高效液相色谱-电感耦合等离子质谱法分析水产品中有机锡的形态

建立了水产品中三甲基锡(TMT)、一丁基锡(MBT)、二丁基锡(DBT)、三丁基锡(TBT)、一苯基锡(MPhT)、二苯基锡(DPhT)、三苯基锡(TPhT)7种有机锡化合物的高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)的分离检测方法.方法利用Eclipse Plus C18反相色谱柱对水产品中7种有机锡化合物进行分离,利用电感耦合等离子体质谱对锡元素进行检测,外标法定量测定水产品中7种有机锡化合物的含量.研究采用30 mL 30％乙酸-甲醇提取液(V/V),低温超声萃取10 min后离心3 min,取上清液20 mL浓缩,用流动相定容至2 mL,以乙酸(0.2％三乙胺,V/V)-甲醇溶液为流动相,梯度洗脱,7种有机锡化合物在30 min内得到了有效分离.7种有机锡化合物标准曲线的线性相关系数大于0.995,检出限0.11 ～0.60 μg/kg.此前处理方法样品加标回收率为72.1％～ 111.7％.本方法操作简便,分离效果好,检出限低,适用于水产品中有机锡的检测.     

Separation and analysis of trace volatile formaldehyde in aquatic products by a MoO3/polypyrrole intercalative sampling adsorbent with thermal desorption gas chromatography and mass spectrometry

An in situ embedded synthesis strategy was developed for the preparation of a MoO₃/polypyrrole intercalative sampling adsorbent for the separation and analysis of trace volatile formaldehyde in aquatic products. Structural and morphological characteristics of the MoO₃/polypyrrole intercalative adsorbent were investigated by a series of characterization methods. The MoO₃/polypyrrole sampling adsorbent possessed a higher sampling capacity and selectivity for polar formaldehyde than commonly used commercial adsorbent Tenax TA. Finally, the MoO₃/polypyrrole adsorbent was packed in the thermal desorption tube that was directly coupled to gas chromatography with mass spectrometry for the analysis of trace volatile formaldehyde in aquatic products. Trace volatile formaldehyde from real aquatic products could be selectively sampled and quantified to be 0.43–6.6 mg/kg. The detection limit was achieved as 0.004 μg/L by this method. Good recoveries for spiked aquatic products were achieved in range of 75.0–108% with relative standard deviations of 1.2–9.0%.     

Tandem use of solid-phase extraction and dispersive liquid-liquid microextraction for the determination of mononitrotoluenes in aquatic environment

Solid‐phase extraction (SPE) in tandem with dispersive liquid–liquid microextraction (DLLME) has been developed for the determination of mononitrotoluenes (MNTs) in several aquatic samples using gas chromatography‐flame ionization (GC‐FID) detection system. In the hyphenated SPE‐DLLME, initially MNTs were extracted from a large volume of aqueous samples (100 mL) into a 500‐mg octadecyl silane (C₁₈) sorbent. After the elution of analytes from the sorbent with acetonitrile, the obtained solution was put under the DLLME procedure, so that the extra preconcentration factors could be achieved. The parameters influencing the extraction efficiency such as breakthrough volume, type and volume of the elution solvent (disperser solvent) and extracting solvent, as well as the salt addition, were studied and optimized. The calibration curves were linear in the range of 0.5–500 μg/L and the limit of detection for all analytes was found to be 0.2 μg/L. The relative standard deviations (for 0.75 μg/L of MNTs) without internal standard varied from 2.0 to 6.4% (n=5). The relative recoveries of the well, river and sea water samples, spiked at the concentration level of 0.75 μg/L of the analytes, were in the range of 85–118%.     

Performance improvement through passive mechanics in jellyfish-inspired swimming

This computational investigation explores the effect that passively responsive components of a body can have on swimming performance. The swimmer is an articulated two-dimensional system of linked rigid bodies that is prescribed with a reciprocating shape change loosely inspired by jellyfish mechanics. The six constituent hinges can be either actively controlled by fully prescribing the kinematics, or passively responsive by substituting a torsion spring in place of an actuator. The computational solver is a high-fidelity viscous vortex particle method with coupled fluid-body interactions. The prescribed kinematic Reynolds numbers involved in this investigation fall within the range 70-700. Several configurations are explored, including cases with passively responsive hinges and cases in which pairs of the hinges were held in a rigid locked position. Certain choices of passive structure lead to optimal swimming speed and efficiency. This is elucidated by a simple model, which shows that optimal performance is obtained through a balance of maximized deflection of peripheral bodies and phasing that draws benefits from both reactive and resistive force mechanisms. A study is also made of an inviscid swimmer but, due to the reciprocating kinematics of the system, the swimmer is unable to achieve meaningful locomotion, showing that vortex shedding is essential to break the symmetry of the kinematics.     

Determination of chloramphenicol in aquatic products by graphene‐based SPE coupled with HPLC‐MS/MS

An effective analytical protocol using graphene‐based SPE coupled with HPLC‐MS/MS for determination of chloramphenicol (CAP) in aquatic products has been developed. In the present work, graphene was evaluated as SPE sorbents for the analytes enrichment and clean up. The target analytes were quantified by a triple‐quadrupole linear ion trap MS in multiple‐reaction monitoring mode. In addition, the proposed method was validated according to Commission Decision 2002/657/EC. The calibration curve was linear over the range of 0.5–100 ng/mL. The mean values of RSD of intra‐ and interday ranging from 1.48 to 4.29% and from 3.25 to 7.42% were obtained, respectively. In the three fortified levels, the recoveries of CAP ranging from 92.3 to 103.4% with RSDs ≤ 5.58% were obtained. The proposed method has been successfully applied to the analysis of CAP in several aquatic product samples, indicating that graphene was a potential SPE sorbent for the enrichment of trace residues in food samples.     

液相色谱串联质谱法测定水产品中的敌百虫残留量

将水产品样品经乙腈提取,正已烷除脂,旋转浓缩后采用液相色谱串联质谱法进行定性、定量分析。线性范围为5—100μg/kg,线性相关系数为0.9987,定性检出限1.7μg/kg,定量检出限3.5μg/kg。在鳗鱼、虾和罗非鱼3种不同样品基质中进行添加浓度为10,20,50μg/kg的验证实验,回收率在77.2%—87.5%之间,相对标准偏差(RSD)在5.4%—8.3%之间,并对敌百虫的质谱裂解进行了分析。本法快速简单,高效,灵敏度高,符合检测要求。     

High Efficient Extraction of Phthalates in Aquatic Products by a Modified QuEChERS Method

A simple, environmentally friendly and high efficient extraction method was proposed for the determination of five phthalates in aquatic products by gas chromatography combined with mass spectrometry detector (GC-MS). When this method was adopted, samples were pretreated by modified QuEChERS(quick, easy, cheap, effective, rugged and safe) method. An environmentally friendly extractant(ethanol aqueous solution) replaced toxic acetonitrile for extracting phthalates in the protein-matrix samples. Fluorescence quenching spectra of bovine serum albumin(BSA) with phthalates show that there was a high-affinity interaction between phthalate and protein, decreasing the extraction efficiency of phthalates from fish samples. However, in the 80%(volume fraction, φ) ethanol aqueous solution, a slow but full protein denaturation takes place, which would cause the unfolding of protein and the release of phthalates. Meanwhile, the fat-soluble impurities are extracted less in φ(ethanol) 80% aqueous solution than in either φ(ethanol) 100% or hydrophobic solvents in the liquid-liquid extraction procedure. Therefore the purification steps were greatly simplified. Overall recoveries were 81.77%―90.5% with limits of detection between 2.53 and 9.61 μg/L, and relative standard deviation values at 1.15%―4.85%. The proposed approach was satisfactorily applied to the determination of phthalates in real aquatic products, such as fish, shrimp and oyster.     

高效液相色谱法检测水产品中硝基呋喃类代谢物残留量

建立了水产品中硝基呋喃类代谢物残留量测定的样品处理方法和高效液相色谱分析方法.样品经酸解、2.氯苯甲醛衍生后用乙酸乙酯萃取、SPE柱净化,经高效液相-紫外检测器测定.本方法4种硝基呋喃类代谢物的定量限均为1.0μg/kg,在5.0～500μg/L质量浓度范围内,4种硝基呋喃类代谢物的工作曲线均呈良好线性,在2个添加浓度水平的平均回收率为76%～102%,相对标准偏差均小于10%(n=6).该方法适用于定性定量水产品中硝基呋喃类代谢物的残留分析.     

近红外光谱技术在水产品检测中的应用研究进展

水产品富含水分、蛋白质、不饱和脂肪酸与游离氨基酸等,是消费者喜爱的食品之一。然而,其在贮藏过程中由于温度波动或操作不当等因素会引起品质下降,引发一系列的食品安全问题。近红外光谱技术是一种利用物质对光的吸收、散射、反射和透射等特性来确定其成分含量的检测技术。该技术作为食品分析方法之一,在食品领域中应用广泛,可进行从气体到液体,从匀浆到粉末,从固体材料到生物组织等样品的快速精准与定性定量分析,具有快速无损,安全高效,多组分同时测定等特点。主要对常用无损检测技术的特点进行比较分析,对近红外光谱技术的主要工作原理予以说明,综述了该技术在水产品鲜度评价、掺伪分析、质量评估与货架期预测等方面的应用实例与最新研究进展,目前存在的主要问题,提出该技术应在进一步提升水产品检测精度的前提下,通过与各类理化指标的相关性分析、多种检测技术相融合等法来实现全面评价水产品品质的最终目标,以使其在水产品快速检测过程中得到更加广泛的应用。     

MP-AES法测定水产饲料中多种金属元素

应用微波等离子体发射光谱(microwave plasma-atomic emission spectrometry,MP-AES)技术,建立水产饲料中铜、铁、锰、锌、钾、钠等元素MP-AES分析方法。样品采用干灰化法消解,开展了方法学研究试验,同时与AAS和ICP-AES方法进行比对,并完成FAPAS能力验证样品和标准物质确证试验。通过优化MP-AES仪器的各项参数,在所选定的条件下,各元素的线性相关系数在0.999以上,检出限在0.4～3.9 mg·kg-1之间,加标回收率在103%～112%之间,精密度试验相对标准偏差在0.2%～0.6%之间;测定结果与AAS法、ICP-AES法比对,单因素方差分析(α=0.05)各元素P值在0.065～0.438之间,均大于0.05,无显著性差异;FAPAS奶牛饲料能力验证和灌木枝叶(GBW07602)标准物质确证试验的各元素测定值均在参考值范围内。结果表明,所建立的方法简单、快速,线性范围宽,具有良好的准确性和精密度;MP-AES无需使用乙炔、氩气,安全、经济、环保,能降低检测成本、提高检测效率,可替代AAS、ICP-AES法测定水产饲料中的六种金属元素,为水产饲料的质量控制提供理想的元素分析方法。