Effect of gold nanoparticle as a novel nanocatalyst on luminol–hydrazine chemiluminescence system and its analytical application

A new NiS nanoparticles-enhanced chemiluminescence method for determination of cephalexin in the pharmaceuticals and spiked human serum

It is reported that NiS nanoparticles (NPs) can enhance the light emission from chemiluminescence (CL) reaction of luminol-O₂ (λ_max = 425 nm), remarkably. Additionally, it was shown that cephalexin (CEF) could further increase the intensity of light emitted from NiS NPs-luminol-O₂ CL reaction. Inspired in these findings, we intended to develop a new and straightforward CL method for the determination of CEF. A calibration graph over the range of 1.00 × 10^-6 - 4.00 × 10^-5 mol L^-1 was established. The limit of detection (LOD) of the CL method was 8.00 × 10^-7 mol L^-1 . The coefficient of variation (CV) of the CL methods was 2.20% (n = 6) for the measurement of 6.00 × 10^-6 mol L^-1 CEF. NiS NPs were produced by exploiting the precipitation method and identified by employing several spectroscopic approaches. The proposed CL method was successfully used to measure CEF in some pharmaceutical and spiked human serum. The chemical mechanism governing the CL reaction was briefly explained.

Fabric-based in situ synthesis of gold nanoparticles for continuous enhanced heterogeneous chemiluminescence online detection of carbon dioxide

A novel method to achieve real-time and long-term continuous measurement of CO2 based on in situ synthesis of AuNPs on fabrics is reported. A heterogeneous CO2 detection method and the application of continuous catalytic chemiluminescence immobilized by nanoparticles were also developed.

Integration of 3D Hydrodynamic Focused Microreactor with Microfluidic Chemiluminescence Sensing for Online Synthesis and Catalytical Characterization of Gold Nanoparticles

Chemiluminescence assays have shown great advantages compared with other optical techniques. Gold nanoparticles have drawn much attention in chemiluminescence analysis systems as an enzyme-free catalyst. The catalytic activity of gold nanoparticles for chemiluminescence sensing depends on size, shape and the surface charge property, which is hard to characterize in batches. As there is no positive or negative correlation between chemiluminescence signals and sizes of gold nanoparticles, the best way to get optimal gold nanoparticles is to control the reaction conditions via online chemiluminescence sensing systems. Therefore, a new method was developed for online synthesis of gold nanoparticles with a three-dimension hydrodynamic focusing microreactor, directly coupled with a microfluidic chemiluminescence sensing chip, which was coupled to a charge-coupled device camera for direct catalytical characterization of gold nanoparticles. All operations were performed in an automatic way with a program controlled by Matlab. Gold nanoparticles were synthesized through a single-phase reaction using glucose as a reducing agent and stabilizer at room temperature. The property of gold nanoparticles was easily controlled with the three-dimension microreactor during synthesis. The catalyst property of synthesized gold nanoparticles was characterized in a luminol-NaOCl chemiluminescence system. After optimizing parameters of synthesis, the chemiluminescence signal was enhanced to a factor of 171. The gold nanoparticles synthesized under optimal conditions for the luminol-NaOCl system were stable for at least one month. To further investigate the catalytic activity of synthesized gold nanoparticles in various situations, two methods were used to change the property of gold nanoparticles. After adding a certain amount of salt (NaCl), gold nanoparticles aggregated with a changed surface charge property and the catalytic activity was greatly enhanced. Glutathione was used as an example of molecules with thiol groups which interact with gold nanoparticles and reduce the catalytic activity. The chemiluminescence intensity was reduced by 98.9%. Therefore, we could show that using a microreactor for gold nanoparticles synthesis and direct coupling with microfluidic chemiluminescence sensing offers a promising monitoring method to find the best synthesis condition of gold nanoparticles for catalytic activity.

Cerium doped magnetite nanoparticles for highly sensitive detection of metronidazole via chemiluminescence assay

Cerium doped magnetite nanoparticle (CDM) was synthesized via a co-precipitation method and used as the co-reactant of luminol-K₃Fe(CN)₆ chemiluminescent system. The physical-chemical features of CDM were studied by XPS, XRD, HRTEM, FESEM, VSM, BET, and FTIR analyses. This simple and highly sensitive nanoprobe enabled the determination of minor concentrations of metronidazole (MNZ). Owing to the quenching efficacy of MNZ in the studied chemiluminescence system, a linear range of 3.47 × 10^-6-9.37 × 10^-5 mol/L was obtained with a limit of detection of 3.91 × 10^-7 mol/L. This biosensor was used for MNZ detection in human serum samples, which was highly efficient. The outcomes of this study give credit to the proposed biosensor to be applied for detection of MNZ in biological samples.

Colorimetric Method for Detection of Hydrazine Decomposition in Chemical Decontamination Process

The aim of nuclear facility decommissioning is to make local settlements safe, sustainable and professedly acceptable. The challenges are the clean-up of the nuclear site and waste management. This means a definite promise in terms of safety and security, taking into account social and environmental accountability. There is an essential need to develop safe and efficient methods for nuclear decommissioning. Thus, chemical decontamination technology is of great significance to the decommissioning of nuclear energy facilities. In particular, chemical decontamination technology is applicable to the pipelines and internal loop. The iron-rich oxides, such as Fe3O4 or NiOFe2O3, of a nuclear power plant should have sound decontamination follow-through and should put through a very small amount of secondary waste. It is important to be able to detect and quantify hydrazine in decontamination situations with high sensitivity and selectivity. A colorimetric assay is a technique used to determine the concentration of colored compounds in a solution. However, detecting targeted species rapidly and easily, and with high sensitivity and specificity, is still challenging. Here, the catalytic reaction of oxidants in the p-dimethylaminobenzaldehyde and hydrazine reaction is elucidated. Oxidants can catalyze the reaction of hydrazine and p-dimethylaminobenzaldehyde to form an azine complex such as p-dimethylaminobenzaldazine, with high selectivity and sensitivity within 30 min at ambient temperatures. In the absence of an oxidant such as iron or hydrogen peroxide no detectable colorimetric change was observed by the reaction of p-dimethylaminobenzaldehyde and hydrazine unless an external oxidant was present in the system. In this study, we demonstrated a colorimetric method for the sensitive detection of hydrazine decomposition in the chemical decontamination process. Furthermore, the colorimetric response was easy to monitor with the unaided eye, without any sophisticated instrumentation. This method is thus suitable for on-site detection of contamination in a nuclear facility. In addition, this colorimetric method is convenient, non-invasive, free of complex equipment, and low-cost, making it possible to analyze hydrazine in industrial nuclear facilities. The proposed method was successfully applied to the determination of hydrazine decomposition in the nuclear decontamination process.

A dual-excitation fluorescent probe EuIII-dtpa-bis(HBT) for hydrazine detection in aqueous solutions and living cells

The Eu^III-dtpa-bis(HBT) dual-excitation fluorescence probe has good selectivity and strong anti-interference ability for the detection of N₂H₄.

Quenching of Luminol Fluorescence at Nano-Bio Interface: Towards the Development of an Efficient Energy Transfer System

Surface modified colloidal gold (Au) and silver (Ag) nanoparticles (NPs) were used as efficient quenchers of luminol (LH₂) fluorescence either in homogeneous aqueous medium or its noncovalent assembly with bovine serum albumin (BSA). The mechanism as well as the extent of fluorescence quenching was found to be strongly dependent on the nature of the nanoparticles. While simple static type fluorescence quenching mechanism was perceived with AuNP, a more complex protocol involving quenching sphere model was envisaged for AgNP quenching. Nevertheless, the magnitude of Stern-Volmer (SV) quenching constant (K_SV ~ 10⁸-10¹⁰ M^-1) was calculated to be ca. 10⁴ times more for surface quoted NPs in comparison with BSA-NP bioconjugates system. On the other hand, a highly efficient (E ≈ 95%) energy transfer (ET) process was predicted for LH₂ captured in the hydrophobic assembly with BSA in presence of AgNP as an acceptor. The ET efficiency is critically dependent on the concentration of BSA and nicely correlated with the extent of NP surface coverage. However, fluorescence quenching on AuNP surface is relatively less responsive towards protein concentration, primarily due to the difference in surface activity as well as the mode of interaction of the protein with NPs. Graphical Abstract Energy transfer from excited luminol to metal nanoparticles is strongly modulated in presence of serum albumins.

Fabrication and characterization of Cu(OH)2/CuO nanowires as a novel sensitivity enhancer of the luminol–H2O2chemiluminescence system: determination of cysteine in human plasma

Cu(OH)₂/CuO nanowires as a sensitivity enhancer in luminol–H₂O₂chemiluminescence system and its application for the determination of cysteine.

Spectrophotometric determination of pico-molar level of hydrazine by using Alizarin red in water and urine samples

In this paper, very simple and rapid sensor has been developed for the spectrophotometric determination of pico-molar level of hydrazine using Alizarin red. There was a decrease of optical intensity of the probe in the presence of hydrazine. The LOD is calculated from the linear graph between 5-100 pM as 0.66 pM of hydrazine which is well below the risk level proposed by Agency for Toxic Substance and Disease Registry. The probe selectivity for the detection of hydrazine was tested in the presence of commonly encountered metal ions and anions. The calibration curves showed good linearity for working ranges from 5-100 pM and 0.5-40 mM respectively, with R(2)=0.9911 and 0.9744, indicate the validity of the Beer-Lambert law. The binding constant and the free energy change values are determined by the Benesi-Hildebrand method. Determination of hydrazine in environmental water and human urine samples are successfully performed by the proposed method with the recovery of 100%.

Highly sensitive colorimetric determination of amoxicillin in pharmaceutical formulations based on induced aggregation of gold nanoparticles

A novel, simple and highly sensitive colorimetric method is developed for determination of Amoxicillin (AMX). The system is based on aggregation of citrate-capped gold nanoparticles (AuNP) in acetate buffer (pH=4.5) in the presence of the degradation product of Amoxicillin (DPAMX). It was found that the color of gold nanoparticles changed from red to purple and the intensity of surface plasmon resonance (SPR) peak of AuNPs decreased. A new absorption band was appeared in the wavelength range of 600-700nm upon addition of DPAMX. The absorbance ratio at the wavelength of 660 and 525nm (A660/A525) was chosen as the analytical signal indirectly related to AMX concentration. The linearity of the calibration graph was found over the concentration range of 0.3-4.5μM AMX with a correlation coefficient of 0.9967. Under the optimum experimental conditions, the detection limit was found to be 0.15μM. The applicability of the method was successfully demonstrated by analysis of AMX in pharmaceutical formulations including capsules and oral suspensions.

A high throughput gold nanoparticles chemiluminescence detection of opioid receptor antagonist naloxone hydrochloride

Background

The opioid antagonist agent naloxone hydrochloride (NLX) is a drug that has high affinity for opiate receptors but do not activate these receptors. Owing to the role of this drug to block the effects of exogenous administered opioids and endogenous released endorphians we can deduce the importance of developing sensitive analytical methods for detection of such drug. In the present study gold nanoparticles (AuNPs) was employed for enhancing the chemiluminescence (CL) signals arising from luminol-ferricyanide reaction in the presence of naloxone hydrochloride using sequential injection chemiluminescence analysis (SIA).

Method

In the present study gold nanoparticles (AuNPs) was employed for enhancing the chemiluminescence (CL) signals arising from luminol-ferricyanide reaction in the presence of naloxone hydrochloride using sequential injection chemiluminescence analysis (SIA).

Results

The developed method was examined under optimum experimental conditions and the obtained results revealed a linear relationship between the relative CL intensity and the investigated drug at a concentration range of 1.0×10⁻⁹-1.0×10⁻² mol L⁻¹, (r = 0.9993, n=9) with detection and quantification limits of 1.6×10⁻¹¹ and 1.0×10⁻⁹ mol L⁻¹, respectively. The relative standard deviation was 0.9%.

Conclusion

The proposed method was employed for the determination of the investigated drug in bulk powder, its pharmaceutical dosage forms and biological fluids. The interference of some metals and amino acids on the CL intensity was investigated. Also the interference of some related pharmacological action drugs was tested. The obtained results of the developed method were statistically treated and compared with those obtained from other reported methods.

Graphical Abstract

CuO nanosheets-enhanced flow-injection chemiluminescence system for determination of vancomycin in water, pharmaceutical and human serum

A novel, rapid and sensitive CuO nanosheets (NSs) amplified flow-injection chemiluminescence (CL) system, luminol-H2O2-CuO nanosheets, was developed for determination of the vancomycin hydrochloride for the first time. It was found that vancomycin could efficiently inhibit the CL intensity of luminol-H2O2-CuO nanosheets system in alkaline medium. Under the optimum conditions, the inhibited CL intensity was linearly proportional to the concentration of vancomycin over the ranges of 0.5-18.0 and 18.0-40.0 mg L(-1), with a detection limit (3σ) of 0.1 mg L(-1). The precision was calculated by analyzing samples containing 5.0 mg L(-1) vancomycin (n=11) and the relative standard deviation (RSD) was 2.8%. Also, a high injection throughput of 120 sample h(-1) was obtained. The CuO nanosheets were synthesized by a sonochemical method. Also, X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were employed to characterize the CuO nanosheets. The method was successfully employed to determine vancomycin hydrochloride in environmental water samples, pharmaceutical formulation and spiked human serum.

Gold nanorods-enhanced rhodamine B-permanganate chemiluminescence and its analytical application

A novel enhanced chemiluminescence system was developed by applying gold nanorods (Au NRs) as catalysts in rhodamine B-permanganate reaction. Au NRs with three different aspect ratios were synthesized by seed mediated growth method and characterized by UV-Vis spectra and transmission electron microscopy. It was demonstrated that Au NRs have much higher catalytic effect than spherical nanoparticles on rhodamine B-permanganate chemiluminescence reaction. Among various sizes of Au NRs, those with average aspect ratio of 3.0 were found to have the most remarkable catalytic activity. As an analytical application of the new chemiluminescence system, albumin as a model protein was quantified based on its interaction with NRs. Albumin binds to Au NRs active surfaces and inhibits their catalytic action and therefore decreases the intensity of chemiluminescence. This diminution effect is linearly related to the concentration of the human and bovine serum albumin over the ranges of 0.45-90 and 0.75-123 nmol L(-1), respectively with the corresponding limits of detection of 0.18 and 0.30 nmol L(-1). The method was successfully applied to the determination of albumin in human and bovine serum samples.

Enhanced chemiluminescence of the luminol-hydrogen peroxide system by colloidal cupric oxide nanoparticles as peroxidase mimic

As a peroxidase mimic, cupric oxide nanoparticles were found to enhance the chemiluminescence (CL) of luminol-H(2)O(2) system up to 400 folds. The CL spectra and radical scavengers were conducted to investigate the possible CL enhancement mechanism. It was suggested that the enhanced CL could be attributed to the peroxidase-like activity of CuO nanoparticles, which effectively catalyzed the decomposition of hydrogen peroxide into hydroxyl radicals. The effects of the reactant concentrations and some organic compounds were also investigated. The proposed method could be used as a sensitive detection tool for hydrogen peroxide and glucose.

Nanomolar concentrations determination of hydrazine by a modified carbon paste electrode incorporating TiO2 nanoparticles

In the present paper, the use of a carbon paste electrode modified by quinizarine (QZ) and TiO(2) nanoparticles prepared by a simple and rapid method was described. The heterogeneous electron-transfer properties of quinizarine coupled to TiO(2) nanoparticles at a carbon paste electrode was investigated using cyclic voltammetry and chronoamperometry in aqueous buffer solutions. The modified electrode showed excellent character for the electrocatalytic oxidization of hydrazine (HZ). Differential pulse voltammetric peak currents of HZ increased linearly with their concentrations at the range of 0.5 µM to 1900.0 µM and the detection limit (2σ) was determined to be 77 nM. Finally, this method was used for the determination of HZ in water samples, using a standard addition method.