Highly selective sensing of lead ion based on α-, β-, γ-, and δ-tetrakis(3,5-dibromo-2-hydroxylphenyl)porphyrin/β-CD inclusion complex

Fluorescent sensor based models for the detection of environmentally-related toxic heavy metals

The quest for industrial and biotechnological revolution has been contributed in increasing environmental contamination issues, worldwide. The controlled or uncontrolled release of hazardous pollutants from various industrial sectors is one of the key problems facing humanity. Among them, adverse influences of lead, cadmium, and mercury on human health are well known to cause many disorders like reproductive, neurological, endocrine system, and cardiovascular, etc. Besides their presence at lower concentrations, most of these toxic heavy metals are posing noteworthy toxicological concerns. In this context, notable efforts from various regulatory authorities, the increase in the concentration of these toxic heavy metals in the environment is of serious concern, so real-time monitoring is urgently required. This necessitates the exploration for novel and efficient probes for recognition of these toxic agents. Among various methodologies adopted for tailoring such probes, generally the methodologies, in which changes associated with spectral properties, are preferred for the deceptive ease in the recognition process. Accordingly, a promising modality has emerged in the form of radiometric and colorimetric monitoring of these toxic agents. Herein, we review fluorescent sensor based models and their potentialities to address the detection fate of hazardous pollutants for a cleaner environment. Second, recent advances regarding small molecule and rhodamine-based fluorescent sensors, radiometric and colorimetric probes are discussed. The information is also given on the photoinduced electron transfer (PET) mechanism, chelation enhancement fluorescence (CHEF) effect and spirocyclic ring opening mechanism.

A highly sensitive and selective fluorescent chemosensor for Pb2+ ions in an aqueous solution

A new fluorescent sensor based on the BODIPY fluorophore and the polyamide receptor for Pb(2+) was designed and synthesized. The sensor is highly selective for Pb(2+) over relevant competing metal ions, and sensitive to ppb levels of Pb(2+). It features the most sensitive probe to date for Pb(2+) ions in water.

Fluorescence-based sensor for Pb(II) using tetra-(3-bromo-4-hydroxyphenyl)porphyrin in liquid and immobilized medium

A new optical sensor for sensing of Pb(2+) in immobilized medium (PVC film) and ethanol medium was developed by using 5,10,15,20-tetra-(3-bromo-4-hydroxyphenyl)porphyrin (TBHPP) synthesized. The sensor-based TBHPP showed a linear response towards Pb(2+) in concentration range from 5x10(-6) to 4x10(-4)molL(-1) in PVC film and 5x10(-6) to 3x10(-4)molL(-1) in ethanol medium, with a working pH 7. The detection limit was 2x10(-8) and 4x10(-8)molL(-1) for Pb(2+) in PVC film and ethanol medium respectively. The response time of Pb(2+) was found as 4min for PVC film and 2min for ethanol medium. The sensor developed in two different mediums was used for lead determination in standard soil sample with satisfactory results.

A fluorescent probe for zinc ions based on N-methyltetraphenylporphine with high selectivity

N-methyl-alpha,beta,gamma,delta-tetraphenylporphine (NMTPPH) has been used to detect trace amount of zinc ions in ethanol-water solution by fluorescence spectroscopy. The fluorescent probe undergoes a fluorescent emission intensity enhancement upon binding to zinc ions in EtOH/H(2)O (1:1, v/v) solution. The fluorescence enhancement of NMTPPH is attributed to the 1:1 complex formation between NMTPPH and Zn(II) which has been utilized as the basis for the selective detection of Zn(II). The linear response range covers a concentration range of Zn(II) from 5.0x10(-7) to 1.0x10(-5)mol/L and the detection limit is 1.5x10(-7)mol/L. The fluorescent probe exhibits high selectivity over other common metal ions except for Cu(II).

A Selective Fluorescent Sensor for Detecting Lead in Living Cells

We present the synthesis, properties, and biological applications of Leadfluor-1 (LF1), a new water-soluble, turn-on fluorescent sensor that is capable of selectively imaging Pb2+ in aqueous solution and in living cells. LF1 combines a fluorescein chromophore and a pseudocrown receptor to provide good selectivity for Pb2+ over a range of biologically and environmentally relevant metal ions in aqueous solution, with sensitivity to parts per billion EPA limits for allowable lead in drinking water. In addition to these attributes, imaging experiments further show that LF1 is the first small-molecule reagent that can be delivered into living cells and report changes in intracellular Pb2+ levels.