• Analytical Science and Technology
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• v.7 no.2
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• pp.141-147
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• 1994

The adsorptive stripping voltammetry of corticosterone was studied in $1.0{\times}10^{-2}M$ sodium hydroxide as supporting electrolyte. The analytical conditions were as follow : 360 sec. for deposition time, -8.0 volts deposition potential, medium size mercury drop, and 20mV/sec scan rate. Calibration curve has shown a linearlity in the range of $5.0{\times}10^{-9}M$ to $8.0{\times}10^{-7}M$ and the detection limits have been $9.5{\times}10^{-10}M$ for corticoterones. This method has shown such a high sensitivity even in dilute solution that has been useful for analyzing sex hormones in medical supplies without interference of additives.

• Analytical Science and Technology
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• v.7 no.2
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• pp.133-140
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• 1994

The determination of sex hormones by adsorpive stripping voltammetry in $1.0{\times}10^{-2}M$ sodium hydroxide as supporting electrolyte has been investigated in the conditions as follows : 240sec. for deposition time, -0.80 volts deposition potential, medium size mercury drop, and 20mV/sec scan rate. Calibration curve has shown a linearlity in the range of $5.0{\times}10^{-9}M$ to $8.0{\times}10^{-7}M$ and the detection limits have been $8.0{\times}10^{-10}M$ for progesterone and $1.4{\times}10^{-9}M$ for testosterone propionate. This method has shown such a good sensitivity even in dilute solution that has been use full for analyzing sex hormones in medical supplies without interference of additives.

• Journal of the Korean Chemical Society
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• v.39 no.3
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• pp.186-190
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• 1995

A simple procedure, readily available at low cost with a sensitivity sufficient to determine trace levels of iron in seawater is proposed, which utilizes adsorptive accumulation of the iron/catechol complex on the mercury drop electrode in a borate medium of pH 8.0. Optimal conditions include a solution concentration of 2 mM catechol, 2.5 mM borate and a pH of 8.0, an accumulation potential of - 0.25 V is applied for 1∼3 min, and the potential scan is in the differential pulse mode. The limit of detection is 1.5 nM Fe using a preconcentration time of 3 min. The interference from copper can be eliminated and baseline slope is greatly improved, because its peak is well separated from that of iron in the proposed medium.

• Journal of the Korean Chemical Society
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• v.35 no.2
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• pp.151-157
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• 1991

A sensitive stripping voltammetric study of the complex of indium with 8-hydroxyquinoline at a hanging mercury drop electrode was investigated in 0.1M acetate buffer solution. The effects of various analytical conditions on the reduction peak current of the adsorbed complex were discussed. Optimal analytical conditions were found to be the ligand concentration of $2 {\times}10^{-5}$M, solution pH 4.75, scan rate of 10 mV/s, deposition potential of -0.450V, a deposition time of 90 second. Interferences by other trace metals and Triton X-100 were also discussed. Detection limit was 0.2 ppb of indium after 90 sec. Deposition time, and the relative standard deviation(n = 10) at 4 ppb was 3.2%.

• Journal of the Korean Chemical Society
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• v.48 no.2
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• pp.137-143
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• 2004

The determination of 2-mercapto-1-methyl-imidazole (MMI) in 5.0${\times}10^{-2}$ M lithium perchlorate suporting electrolyte has been investigated by the differential pulse polarography. The optimum condition of MMI analysis was as follows; -0.9 volts initial potential, 0.08 mV pulse height, 2 mV/sec scan rate, and medium mercury drop size. Standard calibration curve showed a good linearlity in the range of 1.0${\times}10^{-7}M\;to\;8.0{\times}10^{-5}$ M and the detection limit has been (2.2${\pm}0.1){\times}0.1^{-9}$ M. This method was applicated for the determination of MMI in antithyroid drug without interference of additives.

• Analytical Science and Technology
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• v.8 no.1
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• pp.17-23
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• 1995

The determination method of 2-mercapto-1-methyl-imidazole(MMI) in $5.0{\times}10^{-2}M$ lithium perchlorate solution has been investigated by the differential pulse polarography. The optimum conditions for the determination of MMI were as fellows; -0.9 volt(vs. Ag/AgCl) initial potential, 80mV pulse height, 2mV/sec scan rate, and medium mercury drop size. The calibration curve showed a good linearlity in the range of $1.0{\times}10^{-7}M$ to $8.0{\times}10^{-5}M$ and the detection limit was $2.2{\times}10^{-9}M$. This method was applicable to the determination of MMI in thyroid drugs without interference from the additives.

• Journal of Environmental Health Sciences
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• v.45 no.6
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• pp.594-604
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• 2019

Objectives: This study developed and validated an analysis method of urinary metals and metalloids that can be applied inductively with coupled plasma mass spectrometry (ICP-MS). Methods: 0.3 mL of urine was used to analyze 25 metal and metalloid compounds using ICP-MS. The validation of the analytical method included linearity, accuracy, precision, and the calculation of detection limits. In addition, a comparison test was performed with the graphite furnace atomic absorption spectrometry (GF-AAS) method, which is the current standard method, with urine samples of 66 healthy subjects. Results: The linearities (R²) of calibration curves of all 25 compounds were ≥ 0.999. Of the 25 compounds, the intra-day and inter-day accuracy% of 17 and 20 met ≤15%, respectively. In addition, fifteen compounds showed ≤15% recovery% for certificated reference materials. Intraclass correlation coefficients of the comparison between the current methods and new methods in this study were 0.952 (p-value<0.001) and 0.911 (p-value<0.001) for urinary cadmium and mercury, respectively. Conclusion: This study proposes an efficient simultaneous methodology that can analyze multi elements in smaller sample amounts. More reproduction experiments are needed in the future.

• Journal of Environmental Health Sciences
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• v.10 no.2
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• pp.41-51
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• 1984

This study was performed using samples collected at Myungryundong and at Reservoirs. The purpose of this study was to investigate the differences of water quality between tap and raw water, and to analyse drinking water quality by Fe, Zn from corroded galvanized steel pipe. Results were as follows 1. The older the pipe was, the higher the concentration of Ferrum and Zinc was (t-test : p<0.05). Ferrum and Zinc also exceeded the limits in the older galvanized steel pipe. I think that this comes from the corrosion of pipe. 2. Mercury, Arsenic, Cadmium, Lead, Chomium, Argentum and Aurum not detected in raw water were not detected in tap water. Cobalt, Bismuth and Molybudenum detected in raw water were not detected in tap water. I think that this comes from the quality of raw water, the result of water treatment and the improbability of detection of above metals in water delivery system. 3. Silicon measured 2.4698ppm in raw water, but it ranged from 0.4769ppm to 1.982 ppm in tap water. Manganese measured 0.0638ppm in raw water, but it ranged from 0.0026ppm to 0.0198ppm in 17cases(31%) out of 55samples in tap water. I think that this comes from the water treatment. 4. Aluminium not detected in raw water was found in 17 cases (31%) out of the samples (55cases). It may be considered as the use of coagulants $Al_2(SO_4)_3$. $18H_2O$ and PAC (Poly Aluminium Chloride). The concentration of copper in tap water was much higher in 2 cases(3.6%) out of the samples(55) than that of copper in raw water. I think that this may come from the use of ${CuSO}_4$, the preventive of algae growth, and the result of chlorination, but further study must be necoessary to support the proof.

• Journal of Food Hygiene and Safety
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• v.37 no.3
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• pp.159-165
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• 2022

In this study, heavy metals (lead, cadmium, and mercury) and shellfish poisoning toxins (diarrhetic shellfish poisoning toxins, amnesic shellfish poisoning toxins) were investigated in a total of 104 shellfishes. According to the analysis of heavy metals, lead (Pb) was detected in the range of 0.0177-0.5709 mg/kg, cadmium (Cd) was detected in the range of 0.0226-1.4602 mg/kg, and mercury (Hg) was detected in the range of 0.0015-0.0327 mg/kg. Levels of Pb, Cd, and Hg were acceptable by Korean standards. Okadaic acid (OA) and dinophysistoxin-1 (DTX-1) were investigated for monitoring of diarrhetic shellfish poisoning toxins and OA and DTX-1 were not detected. As a result of monitoring of amnesic shellfish poisoning toxins, domoic acid was detected in 5 of 104 samples and detection ratio was 4.8%. The detection period was found as follows; 1 case in January, 1 case in February, 1 case in May, 2 cases in September. These showed that continuous monitoring for the management of shellfish poisoning toxins and heavy metals is required. In addition, this study can be used as reference data to strengthen managing heavy metals in fishery products.

• Journal of Life Science
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• v.26 no.5
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• pp.503-508
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• 2016

Biosensors have been used as first-step monitoring tools to detect on-site samples in a simple and cost-effective manner. Numerous recombinant microbial biosensors have been exploited for monitoring on-site toxic chemicals and biological signals. Herein, a recombinant microbial biosensor was constructed for monitoring cadmium. The cadmium responding cadC regulatory gene and it’s promoter from Staphylococcus aureus was amplified through PCR, fused with the lacZ gene, and transformed into Escherichia coli BL21 (DE3) cells. In the presence of cadmium, the biosensor cells express β-galactosidase showing red color development with chlorophenol red β-galactopyranoside (CPRG) as the enzymatic substrate. The biosensor cells showed the best β-galactosidase activity after 3 hr induction with cadmium at pH 5 and a detection range from 0.01 μM to 10 mM cadmium with a linearity from 0.01 to 0.1 μM cadmium (y = 0.98 x + 0.142, R² = 0.98). Among the heavy metals, cadmium and lead showed good responses, tin and cobalt showed medium responses, and mercury and copper showed no responses. The biosensor cells showed good responses to several waste waters similar to buffer solution, all spiked with cadmium. The biosensor described herein could be applied for on-site cadmium monitoring in a simple and cost-effective manner without sample pretreatments.