建立了基于QuEChERS技术结合固相萃取(Solid-phase extraction,SPE)的气相色谱/四极杆-飞行时间串联质谱法(Gas chromatography-quadrupole time of flight mass spectrometry,GC-Q-TOF/MS)对牛奶中的11种有机磷农药(速灭磷、甲拌磷、二嗪磷、甲基对硫磷、杀螟硫磷、水胺硫磷、溴硫磷、杀扑磷、p,p'-DDE、三唑磷、p,p'-DDT)残留量进行测定.称取牛奶,以10 mL乙腈提取后,盐析离心,氮吹,乙酸乙酯复溶,氮吹浓缩.乙酸乙酯层用石墨化炭黑(Graphitized carbon black,GCB)固相萃取柱净化后,供GC-Q-TOF/MS测定.采用电子轰击离子源(Electron ionization,EI)进行电离,质谱飞行时间模式对目标母离子和子离子进行测定.结果表明,11种有机磷类农药在浓度为10～500μg/L的基质曲线范围内呈良好线性关系.该方法具有操作简便、快速高效、回收率高、灵敏度高、重复性好等优点,可用于测定牛奶的11种有机磷类农药残留量.

Although it is difficult to immunize animals with antibiotics as half-antigens for antibody generation,immunoassay techniques have become the most popular methods for detecting antibiotics in foods and environment,such as commercially available chloramphenicol and neomycin test kits.Nevertheless,actual applications of immunoassay techniques are limited due to the wide variety of antibiotics,high cost of preparing antibodies against some antibiotics,difficulties in large-scale screening of samples and low sensitivity of these techniques.Aptamers,also named chemical antibody,are single stranded DNA or RNA ligands,which can be bound to different targets from a huge library of molecules containing randomly created sequences with high specificity and affinity.Aptamers have some advantages over conventional immune antibodies,such as easy in vitro selection by their target molecules,the possibility of chemical synthesis and modification and high stability.This paper describes the finding history of aptamers,methods for selecting them,their characteristics and techniques established based on them for the detection of antibiotics and other small molecules.Furthermore,application perspectives of the aptamers based detection techniques are proposed.

目的:探讨富油食品中饱和脂肪含量的测定方法.方法:以索氏提取法提取了饼干、月饼等富油食品脂肪,采用甲醇-氢氧化钾甲酯化,利用气相色谱-质谱法分别测定上述食品中脂肪酸的具体组成,用归一化法定量,计算饱和脂肪含量.结果:饼干的脂肪酸以十四酸(27.8%)和亚油酸(32.7%)为主;而月饼的脂肪酸以十六酸(38.8%)和亚油酸(35.0%)为主,两者的不饱和酸均为油酸和亚油酸,且都以亚油酸为主.结论:气相色谱-质谱法测定富油食品中的饱和脂肪,具有简便、快速、准确等特点,适合批量富油食品饱和脂肪的测定.

山梨酸及其钾盐,毒性小,抗菌力强,是月饼中最常使用的防腐剂.目前,山梨酸的测定方法主要有气相色谱法、高效液相色谱法和薄层色谱法[1].由于月饼中蛋白质及油脂含量高,直接用乙醚萃取气相色谱测定,萃取效率低;用玻璃纸层析除去蛋白脂肪,回收率低且费时.本文根据山梨酸具有挥发性的特点[2],采用水蒸气蒸馏法,除去蛋白质及油脂,用高效液相色谱法测定,结果准确,重现性好.

应用XGY-1012型原子荧光光度计测定内墙涂料中的汞含量,指出硼氢化钾、酸度、炉温等对测定结果的影响,在最佳条件下,检出限为0.91μg/kg,加标回收率为94%～97%.

Extract from mature and premature Litchi pericarp showed strong antioxidative activity,which is concentration dependent,0.04% extract shows higher antioxidative activity than that of 0.02% BHT.Phosphoric acid demonstrated synergistic effect to antioxidativ activity.Antioxdative components were determined to be phenolic compounds and flavonoids.

采用氢化物发生-原子荧光光谱法测定饮料中砷的含量,研究硼氢化钾浓度、盐酸浓度等因素对测定结果的影响,建立饮料中微量砷的适宜分析条件.方法检测限为 0.60μg/kg,回收率在 93%～96%之间.

用索氏提取器以正己烷、乙酸乙酯、φ(C2H5OH)=95%的乙醇依次提取成熟荔枝皮2、2、4 h,提取率分别是3.66%、1.43%、9.35%,添加相当于猪油质量0.02%的此3种提取物于猪油中,正己烷、乙酸乙酯提取物可使猪油的氧化酸败的时间延长2.6倍以上,φ(C2H5OH)=95%的乙醇提取物可延长1.7倍以上.以φ(C2H5OH)=95%的乙醇提取成熟荔枝皮6 h,提取率为12.24%,添加此提取物为猪油质量0.04%,在猪油中的抗氧化效果优于0.02%的BHT,且提取物的抗氧化性随添加量的增加而增强.以φ(C2H5OH)=95%的乙醇室温浸提未成熟荔枝(生理落果)皮4 d,提取率达28.7%以上,抗氧化性也很强.经层析分离﹑化学显色初步推断荔枝皮抗氧化成分中有酚酸、黄酮类物质.

采用Kromasil C18(4.6×200mm)柱同时分离了硝基苯甲酸与氨基苯甲酸六种异构体,在不到7min的时间内,硝基苯甲酸与氨基苯甲酸异构体在0.1～1.0g/L 浓度范围内,得到了良好分离.

p ,m ,o )Nitrobenzoic acids and nitrotoluene were separated by OV-101 capillary column using internal standard method .The results of quantative analysis is better.