Determination of 21 kinds of pig urine β- agonists <br> Wangshao Zhen Waters Technology (Shanghai) Co., Ltd. ACQUITY UPLC®-Xevo TQ-S
In March of this year, the event of clenbuterol triggered a nationwide net-type investigation, and the event of lean meat was soaring. In 10 years, the lean meat was repeatedly banned. The pigs fed with lean meat were not only bright in color, but also increased in pigs. The rate of lean meat, now people pay attention to the body, do not eat fatty meat, which also leads to eating habits to eat lean meat, and the addition of lean meat pork is in line with today's people's eating habits, the event of lean meat is everyone Do you still eat this meat?
About <br> Clenbuterol: Any of a class of animal drugs, can promote lean growth of any substance that inhibits the growth of animal fat can be called "lean." Currently, substances that can achieve this function are a class of drugs called beta-agonists. Similarly, similar drugs such as ractopamine, which is an "adrenal receptor agonist" of the traditional clenbuterol Clenbuterol, can also increase the lean rate of pigs. The detection methods of clenbuterol hydrochloride mainly include enzyme-linked immunosorbent assay (ELISA), colloidal gold immunochromatography, high performance liquid chromatography, gas chromatography and mass spectrometry and liquid chromatography. National Standard GB/T 5009.192-2003 The method for determining the residual amount of clenbuterol in animal foods is gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography, enzyme-linked immunosorbent assay, and its method is detected. The limit is 0.5ug/kg. SN/T 1924—2007 The detection method of Clenbuterol, Ractopamine, Salbutamol and terbutaline residues in imported and exported animal foods is LC/MS/MS. The method has high sensitivity and is widely used. UPLC/XEVO TQ-S was used to analyze β-agonists in pig urine.
experimental method
UPLC condition
LC system: ACQUITY UPLC®
Running time: 10min
Column: ACQUITY® BEH C18 1.7μm, 2.1mm x 100mm
Mobile phase A: 0.1% formic acid water mobile phase B: acetonitrile flow rate: 0.40 mL/min 
MS condition
MS system: Xevo TQ-S
Ion mode: ESI+
Capillary voltage: 3.5kv
Source temperature: 150 °C
Atomizing gas temperature: 500 °C
Atomizing gas flow rate: 900L/hr
Cone gas flow rate: 20 L/hr
MRM conditions: Quanpedia database
Quanpedia is a unique and scalable database from Waters that provides LC/MS/MS quantitative method information. There are currently over 1,200 compounds in the database, including chromatographic methods, mass spectrometry methods, quantitative methods, etc. You are free to choose any of these compounds or compound types to automatically form the method you need without having to re-develop the method.
The following figure shows the method information obtained by the database: 
Automatically generate MRM methods:
Sample Preparation The sample preparation <br> reference to GB / T 22286-2008 "more movable measured β- receptor agonist residues derived foods" to.
■Measure a sample of 2.0 mL pig urine, add 8 mL of 0.2 M sodium acetate buffer with a pH of 5.2, and mix well. Add 50 μL of β-Glucuronidase/aryl sulfatase and mix at 37 °C in water bath. The hydrolyzate is shaken for 15 min. After centrifugation for 10 min at 5000 r/min, add 100 uL of 10 ng/mL internal standard solution to 4 mL of the supernatant and mix well. Add 5 mL of 0.1 M perchloric acid and mix well, and adjust the pH of the solution to 1±0.3. After centrifugation at 5000 r/mim for 10 min, the supernatant was removed and the pH was adjusted to 11 with 10 M sodium hydroxide solution.
■Add 10 mL of saturated sodium chloride solution and 10 mL of isopropyl alcohol-ethyl acetate (6:4) mixed solution, centrifuge and separate the organic phase, and dry it with nitrogen at 40 °C in water bath. Add 5 mL to the residue. M sodium acetate buffer (pH 5.2), ultrasonically mixed to dissolve the residue ■Sample purification (as shown below), using Oasis MCX (3cc/60mg) cartridge ■Purified eluate is dried with nitrogen, flow The phase is dissolved to a volume of 1.0 mL and passed through a 0.22 μm filter.
The following figure shows the method information obtained by the database:
Solid phase extraction purification process Oasis MCX ( 3cc/60mg ):
Results and discussion of the method <br> injection only once with pig urine samples while monitoring the 21 kinds of β- agonists detected, satisfactory results in terms of sensitivity, resolution aspect. Unlike conventional tandem quadrupole mass spectrometers, the Xevo TQ-S gives you the best quantitative data while providing you with high quality optical MS/MS information. For porcine urine containing 0.5ug/L of receptor agonist sample, the PICs (Sedium Ion Confirmation Scan) function can be used to obtain the scan of each compound ion ion without affecting the MRM quantification, and match the standard ion map. It can help to judge the positive result of the sample.
Conclusion <br> This method uses multiple reaction monitoring (MRM) mode of the 21 detects β- agonists, rapid, accurate, high sensitivity, short analysis cycle, a wide range of advantages. It is applicable to the measurement of various animal tissues or animal foods.
IntelliStart technology enables the development of analytical method processes into streamlined workflows. This means less time is needed to develop methods that greatly increase productivity. The powerful Quanpedia database contains thousands of compounds, and the automatic generation of method files makes it easy and quick to respond to a variety of emergencies.
The PICs (Secondary Confirmation Scan) feature gives you the best quantitative data while also providing you with high-quality spectral MS/MS information to help determine the positive results in your samples.
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