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81.
Patrik Vrábel 《Journal of luminescence》2006,118(2):283-292
Capillary electrophoresis with laser-induced fluorescence detection (CELIF) is a powerful tool for separation and sensitive determination of fluorescent species. Biologically active compounds, such as amino acids, peptides and proteins may exhibit native fluorescence, which is however often low and/or an expensive laser is required for excitation in UV. Therefore, labelling of the analytes with a fluorescent dye is usually necessary.In this work, a home-built CELIF instrument with diode pumped frequency-doubled continuous wave Nd:YAG excitation laser with feedback power regulation (532 nm) was constructed. The suitability of this type of laser for LIF detection in a separation method was found excellent. A limit of detection (LOD) (S/N=3) of 2×10−13 mol/l was achieved with rhodamine B, which is comparable to those obtained using similar instruments with Ar+ laser [Y.F. Cheng, N.J. Dovichi, Science 242 (1988) 562, E.S. Yeung et al., J. Chromatogr. 608 (1992) 73]. LOD of a protein derivatized according to modified procedures [M.J. Little et al., Anal. Chim. Acta 339 (1997) 279, A. Chersi et al., Biochim. Biophys. Acta 1336 (1997) 83] was determined. Detection of the derivatives was found to be limited by insufficient reaction recovery at low analyte concentration, chemical noise, separation efficiency and quality of the derivatizing reagent rather than by the detector performance. As a consequence, a huge gap between the detection ability of CELIF instruments and LOD determined in real samples is revealed. 相似文献
82.
铂(Ⅳ)-钼酸盐-乙基罗丹明B离子缔合显色反应研究 总被引:2,自引:0,他引:2
本文研究了在聚乙烯醇(PVA)存在下用钼酸盐与乙基罗丹明B(ERB)形成离子缔合物,该缔合物的最大吸收位于580nm,摩尔吸光系数为1.12×106L·mol-1·cm-1,服从比耳定律范围0—2.5μg/25mL,缔合物至少稳定1周,考察了50多种共存离子的影响,除生成杂多酸元素和Au(Ⅲ)、Os(Ⅷ)、Pd(Ⅱ)、Ir(Ⅳ)外,大多数元素不干扰。测定铂的条件为:〔HClO4〕=1.2mol/L,〔MoO42-〕=9.1×10-4mol/L,〔ERB〕=3.2×10-5mol/L,0.08%PVA。缔合物的摩尔比为Pt(Ⅳ)∶ERB=1∶2,本法已用于铂矿中铂的测定,结果满意。 相似文献
83.
《Analytical letters》2012,45(12):1918-1929
A rapid, simple, and sensitive method for the determination of Rhodamine B in chili powder was established based on surface-enhanced Raman spectroscopy using citrate-coated silver nanoparticles as the substrate. This substrate was found to produce enhancement factors of 1.6 × 107 at 625 per centimeter. A portable Raman spectrometer was used allowing on-site measurements. The effects of the volume of silver nanoparticle solution, the volume of hydrochloric acid, the volume of Rhodamine B, and the mixing time were optimized. The linear dynamic range was from 0.2 to 20.0 micrograms per liter and the limit of detection was 0.08 microgram per liter. The method was applied to the determination of Rhodamine B in chili powder, with recoveries between 81.42 and 97.22 percent, and relative standard deviation values lower than 4.84 percent. 相似文献
84.
A novel flow injection chemiluminescence (FI‐CL) method for the determination of genistein was described. The method was based on the reaction between genistein and potassium ferricyanide in alkaline solution to give weak CL signal, which was dramatically enhanced by rhodamine 6G (Rh G). The CL emission allowed quantitation of genistein concentration in the range 1.0 × 10?7–4.0 × 10?5 mol/L with a detection limit (3σ) of 4.2 × 10?8 mol/L. The relative standard deviation for 11 parallel measurements of 5.0 × 10?7 mol/L, 4.0 × 10?6 mol/L and 1.0 × 10?5 mol/L genistein were 2.59%, 2.40% and 1.48%, respectively. The experimental conditions for the CL reaction were optimized and the possible reaction mechanism was discussed. The method was applied to the determination of genistein in biological fluids. 相似文献
85.
《Analytical letters》2012,45(5):898-907
A new aptamer-based fluorescence nanoprobe for potassium ion (K+) has been developed. The nanoprobe employs gold nanoparticles (AuNPs) as the sensing platform and Rhodamine B as the fluorescence indicator. Aptamer acts as the switch of fluorescence signal of Rhodamine B. In the presence of K+, aptamer departs from AuNPs as a result of the formation of G-quartets with K+, leading to the decrease of fluorescence signals. Under the optimum conditions, the limit of detection (LOD) for K+ is as low as 3.8 nM. The proposed method was successfully applied in the determination of K+ in human saliva sample. 相似文献
86.
《Analytical letters》2012,45(17):2751-2761
Quinoline-appended rhodamine B thiohydrazide based fluorescent probe was designed and applied in fluorescent detections of mercury ions in both aqueous solution and living cells. The signal change of the probe is based on a specific metal ion induced reversible ring-opening mechanism of a rhodamine B thiohydrazide. The probe exhibits a dynamic response concentration range for Hg2+ from 1.0 × 10?8 to 1.0 × 10?5 M with a detection limit of 8.5 × 10?9 M. The fluorescent probe is pH independent in medium condition and exhibits high selectivity over other common metal ions. 相似文献
87.
《Analytical letters》2012,45(3):504-516
A novel method for separation and determination of rhodamine B in food samples is described. The work is based on the utilization of an ionic liquid loaded β-cyclodextrin cross-linked polymer coupled with high-performance liquid chromatography for the determination of rhodamine B. The inclusion interaction of the ionic liquid-β-cyclodextrin cross-linked polymer with rhodamine B was studied by FTIR. Under optimum conditions, the preconcentration factor achieved for this method was approximately 20. The linear range, detection limit, and relative standard deviation were 0.80 to 130.0 µg L?1, 0.09 µg L?1, and 0.66% (n = 3, concentration = 10.0 µg L?1), respectively. The technique was successfully applied for determination of rhodamine B in food samples. 相似文献
88.
《Journal of Coordination Chemistry》2012,65(7):1117-1131
Herein, we report the photocatalytic transformation of Rhodamine 6G (Rh 6G) using tetracarbazole zinc phthalocyanine (TCbZnPc) when alone or when conjugated with ZnO macroparticles (ZnOMPs) and silver nanoparticles (AgNPs), represented as TCbZnPc–ZnOMPs and TCbZnPc–AgNPs, respectively. The photocatalysts were supported onto electrospun polystyrene fibers. The efficiency of TCbZnPc was improved by the presence of both ZnOMPs and AgNPs. HPLC equipped with UV–vis was used to study phototransformation products. The mechanism of transformation was via the N-de-ethylation of Rh 6G. 相似文献
89.
90.
罗丹明6G缔合微粒荧光猝灭法测定痕量碘酸根 总被引:2,自引:2,他引:0
研究发现在0.01mol/LHCl-8.0×10-4mol/LKI介质中,罗丹明6G(RhG)在550nm处有1个荧光峰.当有IO-3,I-3与RhG形成缔合微粒,550nm处荧光峰猝灭,在320、400、6103存在时,IO-3与过量的I-反应生成I-nm处有3个共振散射峰,在470nm处有1个同步散射峰.碘酸根浓度在2.0~100×10-7mol/L范围内与荧光猝灭强度成线性关系.据此建立了一个测定食盐中IO-3的荧光猝灭分析法.光谱研究结果表明,(RhG-I3)n缔合微粒和界面的形成是导致体系荧光猝灭的根本原因. 相似文献