Sulfamethazine In Milk Research Articles

Voltametric Sensor Based on Magnetic Chitosan Acetylindole-Based Nanocomposite for the Determination of Sulfamethazine.

Sulfamethazine (SMZ), a persistent antibiotic, is frequently detected in drinking water and milk. For this reason, our research aimed to develop a novel electrochemical sensor based on a magnetic nanocomposite supported on chitosan modified by 3-acetylindole through the formation of chitosan acetylindole Schiff base (Chs-Aci). The objective was to detect extremely low concentrations of SMZ in milk. The synthesized nanocomposites were characterized by various techniques, including FT-IR, XRD, EDX, SEM, and TEM. To enhance the electrocatalytic efficiency for sensitive SMZ detection in food samples, a magnetic chitosan acetylindole nanocomposite (M-Chs-Aci) was employed as a modifier for a carbon paste electrode (CPE). The electrochemical measurements revealed that the M-Chs-Aci/CPE exhibits good electrocatalytic performance compared to a bare CPE. Moreover, low detection limit, repeatability, and stability were achieved at 0.021 μM, 3.83%, and 94.87%, respectively. Finally, the proposed M-Chs-Aci/CPE proved to be highly effective in detecting SMZ in milk samples. The obtained findings paved the way for the effective usability of M-Chs-Aci/CPE as a sensor for detecting SMZ in real samples, with acceptable recoveries of 95%-98.87%.

Ultrasensitive and selective detection of sulfamethazine in milk via a Janus-labeled Au nanoparticle-based surface-enhanced Raman scattering-immunochromatographic assay

Sulfamethazine (SM2) is an antibacterial drug，which has been extensively used in human and veterinary medicine, long-term consumption of which may lead to the accumulation of sulfonamides in the body. Detection of sulfonamides often uses microbiological approaches, mass spectrometry and chromatography, which are expensive and time-consuming. Surface-enhanced Raman scattering-based immunochromatographic assay (SERS-ICA) has been recently applied in the detection. Herein, a Janus-labeled Au nanoparticle with subnanosized SiO2-monoclonal antibody and SERS reporter (DTNB) modified simultaneously (mAbAuNpDTNB) has been developed in a SERS-based lateral flow immunosensor, which can be used for rapid, quantitative and ultrasensitive detection of sulfamethazine residue in milk. The mAbAuNpDTNB exhibits a specific array on a paper stripe, which not only identifies sulfamethazine but also straightforwardly exposes the Raman reporter between the AuNps via self-assembly. The detection sensitivity of SERS-ICA for sulfamethazine reached 0.1 pg/mL, which was far below the previously published value by ELISA and the maximum residue limit set by the European Union. The entire SERS-ICA detection for sulfamethazine was completed within 15 min. Furthermore, high accuracy for this assay was exhibited in the spiking experiment with a recovery percentage of 88.1%–112.7%. The results demonstrated that this SERS-ICA can potentially be applied in point-of-care testing as an ultrasensitive and quantitative to semi-quantitative analytical method.

Sensitive and visual determination of sulfamethazine in milk and drinking water using aggregation-induced emission fluorescent sensor based on luminol-europium nanocomposites

Sensitive and visual determination of sulfamethazine in milk and drinking water using aggregation-induced emission fluorescent sensor based on luminol-europium nanocomposites

Adsorption and convenient ELISA detection of sulfamethazine in milk based on MOFs pretreatment

Metal-organic frameworks (MOFs) has excellent adsorption performance, herein, three kinds of common MOFs were used for the adsorption of sulfamethazine (SM2) in milk, then enzyme-linked immunosorbent assay (MOF-ELISA) was established. Firstly, NH2-UiO-66, NH2-MIL-101, and ZIF-8 were successfully prepared and their adsorption characteristics for SM2 were investigated. The kinetic models of the three MOFs were more in line with the pseudo-second-order adsorption kinetics, and the saturated adsorption capacity of NH2-UiO-66, NH2-MIL-101, and ZIF-8 for SM2 at 298 K were 139.64, 29.98, and 36.5 mg/g, respectively. Using three different MOFs as adsorbents, the pretreatment of milk samples could be completed within 1 h, the half inhibitory concentrations (IC50) of MOF-ELISA were 1.26, 1.86 and 2.74 ng/mL, the limit of detections (LOD) were 0.05, 0.12, and 0.19 ng/mL and the recovery rate were from 82.30% to 105.62% with the intra-day coefficient of variations (CVs) below 5.81% and inter-day CVs below 7.21%. Detection results showed good correlations with LC-MS/MS (R2 > 0.99), indicated that MOFs could effectively eliminate the interference of sample matrix, and has the potential to become a general pretreatment method for the detection of various matrices residues in food safety monitoring.

Photoresponsive molecularly imprinted polymers based on 4-[(4-methacryloyloxy)phenylazo] benzenesulfonic acid for the determination of sulfamethazine.

Core-shell structured photoresponsive molecularly imprinted polymers were developed for the determination of sulfamethazine in milk samples. The photoresponsive imprinted polymers were prepared with polymethyl methacrylatecontaininga mass of ester groups as core, sulfamethazine as template molecules, self-synthesized water-soluble 4-[(4-methacryloyloxy)phenylazo] benzenesulfonic acid as a photoresponsive monomer, and ethylene dimethacrylate as cross-linker. Interestingly, the imprinted polymer can specifically adsorb sulfamethazine under dark and 440nm irradiation, and release it at 365nm. A series of adsorption experiments showed that the maximum adsorption capacity reached 12.5mg⋅g-1 , and the adsorptionequilibrium was achieved within 80min. Moreover, the imprinted polymers display excellent reusability, with almost no performance loss after four times photo-controlled adsorption-release cycles, and the imprinted polymers have excellent selectively for sulfamethazine (imprinting factor=3.01). In the end, the imprinted polymers realized effective separation and enrichment of sulfamethazine in milk, with a recovery rate of over 97.5%. The material can be used as a solid-phase extractant in the process of enrichment and separation for the quantitative detection of sulfamethazine in milk samples.

Potentiometric detection of low-levels of sulfamethazine in milk and pharmaceutical formulations using novel plastic membrane sensors

Novel potentiometric sensors for selective screening of sulfamethazine (SMZ) in pharmaceutical preparations and milk samples are reported. The sensor membranes were made from PVC matrix doped with magnesium(II)-, manganese(II)- and dichlorotin (IV)-phthalocyanines as ionophores and aliquat-336 and nitron/SMZ ion-pair complex as ion exchangers. These sensors revealed fast, stable and near-Nernstian anionic response for the singly charged sulfamethazine anion over the concentration range 10-2 - 10-5 M. The sensors exhibited good selectivity towards SMZ over most known anions, excipients and diluents commonly added in drug preparations. Validation of the proposed methods was demonstrated via evaluating the detection limit, linear response range, accuracy, precision (within-day repeatability) and between-day-variability. The sensors are easily interfaced with a double channel flow injection system and used for continuous monitoring of SMZ in drug formulations, spiked milk samples and biological tissues. The method offers the advantages of design simplicity, results accuracy, and automation feasibility.

Lateral flow immunoassays combining enrichment and colorimetry-fluorescence quantitative detection of sulfamethazine in milk based on trifunctional magnetic nanobeads

In this study, magnetic nanobeads (MNBs) were used as a trifunctional material in lateral flow immunoassay for quantitative detection of sulfamethazine (SM2) in milk. Magnetic enrichment aimed to reduce matrix effects. Naked-eye screening of SM2 was based on colorimetry of colored MNBs. The cut-off value of the naked-eye screening was 25 ng mL−1. When the concentration of SM2 in the samples is equal to the cut-off value or higher, the lateral flow strips can be quantitatively detected via grayscale intensity based on colored MNBs. When the concentration of SM2 in the samples is less than the cut-off value, the lateral flow strips can be quantitatively detected by means of fluorescence intensity based on the fluorescence quenching effect of MNBs. Under optimal conditions, the linear range and limit of detection (LOD) of fluorescence lateral flow immunoassay were 0.033–33 ng mL−1 and 0.026 ng mL−1 respectively, while the linear range and LOD of colorimetric lateral flow immunoassay was 1–100 ng mL−1 and 0.71 ng mL−1, respectively. This novel method can be used for rapid and quantitative detection of SM2 in milk.

Comparison of Chicken IgY and Mammalian IgG in Three Immunoassays for Detection of Sulfamethazine in Milk

Antibodies are the most important reagents for the development of highly sensitive and specific immunoassays to quantify analytes of interest in food and environmental samples. While immunoglobulin G (IgG)-derived antibodies from rabbit and mouse are traditionally employed in immunoassays, recent findings suggest that chicken egg yolk antibody (immunoglobulin Y (IgY)) provides several advantages over mammalian IgG. However, limited studies to date have examined the possibility of replacing IgG with IgY in immunoassays. In the current investigation, the performance of chicken IgY and IgG derived from rabbit and mouse was systematically compared in terms of sensitivity, specificity, and matrix effect under parallel conditions with three typical assay formats, specifically, indirect competitive enzyme-linked immunosorbent assay (icELISA), fluorescence polarization immunoassay (FPIA), and colloidal gold immunochromatographic assay (GICA), for detection of sulfamethazine (SMZ) as the reference molecule. We evaluated and discussed the influence of different coating antigens, tracers, and physicochemical factors on the performance of IgY and IgG in the immunoassays. Under optimized conditions, the sensitivities of icELISA (IC50 values of 6.70, 4.76, and 1.66 ng mL−1 with recoveries of 86.1–131.8% and precision of < 12%) and FPIA (IC50 values of 24.79, 20.87, and 10.83 ng mL−1 with recoveries of 81.8–120.2% and precision of < 17.3%) based on both IgY and IgG were sufficient to detect SMZ in milk while only GICA based on mouse IgG provided acceptable sensitivity. Our collective data indicate that IgY could be an acceptable alternative to mammalian antibodies in some situations (in icELISA and FPIA) for use in the development of effective immunoassays for screening and detection of veterinary drug residues in food samples.

Convenient Determination of Sulfamethazine in Milk by Novel Ratiometric Fluorescence with Carbon and Quantum Dots with On-site Naked-eye Detection and Low Interferences

ABSTRACTSulfamethazine, one of the most widely applied feed additives, has been shown to cause negative health effects to humans. In the present work, a novel and facile fluorescence visual detection probe was established to determine sulfamethazine in milk samples with naked-eye detection. Considering the good stability, excellent optical properties, and easy synthesis, blue-emission carbon dots were used as the standard signal and red-emission CdTe quantum dots as the responsive signal for the determination of sulfamethazine. The fluorescence intensity of red-emission CdTe quantum dots was gradually quenched with increasing concentration of sulfamethazine, while the blue-emission carbon dots response remained constant. Apparent color variations were observed by naked-eye detection in the concentration range from 9.0 to 54 µmol · L−1. In addition, the presented strategy was shown to be promising to provide a rapid, facile, and sensitive method for the determination of sulfamethazine in milk samples with few interferences.

Development of a lateral flow fluorescent microsphere immunoassay for the determination of sulfamethazine in milk

The fluorescent microsphere has been increasingly used as detecting label in immunoassay because of its stable configuration, high fluorescence intensity, and photostability. In this paper, we developed a novel lateral flow fluorescent microsphere immunoassay (FMIA) for the determination of sulfamethazine (SMZ) in milk in a quantitative manner with high sensitivity, selectivity, and rapidity. A monoclonal antibody to SMZ was covalently conjugated with the carboxylate-modified fluorescent microsphere, which is polystyrene with a diameter of 200 nm. Quantitative detection of SMZ in milk was accomplished by recording the fluorescence intensity of microspheres captured on the test line after the milk samples were diluted five times. Under optimal conditions, the FMIA displays a rapid response for SMZ with a limit of detection of as low as 0.025 ng mL(-1) in buffer and 0.11 μg L(-1) in milk samples. The FMIA was then successfully applied on spiked milk samples and the recoveries ranged from 101.1 to 113.6% in the inter-batch assay with coefficient of variations of 6.0 to 14.3%. We demonstrate here that the fluorescent microsphere-based lateral flow immunoassay (LFIA) is capable of rapid, sensitive, and quantitative detection of SMZ in milk.

Detection of Sulfamethazine Residues in Milk by Surface Plasmon Resonance-Based Biosensor Inhibition Immunoassay

A method for detection of sulfamethazine（SMT）in milk by coupling indirect inhibition assay with a self-assembled monolayer was developed. The method of immobilization of SMT-BSA on the chip surface was also introuduced. A series of milk samples with spiked 0, 5, 10, 20, 30, 40 ng/mL of SMT were analyzed by the SPR biosensor and the standard calibration curve of SMT in milk was constructed. The intra-assay relative standard deviation (RSD) and recovery were 6.3% and 102.8%, respectively. The inter-assay deviation (7 days) was less than 6 IU, and demonstrated the method’s stability. The high stability of the SPR sensor underlies the potential of the SPR method as a stable and high-precision tool for detection of SMT.

Optimization of a solid-phase extraction procedure in the fluorimetric determination of sulfonamides in milk using the second-order advantage of PARAFAC and D-optimal design

The objective of this work is to optimize a solid-phase extraction procedure for the simultaneous determination of sulfadiazine, sulfamerazine, and sulfamethazine in milk by fluorimetric detection. For this task, an alternative strategy is employed, which allows one to reduce noticeably the number of experiments without losing the quality of the estimations. It consists of the use of a D-optimal design together with PARAFAC decomposition for the calculation of the response in the experimental design. Effects of amount of cartridge sorbent, kind of milk, volume of conditioning solutions, kind of wash and elution, and kind of mixture of sulfonamides have been evaluated, for maximizing sulfonamide mean recovery and minimizing its standard deviation. Since milk without sulfonamides may give some matrix effect over the fluorescence signal, its behavior has also been studied. Optimal conditions have been selected where the ratio between sulfonamide recovery and milk without sulfonamides was the highest, which are 500 mg of cartridge sorbent, acid wash, and elution and 3 mL of conditioning solutions. The type of milk and mixture of sulfonamides not significant. This makes the procedure suitable for the combined determination of sulfadiazine, sulfamerazine, and sulfamethazine in any kind of milk. Finally, an experimental procedure is proposed, obtaining a sulfonamide mean recovery equal to 68.5% with values of standard deviation between 7 and 8 microg kg(-1).

HPLC determination of sulfamethazine in milk using surface-imprinted silica synthesized with iniferter technique

A new method for the synthesis of sulfamethazine-imprinted polymer on the surface of silica via quasi-living radical polymerization and the application of the resulting polymer in determination of the SMZ in milk is developed. In the synthesis, initiator-transfer agent-terminator (iniferter) was immobilized on the silica surface using chemical reagents with good availability. The imprinting polymerization was initialized by the silica-supported iniferter under the UV radiation. The molecularly imprinted polymer (MIP) layer grafted on the silica surface was constructed by using sulfamethazine (SMZ) as the template, methacrylic acid (MAA) as the functional monomer and ethylene dimethacrylate (EDMA) as cross-linker. The resulting MIP-silica has good selectivity for SMZ and high column efficiency in the HPLC analysis. The result demonstrated that the SMZ-imprinted polymer was grafted on the silica surface successfully. Under the optimized HPLC condition, the MIP-silica has been used for the determination of SMZ in milk. The method was linear over the concentration range of 0.1–50 μg mL −1 with correlation coefficient R > 0.999. The detection limit for SMZ was 25 ng mL −1. The recoveries were above 78% at the spiked concentration of 0.024, 0.24 and 0.48 μg mL −1.

How to search the experimental conditions that improve a Partial Least Squares calibration model: Application to a flow system with electrochemical detection for the determination of sulfonamides in milk

This paper deals with the selection of experimental conditions and how the signals obtained in these conditions influence the fitted Partial Least Squares calibration model. The multivariate signals come from a flow analysis system with amperometric detection when determining sulfadiazine, sulfamerazine and sulfamethazine in milk. The solution (carrier plus analyte) was pumped through the system to provide a continuous supply of analyte to the cell. The detector was programmed for a scan mode operation being the multivariate signal the hydrodynamic voltammogram. To obtain an analytical signal of enough analytical quality, the Net Analyte Signal and its standard deviation have been optimised by using an experimental design. The conflicting behaviour of the two responses has been solved by estimating the Pareto-optimal front. The multivariate signals recorded in the optimal conditions found have been calibrated by Partial Least Squares regression and their figures of merit validated according to the criteria established in European Decision 2002/657/EC. In relation to the permitted limit, 100 µg l − 1 in milk, for the total content of sulfonamides established in the Commission Regulation EC no. 281/96 the proposed method has a decision limit of 109.1 µg l − 1 and the capability of detection is 117.9 µg l − 1 for both probability of false non-compliance and of false compliance equal to 5%. A recovery of 86.5% ± 2.4% ( n = 5) has been obtained.

Characterization and application of quantum dot nanocrystal–monoclonal antibody conjugates for the determination of sulfamethazine in milk by fluoroimmunoassay

Quantum dot (Qdot) nanocrystals have been increasingly used as fluorescence labels in fluoroimmunoassays recently because of their excellent optical characteristics. In this paper, a new monoclonal antibody (MAb) against sulfamethazine (SMZ) was successfully produced and linked to Qdot nanocrystals by covalent coupling. The Qdot-MAb conjugates were characterized by SDS-PAGE and high-performance capillary electrophoresis (HPCE). An enzyme-linked immunosorbent assay (ELISA) method was utilized to evaluate the antigen-antibody binding affinity and then a novel direct competitive fluorescence-linked immunosorbent assay (cFLISA) for the detection of SMZ in milk by using Qdots as fluorescent labels was evaluated. The results showed that the 50% inhibition values (IC50) of the cFLISA were 4.3 ng/mL in milk and 5.2 ng/mL in PBS, and the limits of detection (LODs) were 0.6 ng/mL in milk and 0.4 ng/mL in PBS, respectively. The recoveries of SMZ from spiked milk samples at levels of 10-100 ng/mL ranged from 94 to 106%, with coefficients of variation (CVs) of 2.1-9.2%.

Solid-phase molecularly imprinted on-line preconcentration and voltammetric determination of sulfamethazine in milk

The synthesis and evaluation of a molecularly imprinted polymer (MIP) as a selective solid-phase extraction sorbent, coupled to voltammetric detection, for the efficient preconcentration and determination of sulfamethazine in milk is reported. The polymer was prepared using sulfamethazine as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer in the presence of acetonitrile as the solvent. The detection of sulfamethazine was carried out by square wave voltammetry (SVW) at a glassy carbon electrode in a MeOH:acetic acid (9:1) medium. This solvent mixture was also used for the elution of the analyte from the MIP microcolumns. Optimisation of the variables involved in the sulfamethazine binding/extraction process was carried out (solvent used for rebinding, pH of the rebinding solution, eluent volume, analyte and eluent flow rates). Using solid-phase extraction cartridges, containing 0.16–0.18 g of MIP, an eluent volume of 2 ml and a sample volume of 90 ml, resulted in a nominal enrichment factor of 45, which was sufficient to analyse sulfamethazine at the maximum level permitted by the Codex Alimentarius Commission in milk (25 mg 1 −1). The selectivity of the MIP was evaluated by considering different substances with molecular structures similar to sulfamethazine. Sulfamethazine was determined in milk samples spiked at two concentration levels: 696 mg 1 −1 in the buttermilk obtained after milk deproteinisation, and 25 mg 1 −1 both in the buttermilk and in the milk before deproteinisation. Recoveries of practically 100% were achieved in all cases.

Determination of sulfamethazine in milk by solid phase extraction and liquid chromatographic separation with ultraviolet detection

A simple, rapid and inexpensive method has been developed for the determination of sulfamethazine (SMZ) in milk without interferences from other sulfa drugs. The method involves solid-phase extraction, liquid chromatographic separation and ultraviolet detection. Method precision (RSD < 4%) and absolute recovery (>80%) were satisfactory. The quantification limit, 10 μg/kg, indicated that the current maximum permissible concentration of SMZ in milk (100 μg/kg) can be monitored by this method.

Determination of Sulfamethazine in Milk by Biosensor Immunoassay

A biosensor based on surface plasmon resonance (SPR) measurement was developed for use in an immunoassay for detection of sulfamethazine (SMZ) in milk. The biospecific surface was a carboxymethyl dextran-modified gold-surface sensor chip to which SMZ was covalently bound. The assay was based on inhibition of the binding of polyclonal antibodies to immobilized SMZ by SMZ in the sample. The SPR response changed inversely in relation to the antibiotic concentration in the sample. Calibration curves were constructed for SMZ in buffer and in milk at a concentration which included the maximum residue limit (0 to 200 micrograms/kg). The analysis time per sample varied from 8 to 30 min. Different flow rates and antibodies were modified alternatively during the study to assess their influence on the performance of the assay. The active antibody concentration was calculated at approximately 1880 and 180 nM for the antibody anti-SMZ 1 and the antibody anti-SMZ 2, respectively. No cross-reactivity of antibodies with other antibiotics was found. Under optimal conditions, the detection limits in milk for SMZ were 8 and 1.7 micrograms/kg, respectively, for antibody 1 and antibody 2, at a flow rate of 20 microL/min.

Adsorptive-Stripping Determination of Sulfamethazine in Milk

A cleanup procedure is described for the determination of sulfamethazine in milk. The residue is diazotized and coupled with 1-naphthol. The diazotized sulfamethazine (SMZ) is accumulated on a mercury electrode by electrochemical adsorption and is then stripped cathodically. This method determines SMZ quantitatively at low parts-per-billion levels.

Evaluation of Commercial Immunochemical Assays for Detection of Sulfamethazine in Milk

Sulfamethazine (SMZ) is effective in the treatment of bacterial infections in food producing animals but its use is prohibited in dairy cows. Nevertheless, a 1988 survey of milk in ten cities conducted by the Food and Drug Administration revealed the presence of SMZ. Therefore, it was apparent that there was a need for rapid screening methods for SMZ. We evaluated commercial immunochemical test kits for SMZ with detectabilities of 1–10 parts per billion (ppb). Manipulations are suggested to effectively optimize immunochemical detection of SMZ in raw and processed fluid milk. The performances of the enzyme immunochemical test kits were evaluated by studying the effects of sample preparation, sample matrix, calibration and detection range of the kits using raw and processed milk samples. Immunochemical results were compared to quantitative high performance thin layer chromatography and high performance liquid chromatography with electrochemical detection. Both chromatographic methods had detectabilities in the low parts per billion range.