1. Basis: GB / T21981-2008
2. Principle:
The target compound in the sample was homogenized, enzymolyzed, extracted with methanol-water solution, enriched and purified by solid phase extraction, determined by liquid chromatography-mass spectrometry / mass spectrometry, and quantified by internal standard method.
3. Reagents and materials
Unless otherwise specified, the reagents used in this standard are chromatographically pure, and the water is the first grade water specified in GB / T6682. Reference standard GB / T21981-2008
4. Instruments
Liquid chromatography-tandem quadrupole mass spectrometer: equipped with electrospray electron source;
Electronic balance: Sensitivity 0.0001g and 0.01g .;
Tissue homogenizer;
Vortex mixer;
Constant temperature oscillator;
Ultrasonic cleaner
Centrifuge: 10000r / min;
Solid phase extraction device;
Nitrogen blower
pH meter
Pipette.
5. Sample preparation: refer to the standard GB / T21981-2008
6. Analysis steps: purification and extraction reference table quasi-GB / T21981-2008
7. Determination:
7.1 Conditions for estrogen analysis
7.11 HPLC conditions:
Column: C18, 100 x 2.1mm, 1.7 μm
Mobile phase: water; acetonitrile flow rate: 0.3 ml / min
Column temperature: 40 ℃
Injection volume: 10 μl
7.12 Mass spectrometry ionization source: Electrospray negative ion mode ionization source Temperature: 100 ℃
Capillary voltage: 3 kV
Desolvent gas temperature: 450 ℃
Desolvent gas flow: 700l / min
7.2 Analysis conditions of progesterone
7.21 HPLC condition column: C18, 100 x 2.1mm, 1.7 μm
Mobile phase: 0.1% formic acid aqueous solution; methanol gradient elution flow rate: 0.3 ml / min
Column temperature: 40 ℃
Injection volume: 10 μl
7.22 Mass spectrometry ionization source: Electrospray negative ion mode capillary voltage: 3.5 kV
Ionization source temperature: 100 ℃
Desolvent gas temperature: 450 ℃
Desolvent gas flow: 700 l / min
According to Shao Bing, an expert member of the Inspection Method Committee of the National Food Safety Review Committee, we know that the estrogen in milk powder is at a very low level. After extracting the sample, concentration and purification are very important. Tianjin Hengao Technology can be used Nitrogen blowing instrument and solid phase extraction instrument of Development Co., Ltd .; ultrasonic extraction can use our company's ultrasonic cleaning instrument.
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