建立液相色谱串联质谱法快速测定鸡肉和鸡肝中氯苯胍残留量.样品经过前处理条件优化,确定了最优条件:采用2％甲酸乙腈提取,正己烷脱脂净化,净化液经水稀释后过0.22μm尼龙滤膜.质谱检测采用正离子多反应监测模式测定,外标法定量.结果 表明在1.00～20.0 μg/L浓度范围内氯苯胍有良好的线性关系(r＞0.99).方法 的检出限为5.00 μg/kg,定量限为10.0 μg/kg,平均加标回收率为71.9％～110％,相对标准偏差在1.58％～8.68％之间.该方法操作快速、简便、准确,适用于鸡肉和鸡肝中氯苯胍残留量的快速测定.

The molecular structure and physicochemical property of common aminogly-cosides(AGs)antibiotics were systematically analyzed and the residue of animal origin foodstuffs as well as the corresponding damage on human body with long-term intake were introduced.Concrete ideas of the study were raised based on the analysis of pres-ent analytical approaches and the discussion of existing defects.An HPLC-MS/MS analytical method was developed for the simultaneous determination of aminoglycosides (spectinomycin,hygromycin B,dihydrostrepmycin,streptomycin,amkacin,kanamy-cin,apramycin,tobramycin,gentamicin)with a new hydrophilic HPLC column.The residues of aminoglycosides in the test samples were extracted with phosphate buffer solution.After ajusting pH values,the samples were cleaned up with SupelMIP ?SPE column,concentrated and reconstituted,the residues were separated by Obelisc R HPLC column(2.1 mm×150 mm×5 μm,100 ?)by gradient elution with acetonitrile-water(1% formic acid)as mobile phase,and detected by liquid chromatography-mass spectrometry under multiple reaction monitoring(M RM)mode via positive-ion mode. All the analytes were calibrated by the external method.The matrix effects were evalua-ted by comparing solvent prepared standards to matrix-matched standards.T he effects of different solid-phase extraction(SPE)columns were optimized.The use of the SupelMIP SPE-Aminoglycoside cartridge kept the analytes bound to the sorbent while a series of aggressive washes were applied to the sorbent to eliminate matrix interfer-ences.The Obelisc R column has reverse phase property and could be applied to conven-tional reverse phase conditions.It had high density of positive and negative ions on a stationary-phase surface,its adsorption capacity in polar compounds could be greatly improved compared with the traditional revers-phase chromatographic column.This allows retaining polar compounds without using ion-pairing reagents.The content of acetonitrile and pH of buffer were adjusted so that the 9 AGs were better retained and separated.The results showed that all the aminoglycosides had good linearity in the range of 20-1 000 μg/L,and the correlation coefficients(R2)were greater than 0.99. The limits of quantification(LOQs)of the nine targets are 50 μg/kg.The average recoveries range from 76.9% to 89.4% for the 9 targets at three spiked levels in pork, and the relative standard deviations were 3.56%-11.4%.This method is proved to be highly sensitive,accurate and reproducible,and it is suitable for the detection of amin-oglycosides in pork.

In this paper,we first applied compound magnetic nanoparticle Fe3O4@Si-C8/C18 to purify veterinary drugs,and co-precipitation method was employed to synthesize the precursor of magnetic nanoparticles.The surface of nanoparticle precursor was silicified in ethanol and modified with C8(octyltrimethoxysilane)/C18(octadecyltrimethoxysilane) to prepare composite magnetic nanoparticle Fe3O4@Si-C8/C18.The compound magnetic nanoparticles were characterized by TEM,X-ray,magnetic performance analysis,and infrared spectroscopy.These compound magnetic nanoparrticles revealed high uniformity with adjustable particle diameters of 100-1000 nm.Therefore,after several layer-by-layer modifications,the compound magnetic nanoparticle revealed the same magnetic intensity as its original precursor.In order to validate their application possibility in the purification of veterinary drugs,purification of chloramphenicol residues in bean sprout was conducted using these magnetic nanoparticles.The results demonstrated that these compound magnetic nanoparticles had extensive application value for the purification and enrichment of micromolecules,especially in the field of food safety.

将Fe3O4@Si-C8/C18复合磁性纳米材料应用于食品安全中的兽药净化领域,采用共沉淀法制备磁性纳米前躯体,并在乙醇相中进行表面硅化处理及（辛基三甲氧基硅烷）C8/（十八烷基三甲氧基硅烷）C18表面修饰,经透射电镜、X射线、磁性能分析、红外光谱等手段对所制备的复合磁性纳米进行表征,所制备的磁性纳米大小均匀,粒径在100～1000nm范围内可调,经多重修饰后的Fe3O4@Si-C8/C18复合磁性纳米材料其磁性强度没有明显降低,并具有表面富集功能。为考察这种磁性纳米材料在兽药提取中的应用,选取豆芽中氯霉素残留的净化来进行初步研究,结果表明所制备的复合型磁性纳米材料在小分子净化富集中展现出广阔的应用价值,尤其在食品安全领域。

A confirmative method is developed with high-performance liquid chromatography tandem electrospray mass spectrometry (LC/MS/MS) to detect 5 residues of phenothiazines in aquatic products, which include chlor-promazine, acepromazine, propriopromazine, promethazine and xylazine. In the method, the 5 residues are extracted with alkalized acetonitrile, cleaned with HLB solid phase extraction column. Then the reconstituted sample solution is analyzed by LC/MS/MS in positive mode, with YMC-Pack Pro C18 column as the sepa.ration column. The meth-od is validated at 1.0, 2.0 and 4.0 ng/g. The validation results are as following, the linear range is from 0.5 ng/g to 5.0 ng/g; the overall recovery varies from 75.7% to 87.7%, and the relative standard deviation (RSD) is be-tween 9.0% and 15.2%. The method is simple, rapid, and accurate, and simultaneously confirm residues of phe-nothiazines in aquatic products.