| β-agonists, known as the clenbuterol, is a kind of illegal additives used in meat products. This phenethylamine drugs can accelerate the growth of lean meat and inhibite the fat generation when used in feeding pigs. People who have meat product containing clenbuterol will have adverse reactions such as nausea, vomiting, tachycardia, muscle tremors and so on, result in serious health damage.When the β-agonists is put into fodder as illegal additives, its dosage is often ten times much more than normal curative dose and usually for a quite a long time. What’s more, to reduce the cycle of the livestock for more economic interests, they aren’t given withdrawal period before slaughter at most time, leading high leve β-agonists residue in muscle and organs that isn’t easy to be clean.bringing great risk to food security. Nowadays the main methods for clenbuterol detection is the chromatography and The immunoassays. However, chey both have disadvantages.In order to establish a quick,simple and sensitive method for β-agonists test, especially for the field-based test, we apply SERS to the detection of clenbuterol as illegal addictives. In this paper, The main research results is:1.Prepare 4 kinds of colloids:Three different particle sizes of god colloids and one silver colloid were made by chemical reduetion, and charaeterized by UV-visible absorption spectroscopy and transmission electron microseopy(TEM). The results showed that size, shape and distribution will effect its amplification ability. We had preliminary observed amplificating effects on Raman signals of β-agonist molecules combined with these 4 different kinds of sol. Among the 3 kinds of gold sol,the one that reducted by 2ml monohydrate sodium citrate solution whose concentration is 10mg/mL had uniform,moderate size, good dispersion and the best signal-amplificating effect, and we named gold colloid B.And then,comparing gold colloid B with the silver colloid in the same way, we concluded that the amplification effect on Raman signal of the silver colloid for the β-agonist is better than the gold colloid. So, silver colloid was finally chosen as active colloid for our research.2.Find the best conditions to our detection.:BH CH angTS were chosen as representatives to do reserch.By single variant test we concluded the best conditins is:the pH around 5; propotions of silver colloid and clenbuterol is 3:2;the concentration of NaCl is 0.15mol/L3.Confirm 800-850cm-1,1050 cm-1,1450 cm-1 three raman shift as Characteristic peaks of clenbuterol,if we find solution has this three ranman peak,we judge it Containing clenbuterol.Use the intensity of 800-850cm-1 Raman peak to Quantitative calculation clenbuterol. Standard curve Y=2483X-763.2 was established from the data of a series of chloramphenicol concentration and its SERS peak intensity at 800-850cm-1 They exhibited good linear correlation R2=0.997. The detection limit of the method reached 0.1mg/L in case of water as solvent.4.Urine bring interference to the test, we choose 800-850cm-1,1450cm-1 two raman shift as Characteristic peak for clenbuterol,if we find solution has this two ranman peak in urine,we judge they Containing clenbuterol. Use the intensity of 800-850cm-1 Raman peak to Quantitative calculation clenbuterol in urine. Standard curve is Y=2113X+6006 was established from the data of a series of chloramphenicol concentration and its SERS peak intensity at 800-850cm-1 They exhibited good linear correlation R2=0.999. The detection limit of the method reached 0.1 mg/L in urine..At last,we compared the SERS method with the HPLC method by detection limit,exaction, concluded respective advantages and disadvantages of SERS applying to β-agonists detection in urine, and analyzed the advantage of SERS in field-based rapid detection as well as its future. |
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