软骨藻酸分子印迹聚合物的制备及其固相萃取应用

以贝毒-软骨藻酸的结构类似物1,3,5-戊烷三羧酸为模板分子,4-乙烯基吡啶为功能单体,乙二醇二甲基双丙烯酸酯为交联剂,合成了对软骨藻酸具有较好选择性的分子印迹聚合物。经索氏提取去除模板分子后,在聚合物内部形成了与模板分子1,3,5-戊烷三羧酸以及结构类似物软骨藻酸尺寸、形状以及活性基团互补的结合位点。通过静态平衡结合实验研究了该聚合物的结合能力和选择性能,与化学组成相同的相应非印迹聚合物相比,1,3,5-戊烷三羧酸的分子印迹聚合物对软骨藻酸具有较高的吸附性能和选择性。用150mg印迹聚合物填充于1.0mL玻璃注射器制成的分子印迹固相萃取柱,采用离线模式,并结合高效液相色谱实现紫贻贝和海水中软骨藻酸的分离与检测。对于加标2mg/L的紫贻贝和海水样品,回收率分别达到(93.4±4.9)%和(89.7±3.2)%(n=3)。     

Development of a High Performance Liquid Chromatography-Tandem Mass Spectrometry Method for Determination of Lipophilic Toxins in Marine Shellfishes and Edible Safety Evaluation

At present, edible marine shellfishes are often contaminated by a combination of different kinds of marine lipophilic toxins. In this study, several common lipophilic shellfish toxins (LSTs) in marine shellfishes were simultaneously detected by liquid chromatography-tandem mass spectrometry, and the safety risk of commercial marine shellfishes was evaluated based on the materiome of LSTs. Under the optimal conditions, the developed method displayed satisfactory recovery values (63.2%–88.8%), precision (relative standard deviations ≤ 14.5%), and sensitivity (limit of detection in the range of 0.54–2.69 ng g^?1) for all analytes. Among the 105 commercially available shellfish samples, 42.86% of the samples had at least one kind of toxins. The highest average content was 47.60 μg kg^?1 of DTX1, which was the most serious contaminant in marine shellfish samples. Total Exposure Risk Index (∑ERI) was calculated based on Total Daily Intake (TDI) and Acute Reference Dose (ARfD) of each toxin to evaluate the safety risk of commercial marine shellfishes. The results indicated that the risk of toxin poisoning was 19.05% in the commercial available marine shellfishes, and the scallops (Chlamys farreri) have the highest poisoning risk among different shellfishes used in this study. In summary, a new method based on the combined contamination of LSTs was successfully developed for the risk assessment of commercial marine shellfishes. The proposed method is stricter than that in the relevant rules of European Food Safety Authority (EFSA) and can benefit to protect shellfish consumers from poisoning risk.     

利用蛋白磷酸酶活力抑制法检测牡蛎体内的腹泻性贝毒

基于腹泻性贝毒(Diarrhetic Shellfish Poison,DSP)中大田软海绵酸(Okadaic acid,OA)和鳍藻毒素(Dinophysis toxins,DTXs)能够抑制蛋白磷酸酶活力的特点,人们建立了一种利用碱性蛋白磷酸酶活力变化检测贝类中大田软海绵酸毒性当量的生物化学测试方法。本实验利用该方法对威海出入境检验检疫局采集的3个牡蛎样品进行分析,结果表明:3个牡蛎样品中不含有OA和DTXs毒素,但水解后可检出OA毒性,其中两个牡蛎水解样品的毒性当量分别为1.81和1.21μg OA eq./kg贝组织(湿重)。     

过氧化氢柱前荧光衍生化液相色谱法测定麻痹性贝毒的研究

液相色谱-荧光检测法(LC-FLD)测定贝类样品中石房蛤毒素(STX)和decarbamoylsaxitoxin(dcSTX)。样品经30 mmol/L HAc超声提取,C18固相萃取柱净化,2%碱性H2O2荧光衍生,C18色谱柱(4.6 mm×250 mm,5μm)分离,以乙腈-0.1 mol/L甲酸铵溶液(5∶95,V/V)作流动相,流速1.0 mL/m in。结果表明,STX和dcSTX衍生物在7m in内获得完全分离。在空白样品中添加标准品使浓度0.01~2.0μg/g,得到峰面积与浓度呈良好线性,线性相关系数>0.998。添加浓度在0.1、0.8和1.6μg/g的回收率为87%~97%(n=8);相对标准偏差为8%~13%。方法检出限(S/N=3)分别为STX 1.0 ng/g和dcSTX 0.3 ng/g。另外,采用四极杆-飞行时间质谱(Q-TOF-MS)对STX和dcSTX衍生物进行了结构解析。     

Determination of paralytic shellfish toxins in dinoflagellate Alexandrium tamarense by using isotachophoresis/capillary electrophoresis

Baseline separation of seven paralytic shellfish toxins (PSTs), namely decarbamoylsaxitoxin (dcSTX), saxitoxin (STX), neosaxitoxin (NEO), gonyautoxin-2 (GTX-2), gonyautoxin-3 (GTX-3), gonyautoxin-1 (GTX-1), and gonyautoxin-4 (GTX-4), was achieved by using capillary ITP (CITP)/CE with UV detection. Separation parameters including duration time and voltage in CITP process, separation voltage, and pH and concentration of buffer were optimized. The developed method provided linear responses from 1.3 to 200 microM for the PSTs. The LOD ranged from 0.1 to 0.3 microM. PST extracts from two algal strains of Alexandrium tamarense were analyzed and the toxin concentrations in the samples were quantified with an internal standard method by using NEO as the internal standard. The algal extract of A. tamarense HK9301 contained 332 microM GTX-2 and 224 microM GTX-3, while the PSTs were not detected in the extract of A. tamarense CI01.     

阴/阳离子交换色谱-电感耦合等离子体质谱法分析鱼和贝类海产品砷的形态

采用阴(Hamilton PRP X100柱)阳(Dionex Ionpac CS- 10柱)离子交换色谱-电感耦合等离子体质谱联用技术,分别以pH 10.3的20 mmol/L NH4HCO3和pH 2.0的5 mmol/L吡啶溶液为流动相,建立了三价砷As(Ⅲ)、五价砷As(V)、一甲基砷酸MMA、二甲基砷酸DMA...     

微波消解样品-氢化物发生-原子荧光光谱法测定海贝中硒

海贝样品经硝酸和过氧化氢微波加热消解,用氢化物发生-原子荧光光谱法测定其中硒的含量。使用溶于5g·L~（-1）氢氧化钾溶液中的10g·L~（-1）硼氢化钾溶液与溶液中硒离子反应生成氢化物。试样溶液中加入抗坏血酸消除硝酸的干扰。在优化的试验条件下,硒的质量浓度在600μg·L~（-1）以内与其荧光强度呈线性关系;方法检出...     

Saxiphilin蛋白分离纯化及其活性测定

Saxiphilin是一种能与麻痹性贝类毒素（PSPs）特异性结合的可溶性血清蛋白,利用超滤离心及凝胶层析从牛蛙血浆中分离纯化Saxiphilin活性蛋白使其达到一定纯度,通过酶联免疫检测技术对其活性进行研究.结果表明：分离纯化目标蛋白时,采用pH值为6.5的Tris-HCl缓冲液,使用超滤离心、凝胶层析时目标蛋白的纯化倍数分别为5.9和11.2,回收率为67.8%和50%.通过SDS-聚丙酰胺凝胶电泳验证其分子量为90 kDa,并通过毒素粗蛋白的结合曲线可得粗蛋白与PSP浓度比达到46.86时,目标蛋白结合PSP毒素的量达到饱和.将Saxiphilin蛋白应用于微量滴定板来检测PSPs,具有快速、简便、灵敏、特异、经济等优点.     

高效液相色谱/四极杆-飞行时间质谱测定神经性贝毒

采用高效液相色谱/四极杆 飞行时间质谱(HPLC/Q TOFMS)联用技术对贝类样品中的短裸甲藻毒素 PbTx-2 进行了检测研究。样品经丙酮提取、C18小柱净化后,用Zorbax XDB C18色谱柱(2.1 mm i.d.×150 mm,3.5 μ m)进行分离,流动相为甲醇 水(体积比为85∶15)溶液(含0.5 mmol/L NH4Ac),流速0.20 mL/min 。电喷雾正离子模式,选择质子化PbTx 2分子离子 ［M+H］ +作为前体离子进行TOFMS扫描、测定。结果表明,样品的平均加标