毛细管区带电泳法快速测定食品中的金属硫蛋白

 采用毛细管区带电泳法 (CZE) ,以 5 0cm× 75 μmi d 毛细管柱作为分析柱 ,0 .0 2mol/L磷酸二氢钠 0 .0 2mol/L磷酸氢二钠混合体系 (pH 7.0 )作为背景电解质 ,以紫外检测器在波长 2 0 0nm的条件下检测 ,对具有生物活性的金属硫蛋白 (MT)的两种异构体 (MT1,MT2 )进行了分离。样品经过预处理后 ,采用外标法可对食品中的金属硫蛋白进行定量测定。该方法的最低检测质量浓度为 1mg/L ,相对标准偏差低于 10 % ,加标回收率为 82 .0 %～93.4%。     

SYNTHESIS, CHARACTERIZATION AND CATALYTIC ACTIVITY OF N,N''-BIS(3-ALLYL SALICYLIDENE)ETHYLENEDIAMINE COBALT(II) SCHIFF BASE COMPLEX ANCHORED ON A NEW POLYMER SUPPORT

A new chelating polymer support has been prepared by suspension copolymeriz a tion of synthesized N,N'-bis(3-allyl salicylidene)ethylenediamine monomer Schiff base (N,N'-BSEDA) with styrene (St) and divinylbenzene (DVB) using azobisisobutyronitrile (AIBN) as initiator in the presence of poly(vinyl alcohol). The content and complexation ability of monomer Schiff base (N,N'-BSEDA) for cobalt(II) ions in prepared crosslinked polymer beads have shown dependence on the amount of DVB used in reaction mixture. The amount of monomer Schiff base (N,N'-BSEDA) in crosslinked beads showed a substantial decreasing trend at high concentration of DVB in the reaction mixture (＞ 1.5 mol dm-3), hence the efficiency of complexation (EC%) and cobalt(II) ion loading (EL%) of polymer beads showed a decreasing trend. The structure of monomer Schiff base (N,N'-BSEDA) and its cobalt(II) complex on polymer support was elucidated by IR, UV and magnetic measurements. The catalytic activity of polymer bound cobalt(Ⅱ) Schiff base complex was evaluated by analyzing kinetic data of decomposition of hydrogen peroxide in the presence of either supported cobalt (II) complex or free cobalt(II) complex. The activation energy for the decomposition of hydrogen peroxide by polymer supported cobalt(II)complex was found to be low (33.37 kJ mol-l) in comparison with unsupported cobalt(II) complex (56.35 kJ mol-1). On the basis of experimental observations, reaction steps are proposed and a suitable rate expression derived.     

离子对高效液相色谱法对人工合成色素的分离和测定

本文介绍了用离子对反相液相色谱法对五种常用合成色素日落黄、苋菜红、胭脂红、亮蓝、柠檬黄的测定方法。5μm Zorbax-ODS 4.6mm×15cm柱;以含对离子试剂四丁基溴化铵0.005mol/L的甲醇:水=50:50(v/v)为流动相在10min内可全部出峰。回收率为92.2％～105.5％,相对标准偏差为3.1％。     

高效液相色谱-串联质谱法同时检测动物性食品中多种大环内酯类药物

高效液相色谱-串联质谱法同时检测动物性食品中6种大环内酯类药物泰乐霉素、交沙霉素、柱晶白霉素、螺旋霉素、替米考星和红霉素残留。样品经乙腈提取,C18固相萃取柱净化,以0.1%(φ)甲酸-乙腈和0.1%(φ)甲酸-水作流动相梯度洗脱。电喷雾正离子MRM模式检测,罗红霉素作为内标。方法的定量下限为20μg/kg。在2~50μg/L范围内,峰面积与质量浓度成良好的线性关系,相关系数大于0.999。样品在20、100、200μg/kg添加水平的回收率为70%~110%,相对标准偏差为4.1%~10.3%(n=6)。方法灵敏、检出限低、实用性强。     

高效液相色谱法测定食品中抗氧化剂BHA,BHT,PG

用反相高效液相色谱法同时测定了食品中抗氧化剂丁基羟基茴香醚（ＢＨＡ）、二丁基羟基甲苯（ＢＨＴ）和焦性没食子酸丙酯（ＰＧ）。样品用正己烷提取，氮气吹干，水－乙醇（１４，Ｖ／Ｖ）溶解残留物，经０．５μｍ滤膜过滤，直接进样。方法简便、快速、回收率高、重现性好。     

Synthesis of GR 125487, a selective 5-HT4 receptor antagonist

The 5-HT₄ receptor (5-HT₄R) agonists are important in treating gastrointestinal motility disorders. Their role is currently being evaluated for the treatment of cognitive and mood disorders. A selective 5-HT₄R antagonist GR 125487 is used in many biological assays to cross confirm the 5-HT₄R agonist’s activity. A practical synthesis of GR 125487 is developed so as to have it in desired quantities. The synthesis consists of seven steps starting from commercially available methyl 5-fluoroindole 3-carboxylate. The GR 125487 thus synthesized was used in blocking the activity of 5-HT₄R agonist compound in animal models of cognition.     

ICP-AES法快速测定不锈钢食具容器中重金属的迁移量

采用ICP–AES法快速测定不锈钢食具容器中的重金属铅、铬、镍、镉和砷的迁移量。样品用4%乙酸溶液浸泡,ICP–AES法测定浸泡液中铅、铬、镍、镉、砷的含量。铅、铬、镍、镉、砷的质量浓度分别在0.03~0.30,1.0~5.0,0.3~2.0,0.015~0.20,0.020~0.30 mg/L范围内与其光谱强度线性相关,相关系数均大于0.999 6。铅、铬、镍、镉、砷的检出限分别为0.009,0.000 5,0.002,0.000 5,0.007 mg/L,加标回收率分别为100.0%~122.5%,100.0%~115.0%,99.0%~117.5%,108.0%~115.0%,60.0%~68.8%,测定结果的相对标准偏差为0.2%~5.0%(n=6)。结果表明,该方法能够满足对不锈钢食具容器中重金属迁移量的快速测定要求,可应用于食品相关产品的监管工作。     

应用ICP-MS检测转Bt基因玉米中重金属含量

随着转基因食品的推广应用,人们越来越关心其食用安全性。以转基因玉米及其亲本为实验材料,借助于ICP-MS对转基因玉米及其亲本中重金属进行了测定。结果显示,外源基因的整合导致了转基因玉米重金属(Ni,Cu,Cd,As,Cr,Zn和Hg)含量显著低于亲本对照,两对转基因抗虫玉米及其亲本对比结果相似;但是有的重金属(V,Co,Pb)含量与对照相比变化没有明显规律。这些结果说明转Bt基因玉米籽粒中重金属含量会受到Bt基因的影响,但是影响的方向和机理上不清楚,所以转基因技术如果控制不严可能会对玉米的食用安全性产生不良影响,转基因植物的推广应用应当严格审查。具体发生上述变化的原因尚需要进一步研究。     

新资源食品中微量元素测定方法的研究

用硝酸-高氯酸消解样品,用火焰原子吸收光谱法测定新资源食品葛根、葛花、四叶参、仙人掌、菊花、小麦胚和蚕蛹中Cu,Zn和Fe元素的含量,并对其结果进行了分析。结果显示： 在选定的实验条件下,测定方法的回收率为94.66%～105.24%,测定Cu,Zn和Fe的精密度RSD分别为1.79％,0.71%和4.78%。建立的原子吸收光谱法简便、快速、灵敏、准确。经F检验与SNK检验,河南省新资源食品葛根、葛花、四叶参、仙人掌、菊花、小麦胚和蚕蛹中微量元素Cu,Zn和Fe含量分别为： 铜的分布量依次为: 菊花≈蚕蛹＞葛花≈小麦胚≈四叶参≈葛根＞仙人掌,锌的分布量依次为： 仙人掌＞蚕蛹≈葛花≈葛根≈小麦胚≈四叶参≈菊花;铁的分布量依次为： 蚕蛹≈菊花≈葛根＞葛花≈小麦胚≈四叶参≈仙人掌。     

淋洗液自动发生-离子色谱法同时测定食品中的21种有机酸

建立了一种利用离子色谱法同时测定样品中奎尼酸、乙酸、丙酮酸、草酰乙酸、甘露酸、乳酸、琥珀酸、苹果酸、酒石酸、草酸、富马酸、抗坏血酸、α-酮戊二酸、肉桂酸、水杨酸、柠檬酸、异柠檬酸、阿魏酸、顺乌头酸、反乌头酸、β-香豆酸等21种有机酸的方法。样品经提取、脱色、过滤后用IonPac AS11分离柱分离,以EG40自动淋洗液发生器生成的5~34 mmol/L KOH为淋洗液洗脱,抑制电导检测器检测。21种有机酸的浓度与其峰面积在一定的范围内呈良好的线性关系,检出限均低于0.188 mg/L,加标回收率为91.5%~101.8%。该法用于多种食物样品中有机酸的测定,结果令人满意。