• Journal of Food Hygiene and Safety
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• v.28 no.1
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• pp.45-49
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• 2013

This study aimed to determine heavy metal contents in sesame oil samples produced in Korea through microwave-assisted acid digestion without using an emulsifier. Three heavy metal, cadmium (Cd), lead (Pb) and arsenic (As) in twelve sesame oil samples were determined by ICP-MS. The validation of analysis method was checked by standard addition method (10 and $100{\mu}g/kg$). As a result, linearity ($R^2$) was above 0.999 and RSDs were lower than 4%. The recovery of Cd, Pb and As ranged between 98.5-101.6%, 100.3-101.3%, and 102.1-111.2%, respectively. The detected ranges in sesame oil samples were as follows; N.D. to $0.109{\mu}g/g$ for Cd, 0.014 to $0.200{\mu}g/g$ for Pb and 0.014 to $0.125{\mu}g/g$ for As, respectively. Therefore, sesame seeds and products grown in heavy metal-polluted regions which are used as food should be given priority attention and consideration.

• Journal of Pharmacopuncture
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• v.17 no.4
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• pp.36-49
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• 2014

Objectives: Quercetin and curcuminoids are important bioactive compounds found in many herbs. Previously reported high performance liquid chromatography ultraviolet (HPLC-UV) methods for the detection of quercetin and curcuminoids have several disadvantages, including unsatisfactory separation times and lack of validation according the standard guidelines of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use. Methods: A rapid, specific, reversed phase, HPLC-UV method with an isocratic elution of acetonitrile and 2% v/v acetic acid (40% : 60% v/v) (pH 2.6) at a flow rate of 1.3 mL/minutes, a column temperature of $35^{\circ}C$, and ultraviolet (UV) detection at 370 nm was developed. The method was validated and applied to the quantification of different types of market available Chinese medicine extracts, pills and tablets. Results: The method allowed simultaneous determination of quercetin, bisdemethoxycurcumin, demethoxycurcumin and curcumin in the concentration ranges of $0.00488-200{\mu}g/mL$, $0.625-320{\mu}g/mL$, $0.07813-320{\mu}g/mL$ and $0.03906-320{\mu}g/mL$, respectively. The limits of detection and quantification, respectively, were 0.00488 and $0.03906{\mu}g/mL$ for quercetin, 0.62500 and $2.50000{\mu}g/mL$ for bisdemethoxycurcumin, 0.07813 and $0.31250{\mu}g/mL$ for demethoxycurcumin, and 0.03906 and $0.07813{\mu}g/mL$ for curcumin. The percent relative intra day standard deviation (% RSD) values were $0.432-0.806{\mu}g/mL$, $0.576-0.723{\mu}g/mL$, $0.635-0.752{\mu}g/mL$ and $0.655-0.732{\mu}g/mL$ for quercetin, bisdemethoxycurcumin, demethoxycurcumin and curcumin, respectively, and those for intra day precision were $0.323-0.968{\mu}g/mL$, $0.805-0.854{\mu}g/mL$, $0.078-0.844{\mu}g/mL$ and $0.275-0.829{\mu}g/mL$, respectively. The intra day accuracies were 99.589%-100.821%, 98.588%-101.084%, 9.289%-100.88%, and 98.292%-101.022% for quercetin, bisdemethoxycurcumin, demethoxycurcumin and curcumin, respectively, and the inter day accuracy were 99.665%-103.06%, 97.669%-103.513%, 99.569%-103.617%, and 97.929%-103.606%, respectively. Conclusion: The method was found to be simple, accurate and precise and is recommended for routine quality control analysis of commercial Chinese medicine products containing the flour flavonoids as their principle components in the extracts.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1746-1750
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• 2007

The second-order scattering (SOS) phenomenon of the interaction of Pd nanoparticles with protein was reported and a simple, sensitive, palladium nanoparticle-based assay for trace amount of protein with SOS technique was developed. The SOS intensities were significantly enhanced due to the interaction of Pd nanoparticles with bovine serum albumin (BSA) or human serum albumin (HSA) at pH 3.5 or 4.0, respectively. The maximum SOS peak appeared at 260/520 nm (λex/λem). The optimal experiment conditions, affecting factors and the influence of some coexisting substances were checked. The SOS intensity increased proportionally with the increase of Pd concentration below 3.0 × 10?5 mol·L?1, while declined gradually above 4.0 × 10?5 mol·L?1. BSA within the range of 0.01-2.6 μg·mL?1 and HSA of 0.01-1.7 μg·mL?1 can be detected with this method and the detection limits were 2.3 and 11.2 ng·mL?1, respectively. The method was successfully applied to the quantitative detection of total protein content in human serum samples with the maximum relative standard deviation (RSD) lower than 2.6% and the recoveries over the range of 99.5-100.5%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1737-1741
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• 2014

An HPLC method for determination of naringin was developed to standardize it as a marker compound in Goheung yuzu extract as a functional health food. Optimum results were obtained by C-18 column chromatography using solvent mixtures (A: 0.5% acetic acid, B: acetonitrile) as the stationary phase and mobile phase. The method was fully validated and sensitive with a limit of detection (LOD) of 0.0218 mg/L and limit of quantification (LOQ) of 0.0661 mg/L. The method showed high linearity (coefficient of correlation=0.9986) and high accuracy, as recovery rates of naringin at concentrations of 1, 0.5, 0.1, 0.05 mg/mL were in the ranges of 95.74~98.25%, 97.67~101.01%, 97.33~104.64%, and 95.53~106.82%, respectively. Intra-day and inter-day variation, which are measures of method precision, were 1.39~1.95% and 0.17~1.49%, respectively. Therefore, the method could be used without modification for determination of naringin as a marker compound in Goheung yuzu extracts.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.1-5
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• 2011

It is possible that veterinary medicines remain in livestock food products, according to the use of many and various veterinary medicines to protect against disease when livestock animals are breed in limited space. Concentrated and continuous monitoring of residues is needed due to increases in resistance to antibiotics and side effects by eating livestock food products. We developed an analysis method for detecting streptomycin, dihydrostreptomycin, neomycin, gentamicin and spectinomycin in meat using LC/MS/MS and measured sensitivity, precision, accuracy, linearity and recovery according to CODEX guidelines to acquire confidence in the analysis method. Based on the results, we acquired good sensitivity compared to the maximum residue limit (MRL) as limits of detection (LOD) were 0.002-0.016 mg/kg and limits of quantification (LOQ) were 0.006-0.050 mg/kg. The analysis method satisfied the CODEX guidelines. The linearity ($r^2$) values of aminoglycoside antibiotics were 0.9936-0.9980, recoveries were 60-110% and relative standard deviations (RSD) were within 15%. As a result of monitoring for residues in a total 250 samples of livestock foods such as pork, chicken, and beef by the confirmed method, dihydrostreptomycin and gentamicin were detected in 5 pork samples. The residues of these antibiotics were within the MRLs. Thus, the detection ratio was 2% as 5 samples were identified from 250 samples.

• Analytical Science and Technology
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• v.28 no.2
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• pp.86-97
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• 2015

Recently, the consumption of dietary supplements has increased because of people’s greater interest in health. Unfortunately, the sales of dietary supplements containing unauthorized substances such as drugs have also increased. We developed a rapid, accurate method for the simultaneous determination of antihistamines using liquid chromatography tandem mass spectrometry with a multiple reaction monitoring mode. The limit of detection (LOD) and limit of quantification (LOQ) of the instrument used in this method were in the ranges 0.0003-0.3 and 0.0009-0.6 µg mL⁻¹, respectively. The linearity of the method was > 0.99. The precision levels of the method were 0.1-9.8% (intra-day) and 0.3-9.6% (inter-day), and the levels of accuracy of the method were 82.7-115.0% (intra-day) and 84.3-113.0% (inter-day). The mean of recovery of the method was in the range of 83.9-117.9% and the RSD of the stability was less than 5.9%.

• Journal of Food Hygiene and Safety
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• v.30 no.4
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• pp.366-371
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• 2015

This work was conducted to apply the multi class pesticide multiresidue method for determining the use of hexaconazole in the agricultural products using GC-NPD. The multi class pesticide multiresidue method results were validated for the assay of hexaconazole by using linearity, accuracy, precision, limit of detection and quantitation. The linearity in the concentration ranged from 0.025 to 5.0 mg/L ($R^2$ > 0.999). Lettuce recoveries ranged from 89.42% to 94.15% with relative standard deviations below 7.78%, for spiking levels from 0.04 to 4.0 mg/kg. The limit of detection was 0.04 mg/kg, and the limit of quantitation was 0.11 mg/kg. The intra- and inter-day precisions were 2.42~3.49% and 4.90~7.78%, respectively. We suggested that the multi class pesticide multiresidue method for determining hexaconazole was highly accurate and reproducible, and it will be used as a routine analysis in agricultural products.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.725-729
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• 2006

A method was developed for the determination of fructooligosaccharides and raffinose contents in infant formula. The samples were extracted and analyzed by liquid chromatography equipped with carbohydrate column and evaporative light scattering detector. The mobile phase used for the gradient mode was water-acetonitrile, at a flow rate of 1.0mL/min. The method showed a mean recovery of 95-99%, the relative standard deviation obtained in the precision study was 0.774-8.982%, the quantification and detection limits were 25-50mg/L.

• Journal of Korean Society of Transportation
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• v.28 no.3
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• pp.131-143
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• 2010

This study has aimed to develop accident modification factor(AMF) for rural two-lane roadway segments. Accident Modification Factor is a coefficient to assess roadway safety as reflecting characteristics of homogeneous roadway. It estimates accident frequency of roadway segments with developed base model and exposure. We found on items of such factors as crosswalk, driveway density, topography characteristic, land use and median through statistical models and literature review. To develop accident modification factors, we used statistical model methods and analyses of applicability and expert judgement method were practiced to validate it. Although expert judgement for land use item was questionable, most items were rated acceptable. Result of comparative analysis revealed crash frequencies of IHSDM and KHSEM were most similar with actual. However, accident distribution of KHSEM was more proper than IHSDM. Also overall estimated values of RSDS were found to be overestimated.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.224-229
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• 2011

Zearalenone (ZEA) is an estrogenic mycotoxin mainly produced by Fusarium graminerum, a species which colonizes a wide variety of cereals, including wheat, barley and processed products. A survey of ZEA contamination was conducted on 141 dried confectioneries, 59 breads and rice cakes, 135 noodles and 101 other products, for a total of 432 commercial samples. Samples were analyzed by high performance liquid chromatography with fluorescence detection (HPLC-FLD) after immunoaffinity clean-up and was confirmed by liquid chromatography tandem mass spectrometry (LCMS/MS). The limits of detection and quantification were 2.0 and $6.0{\mu}g/kg$, respectively. The recovery ranged from 80.2% to 98.4% in the cereal based product. ZEA was detected in 38 samples (8.8% incidence), including 3 snack, 2 biscuit and 33 other cereal products. The ZEA contamination levels were in the range of $5.38-53.76{\mu}g/kg$. Finally, LC-MS/MS analysis of the contaminated samples was conducted to confirm the detected ZEA, and all 38 samples showing ZEA by HPLC-FLD were confirmed by LC-MS/MS.