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금 나노입자의 증감효과를 이용한 화학발광법적 Perphenazine 정량
( Al Mahmnur Alam ),( Mohammad Kamruzzaman ),이상학 ( Sang Hak Lee ),김영호 ( Young Ho Kim ),장택균 ( Taek Gyun Jang ),홍석주 ( Suk Joo Hong ),오상협 ( Sang Hyub Oh ) 한국공업화학회 2011 응용화학 Vol.15 No.2
A rapid and sensitive chemiluminescence (CL) method was designed for the determination of trace amount of perphenazine (PERN) based on the gold nanoparticles enhanced luminol-H2O2-PERN system. The degree of enhancement of CL signal intensity of the system was proportional with the concentration of PERN. Under optimum experimental conditions, the linearity of CL signal intensity was observed in the range of 3.5×10-9 to 2.0×10-7 mol/L (r2= 0.9995) with a detection limit of 1.37×10-9 mol/L. Precision of the method was tested at the concentration level of 1.0×10-7 mol/L for 8 replicate measurements giving value of RSD 2.25%.
Norepinephrine의 정량을 위한 Terbium (III)-Sodium Dodecyl Benzene Sulfonate의 형광 분석법
( Al Mahmnur Alam ),( Mohammad Kamruzzaman ),김영호 ( Young Ho Kim ),김소연 ( So Yeon Kim ),조해진 ( Hae Jin Jo ),이상학 ( Sang Hak Lee ) 한국공업화학회 2010 응용화학 Vol.14 No.2
The fluorescence (FL) system of the Tb(3+)-sodium dodecylbenzene sulfonate (SDBS)-norepinephrine (NorEPN) was investigated. It was observed that the FL intensity of the Tb3+-SDBS was greatly enhanced by the NorEPN in presence of buffer. Based on this phenomenon, a simple and sensitive fluorimetric method for the quantitative determination of NorEPN was established. The FL intensity was measured with the excitation and emission wavelength of 290 nm and 545 nm respectively. Under optimum conditions, the enhanced FL intensity of the system was linear with the concentration of NorEPN in the range of 2.8×10(-10) to 2.6×10(-8) mol/L with a limit of detection (3σ) of 2.6×10(-10) mol/L. The relative standard deviation (RSD) was 1.35% (n=9).
Alam, Al-Mahmnur,Liu, Yanan,Park, Mira,Park, Soo-Jin,Kim, Hak-Yong Elsevier 2015 Polymer Vol.59 No.-
<P><B>Abstract</B></P> <P>Novel photoluminescence (PL) composite nanofibers (NFs) consist of carbon qunatum dots (CQDs) and polyacrylonitrile blend with polyacrylic acid (PAN/PAA) were fabricated by the coelectrospinning process. The air-dried CQDs containing NFs were characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy, spectrofluorometer, and confocal microscopy. CQDs are familiar to emit blue, green and red color depending on the excitation energy. The PAN/PAA/CQDs NFs were found to be optically transparent and exhibited PL properties similar to CQDs. Therefore, blue, green and red color was observed under confocal microscope from the NFs membrane while the sample was excited by 405 nm, 488 nm and 543 nm lasers. The results indicated the well preserved quantum confinement properties of the CQDs inside the polymer matrix without aggregation or substantial quantum dots growth.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Alam, Al-Mahmnur,Kamruzzaman, Mohammad,Dang, Trung-Dung,Lee, Sang Hak,Kim, Young Ho,Kim, Gyu-Man Springer-Verlag 2012 Analytical and bioanalytical chemistry Vol.404 No.10
<P>Chemiluminescence (CL) emission from luminol-tetrachloroaurate ([AuCl(4)](-)) system studied in presence of monosaccharide sugars such as glucose and fructose was investigated on a microfluidic chip fabricated by the soft lithography technique. CL emission from the luminol-[AuCl(4)](-) system at 430 nm was intensified remarkably by the catalytic activity of glucose and fructose at room temperature. Under optimized conditions, the CL emission intensity of the system was found to be linearly related to the concentration of the sugars. Based on this observation, nonenzymatic determination of total sugar (glucose, fructose, or hydrolyzable sucrose) was performed in a rapid and sensitive analytical method. The results revealed that the linearity ranged from 9 to 1,750 μM for glucose and 80 to 1,750 μM for fructose, with a limit of detection of 0.65 and 0.69 μM, respectively. The relative standard deviations determined at 250 μM based on six repetitive injections were 1.13 and 1.15% for glucose and fructose, respectively. The developed method was successfully applied for determination of the total sugar concentration in food and beverages.</P>
Generating Color from Polydisperse, Near Micron-Sized TiO<sub>2</sub> Particles
Alam, Al-Mahmnur,Baek, Kyungnae,Son, Jieun,Pei, Yi-Rong,Kim, Dong Ha,Choy, Jin-Ho,Hyun, Jerome K. American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.28
<P>Single particle Mie calculations of near micron sized TiO2 particles predict strong light scattering dominating the visible range that would give rise to a white appearance. We demonstrate that a polydisperse collection of these 'white' particles can result in the generation of visible colors through ensemble scattering. The weighted averaging of the scattering over the particle size distribution modifies the sharp, multiple, high order scattering modes from individual particles into broad variations in the collective extinction. These extinction variations are apparent as visible colors for particles suspended in organic solvent at low concentration, or for a monolayer of particles supported on a transparent substrate viewed in front of a white light source. We further exploit the color variations on optical sensitivity to the surrounding environment to promote micron-sized. TiO2 particles as stable and robust agents for detecting the optical index of homogeneous media with high contrast sensitivities. Such distribution-modulated scattering properties provide TiO2 particles an intriguing opportunity to impart color and optical sensitivity to their widespread electronic and chemical platforms such as antibacterial windows, catalysis, photocatalysis, optical sensors, and photovoltaics.</P>
Alam, Al-Mahmnur,Park, Byung-Yong,Ghouri, Zafar Khan,Park, Mira,Kim, Hak-Yong The Royal Society of Chemistry 2015 GREEN CHEMISTRY Vol.17 No.7
<P>Carbon quantum dots (CQD) with down and up-conversion photoluminescence (PL) properties have been synthesized through low-temperature carbonization in a facile one step green method from cabbage as the natural source of carbon. The physiochemical and optical properties of the resultant CQD were performed using transmission electron microscopy, confocal laser scanning microscopy and various spectroscopic methods. The CQD with a quantum yield of 16.5% demonstrated excellent solubility and stability in aqueous media, superior resistance to photo bleaching, consistent PL within a biological pH range, excitation-dependent down conversion and excitation-independent up-conversion PL along with large stock shift behaviour. The purified CQD exhibited low cytotoxicity at higher concentration (500 μg ml<SUP>−1</SUP>) during the cell viability experiment against HaCaT cell, an immortalized non-tumerogenic human keratinocyte cell. Subsequently, CQD treated cells displayed three distinguished blue, green and red colours under a confocal microscope during <I>in vitro</I> imaging. Due to the advantages of green synthesis, high biocompatibility, excellent optical properties, low cytotoxicity and good cellular imaging outcome, the cabbage derived CQD showed considerable promise in biomedical applications.</P> <P>Graphic Abstract</P><P>The synthesis of luminescent and biocompatible carbon quantum dots is demonstrated from cabbage, a new carbonaceous biomaterial, for bio-imaging. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5gc00686d'> </P>
Al-Mahmnur Alam,Mohammad Kamruzzaman,Sang Hak Lee,YOUNG HO KIM,KYUNG MIN KIM 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.9
A simple, rapid and sensitive spectrofluorometric method was developed for the determination of folic acid (FA), based on its quenching effect on the fluorescence intensity of enoxacin (ENX)-europium (Eu3+) complex as a fluorescent probe. Fluorometric interaction between ENX-Eu3+ complex and FA was studied using UVvisible and fluorescence spectroscopy. The quenched fluorescence intensity at an emission wavelength of 614 nm was proportional to the concentration of FA. Optimum conditions for the determination of FA were investigated. Under optimal conditions, the reduced fluorescence intensity at 614 nm was responded linearly with the concentration of FA. The linearity was maintained in the range of 1.25 × 10−9 to 1.50 × 10−7 M (R = 0.9986) with the limit of detection (3Sb/m) (where Sb is the standard deviation of blank and m is the slop of linear calibration curve) of 6.94 × 10−10 M. The relative standard deviation (RSD) for 9 repeated measurements of 1.0 × 10−9 M FA was 1.42%. This method was simple, cost effective, and relatively free of interference from coexisting substances. Successful determinations of FA in pharmaceutical formulation and biological samples with the developed method were demonstrated.
Alam, Al-Mahmnur,Kamruzzaman, Mohammad,Lee, Sang-Hak,Kim, Young-Ho,Min, Kyung Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.9
A simple, rapid and sensitive spectrofluorometric method was developed for the determination of folic acid (FA), based on its quenching effect on the fluorescence intensity of enoxacin (ENX)-europium ($Eu^{3+}$) complex as a fluorescent probe. Fluorometric interaction between ENX-$Eu^{3+}$ complex and FA was studied using UV-visible and fluorescence spectroscopy. The quenched fluorescence intensity at an emission wavelength of 614 nm was proportional to the concentration of FA. Optimum conditions for the determination of FA were investigated. Under optimal conditions, the reduced fluorescence intensity at 614 nm was responded linearly with the concentration of FA. The linearity was maintained in the range of $1.25{\times}10^{-9}$ to $1.50{\times}10^{-7}$ M (R = 0.9986) with the limit of detection ($3S_b/m$) (where $S_b$ is the standard deviation of blank and m is the slop of linear calibration curve) of $6.94{\times}10^{-10}$ M. The relative standard deviation (RSD) for 9 repeated measurements of $1.0{\times}10^{-9}$ M FA was 1.42%. This method was simple, cost effective, and relatively free of interference from coexisting substances. Successful determinations of FA in pharmaceutical formulation and biological samples with the developed method were demonstrated.