Detection Of Ractopamine Research Articles

Nanozyme-Enzyme Cascade Reaction-Enhanced Ratiometric Fluorescence Immunosensing Platform for Sensitive and Accurate Detection of Ractopamine.

As the most widely used immunoassay, enzyme-linked immunosorbent assay (ELISA) relies on perishable enzymes and usually provides poor sensitivity and stability, limiting its application in detecting trace analytes in harsh environments. Herein, a new ratiometric fluorescence (RF) sensing platform enhanced by a nanozyme-enzyme cascade reaction composed of MnO2 nanosheets (MnO2 NSs) and alkaline phosphatase (ALP) was proposed. In this RF platform, the versatile MnO2 NSs worked as a robust oxidase-like nanozyme to catalyze nonfluorescent Amplex Red (AR) into fluorescent resorufin and as a quencher to quench the fluorescence of carbon dots (CDs). Given that ALP could catalyze ascorbic acid 2-phosphate (AAP) into ascorbic acid (AA), followed by AA reducing MnO2 NSs into Mn2+, resulting in the fluorescence of AR decrease but fluorescence of CD recovery simultaneously. The regulation of MnO2 NSs for the fluorescence intensity of AR (Em at 585 nm) and CDs (Em at 460 nm) could cascade with ALP-triggered reaction to construct an RF sensing platform based on RF signal (F585/F460) output. The proposed RF sensing platform could achieve a superior limit of detection (LOD) of 0.037 mU mL-1 for ALP activity quantification. Inspired by the excellent performance of the RF sensing platform, a sensitive and accurate RF ELISA for ractopamine (RAC) detection was established with an LOD of 0.029 ng mL-1, which was nearly 5.5 times more sensitive than traditional colorimetric ELISA. This RF sensing platform based on robust nanozyme-triggered enzymatic cascade signal amplification and excellent RF signal readout has offered a powerful and universal platform for RAC and other trace target detection.

A renewable screen-printed electrode based on magnetic NiCo@N-doped carbon nanotubes derived from Co-MOF for ractopamine detection.

A renewable electrochemical screen-printed electrode (SPE) is proposedbased on magnetic bamboo-like nitrogen-carbon (N-C) nanotubes loaded with nickel-cobalt alloy (NiCo) nanoparticles (NiCo@N-CNTs) for the determination of ractopamine (RAC). During the preparation of NiCo@N-CNTs, Co-MOF-67 (ZIF-67) was firstly synthesized, and then blended with dicyandiamide and nickel acetate, followed by a one-step pyrolysis procedure to prepare NiCo@N-doped carbon nanotubes. The surface morphology, structure, and chemical composition of NiCo@N-CNTs were characterized by SEM, TEM, XRD, XPS, and EDS. The electrocatalytic and electrochemical behavior of NiCo@N-CNTs were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results demonstrated that NiCo@N-CNTs possessed remarkable conductivity and electrocatalysis to the oxidation of ractopamine (RAC). By using screen-printed electrode (SPE), NiCo@N-CNTs, and a designed base support, a magnetic RAC sensor (NiCo@N-CNTs/SPE) was successfully constructed. It presented a detection linear range of 0.05-80μM with a detection limit of 12nM (S/N = 3). It also exhibited good sensitivity, reproducibility, and practicability in spiked real pork samples. Since the adhesion of NiCo/N-CNTs on SPE was controlled by magnet, the NiCo@N-CNTs was easily detached from theSPE surface by magnetism and thus displayed excellent renewability. This work broadened insights into portable devices for on-site and real-time analysis.

Tailored Au@Ag NPs for Rapid Ractopamine Detection in Pork: Optimizing Size for Enhanced SERS Signals

Tailored Au@Ag NPs for Rapid Ractopamine Detection in Pork: Optimizing Size for Enhanced SERS Signals

Comparison of immunoassay and LC-tandem mass spectrometry analyses of ractopamine in hog oral fluid

The accurate detection of ractopamine in food animals is crucial for marketing since some entities require animals or animal carcasses to be free of ractopamine residues. Field-based ractopamine screening tests that are rapid, sensitive, and capable of high-throughput are highly desirable to ensure that inadvertent exposure to ractopamine did not occur in animals marketed as animals that have not been fed ractopamine. An immunochemically based lateral flow assay was used to analyze oral fluids from hogs never exposed to ractopamine and from hogs that were presumed positives and results were confirmed using an enhanced sensitivity LC-MSMS method. We found that an immunochemically based lateral flow system having a working range of 2.5 to 15 ng mL−1 worked well as a screening assay with 1.7% false positive results in freshly collected hog oral fluids. Using ractopamine glucuronide standards and LC-MSMS, we determined that the false positive results were not due to the presence of ractopamine glucuronide metabolites in oral fluids.

ZnZrO2-adorned graphitic carbon nitride (g-C3N4) on a laser-induced graphene electrode as an electrochemical sensor for the detection of ractopamine in meat samples

We fabricated an efficient ZnZrO2@g-C3N4 bimetallic MOFs by simple hydrothermal method and can be used for electrochemical detection of ractopamine.

Core-Satellite Nanoassemblies as SPR/SERS Dual-Mode Plasmonic Sensors for Sensitively Detecting Ractopamine in Complex Media.

Highly sensitive and reliable detection of β-adrenergic agonists is especially necessary due to the illegal abuse of growth-promoting feed additives. Here, we develop a novel surface plasmon resonance/surface-enhanced Raman scattering (SPR/SERS) dual-mode plasmonic sensor based on core-satellite nanoassemblies for the highly sensitive and reliable detection of ractopamine (RAC). The addition of RAC results in the decomposition of core-satellite nanoassemblies and consequently changes the Rayleigh scattering color of dark-field microscopy (DFM) images and the Raman scattering intensity of SERS spectra. The excellent sensitivity, specificity, and uniformity of this strategy were confirmed by detecting RAC in various complex media in the farm-to-table chain, and the limit of detection (LOD) was 0.03 ng/mL in an aqueous solution. In particular, the convenient access to livestock sewage not only ensures animal welfare but also provides great convenience for the market regulation of β-agonists. The success of our on-site strategy only with a portable Raman device promises great application prospects for β-agonist detection.

Nafion/Silver Nanoparticles as an Electrochemically Sensitive Interface for the Detection of Ractopamine in Pork Liver

Nafion/Silver Nanoparticles as an Electrochemically Sensitive Interface for the Detection of Ractopamine in Pork Liver

Hierarchical 3D architecture NiCo–layered double hydroxide decorated functionalized halloysite nanotubes composite. An efficient electrocatalyst for ractopamine detection

As a nutrient partitioning agent and a growth stimulator, ractopamine (RCT) enhances the feed efficiency in animal-based food products and further it is employed clinically in certain pharmaceuticals. Subsequently, metabolites of RCT have long shelf life in animals associated with deleterious repercussions in humans. It is thus, vital to develop an effective design for screening method towards RCT detection to ensure human health, food and environmental safety. Thus, we present an integrate electrocatalyst hydrothermally designed by employing NiCo–LDH (NiCo- Layered Double Hydroxides) and F-HNT (functionalized- Halloysite nanotubes) and further utilized in the electrochemical sensing of RCT. The novelty of the present work shed light upon the unique assembly of the two individual NiCo–LDH and F-HNT components with superior structural features that resulted in a hybrid matrix. The outcomes of CV and i-t analysis under optimum conditions demonstrate outstanding electrochemical performance of the NiCo–LDH/F-HNT modified GCE sensor with a wide linear range 0.003–631 μM and low detection limit 1.1 nM, enhanced selectivity towards the detection of RCT. The uniquely engineered electrode material has therefore been applied to quantitate RCT levels in real-world samples in terms of practical applications.

Au Nanoparticles Functionalized Covalent-Organic-Framework-Based Electrochemical Sensor for Sensitive Detection of Ractopamine

Ractopamine, as a feed additive, has attracted much attention due to its excessive use, leading to the damage of the human nervous system and physiological function. Therefore, it is of great practical significance to establish a rapid and effective method for the detection of ractopamine in food. Electrochemical sensors served as a promising technique for efficiently sensing food contaminants due to their low cost, sensitive response and simple operation. In this study, an electrochemical sensor for ractopamine detection based on Au nanoparticles functionalized covalent organic frameworks (AuNPs@COFs) was constructed. The AuNPs@COF nanocomposite was synthesized by in situ reduction and was characterized by FTIR spectroscopy, transmission electron microscope and electrochemical methods. The electrochemical sensing performance of AuNPs@COF-modified glassy carbon electrode for ractopamine was investigated using the electrochemical method. The proposed sensor exhibited excellent sensing abilities towards ractopamine and was used for the detection of ractopamine in meat samples. The results showed that this method has high sensitivity and good reliability for the detection of ractopamine. The linear range was 1.2-1600 μmol/L, and the limit of detection (LOD) was 0.12 μmol/L. It is expected that the proposed AuNPs@COF nanocomposites hold great promise for food safety sensing and should be extended for application in other related fields.

Bimetallic nanozymes laden DNA hydrogel for ultrasensitive optical detection of ractopamine

Ractopamine (RAC) is a synthetic β-adrenergic agonist, used for the reduction of fat deposition and increasing muscle conversion. Despite its wide application as a feed additive, it has some serious side effects. Therefore, RAC exists at low concentrations in meat products and is difficult to detect, hence its ultrasensitive detection is significant in protecting human health. Herein, a novel nanozymes-laden bioactive hydrogel based on the Au@Pd and DNA hydrogel is developed for ultrasensitive optical detection of RAC. The RAC aptamer acts as a crosslinker and Au@Pd is evenly embedded in the DNA hydrogel. The formed hydrogel collapses when the RAC binds to the aptamer, releasing the embedded Au@Pd. This catalyst is then used in the reaction of hydrogen peroxide (H2O2) with tetramethyl benzidine (TMB) to produce color changes that deepen with increasing RAC concentration. The proposed nanozymes-laden bioactive hydrogel has a low detection limit (7.39 ng L−1) and a wide detection range (0.01–1000 μg L−1) and is of great potential for future practical applications in the ultrasensitive detection of food additives.

A novel electrochemical sensor based on MoS2 electrospun nanofibers and polyoxometalate composite for the simultaneous detection of ractopamine and clenbuterol

A novel electrochemical sensor based on MoS2 nanofibers and polyoxometalate H3PMo12O40 (HPMo) composite was used for the highly selective and sensitive simultaneous detection of ractopamine (RAC) and clenbuterol (CLB). The electrochemical sensor was prepared firstly by MoS2 electrospun nanofibers as polyoxometalate (POM) carrier. Then, the morphology structure and physicochemical properties of the nanofiber composites modified electrode were characterized by X-ray diffraction (XRD), scanning electron microscopic (SEM), nitrogen adsorption/desorption isotherms, X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR) and electrochemical technologies. The results showed that HPMo decorated MoS2 electrospun nanofibers as modified electrodes can not only promote electron transfer but also enhance electrochemical sensing ability towards RAC and CLB. Differential pulse voltammetry (DPV) results proved that the proposed sensor exhibits good stability, high sensitivity and selectivity in terms of a wide range of 1–70 μM for RAC and 1–350 μM for CLB and a low detection limit of 0.056 μM for RAC and 0.085 μM for CLB, respectively. Furthermore, the proposed sensors were applied to real pork sample analysis, which the recovery of RAC and CLB were 98.5 % − 105.6 % and 98.9 % − 103.1 %, respectively. The results indicate that the electrochemical sensors have a wide application prospect in the detection of β-agonists in animal food sample.

Supramolecular recognition enhanced electrochemical sensing: β-cyclodextrin and Pd nanoparticle co-decorated 3D reduced graphene oxide nanocomposite-modified glassy carbon electrode for the quantification of ractopamine.

Ractopamine (RAC) is universally known for improving lean meat percentage in livestock and thus is widely introduced as a feed additive. However, it is difficult to eliminate the RAC residue in animal tissues from the biological system and will inevitably harm human health. Hence, detecting RAC molecules in biological samples is extremely significant. Herein, a novel strategy of supramolecular recognition-enhanced electrochemical sensing is presented. This platform was constructed by coupling β-cyclodextrin (β-CD) with palladium nanoparticles (Pd NPs)-functionalized three-dimensional reduced graphene oxide (3D-rGO) to form a nanocomposite (3D-rGO/Pd/β-CD), which was further used to modify a glassy carbon electrode (GCE) for RAC detection. Benefiting from the attractive electrical conductivity and catalytic activity of 3D-rGO/Pd, as well as the unique small-molecule-recognition ability of β-CD demonstrated by 1H NMR spectrum, which revealed the 1 : 2 binding mode of RAC with β-CD, increased peak current signals of RAC were observed in the cyclic voltammetry (CV) test. Under optimized conditions, the wide linear concentration range spanned 1-95 μM, along with a relatively low detection limit of 0.12 μM (S/N = 3), as evidenced by the differential pulse voltammetry (DPV) approach. The platform also exhibited satisfactory stability and fine reproducibility, as well as high selectivity and good anti-interference capability. Moreover, this as-obtained sensor was efficiently applied in pork samples with a high recovery rate (96.44-103.99%), which provides a promising view of its electrochemical biosensing ability in practical applications.

Simple and rapid detection of ractopamine in pork with comparison of LSPR and LFIA sensors.

This study developed a simple and rapid strategic technique to detect ractopamine (chemical growth-promoting agent) in pork. Two highly sensitive and specific gold nanoparticle-based portable sensors, i.e., localized surface plasmon resonance (LSPR) sensors, and lateral flow immunoassay (LFIA) strips were developed to detect veterinary drug residues in food products, that have detrimental effects on humans. Optimization studies were conducted on several sensor devices to improve sensitivity. Each sensor comprised functionalized gold nanoparticles conjugated with ractopamine antibodies. The LSPR sensor chip achieved excellent detection sensitivity = 1.19 fg/mL and was advantageous for quantitative analysis due to its wide dynamic range. On the other hand, LFIA strips provided visual test confirmation and achieved 2.27 ng/mL detection sensitivity, significantly less sensitive than LSPR. The complementary sensors help overcome each other's shortcomings with both the techniques offering ease of use, affordability and rapid diagnosis. Thus, these sensors can be applied on-site for routine screening of harmful drug residues in pork meat. They also provide useful direction for advanced technologies to enhance assay performance for detecting various other food drug contaminants.

A new sensor for the rapid electrochemical detection of ractopamine in meats with high sensitivity

In this research, g-C3N4/Cu@CoO/NC, which contained graphitic phase carbon nitride (g-C3N4) with a binary nanostructure and Cu@CoO/NC with a bimetallic MOF precursor, was constructed by a low-temperature pyrolysis process. The g-C3N4/Cu@CoO/NC was characterised by several techniques, including X-ray diffraction, scanning electron microscope, transmission electron microscope and X-ray photoelectron spectroscopy. Further, it was used to prepare an electrochemical sensor for the detection of ractopamine (RAC) in meat samples. The sensor showed excellent electrochemical oxidation characteristics for RAC detection, with a wide linear range (0.005 μmol/L to 32.73 μmol/L) and low detection limit (1.53 nmol/L). Meanwhile, the reproducibility, stability and interference of the g-C3N4/Cu@CoO/NC/GCE sensor were found to be excellent. Besides, the g-C3N4/Cu@CoO/NC/GCE sensor was well-used for the detection of RAC in pork, pig liver and lamb samples with recovery rates ranging from 96.5 % to 102.2 %.

Engineered Core-Shell Multifunctional Nano-Tracer in Raman-Silent Region with Highly Retained Affinity to Enhance Lateral Flow Immunoassays.

Stimulated surface-enhanced Raman scattering (SERS) in combination with engineered nano-tracer offers extraordinary potential in lateral flow immunoassays (LFIAs). Nonetheless, the investigation execution of SERS-LFIA is often compromised by the intricacy and overlap of the Raman fingerprint spectrum as well as the affinity-interference of nano-tracer to antibody. To circumvent these critical issues, an engineered core-shell multifunctional nano-tracer (named APNPs) with precise control of the size of nano-core (AuNPs) and coating of the nano-shell (Prussian blue nanomaterials) is prepared for SERS-LFIA via a modified enlarging particle size and coating modification strategy. Importantly, this nano-tracer exhibits enhanced coupling efficiency, highly retained affinity, reinforced colloid stability, and unique SERS signal (2156 cm-1 ) in the silent region (1800-2800 cm-1 ) with high signal-to-background ratio simultaneously, all of which are beneficial to the enhancement of the analysis performance. With a proof-of-concept demonstration for detection of ractopamine (RAC), a dual-pattern LFIA that synergizes both the enlarged particle size and coating modification supported colorimetric/biological silence Raman dual-response (coined as the ECCRD assay) is demonstrated by integrating APNPs with the competitive-type immunoreaction. This research may contribute to the rational design of multifunctional nano-tracer, and the ECCRD assay can be expanded for a wide spectrum of applications in environmental monitoring and biomedical diagnosis.

A customizable automated container-free multi-strip detection and line recognition system for colorimetric analysis with lateral flow immunoassay for lean meat powder based on machine vision and smartphone

Ractopamine (RAC) and clenbuterol (CLE) are feed additives with adverse effects of consuming too much to food safety. It is necessary to develop an efficient and accurate colorimetric analysis method for immune-based detection of RAC and CLE. Traditional human-vision-based colorimetric analysis for lateral flow immunoassay (LFIA) is non-quantifiable and low-in-automation, while container-based and analysis-instrument-based methods are unrepeatable and high-cost. Therefore, a container-free colorimetric analysis method was developed with LFIAs image captured in dark background under smartphone flash. A multi-strip detection algorithm based on contours extraction, as well as line recognition algorithm based on grayscale projection of LFIA was developed. Finally, relative grayscale (RGS) of lines were calculated and then input into editable fitting curves to estimate concentrations. Results showed the multi-strip detection algorithm reached 98.85% and 93.70% of Recall and intersection over union (IoU), while the line recognition algorithm reached 95.07% and 97.95% of Recall and color similarity, respectively. As a result, an App was fabricated through employing LFIA of RAC and CLE, with colorimetric analysis accuracy of 98.25% and 94.50%, respectively. This study provides a container-free multi-strip colorimetric analysis method with low-cost and illumination robustness, which is a substitution for container-based and single-strip colorimetric analysis methods.

Sensitive and simultaneous detection of ractopamine and salbutamol using multiplex lateral flow immunoassay based on polyethyleneimine-mediated SiO2@QDs nanocomposites: Comparison and application

The abuse of illegal additives poses a severe threat to human health. As such, it is of great significance to develop a simple, rapid and high-throughput analysis method for ensuring food safety from source to terminal. Herein, we proposed a multiplex fluorescent lateral flow immunoassay (LFIA) using the nanoassembly of silicon dioxide (SiO2) and quantum dots (QDs) as the advanced signal probe that can simultaneously detect ractopamine (RAC) and salbutamol (SAL) in swine urine and pork samples, and compared with other four conventional labels. The core–shell SiO2@QDs nanocomposites with strong luminescence, high stability, and abundant surface carboxyl groups were conjugated with antibodies to form high-performance SiO2@QDs immunoprobes, which improve the sensitivity and reliability of the LFIA. The developed SiO2@QDs-based LFIA achieved simultaneous detection of RAC and SAL in one strip within 13 min, with the limit of detection at 0.007 ng/mL and 0.032 ng/mL, respectively. The sensitivity of SiO2@QDs was superior to gold nanoparticles (AuNPs) and fluorescent microspheres (FMs), and exhibited comparative sensitivity with time-resolved microspheres (TRFMs), while overcoming the shortcomings of QDs that tend to aggregate. The recoveries in spiked swine urine and pork samples ranged from 73.7 to 111.0% with relative standard deviations between 4.7% and 15.5%. Good correlations were observed between the SiO2@QDs-based LFIA and commercial enzyme-linked immunosorbent assay for RAC (R2 = 0.936) and SAL (R2 = 0.979) detection. Briefly, the proposed method could be a promising screening on-site tool for convenient, rapid and sensitive detection of multiple illegal additives residues from the source to the terminal in food safety.

Perovskite nanocomposite of defective yolk-shell BaHo2Co3O8-x for electrochemical sensing of ractopamine in pork meat sample

Since ractopamine (RPA) can increase high growth rates in cattle and swine, illegal RPA usage has been widespread in many farming enterprises. Owing to the possible damage to public health, RPA detection has become a critical issue in recent decades. As a result, in order to maintain food safety, an analytical tool for rapid, precise, portable, and sensitive monitoring of RPA in animal tissues is required. In this study, the electrochemical sensor is developed for the first time by the defective yolk-shell of BaHo2Co3O8-x nanocomposites (perovskite types), which are synthesized using a hydrothermal followed by a calcination process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FE-SEM), and high-resolution transmission electron microscope (HR-TEM) are used to investigate physicochemical characterizations. Moreover, the elements are confirmed by the energy dispersive X-ray spectrum (EDS) and elemental mapping analysis. Cyclic voltammetry (CV) and difference pulse voltammetry (DPV) are used to detect RPA by modified BaHo2Co3O8-x/SPCE. The electrochemical sensing ability of the modified BaHo2Co3O8-x/SPCE displays a broad linear response range (up to 200 μM) and an ultralow detection limit (0.029 μM). Furthermore, the BaHo2Co3O8-x/SPCE presents outstanding selectivity, good repeatability, long-term storage stability, and reproducibility for RPA detection in pork meat samples.

Titanium nanoparticle anchored functionalized MWCNTs for electrochemical detection of ractopamine in porcine samples with ultrahigh sensitivity

We develop a disposable electrochemical sensor using a titanium nanoparticles (Ti NPs)-anchored functionalized multi-walled carbon nanotube (Ti@f-MWCNTs) composite as electrochemical sensing interface for the detection of ractopamine (RAC). The sensor demonstrated superior electrochemical sensing ability with a broad linear response range (0.01–185 μM) and ultralow detection limit (0.0038 µM). In addition, the stability, repeatability, reproducibility, and anti-interference ability of the Ti@f-MWCNTs sensor were satisfactory. The practicability of the sensor was effectively employed for the determination of RAC in porcine samples including pork, pig urine, and pig serum with substantial recoveries in the range of 92%–99% and a relative standard deviation of less than 5%.

Cationic conjugated polymer-based FRET aptasensor for label-free and ultrasensitive ractopamine detection.

A label-free fluorescence resonance energy transfer (FRET) platform based on cationic conjugated polymers and aptamers for ultrasensitive and specific ractopamine detection was constructed. This method exhibited a wide linear range from 0.05 to 500 μM and a low limit of detection of 47 nM, which make it an attractive assay platform for foodborne doping.