AuPt合金的两种典型生长机理研究

分别采用晶种生长法和快速共还原法制备得到了AuPt合金。采用晶种生长法制备AuPt合金时,Au晶种的尺寸对Au-Pt双金属结构的形成有关键性影响,当用小尺寸的Au纳米颗粒(3nm)作为晶种时才会形成AuPt合金结构,当Au晶种尺寸较小时,由于颗粒内纳米尺度的原子快速扩散导致合金结构的形成。高温下油胺对Au和Pt前体的快速共还原会使Au和Pt在极短的时间内同时得到还原,避免了两相的分离,得到了AuPt合金结构。     

Simplified pesticide multiresidues analysis in fish by low-temperature cleanup and solid-phase extraction coupled with gas chromatography/mass spectrometry

A simple and fast method for the simultaneous analysis of thiobencarb, deltamethrin and 19 organochlorine pesticide residues in fish by gas chromatography–mass spectrometry was investigated in this study. Samples are extracted with acetonitrile. Most of lipids in the extract are eliminated by low-temperature cleanup, prior to solid-phase extraction cleanup. The lipids extracted from the fish samples were easily removed without any significant losses of the pesticides. Aminopropyl (NH₂) cartridge was effective to eliminate the remaining interference. Spiked experiments were carried out to determine the recovery, precision and limits of detection (LODs) of the method. The method detection limits ranged from 0.5 μg kg⁻¹ to 20 μg kg⁻¹, whilst recoveries of the pesticides were in the range of 81.3–113.7% with relative standard deviations ?13.5% at a spiked concentration of 0.05 mg kg⁻¹, 0.02 mg kg⁻¹ and 0.1 mg kg⁻¹. The newly developed method is demonstrated to give efficient recoveries and LODs for detecting pesticide multiresidues in fish.     

鲣鱼(Eleotridae)不同部位中5种生物胺的分布及贮藏期间的变化研究

初步分析鲣鱼中不同部位5种生物胺(尸胺、组胺、苯乙胺、酪胺、色胺)的分布及含量,比较赤身、鱼腹、内脏中生物胺的含量及差异,并对生物胺在不同温度储藏期间的变化进行测定。方法:采用基质固相分散萃取,液相色谱-串联质谱法测定生物胺含量。结果:在新鲜鲣鱼各个部位中,内脏中生物胺含量最高,达到所有检测部位生物胺总量的50.4%,由酪胺及尸胺组成;赤身及鱼腹中组胺含量较高,鱼腹中还含有尸胺。新鲜鲣鱼赤身肉(背中部)在4℃下储藏至13d时,各生物胺含量基本无变化;20℃下储藏时,鱼肉快速腐败,自第3d起尸胺、组胺及酪胺迅速增加,从第4d起尸胺及酪胺含量超过组胺。     

食品中农药残留分析技术研究

本文论述了我国食品中农药残留污染的现状,阐述了色-质联用技术、极谱分析、串联质谱技术、毛细管电泳技术等在食品农药残留分析中应用比较广泛的分析技术的特性,同时阐述了具有更广泛应用前景的现场快速检测技术:免疫分析、生物传感器、酶抑制技术等。     

加速溶剂萃取-高效液相色谱法检测瓦楞纸箱(板)中的多溴二苯醚

目的建立一种加速溶剂萃取提取多溴二苯醚的高效液相色谱检测方法。方法将多层瓦楞纸箱(板)剪至1 cm×1 cm大小,取适量样品,以乙醇-丙酮(1:1,V:V)为萃取溶剂,加速溶剂萃取温度为150℃,萃取压力为1500 psi,静态萃取10 min,重复萃取3次后,用甲醇-水为流动相,进行梯度洗脱,226 nm波长进行检测。结果对8种PBDEs的回收率在95%~105%之间,精密度试验(n=6)的RSD3%,检测限为0.1~0.2μg/m L,线性回归系数0.999。结论建立的方法与标准方法 GB/Z 21276-2007检测结果无明显差异,可以用于瓦楞纸箱(板)中的PBDEs检测。     

气相色谱-质谱法测定食品模拟物中全氟正丙基乙烯基醚的迁移量

目的 建立一种顶空进样-气相色谱-质谱联用法测定各类食品模拟物(酸性、醇类、油性等)中全氟正丙基乙烯基醚的迁移量。方法 浸泡液中全氟正丙基乙烯基醚通过顶空进样的方式(顶空瓶中样品在80 ℃温度下平衡30 min)进入气相色谱柱, 经过键合苯乙烯-二乙烯基苯多孔高聚物的毛细管柱分离后由质谱检测分析(质荷比69作为定量离子)。结果 在优化的色谱柱、顶空平衡时间与温度等仪器条件下, 本方法最低检出限达到0.01 mg/kg, 回收率在86.5%~112.0%之间, 相对标准偏差小于10%(n=6)。结论 该方法操作简单, 灵敏度高, 适合测定各类食品模拟物中全氟正丙基乙烯基醚迁移量。     

Evaluation of transient eddy current oscillations response for thickness measurement of stainless steel plate

Detection of a wall thickness change in pipelines is extremely important to avoid unwanted leakages and accident reduction in industrial structures. In the present study, transient eddy current oscillation (TECO) nondestructive testing (NDT) method has been used to detect the thickness of stainless specimen. Damped free running oscillations that are generated by cyclic exchange of energy between a capacitor and an induction coil in the TECO probe, are used to induce the eddy currents into the test specimen. The resultant magnetic field is detected by using a Hall sensor in the vicinity of the test specimen. The experimental results are analyzed in the frequency domain by calculating the power spectral density (PSD) of the detected decay of oscillations response from the probe. Two features, peak frequency and −3 dB bandwidth of the PSD, are used to interpret the thickness variation in test specimen. The TECO method has been successfully applied to measure the thickness of stainless steel plates.     

水产品中的生物胺及其检测方法研究进展

本文简要介绍了易产生生物胺的主要水产品种类及其产生过程,一些国家设置的水产品中生物胺的限量要求及其加工控制方法,同时重点介绍了酶联免疫法、电化学检测法、毛细管电泳法、离子色谱法、液相色谱法、液相色谱-质谱法等水产品中生物胺检测技术应用及研究进展。     

SPE净化HPLC-APCI（+）-MS/MS分析肉类食品中硝基咪唑类药物原药及代谢物残留量

采取固相萃取柱净化处理后进行液相色谱-大气压化学电离源串联四极杆质谱,在正离子检测模式下(HPLC-APCI(+)-MS/MS)对动物源性肉类食品中甲硝唑、地美硝唑(二甲硝唑)、替硝唑、洛硝唑(罗硝唑)、特尼哒唑、异丙硝唑、以及羟基化甲硝唑、羟基化异丙硝唑、2-羟甲基-1-甲基化-5-硝咪唑9种硝基咪唑类药物残留量进行分析。样品添加氘代标示物HMMNI-D³、IPZ-OH-D³后,用乙腈提取,通过OASIS MCX C₁₈ SPE柱净化,Superiorex ODS C₁₈ 色谱柱分离,采用梯度洗脱,流动相为0.1%甲酸水溶液和0.1%甲酸乙腈溶液,大气压电离源正离子MRM模式检测。肉类肌肉样品的方法定量下限(LOQ,S/N＞10)为0.5 μg•kg^-1。在质量浓度0.5～100.0 μg•L^-1范围内,峰面积与浓度呈良好的线性关系(r: 0.997 1～0.999 6)。     

液相色谱-串联质谱测定葡萄酒中4-乙基苯酚和 4-乙基愈创木酚

目的建立液相色谱-串联质谱法同时测定葡萄酒中4-乙基苯酚和4-乙基愈创木酚的方法。方法样品经甲醇(1.0%甲酸)溶液提取,Oasis HLB固相萃取柱净化后,采用液相色谱-串联质谱法负离子模式检测,通过多反应监测模式,对葡萄酒中4-乙基苯酚和4-乙基愈创木酚进行定量分析。结果 4-乙基苯酚和4-乙基愈创木酚线性范围为0.01～0.1μg/m L,定量限(limit of quantification,LOQ)为0.01μg/kg,加标回收率为77.6%～93.5%,相对标准偏差均小于10%。结论本方法操作简单,结果准确可靠,对葡萄酒中4-乙基苯酚和4-乙基愈创木酚的检测具有较强的适用性。