【作者】 郑军红；

【导师】 王明林；

【作者基本信息】 山东农业大学 ， 食品科学， 2009， 硕士

【摘要】 随着乳制品消费量的增加,人们对乳制品安全提出更高要求,农药的广泛应用所引起的食品安全性问题业已受到了人们的普遍关注,农药残留是影响乳制品安全的因素之一。目前,牛奶和奶粉中农药残留分析方法的研究主要集中于单残留或选择性多残留,缺少农药多残留检测方法和新技术的应用。建立一套快速、高效的能应用于牛奶和奶粉生产及流通各环节中农药多残留的检测方法己成为亟待解决的问题。本文利用固相萃取技术(SPE)进行样品前处理,以高效液相色谱-串联质谱作为检测手段,建立起牛奶和奶粉中包括有机磷类、有机氯类和拟除虫菊酯类等285种农药及相关化学品的分析方法。具体结果如下:(1)牛奶中农药的检测方法:取10 mL牛奶,加入20 mL乙腈、4 g硫酸镁和1 g氯化钠,振荡后离心分离,收集有机相层,重复提取两次,合并有机相。提取液浓缩后经C18固相萃取柱净化以除去亲脂性化合物等干扰杂质。收集洗脱液并浓缩至0.5 mL左右,于45℃下氮气吹干,用1 mL乙腈-水(3:2,V/V)溶解残渣,溶液经微孔滤膜过滤后,供液相色谱—串联质谱仪(ESI源)测定。添加回收结果表明,牛奶样品在0.05μg/L ~ 1.12 mg/L的添加范围内,平均回收率在60.42 %～119.57 %之间共有258个,占所测总农药及相关化学品总数的91.8 % ,相对标准偏差RSD < 20 %的共有246个,占所测农药及相关化学品总数的87.5 %;在0.2μg/L～4.48 mg/L添加范围内,得到的平均回收率在60.32 %～118.52 %共267个,占所测农药及相关化学品总数的95.0 %,相对标准偏差RSD < 20 %的共有263个,占所测农药及相关化学品总数的94.2 %。(2)奶粉中农药的检测方法:取3 g奶粉,加入20 mL乙腈、4 g硫酸镁,均质后离心分离,收集提取液,重复提取两次,合并提取液。提取液浓缩后经C18固相萃取柱净化以除去亲脂性化合物等干扰杂质。收集洗脱液并浓缩至0.5 mL左右,于45℃下氮气吹干,用1 mL乙腈-水(3:2,V/V)溶解残渣,溶液经微孔滤膜过滤后,供液相色谱-串联质谱仪(ESI源)测定。添加回收结果表明,奶粉样品在0.17μg/kg～3.73 mg/kg的添加范围内,平均回收率在60.27 %～119.55 %之间的有236个,占所测总农药及相关化学品总数的84.6 %,相对标准偏差RSD < 20 %,有244个,占所测总农药及相关化学品总数的87.5 %;在0.67μg/kg～14.93 mg/kg添加范围内,得到的平均回收率在60.11 %～115.13 %共252个,占所测总农药及相关化学品总数的90.3 %,相对标准偏差RSD < 20 %,有260个,占所测农药总数的93.2 %。(3)使用本研究所建立的方法,能共同测定的为275种,另外有6种只适合在牛奶基质中测定,有4种只适合在奶粉基质中测定。牛奶和奶粉的方法检出限(LOD)分别为:0.05μg/L～0.56 mg/L之间和0.08μg/L～1.87 mg/L之间。该方法具有操作简单,实用性强,易于推广等特点,能适应当今社会的需求、食品质量安全的需要。更多还原

【Abstract】 With the increasing consumption of milk products, analysts are paying increasing attention to the study of techniques for analysis of pesticide residues in milk and milk powder products. However, according to the study of the current status, milk and milk powder in the presence of pesticide residue analysis was obviously inadequate. Most studies focused on single residue or selective multi-residue residues, lacked of multi-pesticide residues detection methods and new technologies. Establishing a rapid and efficient multi-pesticide residues determination method for milk products has become urgent problem to solve.In this study, solid phase extraction (SPE) was chosen for sample processing, and LC-MS/MS was chosen as detecting technique, establishing a determination method for 285 pesticides (including organophosphate, organochlorine, pyrethroid category, and so on) in milk and milk powder. Experimental results and conclusions were as follows:(1) Determination method for pesticides residues in milk: Adding 20 mL acetonitrile, 4 g of magnesium sulfate and 1 g NaCl into 10 mL milk, shaking, and then separating by centrifuge, collecting the supernatant, extraction processing was repeated two times. Then cleaned up by a C18 solid phase extraction cartridge to remove the lipophilic compounds after the supernatant concentrated with a rotary evaporator. Eluate was collected, and concentrated at 45℃under dry nitrogen. The 1 mL mixture of acetonitrile and water (3:2,V/V) was added to the sample and mixed thoroughly for 30 s. The sample solution was filterd by millipore filters before liquid chromatography-tandem mass spectrometry (ESI source) determination. The the average spiking recoveries in milk martrix for 281 kinds pesticides at low level (0.05μg/L ~ 1.12 mg/L ) there were 258 kinds in the range 60.42 % ~ 119.57 %, and 246 kinds with RSDs < 20 %; the average spiking recoveries at high level (0.2μg/L ~ 4.48 mg/L) there were 267 kinds in range 60.32 % ~ 118.52 %, and 263 kinds with RSDs < 20 %.(2) Determination method for pesticides residues in milk: Adding 20 mL acetonitrile, 4 g of magnesium sulfate into 3 g milk powder, shaking, and then separating by centrifuge, collecting the supernatant, extraction processing was repeated two times. Then cleaned up by a C18 solid phase extraction cartridge to remove the lipophilic compounds after the supernatant concentrated with a rotary evaporator. Eluate was collected, and concentrated at 45℃under dry nitrogen. The 1 mL mixture of acetonitrile and water (3:2,V/V) was added to the sample and mixed thoroughly for 30 s. The sample solution was filterd by millipore filters before liquid chromatography-tandem mass spectrometry (ESI source) determination. The the average spiking recoveries in milk powder martrix for 279 kinds pesticides and related chemicals at low-level (0.17μg/kg ~ 3.73 mg/kg ) there were 236 kinds in the range 60.27 % ~ 119.55 %,and 244 kinds with RSDs < 20 %, the average spiking recoveries at high level (0.67μg/kg ~ 14.93 mg/kg ) ther were 252 kinds in the range 60.11 % ~ 115.13 % ,and 260 kinds with RSDs < 20 %.(3) The results also shown that the method established by this study, 275 kinds of pesticides are suitable for the determination of milk and milk powder matrix, 6 other kinds of pesticide are only suitable for the determination of milk matrix , and 4 kinds of pesticides are only suitable for species measured in the milk powder matrix. The detection limits of milk and milk powder martrix were during 0.05μg / L ~ 0.56 mg / L and 0.08μg/kg ~ 1.87 mg/kg.The results demonstrated that this method is simple, rapid and character-ized with acceptable sensitivity and accuracy to meet the requirements of the multiple pesticide residue analysis.更多还原