An ultrasensitive fluorescence sensor for determination of trace levels of copper in blood samples.

A novel SBA-15-based fluorescent sensor, SBA-PI: mesoporous SBA-15 structure modified with iminostilbene groups, was designed, synthesized, and characterized by Fourier transform-infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), low-angle X-ray diffraction techniques (low-angle XRD), and N adsorption-desorption techniques. The SBA-PI as a sensor with a selective behavior for detection of Cu comprises iminostilbene carbonyl as the fluorophore group. The SBA-PI sensor displays an excellent fluorescence response in aqueous solutions and the fluorescence intensity quenches remarkably upon addition of Cu. Other common interfering ions even at high concentration ratio showed either no or very small changes in the fluorescence intensity of SBA-PI in the absence of Cu. A limit of detection of 8.7 × 10 M for Cu indicated that this fluorescence sensor has a high sensitivity and selectivity toward the target copper (II) ion. The fabricated Cu sensor was successfully applied for the determination of the Cu in human blood samples without any significant interference. With the selective analysis of Cu ions down to 0.9 nM in blood, the sensor is a promising and a novel detection candidate for Cu and can be applied in the clinical laboratory. A reversibility and accuracy in the fluorescence behavior of the sensor was found in the presence of I that was described as a masking agent for Cu. Graphical abstract.