• Korean Journal of Food Science and Technology
• /
• v.39 no.4
• /
• pp.360-365
• /
• 2007

The studies for the derivatization of 3-monochloropropane-1,2-diol (3-MCPD) were performed mainly as acylation with HFBI (heptafluorobutyrylimidazole), alkylation with PBA (phenylboric acid) and silylation with BSTFA (N,O-bis[trimethylsilyl]trifluoroacetamide). Also silylation with MTBSTFA(N-methyl-N-[tert.-butyldimethylsilyl] trifluoroacetamide) and acylation with MBTFA (N-Methyl-bis[trifluoro-acetamide]) were also considered. Except the TBDMS derivative of 3-MCPD, all the derivatives were detected well. The derivatives of 3-MCPD with HFBI, PBA and BSTFA showed below 10 ${\mu}g/kg$ which was sensitive enough to satisfy Korea maximum residue limit 0.3 mg/kg. Among the tested adsorbents, Extrelut20 and Florisil were evaluated as the proper adsorbents to eliminate the soy sauce matrix for 3-MCPD. Ethyl acetate was the most efficient eluent with good recovery rate. The desired surrogate compound and internal standard were 1,2-butanediol and 1,2-dibromo-3-chloropropane, respectively. The limit of detection for PB-MCPD and TMS-MCPD were 10.16 and 7.06 ${\mu}g/kg$ on GC/MSD, respectively. HFB-MCPD derivative showed the lowest detection limits 2.98 and 5.32 ${\mu}g/kg$ by GC/ECD and GC/MSD, respectively.

• Journal of Food Hygiene and Safety
• /
• v.28 no.2
• /
• pp.158-167
• /
• 2013

This study was carried out to assess the safety of cereals and their products (20 species, 205 samples) distributed in Gyeonggi province by analyzing contamination levels such as exposure frequency of Aflatoxins and Deoxynivalenol (DON). Aflatoxins were detected in 16 (8%) samples in total with a range of 0.01~27.88 ${\mu}g/kg$, including 3 of 9 bake flour (33%), 2 of 6 dried corn (33%), 3 of 12 frying flour (25%) and 2 of 11 sorghum (18%). DON was found in 56 (27%) samples including 11 of 13 adlay (85%), 6 of 8 wheat (75%), 6 of 10 processed corn for popcorn (60%), 6 of 11 sorghum (55%) and 7 of 16 barley (44%) with a range of 2.2~754.4 ${\mu}g/kg$. In particular, both Aflatoxins and DON were detected in 8 samples (2 millet, 2 wheat, 1 sorghum, 1 adlay, 1 dried corn, 1 bake flour) simultaneously. As a result of this study, we found that an adult is exposed to Aflatoxins of $0.80({\times})10^{-3}{\mu}g/kg$ b.w./day and DON of 0.18 ${\mu}g/kg$ b.w./day. The quantity of exposure to DON amounted to 18.5 percentage level compared with PMTDI 1 ${\mu}g/kg$ b.w./day suggested on JECFA, therefore we can assess that the possibility of health risks by intake cereals distributed in Gyeonggi province is low. However the concentration of Aflatoxins in one dried corn was 27.88 ${\mu}g/kg$ which was over the maximum residue limits (MRL) suggested on internal and external level, the monitoring about mycotoxin should be conducted on continuously.

• Korean Journal of Food Science and Technology
• /
• v.44 no.3
• /
• pp.293-299
• /
• 2012

The residual contents of fluoroquinolones in fish and shrimp were analyzed by using HPLC-FLD and LC-MS. The limit of detection (LOD) and limit of quantification (LOQ) for fluoroquinolones by HPLC-FLD were 0.0030-0.0083 and 0.0090-0.0252 mg/kg, respectively. Those by LC-MS were 0.0019-0.0040 and 0.0059-0.0122 mg/kg, respectively. Recoveries regarding ofloxacin, norfloxacin, pefloxacin, ciprofloxacin and enrofloxacin ranged from 76.4-104.6%. The detection rate of fluoroquinolones was 7.5% from a total of 268 samples. In only one Korean bullhead sample, the sum of ciprofloxacin and enrofloxacin contents was detected at a higher level than its maximum residue limits (MRL) of 0.1 mg/kg. Ofloxacin, norfloxacin and pefloxacin were not detected in any samples and detection rates of ciprofloxacin and enrofloxacin were 3.4% and 6.7%, respectively. In detection rate by species eel (2.6%), loach (2.2%), Korean bullhead (1.5%), carp (0.7%) and snakehead (0.4%) were in order.

• Korean Journal of Environmental Agriculture
• /
• v.1 no.1
• /
• pp.14-21
• /
• 1982

Analytical methods for residues of six N-methylcarbamate insecticides were investigated to compare the minimum detectability, recovery from several crops and feasibility of multiple residue analysis. Those methods studied in this work included spectrophotometry by diazotization and gas chromatography by N-trifluoroacetylation(TFA), pentafluorobenzylether(PFB) and dinitrophenylether (DNP) derivatization. Maximum absorbed wavelength of the diazotized MIPC, XMC, BPMC, propoxur and carbofu ran was around 460 ㎚, while that of carbaryl recorded 510 ㎚. Recovery from brown rice and apple by diazotization method ranged from 80 to 120% and minimum detectable limits were 0.03 to 0.05 ppm in 50 g of the sample. Minimum detectability of PFB derivatives by gas chromatography was superior to TFA and DNP derivatives. DNP derivatives showed the longest retention time among the given derivatives. Recovery from crops by gas chromatographic met hod ranged 74 to 94%, 78 to 93%, and 85 to 99% in brown rice, rice straw and apple, respectively. Limit of detection was 0.01 ppm for TFA, 0.005 ppm for PFB and 0.02 ppm for DNP derivatives in 50 g of the crop samples.

• Korean Journal of Environmental Agriculture
• /
• v.3 no.1
• /
• pp.16-21
• /
• 1984

The present study was aimed to investigate persistence of dichlorvos EC, fenitrothion EC, fenthion EC, and phenthoate EC in and on mulberry leaves with special reference to silkworm mortality and cocoon production under greenhouse condition. The halflives of fenitrothion, fenthion, and phenthoate in and on mulberry leaves were ranged from two to three days, while that of dichlorvos was less than 9 hours. The insecticide residues in and on mulberry leaves persisted longer in spring cropping season than in autumn cropping season. Elapsed periods from last application of each insecticide to leaf harvest for silkworm feed and maximum residue limits for safe cocoon production as well as relations between insecticide residues in and on mulberry leaves and silkworm mortality were produced.

• Journal of Applied Biological Chemistry
• /
• v.56 no.1
• /
• pp.29-35
• /
• 2013

This study was performed to analyze 48 kinds of pesticide residues using gas chromatography (GC)/nitrogen phosphorous detector, GC/micro electron capture detector, GC/mass selective detector, and high performance liquid chromatograph/diode array detector in 186 fresh ginseng samples collected in the Seoul area from 2010 to 2011. Fresh ginseng dietary intakes were estimated using the data from the 2009 Korea National Health and Nutrition examination survey. Residual pesticides were detected in 79 samples (42.5%) with eight different fungicides. Only 20 samples (10.8%) exceeded the maximum residue limits (MRLs) for pesticides registered by the Korea Food & Drug Administration. Among them, tolclofos-methyl residues (10.2%) exceeded the MRL for fresh ginseng in 18 ginseng seedlings and one of the two-year old fresh ginseng plants, and the residual level in just one ginseng seedling violated the MRL for pyrimethanil. The results showed that residual pesticides levels in marketable fresh ginseng around Seoul were relatively safe. The percent acceptable daily intake (%ADI) was calculated using pesticide residues in fresh ginseng and dietary intakes of fresh ginseng. The risk caused by pesticide residues in fresh ginseng was very low.

• Korean Journal of Food Science and Technology
• /
• v.42 no.6
• /
• pp.643-647
• /
• 2010

This research was carried out to investigate residues of neomycin, streptomycin, dihydrostreptomycin, amitraz, 2,4-dimethylaniline (one of amitraz's metabolites), and coumaphos in honey in order to intensively control their use following the establishment of Korean maximum residue limits (MRLs) for veterinary drugs in honey in 2007. To monitor for residues, 110 honeys and food products with honey were collected and analyzed. The collected honeys included acasia, mixed flower, chestnut, rape flower, jujube, and native types. Neomycin, streptomycin, dihydrostreptomycin, oxytetracycline, and amitraz were not detected among samples. Coumaphos was found in the Korean acasia honey at 0.02 mg/kg, but its concentration was under the MRL (0.1 mg/kg) for coumaphos. According to the results, there were no violations of the Korean MRLs of veterinary drugs in honey.

• The Korean Journal of Pesticide Science
• /
• v.19 no.1
• /
• pp.22-31
• /
• 2015

This study was carried out to monitor the current status of pesticide residues in selling agricultural products via online and assessed their safety in 2014. A total of 124 samples were purchased six times from March to August 2014 twenty online shopping malls randomly. These samples were analysed 208 pesticides by multiresidue method using a GC-ECD/NPD and a LC-MS/MS and confirmed by a GC-MSD. As a result of analysis, residual pesticides samples were 11 (8.9%) such as leek, young radish, welsh onion etc, of which 2 samples (1.6%) such as sesame bud (Chlorothalonil), artemisia (Chlorpyrifos) were violated Korea Maximum Residue limits (MRLs). 11 kinds of pesticides (19 times) were detected in 11 samples. Risk assessment evaluated human health exposure with the ratio of EDI (Estimated daily intake) to ADI (Acceptable daily intake) of pesticides detected. %ADI (the ratios of EDI to ADI) were 0.04~95.70% and some samples represented a fairly dangerous levels. In particular, Chlorothalonil in the sesame bud was shown as a significant risk close to 100% of %ADI. Accordingly, it is recommended to strengthen a safety check on agricultural products in online sales.

• The Korean Journal of Pesticide Science
• /
• v.15 no.1
• /
• pp.28-35
• /
• 2011

The investigation of 218 residual pesticides for 19 types of tea (persimmon leaf tea, chrysanthemum tea, green tea, lavender tea, rosemary tea, dandelion leaf tea, puer tea, mulberry leaf tea, hydrangea leaf tea, jasmine tea, nuomixiang tea, buckwheat tea, mugwort tea, lotus leaf tea, oolong tea, longjing tea, rose tea, tiehkwanyin tea and huoguo tea) obtained from markets in Ansan and Suwon was carried out to assess the risk for residual pesticides in tea. The detection rate was 23.1 % (19 samples of total 65 tea samples) and the detected pesticides were 15 pesticides, such as bifenthrin, bromopropylate, chlorpyrifos, cyhalothrin, cypermethrin, chlorfenapyr, dicofol, endosulfan, fenpropathrin, fludioxonil, fenvalerate, iprobenfos, isoprothiolane, tetradifon and triazophos. The range of concentrations for the detected residual pesticides was 0.01 to 1.24 mg/kg which showed below their maximum residue limits (MRL), but the residual concentration of bifenthrin in a puer tea showed above the legal limit of 0.3 mg/kg. The result of risk assessment of residual pesticides for the detected 15 samples showed that EDI (estimated daily intake) of the pesticides detected ranged 0.0001~0.0844% of their ADI (acceptable daily intake).

• The Korean Journal of Pesticide Science
• /
• v.15 no.1
• /
• pp.15-21
• /
• 2011

Monitoring or follow-up surveying pesticide residues in agricultural commodities is the key to meet the international regulations and to enhance international competitiveness of Korean agricultural commodities. Six neonicotinoid insecticides, acctamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam were monitored in 95 paprika samples collected from Gyeongnam area. Thc pesticide residues were extracted by EN 15662 buffer based on the QuEChERS method, clean-upped with dispersive solid-phase extraction method to remove interfering pigments, and analyzed using UPLC-MS/MS. The neonicotinoid pesticides were detected in 90.5% of the paprika samples. Two or more pesticides were detected in 82.3% of samples. Although detection frequencies were high, all samples complied with the maximum residue limits (MRLs) set by both the Korea Food and Drug Administration (KFDA) and Japanese Ministry of Health, Labour and Welfare.