Determination of 9 glucocorticoid residues in puffer fish, eels and grilled eels by liquid chromatography-tandem mass spectrometry

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Suitable for 9 glucocorticoids in puffer fish, eels and grilled eels ( prednisolone , prednisone , hydrocortisone , cortisone, methylprednisolone , betamethasone, dexamethasone , dexamethasone ) Determination of the residual content of clomethasone and fludrocortisone acetate by liquid chromatography-tandem mass spectrometry

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Prednisolone, prednisone, hydrocortisone, cortisone, methylprednisolone, betamethasone, dexamethasone, beclomethasone, fludrocortisone acetate in puffer fish, eels and grilled eels The 9 kinds of glucocorticoid residues of pine were added with anhydrous sodium sulfate and extracted with ethyl acetate.

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Methanol , acetonitrile, ethyl acetate, n-hexane, acetone: chromatographically pure; formic acid: excellent grade

Acetone-n-hexane solution: acetone+n-hexane (2+3, v/v)

Prednisolone, prednisone, hydrocortisone, cortisone, methylprednisolone, betamethasone, dexamethasone, beclomethasone, fludrocortisone acetate (CAS: 514-36- 3) Standard material: purity ≥98%

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Mixed standard working solution I: Draw appropriate amounts of hydrocortisone and cortisone standard working solutions, and use methanol to prepare a mixed standard working solution with a concentration of 0.

Mixed standard working solution II: Draw appropriate amounts of prednisolone, prednisone, methylprednisolone, betamethasone, dexamethasone, beclomethasone, fludrocortisone acetate standard working solutions, respectively, and mix with methanol It is a mixed standard working solution of prednisolone, prednisone, methylprednisolone, betamethasone, and dexamethasone at 0.

Matrix mixed standard working solution: When measuring the sample, use the blank sample extract to prepare the mixed standard working solution II into matrix mixed standard working solutions of different concentrations

Cleanert Silica solid phase extraction column or equivalent: 500mg, 6mL

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Liquid chromatography-tandem mass spectrometer: equipped with electrospray ionization source (ESI); analytical balance: sensitivity 0.

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5 Sample preparation

(1) Sample preparation

Take out a representative sample of about 1 kg from all the samples, fully mash, mix, and divide them into two parts, and put them into clean containers
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Seal it as a sample and mark it
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During the operation of sampling and sample preparation, the samples should be prevented from being contaminated or from changing the content of residues
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The samples were frozen and stored at -18°C
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(2) Extraction

Weigh 5g of the sample (accurate to 0.
01g), place it in a 50mL plastic centrifuge tube with a stopper, add 10g of anhydrous sodium sulfate, add 25mL of ethyl acetate, homogenize with a homogenizer for 1 min, and shake in a shaker for 20 min.
Centrifuge at 10000r/min for 10min, and transfer the supernatant to a pear-shaped bottle
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Extract again with 25 mL of ethyl acetate, combine the supernatants, evaporate to near dryness under reduced pressure on a 45°C water bath with a rotary evaporator, and dissolve with 1 mL of ethyl acetate and 5 mL of n-hexane
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(3) Purification

The extract was transferred to the pretreated Cleanert Silica solid phase extraction column, and the pear-shaped flask and extraction column were washed with 6 mL of n-hexane, and all the effluent was discarded
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Drain under reduced pressure for 1 min, eluted with 6mL acetone+n-hexane (2+3, v/v), collect the eluate in a 10mL sample tube, blow dry with a nitrogen concentrator, and dissolve the residue with 1mL 20% acetonitrile solution.
Centrifuge at 4000r/min for 5min, and pass the supernatant through a 0.
2μm filter membrane for liquid chromatography-tandem mass spectrometer determination
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