• 분석과학
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• 제27권6호
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• pp.333-338
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• 2014

불산 노출 평가를 위한 생체시료 중 불소 이온 분석을 위해서 초산완충용액을 사용한 이온선택전극(ISE: ion selective electrode) 분석법을 이용한 불소 이온 분석 방법을 제시하였다. MES-CyDTA 완충용액과 1회용 플라스틱 시험관을 사용함으로써 기존의 분석 방법에 비해 1/10의 시료를 사용하여 더 짧은 시간에 정확하고 정밀한 소변 중 불소 이온 분석이 가능하였다. 1.8-7.8 mg/L의 기지 시료에 대해 분석 방법의 정확도는 95-97.5%, 정밀도는 1.9-7.9%, 정량 한계는 0.1 mg/L였다. 이 방법을 불화수소 노출군 15명과 비노출군 12명의 소변 중 불소 이온 분석에 적용한 결과는 각각 $0.98{\pm}0.38mg/g$ creatinine, $0.59{\pm}0.30mg/g$ creatinine이었다.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.161-173
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• 1996

The cariostatic effect of fluoride had been established by many epidemiologic and experimental studies. But, there are still different views on the mechnism of cariostasis and remineralization, especially about the proper fluoride concentration. The purpose of this study is to ascertain the remineralization of caries lesion and influence of fluoride concentration which affect remineralization by a study based on dynamic mechanism. The subjects, sound permanent teeth without demineralization or crack, were immersed in lactic acid buffered demineralization solution for 4 days. Dental caries with surface zone and subsurface lesion were artificially produced. All specimens were immersed in lactic acid buffered remineralization solution which had fluoride concentrations of 1 ppm, 2 ppm, 3 ppm for 10days. Final conclusions were obtained by observing the specimens for every 10 days under polarized microscopy. 1. Remineralization of caries lesion as well as demineralization of enamel were produced by changing the degree of saturation of lactic acid buffer solution. 2. Remineralization of caries lesion was facillitated by fluoride ion in lactic acid buffer solution. but, remineralization of the entire caries lesion was not increased as fluoride ion concentration increased.

• 한국세라믹학회지
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• 제26권5호
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• pp.601-608
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• 1989

Electrical properties of ZrF4-based heavy metla fluoride glasses were measured by the ac complex impedance method. The effects of alkali and chloride ions addition into fluoro zirconate glasses on the electrical conductivity were examined. The electrical conductivities of fluoride glasses show Arrhenian behavior in the temperature range of the experiment and were decreased by the addition of sodium fluoride up to 15mol%. Mixed alkali substitution resulted in conductivity minimum at intermediate composition which is commonly observed as mixed alkali effect' in alkali oxide glasses. Chloride ion substituted for fluoride ion was found to lower the conductivity.

• 대한소아치과학회지
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• 제24권1호
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• pp.125-138
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• 1997

Along with recent economic prosperity, the consumption of commercially available beverages has increased dramatically. Beverages on the market are replacing tap water and constituting an increasing large proportion of the total daily fluoride intake. If such changes in the source of fluid intake are not taken into consideration, effective fluoride intake would become difficult in the fluoridated area while there would be confusion as to the basis for proper fluoride supplement prescription in the nonfluoridated area. So, dietary consultation is recommended for every pediatric patient. This study was conducted to provide the reference for dietary consultations on the subject of fluoride supplement using 72 beverages on the market. The fluoride content was measured and the fluoride intake from each age groups was calculated using fluoride ion specific electrode and HMDS-microdiffusion technique. 1. The average fluoride concentration of the 72 beverages was $0.23{\pm}0.10ppm$, from 0.0106ppm to 2.2050ppm. 2. Natural fruit juices, diluted fruit juices, carbonated beverages and mixed beverages showed average fluoride concentration of $0.15{\pm}0.66ppm$, $0.09{\pm}0.11ppm$, $0.15{\pm}0.23ppm$, $0.50{\pm}0.66ppm$, respectively. There were significant differrence between diluted friut juice drinks and mixed beverage, and between the carbonated beverages and mixed beverges(p<0.05). 3. Using available data on the daily total consumption of beverages and the relative consumption of beverages on the market according to age, daily fluoride intake for various age groups was calculated. According to the results, 2 to 3 year-old children need 0.13mgF/day, those between 4 and 6 year-old need 0.15mgF/day, and those between 7 and 10 year-old need 0.17mgF/day.

• 한국재료학회지
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• 제15권6호
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• pp.382-387
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• 2005

Polyvinylidene fluoride (PVDF) surface was irradiated and became superhydrophilic by low energy (180 eV) and high flux $(\~10^{15}/cm{\cdot}s)$ ion beam. As an ion source, a closed electron Hall drift thruster of $\phi=70mm$ outer channel size without grid was adopted. Ar, $O_2$ and $N_2O$ were used for source gases. When $N_2O^+$ and $O_2^+$ reactive gas ion beam were irradiated with the ion fluence of $5\times10^{15}/cm^2$, the wetting angle for deionized water was drastically dropped from $61^{\circ}\;to\;4^{\circ}\;and\;2^{\circ}$, respectively. Surface energy was also increased up to from 44 mN/m to 81 mN/m. Change of chemical component in PVDF surface was analyzed by x-ray photoelectron spectroscopy. Such a great increase of the surface energy was intimately related with the increase of hydrophilic group component in reactive ion irradiated PVDF surfaces. By using an atomic force microscopy, the root-mean-square of surface roughness of ion irradiated PVDF was not much altered compared to that of pristine PVDF.

• 분석과학
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• 제14권5호
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• pp.416-421
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• 2001

수소화물 발생 유도결합 플라스마 원자 방출 분광법으로 주석을 분석할 때 연속 흐름 수소화물 발생 장치에 사용되는 환원제 및 산의 농도에 대하여 최적조건을 확립하였다. 시료에 함유되어 있는 플루오르화 이온이 주석의 수소화물 발생을 방해하는 영향과 이러한 영향을 최소화하기 위한 여러 가지 예비환원제를 비교 실험하였다. 환원제 및 안정제의 농도가 $NaBH_4$ 1~2%/NaOH 1.0 M인 조건에서 우수한 수소화물을 발생시키는 산농도는 0.5~1.0 M 이었으며, 또한 플루오르화 이온의 방해영향이 매우 크게 관찰되었지만 boric acid 및 L-cysteine의 혼합용액은 이런 영향을 최소화하여 가장 효과적인 주석의 수소화물 발생 보조제로 확인되었다. 플루오르화 이온이 함유되어 있는 용액에서 미량의 주석을 분석하여 회수율이 100~108 %의 결과를 얻었다.

• Fisheries and Aquatic Sciences
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• 제15권3호
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• pp.203-207
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• 2012

The amount of fluoride removed from Antarctic krill via organic acid extraction depends on the extraction time, concentration, extraction volume, and the nature of the acid itself. The fluoride content in Euphausia superba was determined by measuring the concentration of fluoride ion in acidic extracts using an ion-selective electrode. The best results were obtained by adding 50 mL of 0.01 M citric acid to 0.3-0.5 g of krill and extracting for 5 min. Under these conditions, recoveries of fluoride from frozen whole krill and krill meat were 95.6-99.5% and 97.5-101.3%, respectively. The dry basis fluoride contents of krill by-product, krill meat and the boiled krill were 705, 298, and 575 ppm, respectively. These levels were significantly reduced by citric acid extraction.

• Environmental Engineering Research
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• 제11권2호
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• pp.77-83
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• 2006

The hot spring water of the north Jeonla province such as Wanggung, Jookrim, Seokjung, and Hwasim, has fluoride concentration of 3.9 mg/L, 12.7 mg/L, 1.9 mg/L, and 6.3 mg/L, respectively. These figures fairly exceed the Korean and WHO standard for potable water, which is 1.5 mg/L. Therefore, in this study, research on elimination of fluoride in a hot spring water of Jookrim region, which has the highest level of fluoride concentration level in the north Jeonla province, was carried out. In analysis of Jookrim hot spring water according to the water quality standard for potable water, pH was very high at 9.25 and the concentration of fluoride was 10 times higher than the standard at 18.2 mg/L. Other measurements were within the standard or not detected. After injecting 10g of activated carbon for elimination of fluoride, the fluoride concentration was measured at 13.5 mg/L, and when 70mL or more of alum 10 g/L solution was injected, the concentration was measured at 2.8 mg/L, and injecting 3g of lime was measured at 9 mg/L. Alum showed the best elimination performance among all individual injections. Injection of 25 mL of activated carbon and 100 mL of alum solution together reduced the fluoride concentration down to 1.3 mg/L, which is under the potable standard. Injection of lime 1g and 75 mL of alum 10 g/L solution together reduced fluoride concentration to 4.1 mg/L. From the modifying HRT, by using ion exchange resin column, the pH was stabilized when HRT was Imin and showed range of $6.7{\sim}7.8$. The fluoride concentration reduced gradually as the HRT increased, and satisfied the potable standard when HRT passed 6 min, and after 30 min HRT, the concentration of fluoride was 0.05 mg/L: almost eliminated.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2145-2148
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• 2012

A new thiourea based receptor (1) was synthesized and applied to fluoride ion recognition in acetonitrile solution. Receptor 1 displayed dual changes in absorption and fluorescence emission intensities selectively for fluoride ions. The interaction of 1 with fluoride undergoes a deprotonation process that is confirmed by $^1H$ NMR titration.

• 분석과학
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• 제19권5호
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• pp.383-388
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• 2006

간단한 후세척의 이온 크로마토그래피를 이용하여 형석 광화대 지역의 광산 폐수에서 플루오라이드 이온을 빠르고 정확하게 정량하는 방법을 확립하였다. 시료중의 높은 농도의 황산 이온은 전치 컬럼(pre-column)에 머물러있고 머무름 시간이 적은 플루오라이드 이온은 제시된 이온 크로마토그래프 시스템과 스위칭 기술을 이용하여 분리 시스템에 주입되었다. 사전 농축(pre-concentration) 컬럼은 다량의 황산 이온을 보유할 수 있는 이온 교환 용량이 큰 분석용 컬럼(AS 9 HC)을 사용하였다. 분리용 컬럼은 플루오라이드 이온의 감도를 증가시키기 위하여 틈새 부피(void volumn)와 시스템 압력을 감소시킬 수 있도록 보호 컬럼(AG 14)을 사용하였다. 첫 번째 전기전도도 검출기로는 플루오라이드 이온의 회수율을, 두 번째 전기전도도 검출기로는 제거되는 황산 이온 피크를 관찰함으로써 결정된 최적의 10-포트주입기의 스위칭 시간은 4.3 분 이었다. 시료 주입량이 $25{\mu}L$ 일때, $500mg\;L^{-1}$ 의 높은 황산 이온이 포함된 용액에서 플루오라이드 이온의 검출한계(S/N = 3)는 $2.4{\mu}g/L$였다.