The Attogene Ractopamine ELISA Kit (EL2052-01) is a competitive ractopamine ELISA kit for quantitative measurement of ractopamine residues in meat, animal feed and urine. It has an overall sensitivity of 0.03 ppb, a standard curve from 0.03 to 5 ppb, and a total incubation time of 75 minutes on a 96-well strip plate read at 450 nm.
Ractopamine is a beta-agonist feed additive used to increase muscle in swine, cattle and turkeys. Many countries ban it as a growth promoter and others enforce residue limits.
Key Features
- Low detection limits: 0.1 ppb in meat, 0.4 ppb in urine and 1 ppb in feed.
- Quantitative results: six standards (0, 0.03, 0.1, 0.3, 1 and 5 ppb) for a full standard curve.
- Fast workflow: two 30-minute incubations and a 15-minute substrate step, 75 minutes in total.
- High specificity: cross-reactivity with clenbuterol and salbutamol is below 0.1%.
- Flexible format: 12 strips of 8 wells, read on a standard plate reader at 450 nm.
What’s in the Kit
Each ractopamine ELISA kit includes:
- Microtiter plate with 96 wells coated with ractopamine (12 strips × 8 wells)
- Ractopamine standards, 6 vials × 0.8 mL: 0, 0.03, 0.1, 0.3, 1 and 5 ppb
- Ractopamine Antibody #1, 11 mL
- 100X HRP-conjugated Antibody #2, 0.25 mL
- Antibody #2 Diluent, 20 mL
- 20X Wash Solution, 28 mL
- TMB Substrate Solution, 12 mL
- Stop Solution, 14 mL
You will also need: an ELISA plate reader (450 nm/630 nm), deionized water, a tissue homogenizer, vortex mixer, timer, wash bottle, 50 mL and 2 mL polystyrene centrifuge tubes, micropipettes (20–200 µL and 100–1000 µL) and a 300 µL multichannel pipette. A multichannel pipette is required when running more than two strips at once.
Who It’s For
- Meat and feed producers verifying ractopamine-free supply.
- Importers and food safety laboratories screening incoming meat and feed lots.
- Regulatory and contract testing labs running residue surveillance in urine, tissue and feed.
- Researchers studying beta-agonist residues in livestock.
How to Use the Ractopamine ELISA Kit
- Bring reagents and microwells to room temperature (20–25 °C) for at least 30 minutes. Dilute the 20X Wash Solution 1:20 with deionized water.
- Add 50 µL of each standard or prepared sample to the wells. Run standards and samples in duplicate.
- Add 100 µL of Antibody #1 to each well, shake gently for 30 seconds, cover and incubate for 30 minutes at room temperature.
- Decant the wells, wash 3 times with 250 µL of 1X Wash Solution and blot dry on absorbent paper.
- Add 150 µL of freshly prepared 1X HRP-conjugated Antibody #2 (1 part 100X conjugate to 99 parts diluent). Shake, cover and incubate for 30 minutes at room temperature.
- Wash 3 times as before and blot dry.
- Add 100 µL of TMB Substrate, mix gently and incubate covered for 15 minutes at 25 °C.
- Add 100 µL of Stop Solution and read absorbance at 450 nm within 5 minutes.
Full instructions and precautions are in the Ractopamine ELISA Kit manual (PDF).
How the Assay Works and Reading Results
The kit uses a competitive format: ractopamine in the sample competes with ractopamine coated on the well for binding to Antibody #1. An HRP-conjugated secondary antibody and TMB substrate then develop color, so more ractopamine in the sample means less color.
To calculate results, divide the mean absorbance of each standard and sample by the absorbance of the zero standard and multiply by 100 (B/B0 %). Plot B/B0 % for the standards against the log of concentration, read sample values from the curve, and multiply by the sample dilution factor. Samples with absorbance below the 5 ppb standard should be diluted and rerun.
Performance and Specificity
- Overall sensitivity: 0.03 ppb
- Detection limits: meat 0.1 ppb, urine 0.4 ppb, feed 1 ppb
- Cross-reactivity: ractopamine 100%, clenbuterol < 0.1%, salbutamol < 0.1%
- Accuracy: 80 ± 10% (feed, meat and urine)
- Precision: CV < 10%
For reference, Codex maximum residue limits for ractopamine in pig and cattle tissue are 10 µg/kg in muscle, 40 µg/kg in liver and 90 µg/kg in kidney. The 0.1 ppb meat detection limit is about 100-fold below the muscle limit.
Frequently Asked Questions
What sample types can I test with this ractopamine ELISA kit?
The kit is designed for meat, animal feed and urine. Detection limits are 0.1 ppb in meat, 0.4 ppb in urine and 1 ppb in feed. Contact Attogene for guidance on preparing your specific matrix.
How long does the assay take?
Total incubation time is 75 minutes (30 + 30 + 15 minutes), plus wash and reading steps.
Does the kit detect clenbuterol or salbutamol?
No. Cross-reactivity with clenbuterol and salbutamol is below 0.1%, so the ractopamine ELISA kit is specific for ractopamine.
What if a sample is above the top standard?
If a sample’s absorbance is lower than the 5 ppb standard, it is outside the curve. Dilute the sample, rerun it, and multiply the result by the dilution factor.
How should the kit and prepared samples be stored?
Store the kit at 2–8 °C and do not freeze; shelf life is 12 months. Treated samples can be held at 2–8 °C in the dark for up to 24 hours.
Testing for other residues and contaminants? See the Aflatoxin M1 ELISA Kit for milk and dairy, the DDT ELISA Kit for pesticide residues, the Antibiotic ELISA Kit Menu, or the full Food Safety ELISA Kit Menu.
For research use only. Not for use in diagnostic procedures. Questions? Call 512-333-1330 or email sales@attogene.com.
