烤鳗中6种农药残留量的液相色谱-质谱/质谱法同时测定

建立了烤鳗中苯胺灵、嘧菌酯、氨苯乙酯、氟酮唑草、丙蝇驱、唑螨酯6种农药残留的同时检测方法.烤鳗样品采用乙腈、中性氧化铝超声基体分散吸附、涡旋混合提取,Florisil固相萃取小柱净化、浓缩,以乙腈-乙酸铵缓冲液为流动相进行色谱分离,串联质谱检测.结果表明,6种化合物在0.5 ～1 000 μg/L范围内线性关系良好,方法的检出限为0.03 ～2.3 μg/kg,定量下限为0.09 ～7.7 μg/kg,平均加标回收率为75% ～104%,相对标准偏差(RSD)为1.6% ～15%,满足当前进出口残留控制要求.     

Determination of polybrominated diphenyl ethers in fish tissues by matrix solid-phase dispersion and gas chromatography coupled to triple quadrupole mass spectrometry: Case study on European eel (Anguilla anguilla) from Mediterranean coastal lagoons

This paper describes the development and validation of an analytical methodology to determine 28 polybrominated diphenyl ethers (PBDEs) in European eel (Anguilla anguilla) tissues using matrix solid-phase dispersion (MSPD) and gas chromatography coupled to triple quadrupole mass spectrometry (GC-QQQ-MS/MS). A total of 28 PBDEs were targeted, including tri- to deca-brominated congeners.The robustness and effectiveness of the proposed sample preparation procedure was demonstrated in lipid-rich eel tissues. The use of batch MSPD with activated silica gel and H₂SO₄-impregnated silica gel, followed by H₂SO₄ digestion and multilayer cartridge clean-up allowed for complete lipid removal and eliminated matrix effects during GC-QQQ-MS/MS analysis. The average PBDE recoveries from eel muscle samples spiked with PBDEs at two levels were in the range 56.2-119.0%. Precision was satisfactory since relative standard deviations were lower than 19.6%, regardless of spike level, and method quantification limits ranged between 1 and 170 pg g⁻¹ (wet weight).The method demonstrated its successful application for the analysis of eel samples from two coastal lagoons located on the western French Mediterranean coast. All samples tested positive, but for tri- to hexa-brominated congeners only and total PBDE levels observed in this study were in the range 0.08-1.80 ng g⁻¹ wet weight.     

反相离子对液相色谱法测定欧洲鳗鲡体中丙硫咪唑及其代谢物的残留量

建立了鳗鲡体中丙硫咪唑及其代谢物残留量测定方法。样品用乙腈提取,经正己烷净化后,液相色谱一荧光法测定,标准加入法定量。流动相为：甲醇、乙腈和乙酸铵,梯度洗脱。检测波长为：激发波长290nm,发射波长320nm,丙硫咪唑、2氨基丙硫咪唑砜、丙硫咪唑亚砜、丙硫咪唑砜检出限依次为：25、5、10、1μg／kg。回收率大于95％,相对标准偏差小于8％。     

胃瘤线虫与宿主黄鳝组织的酯酶同工酶分析

采用不连续凝胶垂直板电泳分析胃瘤线虫、线虫包囊以及黄鳝的各组织,比较样品酯酶电泳结果的异同,分析其相互之间的关系.酯酶在黄鳝的各个组织、胃瘤线虫与线虫包囊中均有表达,并且呈现出一定的特异性.电泳结果表明黄鳝心脏和肌肉的酯酶只有一条弱酶带,其它组织都有三条染色明显的条带,说明黄鳝心脏和肌肉的酯酶发挥的水解功能要低于其它组织;胃瘤线虫包囊具有与黄鳝的肠道相似的酶带,但其活性较弱,因此,推测其已经丧失了肠道组织的水解吸收营养物质的大部分功能;胃瘤线虫有4条酶带,其中2ab和2b是胃瘤线虫特有的酶带,而1a和2a是胃瘤线虫与其包囊、黄鳝的肠道、性腺、肾脏、肝脏共有的酶带,由此推测线虫与黄鳝之间也可能存在着协同进化的关系.     

黄鳝肌肉中11种性激素的气质联用检测方法

报道了一种同时筛选、定量和确证黄鳝中的11种性激素的灵敏、特异可靠的检测方法。对5.0 g肌肉样品,采用β-葡糖苷酸酶(来自Helix pomatia)对提取物水解后,经叔丁基甲醚提取,正己烷脱脂,再经C18小柱和NH2小柱净化,七氟丁酸酐对其进行衍生,最后利用GC-MS进行检测。采用外标法定量,通过对空白样品添加标准品,使之理论含量为1.00,2.50和5.00μg.kg-1,检出限在0.50~1.00μg.kg-1,平均回收率范围为56%~103%,平均相对标准偏差范围为3.1%~29.5%。对不同批次添加水平为1.00μg.kg-1的回收率进行比较,相对标准偏差范围为4.8%~22.2%,重复性好。因此,本方法对目前动物源食品中的性激素监督检验非常有用。     

Primary Structure of the Pike Eel (Muranesox Cinereus) Growth Hormone

By means of alkaline extraction, gel filtration and two kinds of high-performance liquid chromatography, a growth hormone from pike eel pituitary was purified and its primary structure determined. There are two forms of growth hormone, one of which has three more amino acids at the N-terminal. The same situation arises in the Japanese eel. With invariant four half-cystines, it is composed of 190 amino acids; similar to the growth hormone of the Japanese eel, it differs only in six amino-acid residues.     

鳗鱼、蜂蜜中链霉素、双氢链霉素残留量的液相色谱-串联质谱法测定

建立了液相色谱-串联质谱(HPLC-MS/MS)法同时检测鳗鱼和蜂蜜中链霉素和双氢链霉素残留量的方法。样品用庚烷磺酸钠和磷酸盐缓冲液提取,经SUPELCO LC-C18固相萃取净化后,采用Thermo Aquasil-C18色谱柱(150 mm×4.6 mm,3μm)分离,以含0.3%乙酸的乙腈溶液和0.3%乙酸水溶液为流动相进行梯度洗脱,多反应监测模式测定,外标法定量。该方法在10~100μg/kg质量浓度范围内线性关系良好,定量下限均为10μg/kg。方法的回收率为89.6%~110.3%,相对标准偏差为2.3%~20.9%。该方法简便、实用、准确、快捷,能够满足蜂蜜和鳗鱼中链霉素和双氢链霉素残留量的检测需要。     

含氟甲喹残留的鳗鲡肉糜自然基体标准样品的制备

为了获得与实际检测样品完全一致的检测质量控制样品,研制了含氟甲喹的自然基体鳗鲡肉糜标准样品。在模拟人工养殖的自然条件下适量施用氟甲喹药物,采集符合预期水平(氟甲喹含量为5～10 μg/kg)的阳性材料。取带皮的阳性肌肉均质,过10目筛网。样品用尼龙/聚丙烯(PA/CPP)耐蒸煮复合膜袋包装,经Co60-γ射线12 kGy剂量的辐照灭菌;经均匀性检验、稳定性检验、中国合格评定国家认可委员会认可实验室液相色谱-串联质谱法检测协同定值。所建立的制备方法为含药物残留的鳗鲡肉糜的自然基体标准样品的实验室制备提供了一种选择。     

河豚鱼、鳗鱼和烤鳗中角黄素残留的超高效液相色谱法测定和超高效液相色谱-串联质谱法确证

建立了河豚鱼、鳗鱼和烤鳗中角黄素残留的超高效液相色谱测定方法和超高效液相色谱-串联质谱确证方法。样品用抗氧化剂焦性没食子酸保护,乙腈均质提取,正己烷液-液分配净化,超高效液相色谱-紫外检测器测定,外标法定量,超高效液相色谱-串联质谱法确证。测定方法采用BEHC18色谱柱(50 mm×2.1 mm,i.d.1.7μm),流动相为V(0.1%的甲酸)∶V(乙腈)=3∶97,检测波长470 nm。实验结果表明,角黄素在0.05~2.0 mg/L范围内线性关系良好(r=0.9999),在空白样品中,添加低、中、高3个浓度水平(0.05,0.1,1.0 mg/kg),角黄素的回收率均在82.52%~96.96%之间,相对标准偏差为6.9%~15%。方法的检出限(LOD)为0.02 mg/kg,定量限(LOQ)为0.05 mg/kg。串联质谱确证方法采用电喷雾(ESI)离子源,在正离子模式下以多反应监测(MRM)扫描方式检测,定性离子对565.5/203.2和565.5/133.1,定量离子对565.5/203.2。     

Flapping dynamics of a piezoelectric membrane behind a circular cylinder

The flapping dynamics of a piezoelectric membrane placed behind a circular cylinder, which are closely related to its energy harvesting performance, were extensively studied near the critical regime by varying the distance between the cylinder and the membrane. A total of four configurations were used for the comparative study: the baseline configuration in the absence of the upstream circular cylinder, and three configurations with different distances (S) between the cylinder and the membrane (S/D=0, 1, and 2). A polyvinylidene fluoride (PVDF) membrane was configured to flutter at its second mode in these experiments. The Reynolds number based on the membrane’s length was 6.35×10⁴ to 1.28×10⁵, resulting in a full view of membrane dynamics in the subcritical, critical, and postcritical regimes. The membrane shape and the terminal voltage were simultaneously measured with a high-speed camera and an oscilloscope, respectively. The influence of the upstream cylinder on the membrane dynamics was discussed in terms of time-mean electricity, instantaneous variations and power spectra of terminal voltage and membrane shape, fluctuating voltage amplitude, and flapping frequency. The experimental results overwhelmingly demonstrated that the terminal voltage faithfully reflected various unsteady events embedded in the membrane’s flapping motion. For all configurations, dependency of the captured electricity on a flow speed beyond the critical status was found to follow the parabolic relationship. In the two configurations in which S/D=0 and 1, the extraneously induced excitation by the Kármán vortex street behind the circular cylinder substantially reduced the critical flow speed, giving rise to effective energy capture at a lower flow speed and a relatively high gain in power output. However, in the configuration in which S/D=2, the intensified excitation by the Kármán vortex street on the membrane considerably reduced the captured energy. Finally, a transient analysis of the membrane’s flapping dynamics in the configuration in which S/D=0 was performed in terms of phase-dependent variations of the membrane segment’s moving speed, membrane curvature, and terminal voltage; the analysis resulted in a full understanding of the energy harvesting process with consecutive inter transfer of elastic, kinetic, and electric energies.