Determination of 5 cephalosporins in puffer fish and eels by liquid chromatography-tandem mass spectrometry

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1 Scope of application

Suitable fugu and eels cefazolin , cephapirin , cephalexin, CTP, cefquinome residues in liquid chromatography - tandem mass spectrometry
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2 Principle of the method

Fugu and eels cefazolin, cephapirin, cephalexin, CTP, cefquinome residue was extracted with acetonitrile removed by rotary evaporation acetonitrile , water volume, liquid chromatography - tandem mass spectrometer, the external standard method Quantitative
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3 Reagents and materials

Methanol and acetonitrile: chromatographically pure; acetic acid and n-hexane are analytically pure: acetonitrile saturated n-hexane: take 100 mL of n-hexane and 50 mL of acetonitrile in a 250 mL separatory funnel, shake for 1 min, stand still for layering, discard the acetonitrile
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Cefazolin, Cefpirin, Cefalexin, Cefalonine, Cefquinoxime Standard Substances Purity ≥9%
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0mg/mL 5 kinds of cephalosporin standard stock solutions: accurately weigh an appropriate amount of each standard substance and prepare a standard stock solution with a concentration of 1.
0mg/mL with water
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5 kinds of cephalosporin standard mixed working solution: draw an appropriate amount of each cephalosporin standard stock solution as needed, and dilute with water to form a standard mixed working solution of appropriate concentration
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4 Instruments and equipment

Liquid chromatography-tandem quadrupole mass spectrometer: equipped with electrospray ion source; analytical balance: sensitivity 0.
1mg, 0.
01g; homogenizer; micro syringe: 25μL, 100μL; graduated sample tube: 5mL, accuracy of 0.
1mL ; High-speed refrigerated centrifuge: with a 50mL centrifuge tube with stopper, the speed can reach more than 10000r/min; nitrogen concentrator
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5 Sample pretreatment

(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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(2) Preparation of sample solution

Weigh 5g of sample (accurate to 0.
01g) into a 50mL centrifuge tube, add 20mL of acetonitrile, homogenize with a homogenizer for 1min, and centrifuge the extract with a high-speed refrigerated centrifuge at 10℃, 10000r/min for 10min, and extract the upper layer Transfer the liquid to another centrifuge tube
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(3) Preparation of blank sample and standard mixed working solution

Accurately pipette appropriate amounts of 5 kinds of cephalosporin standard mixed working solutions, add them to 5.