• Food Science and Preservation
• /
• v.21 no.1
• /
• pp.69-74
• /
• 2014

We tested for residual pesticide levels in school foodservice agricultural products in Seoul, Korea from 2010 to 2012. A total of 316 samples of 23 different types of agricultural products were analyzed via gas chromatography-nitrogen phosphate detector (GC-NPD), an electron capture detector (GC-${\mu}ECD$), a mass spectrometry detector (GC-MSD), and a high performance liquid chromatography-ultraviolet detector (HPLC-UV). We used multi-analysis methods to analyze 185 different pesticide types. Among the selected agricultural products, residual pesticides were detected in 26 samples (8.2%), of which 6 samples (1.9%) exceeded the Korea Maximum Residue limits (MRLs). We detected pesticide residue in more than 65% of the Chwinamul, while 6 among 9 analyzed samples contained pesticide residue, and 1 sample exceeded the Korea MRLs. Among the 185 kinds of pesticides that we have tested, 18 were detected, while 7 of them were detected more than twice. Data obtained were then used for estimating the potential health risks associated with the exposures to these pesticides. The most critical commodity is carbofuran in the perilla leaves, which has contributed 3.8% to the hazard index (HI). These results showed that the detected pesticides could not be considered as a serious public health problem. Nevertheless, constant supervision is recommended.

• 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.

• Journal of Radiation Protection and Research
• /
• v.18 no.1
• /
• pp.63-70
• /
• 1993

Double ionization of the K- shell accompanying K- shell electron capture of the 0.035 MeV transition of $^{125}I$ has been studied by counting coincidences between $K_{\alpha}$ hypersatellite X-rays and Ka satellite X-rays emitted when double vacancies are filled. The $^{125}I\;and\;^{125}Te^m$ source materials were used in the measurement. We obtained the coincidence spectrum using two NaI(T1) detectors and a Ge(Li) detector and TAC(Time-to-Amplitude Converter), and then analysed the measured coincidence number $N(K_{\alpha}^{II},\;K_{\alpha}^s)$, the total number $N(K_{\alpha})$ of K X-ray. The probability per K-shell electron capture that a double vacancy is formed, $P_{KK}$ is formed, $P_{KK}$ is found to be $2.15{\times}10^{-4}$.

• The Korean Journal of Pesticide Science
• /
• v.17 no.1
• /
• pp.65-71
• /
• 2013

The modified QuEChERS method was evaluated for rapid determination of pesticide residues in spinach by gas chromatography-nitrogen phosphorous detector (NPD) and electron capture detector (ECD). Fifty GC-amenable pesticides which were most frequently detected in monitoring were selected in the current study. Matrix-matched calibration was performed. The detector response for all pesticides was linear with determination coefficients higher than 0.995. LODs for most compounds ranged between 0.001 and 0.1 ug/g, and about 90% of the compounds had LODs of less than 0.05 ug/g. LOQs ranged from 0.001 to 0.32 ug/g, which were well below the MRLs permitted for most of pesticides. In the majority of cases, the recoveries (80-120%) and relative standard deviations (RSDs) (less than 20%) were within acceptable levels except for dichlorvos, propamocarb, chlorothalonil, dichlofluanid, cyhalothrin and fenvalerate. Also, this method which is applied to routine samples showed good results when comparing with traditional multi-residue method.

• Korean Journal of Environmental Agriculture
• /
• v.33 no.2
• /
• pp.111-120
• /
• 2014

BACKGROUND: This study was conducted to investigate the levels of pesticide residues in fruits and to assess their risk to human health. METHODS AND RESULTS: Monitoring of 215 samples of fruits collected from local markets in incheon during 2013 was performed. 259 pesticides were analyzed by multi-residue method and Quick, Easy, Cheap, Effective, Rugged, and safe/Mass/Mass(QuEChERS/MS/MS) method using Gas Chromatography-Electron Capture Detector/Nitrogen Phosphorus Detector(GC-ECD/NPD), GC-MS, LC(Liquid Chromatography-Mass/Mass(LC-MS/MS) and High Performance Liquid Chromatography-Photodiode Array/Fluorescence Detector(HPLC-PDA/FLD). In 56.3% of the samples detected pesticide residues and were not found to exceed Maximum Residue Limits(MRL). The highest detected samples were found in citrus fruits(83.9%). Among the detected compounds, carbendazim(13.1%), imazalil (11.7%), thiabendazole(10.7%) and fludioxonil(9.8%) were frequently found in fruits. A risk assessment of pesticide residues in fruits was performed by calculating Estimated Daily Intake(EDI) and Acceptable Daily Intake(ADI). Also, we were evaluated removal efficiency of pesticide residues by washing and peeling. The removal efficiency of pesticide residues in citrus and tropical fruits by peeling processes were 91.6%. After the washing process, the removal rates were 43.1%(Cherry, Grape, Blueberry). CONCLUSION: The level of pesticide residues in fruits was within the MRL. The range of %ADI values was from 0.00011 to 0.98795%. The process of washing or peeling reduces the level of pesticide residues. The results of this research concluded that the detected pesticides are not harmful to human being.

• The Korean Journal of Pesticide Science
• /
• v.16 no.3
• /
• pp.195-201
• /
• 2012

We tested for pesticide residues in 124 samples of 22 different items of imported fruits circulated in Gyeonggido. Total 218 pesticides were analyzed by multi-residue method using gas chromatography/nitrogen phosphorus detector-electron capture detector (GC/NPD-ECD), time of flight/mass spectrometer (TOF/MS), ultra performance liquid chromatography/photo diode array (UPLC/PDA), high performance liquid chromatography/fluorescence detector (HPLC/FLD) and mass spectrometer (LC/MS/MS). The pesticides were detected in 18 fruits samples, ranging 0.003~0.3 mg/kg and no samples had violative residue. The separation test to 14 sample pesticides detected was conducted to monitor the current status of pesticide residues according to the partial characteristic. The pesticides were detected in 14 peels ranging 0.03~1.5 mg/kg and 2 fleshes in less than detection limits. These results indicate that imported fruits are safe when the human takes normally but even the small amount of pesticides is harmful when the human takes it in a prolonged period. Therefore, the pesticide residual amounts of imported friuts should be constantly monitored for food safety.

• Korean Journal of Environmental Agriculture
• /
• v.23 no.3
• /
• pp.148-157
• /
• 2004

A rapid analytical method was developed to determine multiple pesticide residues in apples and pears using gas-liquid chromatography (GLC). The samples were extracted with water-miscible solvents and purified by cleanup procedures serially comprising liquid-liquid partition and solid-phase extraction (SPE). Each analyte was separated and determined by a high-resolution GLC equipped with electron-capture detector (ECD) and nitrogen-phosphorous detector (NPD). A total of 196 pesticides, which were previously classified into 5 groups each for ECD and NPD based on their retention behaviors on the capillary column and responses to the detector, were subjected to the recovery experiment. In compliance with the analytical criteria, 70 to 120% of recovery and less than 20% relative standard deviation the proposed method could be successfully applied to analyze 136 and 133 pesticide residues in apples and pears, respectively, which enabled not only rapid screening but quantitation of the residues. Even though less reliability was resulted from unacceptable recovery range, rest of pesticides including 43 and 45 analyzes in apples and pears, could be also detected for their identity. The proposed method fliled to cover 17 and 18 pesticides for apples and pears, which mostly showed high polarity or heat-lability but could be suitable far fast surveilance or monitoring of fruit harvests.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.2
• /
• pp.301-308
• /
• 2002

As part of perfluorocarbon (PFC) tracer release experiment conducted at the western coastal area of Korea in February 2001, the background concentration level of perfluorocarbons (PFCs) in the atmosphere was determined by gas chromatography with electron capture detector. Prior to the PFC tracer release experiment in the field, air samples were collected using active samplers and the background concentrations of PFCs were determined. The concentrations of perfluoromethylcyclohexane ($C_7F_{14}$, PMCH) in the western coastal area of Korea were in the range of 5.8-8.7 fL/L. The mean concentration of the PMCH in the region exhibited no significant spatial and temporal variations. This concentration level is somewhat higher and has larger standard deviation than those of studies previously conducted in USA and Europe on the background concentration levels of PFCs. Because the background concentration of PMCH in Korea is still very low and consistent temporally and spatially, the PMCH tracer can be used suitably for the studies of long-range atmospheric transport.

• Applied Chemistry for Engineering
• /
• v.10 no.1
• /
• pp.30-34
• /
• 1999

Photolysis behavoirs of pesticides(Chlorothalonil and Endosulfan) over UV irradiation UV irradiation with pH 3.0 and irradiation with 3.5% salt were studied. The analyses of pesticides were carried out using gas chromatograph with an electron-capture detector, total organic carbon, and Ion chromatograph, respectively. The reactions were conducted in a alumium annular reactor equipped with a low pressure mercury multilamp ($8W{\times}6$) and initial concentration was 10 ppm. Chlorothalonil was almost photodegraded by UV irradiation, UV irradiation with pH 3.0 and 3.5% salt within 30 min of reaction time. Endosulfan-${\alpha}$,${\beta}$(100%) were photodegraded to 38% of Endosulfan-${\alpha}$ and 25% of Endisulfan-${\beta}$ by UV irradiation. Endosulfan-${\alpha}$(83%) was photodegraded to 66% by UV irradiation, 70% by UV irradiation and pH 3.0 and 75% by UV irradiation and 3.5% salt. Endosulfan-${\beta}$(16%) was photodegraded to 80% by UV irradiation, 98% by UV irradiation and pH 3.0 and 90% by UV irradiation and 3.5% salt.

• Korean Journal of Environmental Agriculture
• /
• v.5 no.2
• /
• pp.119-129
• /
• 1986

Disappearence of the trichlorfon (Dipterex) in the forest, following aerial to control Agelastica coerulea B., were studied by sampling deposits on slide glasses, soils, water, and leaves, and analysing with a gas chromatograph equipped with an electron capture detector. By analysing the amount remained on slide glasses, it was shown that the pesticide was adequately sprayed and nearly all deposit was lost in a day. The amount deposited under the tree was about 1/100 of the amount at an exposed site. Concentration of trichlorfon in creek water was 10 to 100 times as high as the acute toxic level to zooplankton for 6 to 24 hours, The rain could recontaminate the stream water up to the toxic level. Loss rate of trichlorfon from soils showed variations by sampling sites and was generally slower than from slide glasses. Amount deposited on leaves were less than the calculated or expected amount. The loss from leaves were similar to that from soil.