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Sulfonamides are widely used as feed additives, primarily for fattening calves and pigs. Combined with dihydrofolate reductase inhibitors such as trimethoprim, tetroxoprim, or pyrimethamine, sulfonamides are also employed in veterinary medicine to treat intestinal infections, mastitis, pulmonitis, and other systemic diseases. However, their widespread use can lead to residues in animal-derived foods such as meat and milk. Among these, sulfamethazine—a compound with potential carcinogenic effects—poses a particular threat to human health.
To address this food safety challenge, Clover Technology Group, Inc. offers the iElisa sulfamethazine KIT, a competitive direct enzyme-linked immunosorbent assay (ELISA) designed for the quantitative determination of sulfamethazine residues in grains and processed grain products, as well as in animal-derived matrices. This kit delivers precise concentrations in parts per billion (ppb), enabling laboratories to meet stringent regulatory requirements with confidence.
Sulfonamide residues in food of animal origin are a major concern for food safety regulators worldwide. Key reasons for routine testing include:
Human Health Protection: Sulfamethazine has been linked to carcinogenic effects. Chronic exposure through contaminated food may increase health risks for consumers.
Regulatory Compliance: According to EU law, a maximum residue limit (MRL) of 100 ppb applies for all substances of the sulfonamide group in muscle, fat, liver, kidney, and milk. Similar stringent limits exist in other major markets, including China and the United States.
Trade & Brand Reputation: Non-compliant products can lead to import bans, recalls, legal liability, and lasting damage to brand trust.
iElisa sulfamethazine KIT is a competitive direct ELISA that provides rapid, accurate, and high-throughput detection.
Assay Principle:
Free sulfamethazine present in the sample or standards competes with an enzyme-labeled sulfamethazine conjugate for binding sites on specific antibodies pre-coated onto the microplate wells. After a thorough wash step to remove unbound materials, a substrate solution (TMB) is added. The bound enzyme conjugate catalyzes a color reaction, producing a blue color. The intensity of the color is inversely proportional to the concentration of sulfamethazine in the sample. The reaction is stopped with a stop solution, turning the color yellow, and absorbance is measured at 450 nm using a standard microplate reader.
| Component | Quantity | Description |
|---|---|---|
| Microtiter plate | 8 wells × 12 strips | Pre-coated with antibodies to mouse IgG |
| Sulfamethazine standards | 6 vials (1 mL each) | 0, 0.5, 2.0, 5.0, 20.0, and 50.0 ng/mL (ppb) |
| Antibody (100×) | 0.2 mL | Highly specific monoclonal antibody |
| Enzyme Conjugate (100×) | 0.2 mL | Enzyme-labeled sulfamethazine tracer |
| Washing buffer (10×) | 50 mL | Concentrated wash solution |
| Antibody & Enzyme diluent buffer | 30 mL | For diluting antibody and conjugate |
| Diluent buffer A | 40 mL | For sample preparation |
| Diluent buffer B | 40 mL | For sample preparation |
| Diluent buffer C | 40 mL | For sample preparation |
| TMB Substrate | 18 mL | Color development solution |
| Stop solution | 7 mL | 1N H₂SO₄ or equivalent |
| Product Manual | 1 copy | Complete protocol and validation data |
✅ High Sensitivity & Specificity: Detection range from 0.5 to 50.0 ppb, with a limit of detection (LOD) well below the 100 ppb EU MRL. Minimal cross-reactivity with other sulfonamides ensures accurate quantification of sulfamethazine.
✅ Competitive Direct ELISA Format: Eliminates the need for indirect labeling steps, simplifying workflow and reducing assay time.
✅ High-Throughput Design: 96-well plate format allows simultaneous testing of up to 40+ samples in duplicate, making it ideal for routine monitoring.
✅ Ready-to-Use Standards: Six prediluted standards (0, 0.5, 2.0, 5.0, 20.0, and 50.0 ng/mL) eliminate serial dilution errors and save preparation time.
✅ Comprehensive Sample Preparation: Includes three specialized diluent buffers (A, B, C) to optimize extraction and cleanup from grain and processed grain matrices.
✅ Full Kit with Controls: All necessary components—including washing buffer, substrate, stop solution, and antibody/conjugate diluents—are provided. No additional critical reagents are required.
✅ Standard Microplate Reader Compatibility: Results are read at 450 nm on any standard ELISA reader, making the kit accessible to most food safety and quality control laboratories.
| Step | Description | Time |
|---|---|---|
| 1. Sample Preparation | Extract sulfamethazine from sample using provided diluents (A, B, C) | 20–30 min |
| 2. Assay Setup | Add standards and samples to wells, followed by antibody | 10 min |
| 3. Competition Incubation | Allow competition between free and labeled sulfamethazine for antibody binding | 30–45 min |
| 4. Wash | Remove unbound materials using washing buffer (3–5 cycles) | 5 min |
| 5. Enzyme Conjugate Addition | Add enzyme conjugate and incubate | 30 min |
| 6. Wash | Repeat wash step to remove excess conjugate | 5 min |
| 7. Color Development | Add TMB substrate; incubate until sufficient color develops | 15 min |
| 8. Stop & Read | Add stop solution; read absorbance at 450 nm | 2 min |
| 9. Data Analysis | Construct standard curve (OD vs. concentration); calculate sample concentrations | 10–15 min |
Total assay time: Approximately 2–2.5 hours (depending on number of samples and manual vs. automated washing).
Grain & Processed Grain Products: Rice, wheat, corn, flour, breakfast cereals, and bakery ingredients
Animal-Derived Foods (with appropriate validation): Meat (muscle, liver, kidney), milk, and dairy products
Animal Feed: Feed raw materials and finished feeds for cattle, swine, and poultry
Regulatory & Third-Party Labs: High-throughput screening for sulfonamide residue monitoring programs
Food Exporters: Pre-shipment testing to ensure compliance with importing country MRLs (EU, China, US, etc.)
| Parameter | Value |
|---|---|
| Detection Range | 0.5 – 50.0 ppb (ng/mL) |
| Limit of Detection (LOD) | ≤ 0.5 ppb (varies slightly by matrix) |
| Limit of Quantitation (LOQ) | Typically 0.5 – 1.0 ppb |
| Recovery Rate (spiked samples) | 75% – 110% (matrix dependent) |
| Intra-Assay CV (precision) | < 10% |
| Inter-Assay CV (reproducibility) | < 15% |
Note: Performance may vary slightly depending on sample matrix and extraction efficiency. Validation data specific to your matrix can be requested from Clover Technology support.
Clover Technology Group, Inc. specializes in intelligent, rapid, and user-friendly immunoassay kits for food safety and quality control. Our iElisa™ Sulfamethazine Kit is manufactured under strict quality control to ensure batch-to-batch consistency, reliability, and regulatory alignment.
Additional benefits of choosing Clover:
Technical Support: Experienced application specialists available to assist with protocol optimization and troubleshooting.
Customized Validation: CWVK can provide validation data for specific sample matrices upon request.
Comprehensive Documentation: Product manuals include detailed procedures, standard curves, and quality control guidelines.
Global Regulatory Alignment: Detection limits designed to meet or exceed MRLs set by the European Union, China (GB standards), the United States (FSIS), and Codex Alimentarius.
| Product Name | Catalog Number | Plate Format | Standard Range | Sample Types |
|---|---|---|---|---|
| iElisa™ Sulfamethazine Kit | CWVK-SMZ-96 | 96 wells (8×12 strip plate) | 0, 0.5, 2, 5, 20, 50 ppb | Grains, processed grains, meat, milk, feed |
Available Resources:
Detailed product manual (protocol, validation data, safety information)
Certificate of Analysis (CoA) for each production lot
Application notes for specific matrices (meat, milk, grains)
Technical support via phone, or online meeting
Sulfonamide residues—particularly sulfamethazine—remain a critical food safety risk in animal-derived products. The iElisa sulfamethazine KIT from Beijing CWVK Biotechnology offers a reliable, sensitive, and high-throughput solution for routine monitoring and regulatory compliance. With its competitive direct ELISA format, comprehensive kit contents, and user-friendly protocol, this kit empowers laboratories to protect public health, meet global MRLs, and safeguard brand integrity.
For pricing, technical specifications, a quotation, or to discuss your specific testing requirements, please visit our product page or contact our sales team today.