Application of in-house method for determinationof radium isotopes in environmental samples usingthe Liquid Scintillation counting technique

A method for determination of 226Ra and 228Ra in environmental samples using the α-β coincidence liquid scintillation counting (LSC) has been developed. Radium were preconcentrated from environmental samples by coprecipitation with BaSO4, then purified from others radionuclide interferences using the cation column exchange (Bio-Rad AG 50 W-X4 resin with 200-400 mesh size and H+ form) and operating in warm temperature which is between 70-80oC. Then, the Ba(Ra)SO4 precipitate was filtered through the Millipore filter paper, dried and weighed to calculate chemical yield. The activity concentration of radium isotopes in mixture of liquid scintillation cocktails were measured using LSC after being stored for over 21 days to allow the growth of the progeny nuclides. The method has been validated with a certi-fied reference material supplied by the International Atomic Energy Agency and reliable results were obtained. The radiochemical yields for radium were 59% - 90% and recovery was 97% and 80% for 226Ra and 228Ra, respectively. Sixteen seawater and fish flesh samples collected in Kapar coastal water have been analyzed with the developed method. The obtained radium activity concentrations in seawater were in the range of 02.08 ± 0.82 mBq/L to 3.69 ± 1.29 mBq/L for 226Ra and 6.01 ± 3.05 mBq/L to 17.07 ± 6.62 mBq/L for 228Ra. Meanwhile, the activity concentrations of 226Ra and 228Ra in fish flesh were in the range of 11.82 ± 5.23 – 16.53 ± 6.53 Bq/kg dry wt. and 43.52 ± 16.34 – 53.57 ± 19.86 Bq/kg dry wt., respectively.

Lysophosphatidylcholine Biomarkers of Lung Cancer Detected by Ultra-performance Liquid Chromatography Coupled with Quadrupole Time-of-flight Mass Spectrometry

Centrifugal ultrafiltration after methanol extraction of whole plasma was used as an optimal condition for the preparation of blood plasma before metabonomic studies. The plasma samples from 102 lung cancer patients and 34 healthy volunteers were prepared with this approach. With ultra-performance liquid chromatography（UPLC） coupled with quadrupole time-of-flight mass spectrometry（Q-TOF MS） analysis, the samples were investigated in order to find potential disease biomarkers. After data acquisition, orthogonal signal correction partial least squares models were built to differentiate the healthy volunteers from lung cancer patients and to identify metabolites that showed significantly different expression between the two groups. Several metabolite ions were identified as potential biomarkers according to the variable importance in the project（VIP） value in both ion modes. Five lysophosphatidylcholines were further identified as specifically lysoPC 16：0, isomer of lysoPC 16：0, lysoPC 18：0, lysoPC 18：1 and lysoPC 18：2. These results suggest that UPLC coupled with Q-TOF MS is an effective technique for the analysis of plasma metabolites in metabonomic studies.

磁性离子液体在食品化学污染物预处理应用的研究进展

磁性离子液体是一种磁性功能化的离子液体材料,不仅具有蒸气压低、液程宽、热稳定性好等特点,还具备可设计性强、产物易于分离、可回收重复利用等优势,能够解决微萃取技术中相分离困难和重复利用率低等难题,在食品分析预处理领域具有非常广泛的应用前景。本文梳理总结了用于食品分析预处理的磁性离子液体的种类及制备方法,系统介绍了磁性离子液体分离富集食品中生物胺类、药物类、食品添加剂类、持久性有毒类、无机重金属类化学污染物的应用研究进展,并对基于磁性离子液体在食品分析预处理技术的未来发展前景进行了展望。

食品安全检测中基于高效液相色谱-质谱联用技术的农药残留分析研究

本文研究了基于高效液相色谱-质谱联用技术(HPLC-MS)的农药残留分析方法。通过对HPLC-MS技术的基本原理、样品的制备及前处理方法以及具体应用进行全面的探究,旨在为食品安全保驾护航。

Miniaturization of Separation Systems and Its Applications

Development of miniaturized separation system consisted of microscale extraction and liquid phase separation processes has been reviewed. Various types of novel bonded stationary phases have been developed on the basis of the systematic analysis for the retention behavior of polycyclic aromatic hydrocarbons on experimentally synthesized phases.In this review,the miniaturization of microscale sample preparation technique and the effective on-line coupling to microcolumn liquid phase separations are also described especially focusing on the approach by the author’s group.The novel use of synthetic polymer filaments as the stationary phase and extraction media in those microscale separation systems will be introduced along with the applications in gas chromatographic separation.

A new sample preparation method for the determination of acyclovir by RP-HPLC:application to a drug-drug interaction study between gefitinib and acyclovir in rats

The assay of acyclovir in plasma seems to be a challenge because of its high hydrophily.In our present study,a reversed-phase high-performance liquid chromatography(RP-HPLC)method for the determination of acyclovir in rat plasma was described and validated in drug-drug interaction(DDI)between gefitinib and acyclovir in rats.The analytes were separated with gradient elution on C18 column(4.6 mm×250 mm,5μm),and the peaks were recorded using ultraviolet detector at a wavelength of 254 nm.Protein precipitation followed by methyl tertiary butyl ether extraction was used for sample preparation.The calibration curve was established between 0.2 and 40μg/mL(r^(2)=0.9999).The intra-and inter-day precisions were all less than 8%,and all the biases were not more than 10%.This new method was successfully applied to a DDI study between gefitinib and acyclovir in rats.Gefitinib up-regulated the absorption of acyclovir by about three times,and our findings guided the clinical co-administration of epidermal growth factor receptor-tyrosine kinase inhibitors(EGFR-TKIs)with acyclovir.

Modifying current thin-film microextraction(TFME)solutions for analyzing prohibited substances:Evaluating new coatings using liquid chromatography

For identifying and quantifying prohibited substances,solid-phase microextraction(SPME)continues to arouse interest as a sample preparation method.However,the practical implementation of this method in routine laboratory testing is currently hindered by the limited number of coatings compatible with the ubiquitous high-performance liquid chromatography(HPLC)systems.Only octadecyl(C18)and polydimethylsiloxane/divinylbenzene ligands are currently marketed for this purpose.To address this situation,the present study evaluated 12 HPLC-compatible coatings,including several chemistries not currently used in this application.The stationary phases of SPME devices in the geometry of thin filmcoated blades were prepared by applying silica particles bonded with various functional ligands(C18,octyl,phenyl-hexyl,3-cyanopropyl,benzenesulfonic acid,and selected combinations of these),as well as unbonded silica,to a metal support.Most of these chemistries have not been previously used as microextraction coatings.The 48 most commonly misused substances were selected to assess the extraction efficacy of each coating,and eight desorption solvent compositions were used to optimize the desorption conditions.All samples were analyzed using an HPLC system coupled with triple quadrupole tandem mass spectrometry.This evaluation enables selection of the best-performing coatings for quantifying prohibited substances and investigates the relationship between extraction efficacy and the physicochemical characteristics of the analytes.Ultimately,using the most suitable coatings is essential for trace-level analysis of chemically diverse prohibited substances.

液体闪烁计数法分析水中^(226)Ra活度浓度及其不确定度评价

通过建立以硫酸钡为载体共沉淀分离水中镭,液体闪烁计数法直接测量镭-226(^(226)Ra)的方法,实现水中^(226)Ra活度浓度的快速分析,并对方法不确定度进行评价。实验结果表明:该方法分析水中^(226)Ra总效率为91.3%~98.5%,方法探测下限为0.01 Bq/L,相对扩展不确定度为7%(k=2),样品计数率和总效率引入的误差是水中^(226)Ra不确定度的主要来源。该方法具有良好的精密度和准确度,适用于饮用水中^(226)Ra的快速分析。

Determination of five endosulfan pesticides in the fish pond water by dispersive liquid–liquid microextraction combined with GC–MS

A simple and rapid dispersive liquid-liquid microextraction(DLLME)technique coupled with gas chromatography-ion trap mass spectrometry(GC-MS)was developed for the extraction and analysis of five endosulfan pesticides from the fish pond water.In this work,different parameters affecting the extraction process such as the type and volume of extraction solvent,type and volume of disperser solvent,and extraction time were studied and optimized.Under optimized conditions,the enrichment factor ranged from 189 to 269 and the relative recovery ranged from 88.5%to 94.9%.The linear range was 2.0-80.0 mg/L;the limits of detection and quantitation were in the range 0.04-1.06 mg/L and 0.12-3.53 mg/L,respectively.The relative standard deviations were in the range 0.94%-2.08%(n D 5).The obtained results show that DLLME combined with GC-MS is a fast and simple method for the determination of endosulfan pesticides in fish pond water.

微波能用于酵母中海藻糖高效液相色谱分析样品制备的研究

利用微波能提取酵母中的海藻糖,建立了一种海藻糖分析样品的快速制备方法.高效液相色谱分析结果表明,无论是提取选择性、还是提取时间消耗,用微波法提取均具有常规提取法所无法比拟的优越性.经20s微波处理后,海藻糖酶已失活,故有效防止了提取过程中海藻糖的降解.微波提取不失为一种良好的样品的制备方法,尤其适用于对酵母代谢的研究.

液相微萃取技术在农药残留分析中的应用研究进展

液相微萃取技术(LPME)是一种新型的样品前处理方法,具有快速、简单、廉价、选择性强、准确度高、溶剂消耗量少、环境污染小等优点,方便与各种分析仪器联用。其具有多种模式:单滴液相微萃取(SDME)、中空纤维液相微萃取(HF-LPME)、分散液相微萃取(DLLME)、悬浮固化液微萃取(SFODME)、连续流动微萃取(CFME)、直接悬挂液滴微萃取(DSDME)等,具有很好的研究潜力和应用前景。对液相微萃取技术在农药残留分析中的应用研究进展进行了综述。

分散液相微萃取技术研究的最新进展

分散液相微萃取(DLLME)作为一种新型样品前处理技术,具有操作简便、快速,富集效率高,萃取剂使用量少等优点。本文对近年来该技术在分离科学领域应用的最新进展进行了简要评述。主要讨论了以下3个方面:(1)DLLME与其他净化或萃取技术的结合;(2)萃取剂的拓展;(3)萃取装置的改进。

液相微萃取-高效液相色谱法快速测定唾液中尼古丁含量

建立了一种以液相微萃取为样品前处理技术,结合高效液相色谱快速、有效测定唾液中尼古丁含量的方法。确定了以磷酸三丁酯为有机溶剂、2 mL 0.05 mol/L KOH调节2 mL样品溶液为给出相,10 mmol/LKH2PO4(pH=3.0)为接收相;搅拌速率为500 r/min,萃取时间为17 min的尼古丁优化萃取条件。方法的线性范围0.1-50 mg/L,相关系数r2=0.9996;检出限为0.05 mg/L(S/N=3);相对标准偏差<5%(n=5);相对回收率为96.3%-102.2%。实验证明该法可用于唾液等生物体液中碱性物质的测定。

三相中空纤维式液相微萃取用于快速富集血浆中的尼古丁

建立了一种以三相中空纤维式液相微萃取（TP-HF—LPME）进行样品前处理，采用高效液相色谱快速、准确测定血浆中尼古丁含量的方法。研究表明陔方法集萃取、富集、净化为一步，极大地简化了传统血浆成分测定的前处理过程，是一种快速、有效、绿色的前处理方法。方法的线性范围为0．1～50mg／L，相关系数（r^2）为0．9996，检测限为0．05mg／L（信噪比为3），相对标准偏差小于5％。

固相微萃取-液相色谱联用技术研究进展

本文较系统地介绍了固相微萃取 液相色谱联用技术的原理、特点、发展现状及其发展趋势 。

微柱固相萃取-毛细管液相色谱在线联用技术

以填充毛细管柱作为固相萃取柱,通过定体积阀进样和阀切换技术与毛细管液相色谱在线联用.用65 mm×0.45 mm i.d. 5 μm C18毛细管填充柱作为萃取柱,以对甲氧基苯甲醛水标样考察了该系统性能.线性范围为0.01～0.5 mg/L;保留时间、峰高以及峰面积的相对标准偏差分别为1.4%～2.2%、4.2%～5.7%和6.0%～10.1%,标准曲线回归系数 （r） 大于0.998.与直接进样相比,所用方法使检出限降低3个数量级,浓度检出限为6.0 ng/L （S/N=3）.另外,对多环芳烃化合物的富集倍数在30～100倍.采用该方法在大连香炉礁海水中检测到了萘,通过向空白海水中加标样,确定海水中萘的检出限为0.128 μg/L （S/N=3）.填充毛细管固相萃取柱的优点是柱性能重复可靠,商品填料种类丰富.

动物源性食品兽药残留分析中样品前处理方法的研究进展

随着养殖业的迅猛发展,动物源食品兽药残留问题日益成为食品安全领域的重要内容,引起了世界范围内的广泛关注。动物源食品基质复杂,而其中残留的兽药含量甚微,因此,发展快速、简易、高灵敏度、高通量的兽药残留检测技术已成为迫切需要。样品前处理技术是农兽药残留分析的关键步骤,直接影响检测的结果。目前兽药残留检测中常用的样品前处理方法有液-液萃取、固相萃取、QuEChERS等。本文分别对兽药残留分析中常用的前处理技术进行比较全面的综述,对近年来各种前处理技术在兽药残留分析中的新应用进行了探讨,并对兽药残留检测技术在未来的发展方向作了进一步的展望。

四环素类药物在水产品中的存在形态研究及其分析应用

采用紫外分光光度法研究了四环素类药物(Tetracyclines,TCs)在不同pH条件下分子结构的变化,用分子荧光法、高效液相色谱法(HPLC)探讨了TCs在蛋白质基体中的存在形态,同时讨论了蛋白质对提取水产品样品中TCs残留的影响。结果表明,TCs与蛋白质有较强结合作用;适当浓度的(NH4)2SO4与HPLC流动相(甲醇-乙腈-0.02 mol/L草酸混合溶液,20∶20∶60,V/V)混合提取液可引起蛋白质缓慢且完全变性,导致蛋白质与TCs络合物离解,释放结合的药物,从而提高蛋白质样品中TCs残留提取的效率。本方法用于测定水产品中的土霉素、四环素、金霉素和强力霉素,测定回收率为88.2%～95.4%,RSD为1.3%～4.9%,检出限为14.8～39.2 ng/g。本方法操作步骤简单、快速、可靠。

液膜萃取技术在环境样品前处理中的应用

对液膜萃取技术在环境样品前处理中的应用进行了综述。其应用概括起来分为以下3类:以扁平膜为基础的支撑液膜萃取(SLME)和微孔膜液液萃取(MMLLE),以中空纤维膜为基础的液相微萃取(HFLPME)。分别介绍了这3类方法的萃取装置、原理及在环境样品前处理中的实际应用。

毛细管固相微萃取-液相色谱法测定水中的多环芳烃

建立了一种新的水环境样品预处理方法。将水相中目标污染物萃取至毛细管固定相中 ,经微量有机溶剂解吸 ,直接在高效液相色谱上进样分析。该方法对蒽、荧蒽和 1 ,2 苯并蒽 3种多环芳烃的检测限分别为0 .9μg L ,0 .7μg L和 0 .1 μg L。相对标准偏差 5 .1 %～ 6.3 % (n =7)。