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1 Scope
This standard specifies the method for the determination of β-estradiol residues in aquatic products by gas chromatography-mass spectrometr.
This standard applies to the determination of β-estradiol residues in edible parts of aquatic product.
beta-estradiol
2 Normative references
The clauses in the following documents become clauses of this standard through reference in this standar.
GB/T 6682 Analysis Laboratory Water Specifications and Test Methods
3 Principles
Under acidic conditions, β-estradiol in the sample was extracted with acetonitrile, degreased with n-hexane, purified with C18 solid phase extraction column, derivatized with silanization reagent, and then determined by gas chromatography-mass spectrometer, and quantified by internal standard metho.
n-hexane
4 Reagents
1 All reagents should have no interference peak.
2 β-estradiol standard: purity ≥97.
3 β-estradiol-D2 standard: purity ≥98.
4 Acetonitrile: chromatographically pur.
5 Methanol: chromatographically pur.
6 n-hexane: chromatographically pur.
7 n-Propano.
8 Sodium acetate buffer solution (2mol/L, pH2): Take 237mL of 2mol/L sodium acetate solution and 63mL of 2mol/L acetic acid solution, mix well, and adjust to pH2 with glacial acetic aci.
9 Acetic acid solution (1%): take 25mL of glacial acetic acid, dissolve in water, and dilute to 250m.
10 β-estradiol standard stock solution: Accurately weigh 01 g of β-estradiol, dissolve it in methanol, and dilute it to a 100 mL volumetric flask to make a standard solution with a concentration of 100 μg/mL, and store it at -18°.
11 β-estradiol internal standard stock solution: Accurately weigh 01 g of β-estradiol-D2, dissolve in methanol, and dilute to a 50 mL volumetric flask to make a standard solution with a concentration of 200 μg/mL, at -18° C storage, the storage time does not exceed 6 month.
12 β-estradiol standard working solution: before use, accurately draw the β-estradiol standard stock solution, dilute it with methanol to a concentration of 005μg/mL~25μg/mL standard working solution, and temporarily store it at 4°.
13 β-estradiol-D2 internal standard working solution: Before use, accurately draw the internal standard standard stock solution, dilute it with methanol to a standard working solution with a concentration of 05 μg/mL, and temporarily store it at 4°.
14 Derivatization reagent: accurately weigh 01g dithioerythritol (DTE), dissolve it in 5mL N-methyltrimethylsilyl trifluoroacetamide (MSTFA), and then add 10μL trimethyl Iodosilane (TMIS), mixed well, placed at 4°C overnight before use, and stored in a sealed container away from light and moistur.
The derivatization reagent should be colorless, if there is a color change such as brown-red, it indicates that the reagent is invali.
5 Instruments
1 Gas chromatography single quadrupole mass spectrometer: equipped with electron impact ionization (EI) ion sourc.
2 Electronic balance: Sensitivity 0001.
3 Vortex mixe.
4 High-speed refrigerated centrifuge: the maximum speed is 10 000r/mi.
5 Solid phase extraction apparatu.
6 Nitrogen blowe.
7 Centrifuge tube with stopper: 50m.
8 Chicken heart bottle: 50m.
9 Glass tube with stopper scale: 10m.
10 C18 solid phase extraction column: packing 500mg/3mL, choose Cleanert ODSC18 (end-capped), or equivalen.
11 Sample reaction vial: 2mL, deactivated, threade.