• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.420-426
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• 2019

Selenoproteins,in Korean blood serum, GPx, SelP, and SeAlb were separated and determined with the use of HPLC-ICP/MS. Deuterium was used as a collision gas and affinity column with ammonium formate was used as an eluting solvent for the accurate quantitation of selenoproteins in human blood serum. Certified reference material BCR 639 (133±12 ng g^-1) was tested for the accuracy and the result was satisfactory 130±6 ng g^-1. Blood serum for the rectal cancer and controlled groups were collected and analyzed to give 84±27 ng g^-1, and 119±28 ng g^-1, respectively. The difference was statistically obvious when t-test was performed (t_cal 4.93 > t_95% 2.04). The decrease for cancer group was more obvious for female and aged group. The distributions of three selenoproteins were similar with each other, which means rectal cancer group did not show any specificity for any selenoproteins. As cancer developed, GPx showed a slight decrease but not obvious while the total concentration was increasing particularly at the second stage of cancer.

• Analytical Science and Technology
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• v.22 no.6
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• pp.449-457
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• 2009

Total PCBs (62 congeners) has been determined in the retailed foods by the isotopic dilution method and the exposure assessment has been performed. Put into a food sample $^{13}C$-labeled standard for recovery was added and then it was extracted, cleaned-up by multi-layer column chromatography and then analyzed by HRGC/MS. The average levels (ng/g) detected was 0.1 for rice, 1.8~3.4 for meats, 0.3~3.7 for milk and dairy products, 10.0 for egg and 0.8~34.4 for fishes. Distribution of total PCBs was in order of fishes (94.4%) > meats (2.3%) > eggs (1.7%) > milk and dairy products (1.3%) > rice (0.3%). The estimated daily intake(EDI) was 14 ng/kg bw/day. It was concluded that there was no health risk at all.

• Analytical Science and Technology
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• v.23 no.5
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• pp.485-491
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• 2010

A certified reference material (CRM) of KRISS 109-03-SSD was developed for the analysis of hazardous elements in soil. The target elements were As, Cd, Cr, Cu, Hg, Ni, Pb, Zn being regulated by the Soil Environment Conservation Act. Starting material was collected from tailing dump of an unworked tungsten mine at Sangdong (Gangwon-do, Korea). The starting material under-went through a series of fabricating process steps of screening, drying, grinding, sieving, blending, bottling, sterilization and was certified according to the ISO Guide 35. Isotope dilution-inductively coupled mass spectrometry (ID-ICP/MS) and instrumental neutron activation analysis (INAA) were used for the measurement. Homogeneity was tested according to ISO 13528 annex B. The certified values were determined using the results from two different methods or from two independent measurements using a method. Finally, certified values of seven elements of arsenic, cadmium, chromium, copper, lead, nickel and zinc were determined. Mercury did not satisfied the criteria of homogeneity and the result would be provided for information only, together with iron and tungsten. It was also studied, the extractable fraction of elements by aqua regia according to the ISO 11466 protocol being frequently studied for the purpose of environmental monitoring. It was performed as a inter-laboratory study by 6 laboratories of a public institute and universities. Standard deviation among the laboratories was much bigger than the uncertainty of the certified value. The result of inter-laboratory study on the extractable fraction will be provided for information, only.

• Analytical Science and Technology
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• v.26 no.5
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• pp.307-314
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• 2013

Selenium exists in various forms of chemical species. The activity and bioavailability is strongly dependent on its chemical form and concentration. Consequently the information on each selenium species and its concentration must be exactly determined for the food we take in. In this study, selenium species in seafood were separated and quantified by RP (reversed phase) HPLC (high performance liquid chromatography) coupled with ICP-MS (inductively coupled plasma mass spectrometry) using post-column isotope dilution. $^{79}Br$, which interferes on $^{80}Se$, has mostly been removed by solid phase extraction and then mathematical correction has been applied for the more accurate correction. The experimental result for CRM (certified reference material) DOLT-4 agreed well with the certified value but each selenium species could not be compared. SeCys (selenocysteine) and SeMet (selenomethionine) were the major species detected in seafood such as belt fish, spanish mackerel, and squid that have been serving as Korean diet. The concentrations found in Korean sea food for SeCys and SeMet were in the range of 0-661.6 mg/kg and 137.3-462.7 mg/kg, respectively.

• Applied Biological Chemistry
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• v.37 no.4
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• pp.277-286
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• 1994

The pot experiment using $^{15}N$ isotope dilution technique was carried out to calculate the balance of nitrogen of surface applied urea in the rice-soil system. The $^{15}N$ concentration was determined by stable isotope ratio mass spcetrometer (model: VG ISO-GAS MM622). In the pots with $^{15}N$ labeled urea application at the rates of 15 and 30 kg N/10a, the percentage of nitrogen derived from fertilizer (NDFF) in rice was higher at the rate of 30 kg N/10a (average 89%) than at the rate of 15 kg N/10a (average 64%). However, the recovery as percentage of fertilizer N by rice was higher at the rate of 15 kg N/10a (65.5%) than at the rate of 30 kg N/10a (54.2%). The percentage of the fertilizer N remained in extractable inorganic N form at the rates of 15 and 30 kg N/10a were $13.5%\;(NH_4-N\;5.53%,\;NO_3-N\;7.99%)$ and $16.5%\;(NH_4-N\;7.49%,\;NO_3-N\;8.98%)$ in unplanted soil, and $2.0%\;(NH_4-N\;0.63%,\;NO_3-N\;1.32%)$ and$2.3%\;(NH_4-N\;0.87%,\;NO_3-N\;1.40%)$ in soil planted to rice, respectively. The dominant form of inorganic-N in soil after harvest was $NO_3-N$ form rather than $NH_4-N$ form regardless of urea application rate or rice cultivation. The percentage of the fertilizer N remained in organic N form at the rates of 15 and 30 kg N/10a were 65.0 and 41.8% in unplanted soil, and 23.7 and 26.9% in soil planted to rice, respectively. In conclusion, the efficiency of surface-applied urea was greater at the rate 15 kg N/10a than at the rate of 30 kg N/10a.

• Analytical Science and Technology
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• v.14 no.1
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• pp.88-93
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• 2001

To measure the levels of dioxins in food selling at local markets, meat was analyzed by high resolution gas chromatography/high resolution ass spectrometry (HRGC/HRMS). The food samples were obtained from 5 large cities of Seoul, Chunchon, Daejon, Kwangju and Busan in Korea. All the samples were minced and extracted with Soxhlet extractor for 18 hours. After extraction, extracts were cleaned up by sulfuric acid impregnated silica gel, purified on a series of silica gel, alumina, carbon column chromatography and then analyzed by HRGC/HRMS. The contaminated levels were calculated as the TEQs by multiplying with the corresponding WHO-TEFs for each congeners. The overall recoveries were ranged from 80% to 153% and the limit of detection was about 0.01 ppt at S/N>3. The levels of PCDD/Fs for beef, pork and chicken were 0.018, 0.008 and <0.001 pgTEQ/g, respectively. In addition, the levels of non-ortho-co-planar PCBs for beef, pork and chicken were 0.008, 0.002 and 0.001 pgTEQ/g, respectively. Among food samples analyzed, chicken showed the lowest level of dioxin-like compounds. Regarding congener pattern, OCDD and PCB #77 were the highest contributing congeners.

• Journal of the Korean Chemical Society
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• v.64 no.4
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• pp.203-209
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• 2020

Selenium species in hair and nails were extracted, separated and analyzed with HPLC-ICP/MS. The result showed that Se species was mostly SeCys and the information related to the change of selenium concentration in a body could be obtained. The Se fortification study was performed for 5 participants during 12 months. The average of Se concentration was 858.6 ± 201.2 ng g^-1, which did not change much during the research period nor the difference between the individuals was striking. In the case of hair, the average concentration was 205.3 ng g^-1 which was lower than nails. Se supplement of 22 ㎍ day^-1 was taken for 3 months by the volunteers and the difference between before and after (3 months period for each) the taking of supplement was not striking. However, when the dose was increased to 300 ㎍ day^-1 for 2 months, the concentration was increased noticeably to 1,230 ng g^-1. It can be thought that the analysis of finger nail for Se can provide valuable information for the long period (several months) of exposure or intake of Se for a human body.

• Analytical Science and Technology
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• v.23 no.3
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• pp.312-321
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• 2010

Seven indicator PCBs (IUPAC nos 28, 52, 101, 118, 138, 153, 180 congeners) concentrations were measured in food samples including cereal (polished rice), meats, eggs, milk and dairy products, and fisheries and products as representation for the general Korean populations during 2006-2007, and was analyzed using isotopic dilution method. Fishes had the highest average level as 39.8 ng/g, 1.4 ng/g for milk and dairy products, and 0.9 ng/g for meats. The hairtail out of fishes was contaminated at the level of 15.4 ng/g, 5.4 ng/g for pacific mackerel and spanish mackerel, and 4.5 ng/g for yellow croaker. The ratio for indicator PCBs in overall food was contributed as follows; 35.8% for PCB-153, 16.2% for PCB-138, 16.1% for PCB-101, 13.4% for PCB-118, 8.8% for PCB-180, 6.9% for PCB-52, and 2.9% for PCB-28. The hexa-CBs including PCB-153 and 138 were more predominated, and the next was penta-CBs including PCB-101 and 118 in food. For estimated daily intake (EDI) in average and $95^{th}$ percentile, fishes and products out of overall food were taken to represent over 50%. However, it was estimated that there was no adverse health effect for Korean.

• Analytical Science and Technology
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• v.25 no.5
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• pp.273-283
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• 2012

Phthalate plasticizers are regulated by RoHS, REACH and CPSC as hazardous substances. Responding to these international environmental restrictions, we developed ABS certified reference material (CRM) for determination of phthalate plasticizers such as DMP, DEP, DBP, BBP, DEHP and DnOP. The candidate material has been made with ABS resin widely used in electric and electronic products and 6 kinds of phthalate plasticizers. The making of the material involved a series of processes like extruding, cooling, pelletizing, and drying using twin screw extruder. Then it has been certified according to ISO Guide 35. Using isotope dilution-gas chromatography/mass spectrometry (ID-GC/MS), homogeneity, short-term stability, and long-term stability were evaluated. The certified values were determined by using primary reference material (PRM) of KRISS for traceability. From now on, we will provide ABS CRM to national and international companies and research institutes after certification as certified reference material and registering on COMAR (code of reference material).

• Analytical Science and Technology
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• v.23 no.6
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• pp.595-606
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• 2010

A total 221 samples of the retailed foods collected from 2004 to 2007 was examined to estimate the level of dioxins(29 congeners) by the isotopic dilution method, and the exposure of population of Korean to dietary of dioxins was performed. Dioxins levels were calculated using TEF values established in 1998 and 2005, respectively. The average levels (pg TEQ/g) were less than 0.01 for polished rice, 0.04 (poultry)-0.13 (beef) for meats, 0.04 (milk)-0.05(cheese) for milk and dairy products, 0.13 for egg (york, only) and 0.11 (alaska pollack)-1.35 (pacific mackerel) for fishes. The estimated daily intake of Korean through foods was 0.47 pg TEQ/kg bw/day, and it was estimated as about 11% to tolerable daily intake (TDI; 4 pg TEQ/kg bw/day) of Korea and Japan. Consequently, it was concluded that there was no health risk.