Study On Simultaneous Determination Of 42 Steroid Hormones In Dairy Product By UPLC-MS/MS Via QuEChERS

In addition to endogenous progestogen and estrogen in milk and powdered milk,all other chemical synthetic hormones are banned.At present,the method of detecting the hormone residue in dairy products is rarely reported,and authoritative detection national standard has not been released.Ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)is an important method to analyse hormone residues in animal-derived foods,which has high sensitivity,selectivity and specificity,and can be well confirmed for low concentrations of samples and has been used in the determination of hormones in samples with complex matrices.In this study,the dispersion solid phase extraction technology(Qu ECh ERS)was applied and improved for sample pretreatment.Combining with ultra high performance liquid chromatography-tandem mass spectrometry,the method for the detection of 42 kinds of steroid residues in milk and milk powder was established,which was simple,fast and accurate,it filled the gaps in the detection of steroid residues in milk powder.The results were analyzed and evaluated,and the monitoring measures were put forward.The main results are as follows:(1)A modified Qu ECh ERS pretreatment method for the rapid determination of 42 steroid residues in dairy products was established.After optimization,0.1% formic acid acetonitrile was identified as the best extraction solvent for the steroid hormones in dairy products.The pretreatment approach,which combines 50 mg of octadecylsilane(C18),100 mg of pisum sativum lectin(PSA),300 mg of aluminum oxide(Al2O3-N)and 300 mg of magnesium sulfate anhydrous(Mg SO4),produced a clear extraction solution.The interference of the substrate was small,and the recovery rate was good.Formic acid acetonitrile of 40%was determined to be the constant volume liquid of this method,which can produce the highest response and excellent shape for the 42 kinds of hormones.(2)The determination conditions for the steroid hormones in dairy products by ultra performance liquid chromatography tandem mass spectrometry were determined.Acetonitrile with 0.1% formic acid water was the best mobile phase,which can provide the best ionization condition,the strongest peak signal,and the highest sensitivity.A segmented scanning MRM mass spectrometry method for the determination of 42 steroid hormones in infant formula milk powder and milk by high performance liquid chromatography tandem mass spectrometry was established.By optimizing the parameters of capillary voltage,cone voltage,ion source temperature,solvent temperature and flux,enough scanning frequency per unit scanning time was guaranteed,which reduced the interference of compounds,and yields accurate andreliable results.(3)The correlation coefficients for the 42 kinds of steroid hormones were larger than 0.99 in the linear range of 0.5~500?g/L.In milk and powdered milk,3 levels of steroid hormones were added(n=6),and the recovery rates were 70.3%~118.1%,and the relative standard deviations were 0.6%~14.7%.(4)The risk monitoring data of 42 kinds of steroid hormone residues showed that 40 kinds of glucocorticoid(prednisone,beclomethasone,hydrocortisone,etc.)were not detected in 48 batches of dairy products.Only progesterone was detected for the other two pregnancy hormone.And the detection rates of progesterone in milk powder and milk were 95.8% and20.8% respectively.The concentration of progesterone in most of the milk powders was below 20?g/kg with the highest concentration at 23.8?g/kg.The concentration of progesterone in all milk products was less than 1?g/kg with the highest concentration at0.8?g/kg,and progesterone was not detected in most samples.The results showed that progesterone generally exists in milk powder products.However,it was rarely detected in milk products;For samples with positive detection,the concentration was relatively small.(5)Supervision on the quality of dairy products was discussed and explored from the perspective of the government supervision,enterprise self-discipline,media supervision and consumer guidance.