大体积水样专用柱固相萃取-超高效液相色谱串联质谱测定水中5类40种抗生素类药物残留

目的:建立大体积水样专用柱固相萃取柱富集净化-超高效液相色谱-串联质谱(LC-MS/MS)法,同时测定水体中5类40种抗生素。方法:水样通过大体积水样专用柱萃取富集后,用5%氨化甲醇洗脱,以C18反相色谱柱为分析柱,乙腈-0.1%甲酸溶液为流动相,采用LC-MS/MS进行定性定量分析。选择电喷雾正电离源(ESI+),多反应监测模式(MRM),外标法定量。结果:5类40种抗生素在1~500 ng/L范围内均具有良好的线性关系,方法的检出限(S/N=3,1000倍浓缩)为0.1~10 ng/L。以自来水、闽江水和内河水作为基底,加标质量浓度为40 ng/L和100 ng/L时,抗生素的平均加标回收率分别为68.0%~120.3%和67.9%~117.7%,相对标准偏差(RSD)分别为2.0%~14.9%和1.8%~16.6%。结论:建立的大体积水专用柱固相萃取净化、富集,超高效液相色谱-串联质谱(LC-MS/MS)联用技术,可用于测定同时测定水体中5类40种抗生素。     

超高效液相色谱-串联质谱法测定水产品中三聚氰胺残留量

本文建立超高效液相色谱-串联质谱(UPLC-MS/MS)快速测定水产品中三聚氰胺残留的方法。色谱条件:ACQUITY UPLC BEH HILIC柱(2.1×100 mm,1.7m),流动相:乙腈-0.5 mmol/L乙酸铵溶液(0.1%甲酸),流速:0.3mL/min。采用电喷雾质谱检测,以正离子模式5min就完成了质谱分析。实验结果表明,三聚氰胺在水产品中的检测限为0.05 mg/kg,在0.05~0.50 mg/kg添加水平时加标回收率为63%~90%之间,相对标准偏差(RSD,n=6)均小于7.2%。     

液相色谱-串联质谱应用研究进展

液相色谱-串联质谱(Liquid chromatography-tandem mass spectrometry,LC-MS/MS)是由具有高效分离能力的液相色谱和具有高准确分析能力的质谱串联,实现化合物鉴定和定量的重要分析技术.随着先进仪器的研发和相关技术的发展,使得LC-MS/MS的分离分析能力更加强大.简单介绍了...     

药用胶塞常用抗氧剂及可提取硫含量测定方法

目的 建立一种高效液相色谱法，以同时检测药用胶塞中多种抗氧剂和可提取硫。方法 采用二氯甲烷作为提取溶剂，微波萃取药用胶塞中的目标化合物，用高效液相色谱法测定目标物的含量。色谱柱为Waters Symmetry RP 18，流动相为乙腈\甲醇\水，梯度洗脱，检测波长为277 nm。结果 该方法能高效地分离目标化合物，各化合物分离度良好。在0.2~20 μg/mL内线性良好，相关系数r≥0.999 3，检测限为0.03~0.09 μg/mL，回收率为86.73%～108.91%，相对标准偏差RSD为0.47%～5.68%。通过该种方法测定不同厂家不同批次药用胶塞，结果检出了抗氧剂BHT及其降解物BHT–CHO、BHT–Q，抗氧剂1076和1010及其降解物1310，以及可提取硫。结论 文中建立的高效液相方法准确、简便、灵敏度较高，能够高效快速地测定药用胶塞中常用抗氧剂及其降解产物与可提取硫的含量。     

UPLC–MS/MS法测定聚亚苯基砜奶瓶4,4′–联苯二酚迁移量

目的 提出聚亚苯基砜(PPSU)奶瓶4,4′–联苯二酚迁移量的超高效液相色谱–串联质谱分析方法(UPLC–MS/MS)，为婴幼儿食品包装质量安全测试方法提供依据。方法 在70 ℃、2 h条件下，采用体积分数50%的乙醇溶液(食品模拟物)对样品进行迁移实验，采用C18色谱柱分离，以超纯水和甲醇为流动相梯度洗脱，通过电喷雾电离源(ESI)负离子模式和多反应监测(MRM)进行采集、扫描，并进行定性和定量检测，采用外标法进行定量分析。结果 在优化条件下，目标物在5~200 µg/L内线性关系良好，相关系数(R²)大于0.999 9，检出限和定量下限分别为1.5 µg/L和5 µg/L。该方法的基质效应值为95.8%~114%，加标回收率为95.2%~105%，相对标准偏差(RSD)为1.0%~1.7% (n=6)。结论 该方法具有快速、准确且灵敏度高等特点，适用于PPSU奶瓶4,4′–联苯二酚迁移量的测定。     

UPLC-MS/MS法测定虾蟹中4-己基间苯二酚的残留量

建立一种超高效液相色谱-串联质谱(UPLC-MS/MS)测定虾蟹中4-己基间苯二酚残留量的检测方法。样品经乙腈超声提取,C18固相萃取柱净化后,UPLC BEH C18色谱柱分离,多反应监测方式测定,外标法定量。结果显示:加标回收率在88.32%~92.08%之间,相对标准偏差RSD≤2.3%;以S/N=3计算,检出限为5.0μg/kg。该法灵敏度好、准确性高、精密度好、检出限低,适用于虾蟹中4-HR微量和痕量残留的测定。     

同位素内标-UPLC-MS/MS法检测易拉罐啤酒中双酚A含量

目的 为了提高金属易拉罐啤酒中双酚A(BPA)的检测能力,建立一种基于同位素内标的超高效液相色谱-串联质谱分析方法。方法 样品经超声处理后除去CO2,随后添加内标物BPA-¹³C12,用超高效液相色谱-串联质谱法进行检测分析,采用内标法定量。结果 经同位素内标标准曲线校正,方法的定量限为1.00 μg/L,线性方程为y=1.73x+0.206,线性相关系数为0.9992,相对标准偏差为4.68%～6.63%,加标回收率为91.0%～109%。使用该方法对厦门市市售6种易拉罐啤酒样品进行了BPA污染物迁移量检测,结果显示6种啤酒中均检出BPA,平均质量浓度为1.48 μg/L。结论 此方法具有前处理简便快捷、检测限高、灵敏度高、准确度好等特点,能够满足金属易拉罐啤酒中低含量BPA的检测要求。     

超高效液相色谱-串联质谱技术检测番茄制品中矮壮素及缩节胺残留量的方法研究

本文采用超高效液相色谱-串联质谱(UPLC-MS/MS)技术,同时检测番茄制品中矮壮素及缩节胺残留的方法。结果表明,番茄制品经稀释定容、超声浸提、高速离心后,采用UPLC-ES(I+)MS/MS同时测定番茄制品中矮壮素及缩节胺的残留,在0.001～0.05mg/kg浓度范围内,平均加标回收率在80%-110%,方法检出限0.01mg/kg,可同时满足出口番茄酱制品中矮壮素及缩节胺检测工作的需要。     

工业品中全氟化合物的测定

本文介绍了一种全氟化合物(PFCs)的典型代表全氟辛酸(PFOA)和全氟辛磺酸(PFOS)的高效液相色谱串联质谱(HPLC/MS/MS)测定方法。方法简便快捷准确可靠,可应用于纺织品、服装、食品、医药、航天和电子领域等数百种工业和消费品中PFOA、PFOS的测定。     

超高效液相色谱-串联质谱法测定小麦籽粒中25种磺酰脲类除草剂残留

通过改进QuEChERS前处理方法,建立同时测定小麦籽粒中25种磺酰脲类除草剂残留的超高效液相色谱-串联质谱法(UPLC-MS/MS).小麦籽粒样品经含1％甲酸的乙腈提取,QuEChERS方法净化,以Waters?ACQUITY UPLC?CSH?C18?Column(100?mm×2.1?mm,1.7?μm)进行液相...     

Liquid Marbles in Liquid

Traditional liquid marbles (LMs), liquid droplets encapsulated by hydrophobic particles at the liquid–gas interface, are restricted by their short lifetime and low heat transfer efficiency. Herein, a new paradigm for LMs immersed in various liquid mediums with massive enhanced heat transfer and spatial recognition is designed; without compromising the structural integrity, the lifetime of the liquid marbles in liquid (LMIL) is extended by ≈1000 times compared to classical LMs in air or naked droplets in organic reagents. The LMIL shows promising reverse structural re‐configurability while under external stimuli and maintaining their functionality for a very long period of time (≈weeks). These superior behaviors are further exploited as a miniature reactor with prolonged lifetimes and excellent temperature control, combined with its feasible operation, new opportunities will open up in the advanced chemical and biomedical engineering fields. It is also shown that LMIL can be applied in methylene blue degradation and 3D in‐vitro yeast cell cultures. These findings have important implications for real‐world use of LMs, with a number of applications in cell culture technology, lab‐in‐a‐drop, polymerization, encapsulation, formulation, and drug delivery.     

实验室中液氮和液氧的提纯

阐述了以液态空气为冷源、用“重蒸馏”和冷凝的方法获得更纯的液氮和液氧。所得液氧和液氮的正常沸点之差值Ｔ。＿ｎ＝１２．７５Ｋ；与标准值相差＜０．１Ｋ。     

Liquid Letters

Using the interfacial jamming of cellulose nanocrystal (CNC) surfactants, a new concept, termed all‐liquid molding, is introduced to produce all‐liquid objects that retain the shape and details of the mold with high fidelity, yet remain all liquid and are responsive to external stimuli. This simple process, where the viscosity of the CNC dispersion can range from that of water to a crosslinked gel, opens tremendous opportunities for encapsulation, delivery systems, and unique microfluidic devices. The process described is generally applicable to any functionalized nanoparticles dispersed in one liquid and polymer ligands having complementary functionality dissolved in a second immiscible liquid. Such sculpted liquids retain all the characteristics of the liquids but retain shape indefinitely, very much like a solid, and provide a new platform for next‐generation soft materials.     

液氨储罐液体泄漏建模及分析

目的 为了分析液氨储罐纯液体泄漏后的事故影响,探究液氨纯液体泄漏量的计算.方法 针对液氨储罐(卧罐、球罐及立式罐)液体泄漏罐压变化及不同类型储罐结构特征导致液面面积变化的特点,利用范德瓦尔斯方程和流体力学方法,建立液氨储罐液体泄漏模型.利用模型对3种液氨储罐液体泄漏进行数值模拟,对比PHAST计算与模型模拟结果.结论 结果发现液面高度hv,s,h的下降呈现先减缓后增大的趋势,泄漏质量流率Qm-v,s,h的下降幅度及泄漏质量mv,s,h呈现先增加后减缓的趋势.泄漏初始时刻,Qm-v,s,h值最大,分别为0.555,0.553,0.552 kg/s;泄漏停止时,mv,s,h值最大,分别为11.245846,11.084621,7.730932 t.模型计算结果与PHAST模拟结果规律相似,Qm-v,s,h(max)的偏差较小,介于16.577％～16.667％;mv,s,h偏差差别较大,立式罐、球罐及卧罐泄漏液体质量偏差分别为4.565％,5.764％和17.630％.结论 根据各参数的变化规律可得,模型适于计算液氨储罐液体泄漏及风险分析.     

Liquid–Liquid Coexistence Curve of n-Perfluorohexane–n-Hexane System

The shape of the liquid–liquid phase boundary of the C₆F₁₄–C₆H₁₄ system near the critical solution point has been determined by a γ-ray attenuation technique. According to the measurements, the critical solution temperature and composition are 295.69 ± 0.02 K and 36.1 ± 0.3 mol% C₆F₁₄, respectively. The critical exponent of the liquid–liquid coexistence curve is 0.322 ± 0.008. Midpoints of the coexistence curve exhibit a departure from the law of the rectilinear diameter.     

Liquid Crystalline Elastomers

Today, material science is directed towards the development of multifunctional and oriented structures. One example of such supramolecular systems are liquid crystalline (LC) elastomers which combine the properties of LC phases (the combination of order and mobility) with rubber elasticity, one of the most typical polymer properties. Their most outstanding characteristic is their mechanical orientability; strains as small as 20% are enough to obtain a perfectly oriented LC monodomain. This orientability, if LC elastomers with chiral phases are used, leads, for example, to elastomers with chiral smectic C* phases which are likely to show piezo-electric behavior.     

液体密度传感器

介绍了几种典型的液体密度传感器的基本结构、工作原理与应用特点.