Highly Active Coreactant-Capped and Water-Stable 3D@2D Core-Shell Perovskite Quantum Dots as a Novel and Strong Self-Enhanced Electrochemiluminescence Probe.

Self-enhanced electrochemiluminescence (ECL) probes have attracted more and more attention in analytical chemistry for their significant simplification of the ECL sensing operation while improving the ECL sensing sensitivity. However, the development and applications of self-enhanced ECL probes are still in their infancy and mainly suffer from the requirement of a complicated synthesis strategy and relatively low self-enhanced ECL activity. In this work, we took advantage of the recently emerged perovskite quantum dots (PQDs) with high optical quantum yields and easy surface engineering to develop a new type of PQD-based self-enhanced ECL system. The long alkyl chain (C18) diethanolamine (i.e., N-octadecyldiethanolamine (ODA)) with high ECL coreactant activity was selected as a capping ligand to synthesize an ODA-capped PQD self-enhanced ECL probe. The preparation of the coreactant-capped PQDs is as simple as for the ordinary oleylamine (OAm)-capped PQDs, and the obtained ODA-capped PQDs exhibit very strong self-enhanced ECL activity, 82.5 times higher than that of traditional OAm-capped PQDs. Furthermore, the prepared ODA-PQDs have a unique nanostructure (ODA-CsPbBr3@CsPb2Br5), with the highly emissive 3D CsPbBr3 PQD as the core and the water-stable 2D CsPb2Br5 as the shell, which allows ODA-PQDs to be very stable in aqueous media. It is envisioned that the prepared ODA-3D@2D PQDs with the easy preparation method, strong self-enhanced ECL, and excellent water stability have promising applications in ECL sensing.

Photochromic Perovskite Nanocrystals for Ultraviolet Dosimetry.

Excessive ultraviolet (UV) radiation has serious damage to human's health, therefore the development of visible, portable, and wearable sensor for monitoring UV radiation, especially the cumulative UV dosage, is highly desired but full of challenges. Herein, a wearable and flexible UV dosimeter based on photochromic perovskite nanocrystals (PNCs) is designed. The obtained CsPbCl3 PNCs dispersed in dibromomethane (PNCs-DBM) undergo continuous, vivid, and multiple (from very weak purple to blue, cyan, and finally strong green) color change in response to UV radiation. It is demonstrated that the UV-induced degradation of DBM and subsequent anion-exchange reaction between CsPbCl3 and Br-, play a crucial role in the color change of PNCs-DBM. The properties of continuous fluorescence color change and enhanced fluorescence intensity enable the construction of sensitive and visible UV dosimeter. Furthermore, by integrated photochromic PNCs with flexible bracelet or PDMS substrate, a wearable UV sensor or a multi-indicator array for the detection of solar UV dosage is developed. This work may advance the fundamental understanding about photochromic perovskite, and show promising application of perovskite nanomaterials in easily fabricated, low-cost, visualized, and wearable solar UV dosimeter.

Encapsulation of Pure Water-Stable Perovskite Nanocrystals (PNCs) into Biological Environment-Stable PNCs for Cell Imaging.

Recently emerging perovskite nanocrystals (PNCs) are very attractive fluorescence nanomaterials due to their very narrow emission peak, tunable wavelength, and extremely high quantum yield, but their chemosensing, biosensing and bioimaging applications suffer from the poor stability of ordinary PNCs in aqueous media, especially in biological matrices. Recently developed water-stable 2D CsPb2Br5-encapsulated 3D CsPbBr3 PNCs (i.e., CsPbBr3/CsPb2Br5 PNCs) show extremely stable light emission in pure water, but their fluorescence is seriously quenched in aqueous media containing biological molecules due to their chemical reactions. In this work, we used a facile method to encapsulate pure water-stable CsPbBr3/CsPb2Br5 PNCs in water with SiO2 and polyethylene glycol hexadecyl ether (Brij58) into a new kind of biological environment-stable PNCs (CsPbBr3/CsPb2Br5@SiO2-Brij58). The synthesis of the target PNCs can be accomplished in a fast, easy, and green way. The obtained CsPbBr3/CsPb2Br5@SiO2-Brij58 PNCs maintain strong fluorescence emission for a long time, all in pH 7.4 PBS, BSA, and minimum essential medium, exhibiting excellent biological environment stability. Moreover, the developed biological environment-stable PNCs show good biocompatibility and have been successfully used in cell imaging. Overall, the work provides an easy, low-cost, and efficient application of PNCs in bioimaging.

Facile Synthesis of Oxidized Boron Nanosheets for Chemo- and Biosensing.

As recently emerging nanomaterials, boron nanosheets (BNSs) have attracted more and more attention in various fields such as supercapacitors, photodetectors, bioimaging, and electrocatalysis due to their advantages of good biological compatibility, environmental friendliness, and good electro-optical properties. However, the study and application of BNSs in chemical and biological sensing are still in the infant stage, mainly due to the requirement of complicated, high-cost, and time-consuming preparation strategies. In this work, a new class of BNSs, namely oxidized-BNSs (i.e., ox-BNSs), were easily and rapidly synthesized by chemically treating boron powder with diluted HNO3 in a very short time (less than 15 min). The composition, morphology, optical property, and peroxidase mimetic activity of obtained ox-BNSs were investigated in detail. The prepared ox-BNSs were several-layered nanosheets with abundant oxygen-containing groups, emitted blue fluorescence, and possessed good intrinsic peroxidase mimetic activity, based on which a sensitive and selective colorimetric sensor was developed for detection of H2O2 and glucose. The new easy preparation strategy and good sensing performances of the prepared ox-BNSs would greatly stimulate the study and application of BNSs in chemo- and biosensing.

Anion Exchanges of Water-Stable Perovskite Nanocrystals in the Pure Water Phase and Applications in Detecting Halide Ions via a Smartphone-Based Sensing Platform.

Recently, the newly emerging lead halide perovskite nanocrystals (PNCs) have been intensely researched in many fields, such as light-emitting diodes (LEDs), solar cells, lasers, and display devices. The extremely high fluorescence quantum yield (near 100%) of PNCs over classic fluorescent materials would enable good applications of PNCs in sensing. However, the study on PNCs for bio- and chemical sensing, especially for detecting targets that exist in aqueous medium, faces great challenges due to the well-known instability of PNCs in polar solvents, especially water. Although the encapsulation of polymers or inorganic materials can efficiently protect PNCs from decomposition in aqueous solution, the sensing based on the interaction between PNCs and targets is severely hindered by the compact protection coating at the surfaces of PNCs. In this work, novel water-dispersed PNCs (W-PNCs), i.e., CsPbBr3@CsPb2Br5 PNCs, with strong fluorescence and excellent water stability were synthesized from OAm-capped CsPbBr3 PNCs by a simple "oil-solid-water" phase transition. The W-PNCs without being encapsulated with compact polymers or inorganic materials can sensitively and stably sense targets in the pure water phase via direct chemical reactions. For the first time, ion exchanges between PNCs and halide ions and their effects on the fluorescence wavelength of PNCs were investigated in the pure water phase, on the basis of which a new, visualized, selective, and sensitive smartphone-based sensing platform for halide ions has been established by the integration of the conveniently prepared W-PNC nanoprobe and the portable mobile phone. It is envisioned that the uncoated but extremely water-stable and highly fluorescent W-PNCs have promising applications in chemical sensing, biosensing, and bioimaging of targets in aqueous medium.

Hydrochromic Perovskite System with Reversible Blue-Green Color for Advanced Anti-Counterfeiting.

The intrinsic instability of halide perovskites toward to external stimulus, has created a competitive advantage for designing stimuli-responsive materials. However, the external environment tuning reversibly fluorescence emission of perovskite system is still limited. In this work, humidity is verified to act as a new option to modulate the emission properties of mixed-halide perovskite. The perovskite nanocrystals (PNCs) photoirradiated in dichloromethane are easily and stably redispersed in water, and emit bright fluorescence which is quite different from the original. Moreover, the perovskites confined on glass slide can reversibly switch their fluorescence between blue and green colors under moisture. It is demonstrated that the factors of different solubilities of CsCl and CsBr in water, the structural transformation of perovskites and the confine of glass matrix play key roles in the reversible transformation. Finally, the combination of hydrochromic CsPb(Brx Cly )3 and water-resistant CsPb(Brx Cly )3 -polymethyl methacrylate have been applied in advanced anti-counterfeiting, which greatly improves the information security. This work not only give an insight into the effects of humidity on fluorescence and structures of PNCs, but also offer a new class of hydrochromic PNCs materials based on reversible emission transformation for potential application in sensors, anti-counterfeiting and information encryption.

Highly Electrochemiluminescent Cs4PbBr6@CsPbBr3 Perovskite Nanoacanthospheres and Their Application for Sensing Bisphenol A.

Perovskite quantum dots (PQDs) as recently emerging electrochemiluminescence (ECL) luminophores have been paid much attention due to their good ECL activity, narrow ECL spectra, and easy preparation. However, the PQDs used for ECL sensing were mainly inherited from those PQDs prepared as strong fluorescence (FL) luminophores, which would limit the finding of highly ECL PQDs for sensing due to the very different mechanisms in generating excited-state luminophores between ECL and FL. In order to obtain highly electrochemiluminescent PQDs, for the first time we proposed to synthesize PQDs for ECL sensing rather than for FL-based analysis by optimizing the synthesis conditions. It was revealed that the volume of the precursor solution, the concentrations of CsBr and PbBr2, the amount of capping reagents, and the synthesis reaction temperature all significantly affect the ECL activity of PQDs. On the basis of the optimization of the synthesis conditions, we obtained a new type of PQDs with high ECL activity. The new PQDs were characterized by several technologies, such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy dispersive X-ray spectrum, to be the hybrids of 3D PQDs (CsPbBr3) and 0D PQDs (Cs4PbBr6) with unique morphologies, i.e., Cs4PbBr6@CsPbBr3 PQD nanoacanthospheres (PNAs), in which Cs4PbBr6 was as the core and CsPbBr3 served as the shell. The obtained Cs4PbBr6@CsPbBr3 PNAs had much higher (>4 times) ECL activity than the prevailing 3D (CsPbBr3) PQDs. Finally, the novel Cs4PbBr6@CsPbBr3 PNAs have been applied for the ECL sensing of bisphenol A (BPA), showing a promising application of the highly electrochemiluminescent PQDs in analytical chemistry.

Gold nanoparticles-oxidized multi-walled carbon nanotubes as electrochemiluminescence immunosensors.

Oxidized multi-walled carbon nanotube/nano-gold (AuNP-ox-MWCNT) composites with strong electrochemiluminescence (ECL) activity were applied to construct a new ECL immunosensor for the detection of carcinoembryonic antigen (CEA). The immunosensor showed a linear response range of 10-100 ng mL-1 and detection limit of 0.76 ng mL-1 (at a signal-to-noise ratio of 3). The as-developed immunosensor exhibited several advantages, including being simple to fabricate and being label free. The results indicated that ox-MWCNTs as a luminescent material have great application potential in analysis.

Label-Free and Ultrasensitive Electrochemiluminescent Immunosensor Based on Novel Luminophores of Ce2Sn2O7 Nanocubes.

In this research article, a novel and simple label-free electrochemiluminescence (ECL) immunosensor using cerium stannite (Ce2Sn2O7) nanocubes as brand-new ECL emitters has been suggested for the first time. Ce2Sn2O7 nanocubes prepared by a simple hydrothermal method displayed bright ECL emission, promising biocompatibility, low noxiousness, and perfect stability. On comparison of ECL and photoluminescence (PL) spectra, a surface-state mechanism was proposed to be involved in the ECL emission. After aminofunctionalization with 3-aminopropyltriethoxysilane (APTES), Ce2Sn2O7 could be decorated with gold nanoparticles through Au-NH2 covalent linkage, which yielded Au@Ce2Sn2O7 nanocomposites and further enhanced the ECL emission. To confirm the proposed immunosensor feasibility, carcinoembryonic antigen (CEA) was employed as an exemplary analyte. Based on the abovementioned points, our fabricated immunosensor improved the ECL performance to CEA concentrations in a linear range of 0.001-70 ng/mL with a low limit of detection of 0.53 pg/mL (S/N = 3). With outstanding stability, reproducibility, and specificity, this method is expected to be an innovative one for sensitive analyses of CEA and other biomarkers in real samples.

Simultaneous determination of six glycosidic aroma precursors in pomelo by ultra-high performance liquid chromatography-tandem mass spectrometry.

An ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established and validated for the simultaneous determination of six glycosidic aroma precursors in pomelo, including geraniol ß-glucoside, geraniol ß-primeveroside, linalool ß-primeveroside, benzyl ß-primeveroside, 2-phenylethyl ß-primeveroside and nerolidol ß-primeveroside. The results showed that the proposed method has the advantages of rapidity, high sensitivity, and good accuracy. Six glycosidic aroma precursors were effectively separated in a short run time (13 min), and the limit of detection, limit of quantification, recovery, and repeatability of analytes were 0.321-4.47 ng mL-1, 1.07-14.9 ng mL-1, 94.4-109.1%, and 5.2-14.5%, respectively. The developed method was applied to analyze the contents of glycosidic aroma precursors in different organs of pomelo plant, including leaves, flowers and fruits. The analytical result showed that glycosidic aroma precursor contents in plant leaves, flowers and fruits were in the range of 0-5964.9 µg kg-1, and more glycosidic aroma precursors were found in flowers than in leaves or fruits. It is envisioned that the proposed UPLC-MS/MS method have promising application in qualifying and quantifying these six glycosidic aroma precursors in pomelo.

A visualized ratiometric fluorescence sensing system for copper ions based on gold nanoclusters/perovskite quantum dot@SiO2 nanocomposites.

Excessive copper ions (Cu2+) cause serious environmental pollution and even endanger the health of organisms. Fluorescence chemosensing materials are widely used in the detection of metal ions due to their simple operation and high sensitivity. In this study, SiO2-encapsulated single perovskite quantum dot (PQD@SiO2) core-shell nanostructures which show strong, stable, and green fluorescence are synthesized and composited with gold nanoclusters (AuNCs) which show Cu2+-sensitive and red light-emitting fluorescence to obtain a visualized ratiometric fluorescence sensor (AuNCs/PQD@SiO2) for the detection of Cu2+. In the visualized detection of Cu2+, the green fluorescence emitted from the ion-insensitive PQD@SiO2 component is used as a reference signal and the red fluorescence emitted by ion-sensitive AuNC component is adopted as a sensing signal. In the presence of Cu2+, the red fluorescence is quenched whereas the green fluorescence remains stable, which results in a visualized fluorescence color change from orange-red to yellow and finally to green with increasing Cu2+ concentration. The significant change in the fluorescence color of AuNCs/PQD@SiO2 in response to Cu2+ enables a rapid, sensitive, and visualized detection of Cu2+. Further accurate and sensitive ratiometric fluorescence analysis of Cu2+ can be accomplished by measuring the ratio of fluorescence intensities at 643 and 520 nm (I643/I520) at a certain Cu2+ level. The developed AuNCs/PQD@SiO2-based sensor has been validated by its satisfactory application in the detection of Cu2+ in human serum and environmental water samples.

Colorimetric immunosensor based on glassy carbon microspheres test strips for the detection of prostate-specific antigen.

Micro-sized glassy carbon microspheres (GCMs, typically 3 µm in diameter) instead of nano-sized gold nanoparticles (AuNPs, typically 20 nm in diameter) were for the first time used as signal markers for the quantitative detection of antigen such as prostate-specific antigen (PSA). After being treated with concentrated HNO3, GCMs bear carboxyl groups at their surfaces, which enables antibodies to be conjugated with GCMs to yield new type of micro-sized material-based colorimetric probes used for immunochromatographic test strips (ICTSs). The captured black GCMs (with strong and wide-band light absorption) on the T-line of ICTS were used both for qualitative and quantitative determination of PSA. In the case of quantitative determination, a lab-assembled optical strip reader system was used to measure the reflected LED light intensity at 550 nm. The sensing performances of the developed GCM-based ICTSs, such as sensitivity, selectivity, reproducibility, stability, and applicability, were investigated in detail. The developed GCM-based ICTSs can have much higher (3 times) detection sensitivity than AuNP-based ICTSs, showing promising applications in sensitive immunoassay.

A simple enzyme-catalyzed reaction induced "switch" type fluorescence biosensor based on carbon nitride nanosheets for the assay of alkaline phosphatase activity.

An enzyme-catalyzed fluorescence "switch" type sensor was constructed for the determination of alkaline phosphatase (ALP) activity by combining the fluorescence quenching effect of Ag+ on ultrathin g-C3N4 nanosheets (CNNSs) with the simple redox reaction of AA and Ag+. Briefly, Ag+ exhibits a significant quenching effect on the fluorescence of CNNSs. Thus the fluorescence signal of the CNNS-Ag+ system is extremely weak even in the presence of l-ascorbic acid-2-phosphate (AAP) ("off" state). When ALP coexists in the system, the enzyme can specifically catalyze the hydrolysis of AAP to form ascorbic acid (AA), which reduces Ag+ to Ag0. In this case, the fluorescence signal of the system is recovered ("on" state). Based on this principle, a signal-enhanced CNNS fluorescence sensor was developed to determine the activity of alkaline phosphatase. The experimental results show that the detection range of alkaline phosphatase is 0.5-20 U L-1, and the detection limit is 0.05 U L-1 (S/N = 3). Meanwhile, this method was used to assay ALP in serum samples.

Superhydrophobic Silica Aerogels Encapsulated Fluorescent Perovskite Quantum Dots for Reversible Sensing of SO2 in a 3D-Printed Gas Cell.

Recently emerging perovskite quantum dots (PQDs) with several excellent optical properties, such as quantum efficiency, narrow band emission, and tunable emission wavelength, have promising applications in solar cells and light emitting diodes. However, relatively rare applications of PQDs can be found in the field of sensing, mainly due to the very easy degradation of PQDs upon exposure to water or ambient humidity. In this work, for the first time CH3NH3PbBr3 PQDs were encapsulated into superhydrophobic silica aerogels (AGs) to protect PQDs from being degraded by water. The synthesized PQDs@AGs not only maintain the strong fluorescence emission activity of PQDs but also show excellent stability in the presence of water. Additionally, PQDs@AGs have abundant pores making them very suitable for gas sensing. For improving sensing performances, 3D-printing technology is introduced into gas cell design and fabrication for the first time. Finally, a novel, sensitive, selective, and reversible fluorescence sensor for SO2 gas based on the PQDs@AGs functional material and the 3D-printed gas cell has been developed.

Strong Electrochemiluminescence Emission from Oxidized Multiwalled Carbon Nanotubes.

Carbon nanotubes (CNTs) as well-known nanomaterials are extensively studied and widely applied in various fields. Nitric acid (HNO3 ) is often used to treat CNTs for purification purposes and preparing oxidized CNTs for various applications. However, too little attention is paid to investigating the effect of HNO3 treatment on the optical properties of CNTs. In this work, it is observed for the first time that HNO3 -oxidized multiwalled carbon nanotubes (ox-MWCNTs) have strong electrochemiluminescence (ECL) activity, which enables ox-MWCNTs to become new and good ECL carbon nanomaterials after carbon quantum dots (CQDs) and graphene quantum dots (GQDs). Various characterization technologies, such as transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, are used to reveal the relationship between ECL activity and surface states. The ECL behaviors of ox-MWCNTs are investigated in detail and a possible ECL mechanism is proposed. Finally, the new ECL nanomaterials of ox-MWCNTs are envisioned to have promising applications in sensitive ECL sensing and in the study of CNT-based catalysts.

Black oxidized 3,3',5,5'-tetramethylbenzidine nanowires (oxTMB NWs) for enhancing Pt nanoparticle-based strip immunosensing.

It is well known that 3,3',5,5'-tetramethylbenzidine (TMB) can be oxidized into blue or yellow oxidzed TMB (oxTMB) with the catalysis of peroxidase or mimetic enzyme of platinum nanoparticles (Pt NPs). In this work, we found that TMB could be oxidized into very stable black oxTMB with the catalysis of Pt NPs under certain chromogenic reaction conditions. For the first time, the black oxTMB was revealed to consist of nanowires (oxTMB NWs) with lengths of more than 100 µm and diameters of around 100 nm. The black oxTMB NWs showed very strong light absorption ability, thus could be used to greatly amplify the signal of Pt NP-based immunochromatography test strips (ICTSs). The Pt NP-based ICTSs with black oxTMB NW signal amplification have shown much better assay ability (linear response range and limit of detection) than those of gold nanoparticle (Au NP)-based ICTS, Pt NP-based ICTS, and Pt NP-based ICTS with blue or yellow oxTMB signal amplifications. The developed Pt NP-oxTMB NW-based ICTS has been demonstrated to be a new, accurate, sensitive, selective, and rapid immunosensor for quantitative detection of antigens such as human chorionic gonadotropin (HCG).

Effects of C-Related Dangling Bonds and Functional Groups on the Fluorescent and Electrochemiluminescent Properties of Carbon-Based Dots.

Single-layer carbon-based dots (SCDs) were chosen as a model to investigate the effect of the C-related dangling bonds with spin S=1/2 and functional groups on the electrochemiluminescent (ECL) and fluorescent (FL) properties of CDs. The C-related dangling bonds and functional groups of SCDs were tuned by chemical reduction with NaBH4 . There have several main findings via investigating the ECL and FL properties of SCDs before and after the chemical reduction. First, the FL and ECL of CDs are highly dependent on their concentration, and luminescent resonance energy transfer is observed in ECL studies when the concentration of CDs is high. Second, the ECL activity of CDs is greatly enhanced as the C-related dangling bonds increase, proving that the ECL of CDs originates from the C-related dangling bonds. Third, the FL of CDs is the synthesis of the inner FL originated from the contained isolated sp2 units and the defect FL from the C-related dangling bonds. The inner FL of CDs is enhanced greatly by removing the carboxyl groups, while the defect FL is increased slightly due to the increased C-related dangling bonds. We believe this study would promote our understanding in the ECL and FL mechanisms of CDs, advancing the applications of CDs based on their ECL and FL properties.

Ultrasensitive chemiluminescence biosensors using nucleic acid-functionalized silver-cysteine nanowires as signal amplifying labels.

Ultrasensitive chemiluminescence (CL) sensors for biomolecules (DNA and proteins) have been developed by adopting DNA-functionalized silver-cysteine hybrid nanowires (p-SCNWs) as signal amplifying labels. The sensing is established from a sandwich-type DNA hybridization, where the target DNA strands are initially hybridized with the capture DNA located at paramagnetic microspheres (PMs) and subsequently hybridized with p-SCNWs functionalized with the signal DNA probe. After magnetic separation, p-SCNWs on the hybrids were completely decomposed with HNO3 to release numerous silver ions. The powerful catalysis of silver ions toward the redox reaction of K2S2O8-Mn2+-H3PO4 causes the generation of KMnO4 that is capable of oxidizing luminol at high pH, triggering an amplified chemiluminescent signal emission. The sensing combines the extraordinary sensitivity of the catalytic chemiluminescence technology and the amplifying strategy via releasing large quantities of silver ions as the catalyst from each hybrid, enabling the assay of target DNA strands at a concentration as low as 0.34 fM. The CL signals associated with single-base pair mismatched DNA strands and non-complementary DNA strands are able to be discriminated well from the CL signal related to the complementary DNA hybridization. Likewise, the combination of p-SCNWs functionalized with an aptamer and PMs/aptamer/thrombin complex allowed the chemiluminescence sensing of thrombin with a low limit of detection corresponding to 0.17 pM.

Colorimetric determination of glutathione by using a nanohybrid composed of manganese dioxide and carbon dots.

A kind of single-layer carbon based dots (CDs) with abundant carboxyl functional groups was hybridized with manganese dioxide (MnO2). The resulting nanohybrid is stable and can be well dispersed in water. MnO2 is capable of oxidizing the substrate 3,3'5,5'-tetramethylbenzidine (TMB) to form a blue product whose absorption (peaking at 655 nm) fades in the presence of glutathione (GSH). A sensitive and selective colorimetric GSH assay was worked out that has a linear response in the 10 to 0.1 µM GSH concentration range, with a 0.095 µM detection limit. The method was applied to the determination of GSH in spiked fetal calf serum where it gave excellent recoveries. Graphical abstract Schematic of the preparation of a nanohybrid composed of manganese dioxide and carbon based dots (MnO2/CDs). They can be used for the colorimetric detection of glutathione (GSH) based on the color change of 3,3'5,5'-tetramethylbenzidine (TMB).

Exploring the electrochemiluminescent behavior of procaterol hydrochloride in the presence of Ru(bpy)32+ and its analytical application in pharmaceutical preparation.

Based on the strong enhancement effect of procaterol hydrochloride on the electrochemiluminescence (ECL) of Ru(bpy)32+ (bpy = 2,2'-bipyridine) in an alkaline H3 PO4 -NaOH buffer solution on a bare Pt electrode, a simple, rapid and sensitive method was developed for the determination of procaterol hydrochloride. The optimum conditions for the enhanced ECL have been developed in detail in this work. Under optimum conditions, the logarithmic ECL enhancement vs. the logarithmic concentration of procaterol hydrochloride is linear over a wide concentration range of 2.0 × 10-7 to 2.0 × 10-4  M (r = 0.9976), with a limit of detection of 1.1 × 10-8  M (S/N = 3), and a relative standard deviation of 2.1% (n = 7, c = 5.0 × 10-6  M). The proposed method was applied to the determination of this drug in tablets with recoveries of 89.7%-98.5%. In addition, a possible mechanism for the enhanced ECL of Ru(bpy)32+ , which is caused by ProH, has also been proposed.