• pp.79-86
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• 2006

Objectives : The aim of this study was to observe prevention of allergic reactions of Sweet Bee Venom (removing enzyme components from Bee Venom). Methods: Content analysis of Sweet Bee Venom and Bee Venom was rendered using HPLC method and characterization of Anti-Sweet Bee Venom in Rabbit Serum. Clinical observation was conducted for inducement of allergic responses to Sweet BV. Results : 1. Analyzing melittin content using HPLC, Sweet BV contained 34.9% more melittin than Bee venom pharmacopuncture at same concentration. 2. Observing chromatogram of HPLC, removal of the enzyme was successfully rendered on Sweet BV. 3. The anti-serum of Sweet BV showed high titers against melittin and bee venom and relatively low titer against phospholipase A2. 4. After conducting approximately 3,000 cases of Sweet BV administration, not a single case of generalized anaphylatic reaction occurred in clinical observation. 5. Mild compared to the bee venom pharmacopuncture, Sweet BV showed some acute hypersensitive reactions of edema, itchiness, and aching locally. 6. Sweet BV was administered on six patients with previous history of suffering from generalized acute hypersensitive reactions with the bee venom. None of the patients showed allergic reactions with Sweet BV, suggesting it can effectively prevent anaphylatic shock which may occur after the bee venom pharmacopuncture procedure. Conclusion : Summarizing above results, Sweet Bee Venom appears to be an effective measurement against allergic reactions from the bee venom pharmacopuncture especially against anaphylatic shock.

• Environmental Analysis Health and Toxicology
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• v.17 no.2
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• pp.95-107
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• 2002

This study was designed to investigate the characteristics of atmospheric concentrations of toxic volatile organic compounds (VOCs) in Korea. Target compounds included 1,3-butadiene, aromatics such as BTEX, and a number of carbonyl compounds. In this paper, as the first part of the study, the performance of sampling and analytical methods was evaluated for the measurement of selected VOCs and carbonyl compounds in the ambient air. VOCs were determined by the adsorbent tube sampling and automatic thermal desorption coupled with GC/MSD analysis, while carbonyls by the DNPH-silica cartridge sampling with HPLC analysis. The methodology was investigated with a wide range of performance criteria such as repeatability, linearity. lower detection limits, collection efficiency, thermal conditioning, breakthrough volume and calibration methods using internal standards. In addition, the sampling and analytical methods established in this study were applied to real field samples duplicately collected in various ambient environments. Precisions for the duplicate samples appeared to be comparable with the performance criteria recommended by USEPA TO-17. The overall precision of the sampling and analytical methods was estimated to be within 20 ∼ 30% for major aromatic VOCs such as BTEX, whereas the precision for major carbonyl compounds such as formaldehyde and acetaldehyde was within 10 ∼ 20% for field samples. This study demonstrated that the adsorbent sampling and thermal desorption method can be reliably applied for the measurement of BTEX in ppb levels frequently occurred in common indoor and ambient environments.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.154-163
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• 1999

A multiresidue method(MRM) for pesticides must be rapid and must test a wide variety of pesticides at relevant toxicological concentrations. In this study, three kinds of major analytical methods such as Korean Food Code Method, CDFA MRM, and Holstege's method are tested to compare the average recoveries, solvent consumption, and required time for the analysis of 18 organochlorines, 18 organophosphates, and 6 carbamates in spinach samples. Samples for pesticides analysis were extracted and cleaned up according to the respective methods and detected by gas chromatography with selective detectors, ECD and NPD, HPLC with postcolumn reaction system(PCRS). Average recovery of 42 pesticides by Korean Food Code method, CDFA method, and Holstege's method were 91.3%, 88.1%, 89.0%, respectively. Amount of solvent consumption and required time for the analysis of Korean Food Code method were from two and a half times to three times as much as those of another two methods. For the development and legal application of more rapid and effective MRMs, prolonged study is necessary.

• The Korean Journal of Pesticide Science
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• v.18 no.2
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• pp.69-78
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• 2014

In the present study, we developed an official individual analytical method for cymoxanil using HPLC/UVD, respectively in different representative crops. Individual analytical methods for these pesticides are not included in the Korea food code. The samples were extracted with acetonitrile, concentrated and partitioned with dichloromethane and saturated sodium chloride solution. For cymoxanil, extracts were concentrated and clean-up through silica gel column chromatography with dicloromethane/acetone (60/40 v/v) and subjected to instrumental analysis. The limit of detection (LOD) for cymoxanil were 0.1 ng and 1 ng respectively and limit of quantitation (LOQ) were 0.02 mg/kg. Recoveries for cymoxail ranged from 79.6~107.6% respectively, at fortification level of 0.02 mg/kg (LOQ), 0.2 mg/kg (10 LOQ) and 1.0 mg/kg (50 LOQ) and the coefficient of variation (CV) was less than 10%, regardless of sample types. These results were further confirmed with LC/MS. The proposed simultaneous analysis method is reproducible and sensitive enough to determine the residues of cymoxanil in the agricultural commodities. According to the validation data and performance characteristics and high sample throughput, the proposed method is suitable for routine application.

• Analytical Science and Technology
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• v.24 no.6
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• pp.519-526
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• 2011

Chemometrics using near-infrared (NIR) and Raman spectroscopy have found significant uses in a variety quantitative and qualitative analyses of pharmaceutical products in complex matrixes. Most of the pharmaceutical can be measured directly with little or no sample preparation using these spectroscopic methods. During pharmaceutical manufacturing process, analytical techniques with no or less sample preparation are very critical to confirm the quality. This study showed NIR and Raman spectroscopy with principal component analysis (PCA) was very effective for the blending processing control. It is of utmost importance to evaluate critical parameters related to quality of products during pharmaceutical processing. The blending is confirmed by off-line determination of active pharmaceutical ingredient (API) by a conventional method such as high performance liquid chromatography (HPLC) and UV spectroscopy. These analytical methods are time-consuming and ineffective for real time control. This study showed the possibility for the determination of blend uniformity end-point of CR tablets with the use of both NIR and Raman spectroscopy. The samples were acquired from six positions during blending processing with U-type blender from 0 to 30 min. Using both collected NIR and Raman spectral data, principal component analysis (PCA) was used to follow the uniformity of blending and finally determine the end-point. The variation of homogeneity of six samples during blending was clearly found and blend uniformity end-point was successfully confirmed in the domains of principal component (PC) scores.

• The Korea Journal of Herbology
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• v.31 no.3
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• pp.29-35
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• 2016

Objectives : Ijung-tang (IJT) is a traditional herbal formula and has been used to treat digestive diseases such as abdominal pain, vomiting, and diarrhea. IJT consists of four herbal medicines, Ginseng radix, Atractylodis rhizoma alba, Zingiberis rhizoma, and Glycyrrhizae radix et rhizoma, containing various bioactive compounds. Quality assesment of IJT preparations was performed by analytical method for determining marker compounds.Methods : Determination of seven marker compounds in IJT preparations was quantitatively conducted by high-performance liquid chromatography equipped with a diode-array detector. The marker compounds were separated on a reversed-phase C18 column and the analytical method was successfully validated. Chemometric analysis was performed to compare IJT water extracts and commercial IJT granules.Results : Limit of detection and limit of quantification values were in the ranges of 0.093-2.649 μg/mL and 0.283-8.027 μg/mL, respectively. Precisions were 0.30-3.87% within a day and 0.23-2.35% over three consecutive days. Recoveries of the marker compounds ranged from 87.35-107.05%, with relative standard deviation (RSD) values < 6.15%. Repeatabilities were < 1.20% and < 1.71% of RSD value for retention time and absolute peak area, respectively. The results from quantitative analysis showed that the quantities of seven marker compounds of IJT samples varied, as were found in principal component analysis and hierarchical clustering analysis.Conclusions : The analytical method developed in the present study was precise and reliable to simultaneously determine marker compounds of IJT. Therefore, it can be used for the quality assessment of IJT preparations.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.119-128
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• 2017

BACKGROUND: Miscellaneous cereal have been largely consumed in Korea as due to their physiological functions beneficial to human health. The cereals are currently a social concern because they have been found to contain heavy metals. Thus, monitoring heavy metals in the cereals is an important requirement for food safety analysis. In this study, we determined arsenic concentration in the cereals randomly harvested from different markets. METHODS AND RESULTS: Inorganic arsenic was determined by ICP-MS coupled with HPLC system. The HPLC-ICP-MS analysis was optimized based on the limit of detection and recover test to reach $0.13-1.24{\mu}g/kg$ and 94.3-102.1%, respectively. The concentrations of inorganic arsenic equivalent to daily exposure were levels of $19.91{\mu}g/day$ in mixed grain, $1.07{\mu}g/day$ in glutinous rice, $0.77{\mu}g/day$ in black brown rice, $0.13{\mu}g/day$ in barley and $0.11{\mu}g/day$ in soybeans. CONCLUSION: The levels of arsenic in miscellaneous cereals were found lower than the recommended The Joint FAO/WHO Expert Committee on Food Additives (JECFA) levels, suggesting that the cereals marketed in Korea are not potential concern in risk assessment.