Detection Limit For Pb2 Research Articles

Simultaneous determination of lead and cadmium in water by metal oxide framework complex-modified glassy carbon electrodes

Lead (Pb) and cadmium (Cd) are pervasive environmental pollutants known for their significant biological toxicity. The traditional methods for detecting these ions often necessitate large-scale instruments and complex procedures. In contrast, electrochemical detection methods offer advantages such as rapidity, portability, and sensitivity, making them suitable for the simultaneous detection of heavy metals. Metal-organic frameworks (MOFs), characterized by their exceptional adsorption and enrichment capabilities for heavy metal ions, have shown promise in this regard. Nevertheless, the poor conductivity of most MOFs has limited their electrochemical applications. In this study, glassy carbon electrodes (GCEs) were modified using the MOF ZIF-8, in combination with a bismuth complex and carboxylated multi-walled carbon nanotubes, resulting in the fabrication of Bi@ZIF-8/CMWCNTs/GCE electrochemical sensors. Leveraging the porous nature and large specific surface area of ZIF-8, the lead and cadmium ion adsorption by bismuth akin to mercury, and the conductivity of carboxylated multi-walled carbon nanotubes, the sensor developed in this study exhibits excellent capability for simultaneous detection of lead and cadmium ions in water. Under optimized conditions, Pb2+ and Cd2+ showed good linear relationships with the peak current in the concentration range of 2.0–50.0 μg/L. In the concentration range studied, the regression equations for Pb2+ and Cd2+ were determined as follows: y = 0.2982x + 0.4553 (r = 0.9962) for Pb2+ and y = 0.3631x + 0.1242 (r = 0.9949) for Cd2+. The detection limits for Pb2+ and Cd2+ were 0.76 μg/L and 0.87 μg/L, respectively. The relative standard deviations (RSDs) for 50 μg/L mixed standard solution of Pb and Cd were 1.89 % and 1.23 %, respectively. Furthermore, the RSDs for the same modified electrode tested with 50 μg/L Pb2+ and Cd2+ mixed standard solution over seven consecutive days were 2.27 % and 1.42 %, respectively, under identical conditions. In practice, the lead and cadmium concentrations of a lake were found to range from 4.42 μg/L to 5.60 μg/L, while the lead and cadmium concentrations of effluent from a wastewater plant ranged from 11.83 μg/L to 14.49 μg/L. This research not only describes a new electrochemical platform for the simultaneous determination of lead and cadmium in water but also provides a new method for the simultaneous determination of lead and cadmium in water. This research is valuable for promoting the application of MOFs in the field of electrochemistry.

Quinoline-quinoline schiff-base as an effective chromogenic, fluorogenic, and smartphone assisted RGB detection of Pb2+ ion in near aqueous medium

A novel multimode colorimetric and fluorescent chemosensor was developed using an 8-hydroxy quinoline carbaldehyde Schiff base with a quinoline hydrazide probe (E)-2-((2-(quinolin-2-yl)hydrazineylidene)methyl)quinolin-8-ol (L). NMR (1H &13C), FTIR, and HR-mass spectral characterization techniques confirmed the probe L structural conformation. As Probe L contacts Pb2+ ions, a color change and turn-off emission can be visually detected in EtOH:H2O (1:1, v/v, pH = 7.21) medium. The probe displays a good emission at 440 nm due to the combined ESIPT and ICT process. The Pb2+ ion interacts with the probe and selectively quenches fluorescence by inhibiting ESIPT and >CN- isomerization. As per Job's plot, L-Pb2+ complex formation occurred in a 1:1 stoichiometric ratio, with association constant (Ka) and quenching constant (Ksv) estimated at 1.52 × 105 M−1 and 4.12 × 105 M, respectively. The detection limits of Pb2+ by spectrophotometric and spectrofluorometric were 1.99 μM (41 ppb) and 23.4 nM (485 ppt), respectively. Additionally, the test paper kit and RGB tool were used to monitor the color changes of L with Pb2+ and the LOD was found to be 5.99 μM (125 ppb). Its recognition mechanism has been verified by 1H NMR, ESI-mass, and theoretical studies.

CeO2-CePO4 and Ag@CeO2-CePO4 nanocomposites from Penaeus semisulcatus for heavy metals sensing, UV shielding and cytotoxic applications

CeO2-CePO4 and Ag@CeO2-CePO4 nanocomposites (NCs) were prepared using Penaeus semisulcatus and characterized by various analytical techniques. The NCs exhibited spherical morphology, with average particle sizes measuring 2.36 nm, 3.30 nm and 29.64 nm for the samples air dried, annealed at 550 °C and 800 °C respectively, and the Selected Area Electron Diffraction patterns from HR-TEM revealed their crystalline nature. In 3d X-ray Photoelectron Spectra (XPS) of NCs, the highest binding energies were observed at 916.46 eV (3d3/2) and 898.16 eV (3d5/2) with spin–orbit splitting of 18.3 eV. The X-Ray Diffraction (XRD) patterns of the NCs showed peaks typical of both CeO2 and CePO4 phases. The Fourier Transform-Infra Red (FT-IR) spectrum contained bands due to Ce-O stretching at 560 cm−1 and PO43- groups at 1008 and 711 cm−1, which was further substantiated by Raman spectrum, which had an intense peak at 468 cm−1 corresponding to F2g band of CeO2 and another peak at 976 cm−1 due to PO43- tetrahedron. In the Ultraviolet-Visible Diffuse Reflectance Spectra (UV-Vis DRS), the broad absorption peak at 352 nm and minor peaks around 300 nm confirmed the formation of CeO2-CePO4 NCs. The green synthesized NCs were excellent fluorescence sensors for Pb2+, Cd2+ and Hg2+ in a wide range of concentrations, from 5.0x10-9 M to 4.0x10-5 M. The concentration Vs. emission fitting plot had three distinctive linear ranges. At a low concentration range (5x10-9 to 3.5x10-7 M), the limit of detection for Pb2+, Cd2+ and Hg2+ was found to be 2.41x10-8, 2.56x10-8 and 3.11x10-8 M. The sensitive detection of a mixture of heavy metal ions in ppb levels by biocompatible NCs gained insight in treating aqueous industrial wastes. Further, NCs showed cytotoxicity and UV shielding properties.

Research on Improvement of Detection of Pb2+ in Environment Waters by Graphene/Nafion Modified Glassy Carbon Electrode

Abstract An electrochemical determination of Pb2+ by cyclic voltammetry, differential pulse voltammetry, and differential pulse anodic stripping voltammetry in various waters using a glassy carbon electrode modified with graphene/Nafion mixture has been developed. A series of optimum conditions such as graphene concentration, modifying amount, Nafion concentration, scanning speed, pH, accumulation potential, and time were optimized. Under optimal experiments, some evaluation indexes were analyzed. Graphene/Nafion/GCE was successfully used in the detection and quantification of Pb2+ in various real water samples using three methods above. Differential pulse anodic stripping voltammetry method that is adopted to study the linear range and the detection limit for Pb2+ proved to be more effective than the other two. The wider range is 0.02-24.15 μM, the lower detection limit is 5.1mM, and the recovery is 96.1-109.0%. This will provide a theoretical basis and the practical method for the analysis of heavy metal polltants in different kinds of water.

Synthesis of Imino Stabilized Iron Oxide Nanosensor for Selective Detection of Lead Ions

The present work describes the successful preparation of iron oxide nanoparticles (NSB1) stabilized with 4-((2-hydroxybenzylidene)amino)benzoic acid. The characterization has been achieved through ultraviolet visible (UV-Vis), fourier transform infra-red (FTIR) spectroscopy and scanning electron microscopy (SEM) with electron dispersive X-ray elemental analysis (EDX). These magnetic nanoparticles have exhibited significant chemosensing properties in the aqueous media to screen Cr3+, Cd2+, Li+, Co2+, Al3+, Pb2+, Ni2+ and Sr2+ ions. However, lead (Pb2+) ions have shown the highest selectivity as compared to other metal ions without any interference in the competitive ion study. The detection limit of Pb2+ ions was found to be 1.7 µM by this nanosensor. The binding ratio and stoichiometry was found to be 1:1 as measured by Job’s plot. The binding strength was also computed through Benesei-Hildebrand equation.

Photoluminescence Sensing of Soluble Lead in Children’s Crayons Using Perovskite Nanocrystal In Situ Growth on an Aluminum Hydroxide Layer

In this study, a fluorescence sensing approach for lead ion (Pb2+) was developed using in situ growth of methylamine lead bromine (MAPbBr3) perovskite on an aluminum hydroxide (Al(OH)3) thin layer. The Al(OH)3 thin layer could be obtained on a glass slide by liquid phase deposition and is of a large specific surface area and insoluble in water. After sulfhydryl functionalization, the Al(OH)3 thin layer reveals effective adsorption and excellent enrichment ability to Pb2+ and is additionally used as the substrate for the in situ growth of lead halogen perovskite. The fluorescence sensing of Pb2+ could be realized by the fluorescence intensity of lead halogen perovskite on the Al(OH)3 layer. The linear relationship between the fluorescence intensity and the concentration of Pb2+ was found in the range from 80 to 1500 mg/kg. The detection limit of Pb2+ is found to be 40 mg/kg, which is lower than the maximum permission of lead residue in student products (90 mg/kg) stipulated by the National Standard of the People's Republic of China (GB21027-2020). After being grinded and pre-treated, soluble lead in watercolor paint and crayon samples can be extracted by the sulfhydryl functionalization Al(OH)3 layer, then lead halogen perovskite can be generated in situ on the layer to achieve the fluorescence sensing for the determination of soluble lead in the samples.

Modification of Glassy Carbon Electrode Using Microcrystalline Cellulose-Ethylenediaminetetraacetic Acid for the Detection of Lead and Cadmium Ions

There is a greater need for the identification and monitoring of metal contaminants as a result of the growing hazard that heavy metal contamination of water poses to the environment. In this work, microcrystalline cellulose was functionalised with ethylenediaminetetraacetic acid, and the product analysed using scanning electron microscopy and X-ray diffraction techniques. The functionalised microcrystalline cellulose-ethylenediaminetetraacetic acid was employed to modify the glassy carbon electrode. Detection for Pb2+ and Cd2+ ions was determined using square wave anodic stripping voltammetric analysis at square wave potential scan of -1.0 V to -0.2 V, and deposition potential of -1.0 V in 0.1M acetate buffer for 240 sec. Higher current response of Pb2+ was obtained at -0.6 V and that of Cd2+ at -0.8V. Limit of detection for Pb2+ was 1.8 ppb (MCC-EDTA GCE) and 5.0 ppb (MCC-GCE) , while that of Cd2+ was 7 ppb (MCC-EDTA GCE) and 10 ppb (MCC-GCE), these indicate MCC EDTA GCE has higher sensitivity towards detection of the metal ions and selectivity of modifiers for detection of Pd2+ and Cd2+ was achieved successfully.

Detection of Pb2+ in Tea Using Aptamer Labeled with AIEgen Nanospheres Based on MOFs Sensors

Tea is an important economic crop and health beverage in China. The presence of heavy metal ions in tea poses a significant threat to public health. Here, we prepared an aptamer biosensor labelled with AIEgen nanospheres to detect Pb2+ in tea. The dsDNA modified by amino and phosphoric acid was combined with the carboxylated AIEgen NPs to form AIEgen-DNA with a fluorescence group, which was then fixed to the surface of Zr-MOFs to quench the fluorescence of AIEgen NPs. At the same time, PEG was added to remove nonspecific adsorption. Then Pb2+ was added to cut the DNA sequences containing the cutting sites, and AIEgen NPs and part of the DNA sequences were separated from the Zr-MOFs surface to recover the fluorescence. By comparing the fluorescence changes before and after adding Pb2+, the detection limit of Pb2+ can reach 1.70 nM. The fluorescence sensor was applied to detect Pb2+ in tea, and the detection results showed that the tea purchased on the market did not contain the concentration of Pb2+ within the detection range. This study provides new insights into monitoring food and agriculture-related pollutants based on fluorescent biosensors.

Dual signal-based electrochemical aptasensor for simultaneous detection of Lead(II) and Mercury(II) in environmental water samples

The Pb2+-binding aptamer (PBA) and Hg2+-binding aptamer (HBA) have been widely adopted as biosensing elements for lead(II) (Pb2+) and mercury (II) (Hg2+), due to the formation of stable and specific Pb2+-G-quadruplex and T-Hg2+-T structures. However, the currently developed electrochemical sensors are only applicable for single-element analysis of Pb2+ or Hg2+. Herein, a dual signal interface was realized by in-situ grafting the signal tags (Melamine-Cu2+ complex and Nile blue) bearing different redox potentials on the terminal of PBA and HBA that were co-immobilized on gold electrode. The results show that the interface has two pairs of independent redox peaks, ascribing to the melamine-Cu2+ complex and Nile blue, respectively. The sensor is not only applicable for single-element detection of Pb2+ or Hg2+, but also for simultaneous detection of them. The surface density of PBA and HBA on the gold electrode and the grafting efficiency of the electroactive tags on the aptamers have been determined. The detection limits for Pb2+ and Hg2+ were estimated to be 0.98 pM and 19 pM, respectively. The dual signal sensor is successfully applied for Pb2+ and Hg2+ determination in real water samples, showing its potential in the environmental monitoring of Pb2+ and Hg2+.

Determination of lead in food by surface-enhanced Raman spectroscopy with aptamer regulating gold nanoparticles reduction

Lead ion (Pb2+) is a main heavy metal in food that causes heavy teratogenicity and carcinogenicity. In this study, a rapid and sensitive SERS method for detecting Pb2+ in food was established by aptamer regulating gold nanoparticles reduction. The reduction of HAuCl4 catalyzed by H2O2 is a slow process, and graphene oxide (GO) has excellent catalytic performance for the reaction, which enabled the system to generate gold nanoparticles (AuNPs) with high Raman activity. When the aptamer was introduced into the system, its binding with GO reduced the reaction speed. Upon adding Pb2+ to the system, the aptamer preferentially combined with Pb2+ and GO was released to accelerate the AuNPs production. The concentration of the AuNPs was proportional to the intensity of the added Raman signal molecule 4-MBA and the main Raman peak of Pb2+ appeared at 1595.80 cm−1. The ability of a novel aptamer (M4-16) and traditional aptamers (T30695, TBA) for Pb2+ determination was compared, and the concentration of the aptamer, HAuCl4 and heating time were optimized to build optimal detection system. After several pretreatment of the original SERS spectroscopy, combined with the comparison of various models, the first-order derivative preprocessing combined with competitive adaptive reweighted sampling model achieved the best performance (Rc = 0.9966, Rp = 0.9972), the detection limit for Pb2+ was 0.1 μg L−1. The combination of SERS technology and chemometrics is a promising method that could be used to achieve rapid and highly sensitive detection of Pb2+ in food.

Target-receptive structural switching of ssDNA as selective and sensitive biosensor for subsequent detection of toxic Pb2+ and organophosphorus pesticide

A structural switching in Single-stranded DNA (ssDNA) fluorescence biosensor for quick turn-on/off detection of Pb2+ ions and pesticide was reported. The design strategy of Hex-labelled ssDNA consists of two types of aptamer probe, G-rich base pair sequence forms G-quadruplex confirmation with Pb2+ ions. While other part of base pair sequence exhibits affinity to fold isocarbophos pesticide. MoS2 nanosheets were identified as quick quencher of Hex fluorescence intensity via Vander-Waals interaction and its significance was compared with other nanomaterials. This sensing mechanism proposes a specific affinity of GA-rich ssDNA with Pb2+ to form G-quadruplex via G-Pb2+-G sequences. Consequently, ssDNA relived from MoS2 nanosheets to restore the fluorescence intensity (turn-on). Subsequent addition of pesticide shows stronger affinity towards unfolded aptamer probe to form a random coil like structure. This causes Hex-labelled 5′ end closer to the G-quadruplex connected at the 3’ end of ssDNA resulting in a remarkable fluorescence quenching (turn-off) owing to PET process. Moreover, the sensing probe (Hex-labelled GA-rich ssDNA) was recycled by introducing acetylcholinesterase enzyme and thiocoline into the reaction mixture. The detection limits of Pb2+ and isocarbophos pesticide was estimated to be 0.6 nM and 0.018 μg/L respectively. Moreover, this study reveals a high sensitivity and selectivity towards target molecules in environmental samples.

A simple and rapid fluorescent approach for Pb2+ determination and application in water samples and living cells

A novel selective fluorescent chemosensor, thiosemicarbazide-appended naphthalimide derivative (TND), has been designed and synthesized, which exhibited good selectivity and sensibility for Pb2+ in CH3CN:H2O (1:1) solution. The probe TND showed obvious color changes under UV light of 365 nm and displayed turn-on fluorescence response with Pb2+ added. The binding mode of TND with Pb2+ was found to be 1:1 based on the Job's plot analysis. The detection limit of Pb2+ was 4.7 nM, which is far below the allowable concentration determined by WHO in drinking water. Moreover, the fortified recoveries of Pb2+ were from 100.54% to 113.68% in water samples. TND is also applied for fluorescence imaging of Pb2+ in lysosomes of human stromal cell line (HSC). This study indicated that TND would be a potential sensor detecting Pb2+ in real sample.

Resolution improvement for anodic stripping signals of lead and detached indium from reduced graphene oxide/indium tin oxide (rGO/ITO) electrode using bromide ion

The overlapping of the anodic stripping voltammetric peaks between detached indium from indium tin oxide (ITO)-based electrode and lead ions (Pb2+) was separated with 0.14 V by using bromide ion (Br−) solution which is considered a high and appropriate resolution for analytical purposes. The reduced graphene oxide (rGO) was deposited on the ITO for better metals adsorption and conductivity enhancement. The limit of detection for Pb2+ was calculated as 0.6 ppb with the signal-to-noise ratio of 3 with a linear correlation coefficient of R2 = 0.988.

Single-step electrochemical sensing of ppt-level lead in leaf vegetables based on peroxidase-mimicking metal-organic framework

A simple and sensitive electrochemical sensor was established for monitoring parts-per-trillion (ppt)-level lead in leaf vegetables based on Pb2+-dependent DNAzyme and porphyrin-functionalized metal-organic framework (porph@MOF). Especially, the prepared porph@MOF showed excellent peroxidase-mimicking activities and also exhibited high stability in a wide range of temperature and pH. Using porph@MOF as mimic catalyst for sensing construction, the limit of detection for Pb2+ analysis was found to be 5 pM (corresponding to 1 ppt by weight), which was quite qualified for the regular monitoring of lead pollution in leaf vegetables. Moreover, the proposed principle facilitated the anti-jamming assay due to the specific recognition behavior of DNAzyme to Pb2+, and could be applied to detect Pb2+ in presence of the interfering metal ions. When compared with multiple-operation approaches, this sensor was constructed with single-step protocol, thereby greatly simplifying the analytical process and enhancing the temporal efficiency. With these merits of simplicity, rapid response, high sensitivity and specificity, the electrochemical sensor offered a promising means for evaluating the safety of leaf vegetables polluted with lead.

One-pot fabrication of amino acid and peptide stabilized gold nanoclusters for the measurement of the lead in plasma samples using chemically modified cellulose paper

The ultra-small size, excellent photo-stability, and tremendous fluorescence properties make the gold nanoclusters (AuNCs) as novel chemo- and biosensors. Herein, a one-pot approach was implemented for fabricating highly fluorescent AuNCs using histidine (His) and glutathione (GSH) as a reducing and protecting agent. As-synthesized GSH-AuNCs@His exhibits bright green fluorescence with excitation and emission peak of 420 and 502 nm, respectively, with a quantum yield of 7.5 %. The GSH conjugated with law fluorescent AuNCs@His through the free amines of His, and then utilized for the nanomolar detection of Pb2+ ion in aqueous solution via selective fluorescence turn-off mechanism with linear concentration range 5.0−1000 nM. The detection limit for Pb2+ ion was calculated 1.0 nM, which is much lower than the allowed concentration of Pb2+ ion in drinking water. The synthesized GSH-AuNCs@His was applied to Pb2+ ion within the spiked plasma sample and obtained excellent recovery with good precision and accuracy. The study also presents chemically modified cellulose paper strips with the conjugated GSH-AuNCs@His for the detection of Pb2+ ion.

Y0.4Gd1.6O2S: Eu nanocrystals for ratiometric Pb2+ ions sensing via selectively non-radiative relaxation

Toxic divalent lead ions are broadly chosen for famous perovskite systems with great optoelectronic performances, which motivates us to explore a novel strategy for its determination with high sensitivity. In this work, lanthanide doped inorganic oxysulfide nanocrystals (NCs) are verified to be excellent candidates for ratiometric Pb2+ ions sensing. Specifically, the photoluminescence (PL) intensity of Eu3+ ions in Y0.4Gd1.6O2S NCs decreases gradually with the increase of Pb2+ ions concentration under the excitation of 254 nm, while its intensity keep unchanged under 311 nm excitation. In this occasion, a ratiometric PL sensing route for Pb2+ ions is obtained through using I311 as intrinsic reference. The detection limit for Pb2+ ions is 7.1 nM. This work provides a new ratiometric PL sensing route for Pb2+ ions via selectively non-radiative relaxation.

Chitosan/thiol functionalized metal-organic framework composite for the simultaneous determination of lead and cadmium ions in food samples.

In this work, a facile solid phase extraction (SPE) method was developed for the analysis of trace Pb2+ and Cd2+ by using chitosan/thiol modified metal-organic frameworks (CS/MOF-SH) composite as adsorbent followed by graphite furnace atomic absorption spectrometer (GF-AAS) detection. The potential influencing factors, such as solution pH, adsorbent dosage, and extraction time, were fully estimated. Under the optimized extraction conditions, the detection limits of Pb2+ and Cd2+ were 0.033µg L-1 and 0.008µg L-1, respectively. Compared to other studies, CS/MOF-SH not only possessed superior adsorption performance, but also had the advantages of ease of handling and recyclability. Encouragingly, the developed method was of high accuracy and could monitor trace Pb2+ and Cd2+ in various certified reference materials (rice, wheat and tea) with complicated matrices, demonstrating its practical potential for regular monitoring of trace heavy metal ions in real food samples.

Schiff Base Derived from 4,4'-methylenedianiline and p-anisaldehyde: Colorimetric Sensor for Cu2+, Paper Strip Sensor for Al3+ and Fluorescent Sensor for Pb2.

The condensation product (L) of 4,4'-methylenedianiline and p-anisaldehyde acts as colorimetric sensor for Cu2+ and Pb2+ ions. On interaction with Cu2+, ethanolic solution of L changes its color to brown while it becomes light pink on interaction with Pb2+. Interaction of Al3+ with L coated paper strip emits bright blue fluorescence. Metal ions like Mg2+, Cu2+, Li+, K+, Na+, Mn2+, Al3+, Hg2+, Co2+, Pb2+, Ni2+, Cd2+, Zn2+, Fe3+ do not interfere the paper strip sensor. The fluorescent intensity of L in ethanol is quenched 25 times by Pb2+ ion. The interaction between L and Pb2+ is reversible and the detection limit of Pb2+ is 10-6M. The binding constant and stoichiometry of binding between L and Pb2+ was calculated to be 104.8 and 1:2. Theoretical calculations show that the binding of the metal ions to L are favorable and the fluorescence of L is due to π → π* transition.

Determination and quantification of heavy metal ion by electrochemical method

Today’s environment is polluted by heavy metal ions and toxic substances. The lead (Pb2+) is one of them which affect the environment by both natural and anthropogenic ways. Protection of the environment needs proper determination and quantification of these metal ions. Thus developing proper sensor with less cost is the focus of present research. Electrochemical sensor has attracted a great attention to determine these hazardous elements. In the present work sensor modified by blast furnace slag (BFS), provides a new opportunity for enhancing the electrocatalytic performance of fabricated sensor. The BFS was characterized by SEM, XRD, BET and particle size analyzer. Moreover different compositions of BFS were use to optimize the slag ratio. Furthermore the sensor modified material characterized by CV, Chronocoulometry, EIS and DPV. The electrochemical response towards Pb2+ on BFS modified sensor was explored by CV, EIS and DPV. Transfer coefficient (α) was calculated as 0.664 and rate constant (Ks) 1.08 s−1. The electrode was linear in the concentration range of 1–5 μM (R2 = 0.99). Experimental parameter like pulse height, step height, pH were also optimized. Detection and quantification limits were calculated as 0.015 μM and 0.053 μM respectively. This detection limit for Pb2+ is lower than the permissible limit provided by W.H.O. for drinking water. The electrode shows high sensitivity of 1068 μA/μM−1 cm-2 for Pb2+ ions with superior reproducibility and repeatability. The results suggested that blast furnace slag was a better material for heavy metal ion in aqueous solutions.

A turn-on dansyl-based fluorescent chemosensor for the recognition of Pb2+

In this study, a naphthalene-1-sulfonamide/2-hydroxybenzaldehyde conjugation as a selective probe (probe L) was designed for the selective recognition of Pb2+. Probe L displayed an obvious fluorescence enhancement upon binding to Pb2+ in CH3CN solution. The association constant of probe L-Pb2+ complex was calculated to be 7.68 × 108 M−1, and the detection limit for Pb2+ was found to be 23.2 ppb.