Probe For Naked Eye Detection Research Articles

A rhodamine NIR probe for naked eye detection of mercury ions and its application

Fluorescence imaging technology has developed rapidly with its advantages, and near-infrared probes are worthy of attention because of their less background interference, low light damage, and infinite potential. Rhodamine and its derivatives have the unique structure of lactam helices, which is an ideal platform for the construction of on-off fluorescent sensors. In this paper, a novel near-infrared fluorescent probe (RBLS) based on rhodamine derivatives was synthesized for the transient detection of mercury ions. The closed-on structure can realize reversible sensor recovery by adding S2-. The superior imaging capability in living cells and in vivo in zebrafish holds promise for biological applications. In addition, the naked eye test strips prepared with RBLS probes can be used to detect and screen Hg2+ in the environment and show good gradient change performance.

Preparation of topographically remarkable cobalt microspheres for colorimetric detection of dopamine and elucidation of its sensing mechanism

In this work, a new colorimetric probe is prepared and demonstrated for the detection of dopamine (DA), an important neurotransmitter. The proposed colorimetric probe is prepared using bovine serum albumin (BSA) modified cobalt hydroxide microspheres (CoMSPs@BSA) and subsequently explored for the selective colorimetric detection of DA. The sensing studies are monitored using UV–visible absorbance spectroscopy. Interestingly upon addition of DA, an intense blue color is formed suggesting the potential use of this probe for naked eye detection of DA. The mechanism behind the sensing is investigated using time dependent UV–visible absorbance spectroscopic study and cyclic voltammetry. These studies clearly indicate the ligand exchange reaction is responsible for the resultant blue color formation. Further using this colorimetric probe a concentration range from 5.3 to 211 µM DA could easily be detected. Limit of detection of this DA sensor is found to be 5 × 10−6 M. Similarly a linear relation is observed from the calibration graph plotted between the concentration and absorption intensity corresponding to ligand exchange of BSA by DA. Moreover, this sensing probe (CoMSPs@BSA) is found to be highly selective among a wide range of other commonly interfering biomolecules. Topographically remarkable cobalt microspheres are prepared using a simple method and explored for the colorimetric detection of dopamine. The sensing mechanism is elucidated using UV–visible spectroscopic and electrochemical studies.

A dipodal molecular probe for naked eye detection of trivalent cations (Al3+, Fe3+and Cr3+) in aqueous medium and its applications in real sample analysis and molecular logic gates.

A simple and low cost multifunctional colorimetric receptor L has been designed, synthesized and characterized by 1H-NMR, IR spectroscopy, ESI-MS spectrometry and elemental analysis. The chemosensor L can selectively detect three biologically and environmentally important trivalent metal ions (Al3+, Fe3+and Cr3+) both visually and spectrophotometrically in CH3CN–H2O (1 : 1, v/v) solution in the presence of other biologically relevant metal ions. The Job's plot analyses indicate the 2 : 2 binding stereochemistry for Al3+, Fe3+ and Cr3+ ions with L, which was further confirmed by 1H-NMR and ESI-MS studies. The binding constant values were found to be 2.9 × 104 M−1 for Al3+, 1.079 × 105 M−1 for Fe3+ and 1.366 × 105 M−1 for Cr3+ respectively. The detections limits of the sensor for Al3+ (2.8 × 10−7 M), Fe3+ (1.9 × 10−7 M) and Cr3+ (2.5 × 10−7 M) are far below than the limit set by the World Health Organization (WHO) for drinking water. Moreover, colorimetric test kits for rapid detection of Al3+, Fe3+, and Cr3+ could be successively applied for all practical purposes, indicating its potential use in environmental samples. It has also been used in building molecular logic gates.

Azobenzene disperse dye-based colorimetric probe for naked eye detection of Cu2+ in aqueous media: Spectral properties, theoretical insights, and applications

A sensitive colorimetric probe (MRP) was developed by combination of m-methyl red dye-based signalling unit and tridentate chelating moiety. The sensor exhibits high selectivity toward Cu2+ over other common metal ions, displaying a dramatic color change from light yellow to red in the presence of Cu2+ in aqueous media with a physiological pH range. Detailed spectral investigations and mass spectrometry provided corroborative evidence in support of two-step complexation process (2: 1 and 1: 1 stoichiometry for MRP and Cu2+ in turn) by Jahn-Teller effect in the titration experiments. The drastic red-shift nature of the MRP+Cu2+ can be assigned to intramolecular charge transfer (ICT) and metal-to-ligand charge-transfer (MLCT). Additionally, the electronic structures and sensing mechanisms of MRP with Cu2+ were calculated by density functional theory (DFT/TDDFT) calculations. Moreover, using this azo disperse dye-based probe, MRP could be used to monitor Cu2+ adsorbed on live bacteria using an optical microscope.

Design of a ratiometric fluorescent probe for naked eye detection of dopamine

A simple and effective ratiometric fluorescence sensor for selective detection of dopamine (DA) in alkaline media has been developed by simply mixing thioglycolic acid (TGA) functionalized orange fluorescent cadmium telluride (CdTe) quantum dots (QDs) with amino-functionalized blue fluorescent carbon nanodots (CDs).