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Highly selective and sensitive detection of catecholamines using NaLuGdF4:Yb3+/Er3+ upconversion nanoparticles decorated with metal ions
摘要： We developed a novel optical sensor for sensitive and selective detection of catecholamines based on upconversion nanoparticles (UCNPs) decorated with different metal ions (UCNP-Men+). 1,2-ethanedithiol was chosen as a surface additive to synthesize the NaLuGdF4:Yb3+/Er3+ UCNPs by one-step at 200 °C. The as-prepared UCNPs exhibited a strong emission under the continuous excitation at 980 nm. It was found that catecholamines could be more effectively detected in the presence of UCNP-Fe3+, whereas, dopamine and epinephrine were detected selectively using UCNP-Li+ and UCNP-Cu2+ sensors, respectively. Under the optimum conditions, the limit of detections (LODs) for catecholamines, dopamine, and epinephrine are 2.8, 2.5, and 2.4 nM, respectively, with good linearity in the range of 5–320 nM for total catecholamines and 5–30 nM for dopamine and epinephrine. The developed method has been successfully applied to detect dopamine and epinephrine in human urine samples with good accuracy and satisfactory recovery.
关键词： Upconversion nanoparticles,Human urine,Metal ion decorated,Catecholamines,1,2-ethanedithiol
更新于2025-09-23 15:23:52
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A new spectrofluorimetric assay method for vandetanib in tablets, plasma and urine
摘要： Purpose: To develop a simple and sensitive spectrofluorimetric method for the determination of vandetanib (VDB) in tablets (containing 100 mg of the drug) and biological fluids (spiked human plasma and urine). Methods: The proposed method is based on examining the intrinsic fluorescence intensity of VDB in acetonitrile at 480 nm after excitation at 330 nm. Factors affecting fluorescence intensity of the cited drug (VDB), including the influence of pH, diluting solvent and time, were studied and optimized by one factor at a time approach. A calibration curve was constructed by plotting VDB fluorescence intensity at 480 nm versus VDB concentrations in ng mL-1. The method was validated according to the recommendations of International Conference on Harmonisation (ICH) for validation of the analytical procedures Results: The linearity range of the method was 20 – 600 ng mL-1, with limits of quantification (LOQ) and of detection (LOD) of 30.45 and 10.05 ng mL-1, respectively. The adopted method was applied successfully to the quantitation of VDB in pure powder form (100.90 ± 0.91 %), laboratory prepared tablets (97.86 ± 1.42 %), spiked human plasma (97.97 ± 2.36 %) and urine (97.59 ± 0.87 %). Comparison of the proposed method with that of liquid chromatography-tandem mass spectrometry showed that there was no significant difference (p < 0.05) between the two methods in terms of accuracy and precision. Conclusion: The proposed method is simple and highly sensitive and, consequently, can be applied to assay VDB in biological samples as well as in dosage form.
关键词： Human plasma,Dosage forms,Validation,Human urine,Assay,Spectrofluorimetry,Vandetanib
更新于2025-09-23 15:19:57
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Development of a surface plasmon resonance immunosensor and ELISA for 3-nitrotyrosine in human urine
摘要： 3-Nitrotyrosine (3-NT) is thought to be a relevant biomarker of nitrosative stress which is associated with many inflammatory and chronic diseases. It is necessary to develop confidential method for specific and sensitive 3-NT detection. In this paper, on the basis of anti-3-NT specific antibody, we developed a label-free indirect competitive surface plasmon resonance (SPR) immunosensor and ELISA for the detection of 3-NT. Under the optimized conditions, the SPR immunosensor can obtain a linear range of 0.17–6.07 μg/mL and a limit of detection (LOD) of 0.12 μg/mL while the ELISA can reach 0.33–9.94 μg/mL and a LOD of 0.24 μg/mL.The selectivity of 3-NT was also testified by six kinds of amino acid analogues. Besides, the developed SPR immunosensor was compared thoroughly with a conventional ELISA in spiked analysis of urine samples. Good recoveries and correlation between these two methods were observed (R2 = 0.964). Therefore, it is concluded that the automated SPR platform can be applied to quantify 3-NT in biological samples with its sensitivity, accuracy, and real-timing.
关键词： ELISA,Human urine,3-nitrotyrosine,Surface plasmon resonance (SPR)
更新于2025-09-09 09:28:46