Determination of Two Pesticides in Soils by Dispersive Liquid–Liquid Microextraction Combined with LC-Fluorescence Detection

In the present work, a simple, rapid and sensitive sample pre-treatment technique, dispersive liquid–liquid microextraction (DLLME) coupled with liquid chromatography-fluorescence detection (LC-FLD), has been developed to determine carbamate (carbaryl) and organophosphorus (triazophos) pesticide residues in soil samples. Methanol was first used as extraction solvent for the extraction of pesticides from the soil samples and then as dispersive solvent in the DLLME procedure. Under the optimum extraction conditions, the linearity was obtained in the concentration range of 0.1–1,000 ng g⁻¹ for carbaryl and 1–5,000 ng g⁻¹ for triazophos, respectively. Correlation coefficients varied from 0.9997 to 0.9999. The limits of detection (LODs), based on signal-to-noise ratio (S/N) of 3, ranged from 14 to 110 pg g⁻¹. The relative standard deviation (RSDs, for 20.0 ng g⁻¹ of each pesticide) varied from 1.96 to 4.24% (n = 6). The relative recoveries of two pesticides from soil A1, A2 and A3 at spiking levels of 10.0, 20.0 and 50.0 ng g⁻¹ were in the range of 88.2–108.8%, 80.8–110.7% and 81.0–111.1%, respectively. The results demonstrated that DLLME was a sensitive and accurate method to determine the target pesticides, at trace levels, in soils.

     

Analysis of Chlorpyrifos in Water,Fruit Juice,and Honeybee Extract by Chemiluminescent Elisa

Abstract

The suitability of competitive enzyme-linked immunosorbent assays (ELISAs) with chemiluminescent detection-based immobilized antigen (indirect assay) for rapid and accurate determination of chlorpyrifos in various food matrices was tested. The limit of detection (LOD) values were 1–1.75 ng mL^?1, the standard curve midpoint (IC₅₀) was 3.5 ng mL^?1, and the assay duration was 1.5 h. Assay application to the analysis of honeybee extract resulted in chlorpyrifos recoveries varying between 62 and 83% in 5–15 ng mL^?1 herbicide concentration range.     

水果风味物质的SPME-SPE-GC-MS 分析体系研究

水果果汁中的芳香性风味物质尽管含量很低,却是区别各种果汁最重要的1个特征参数,是判断果汁饮料的指纹性指标.近年来随着质谱技术的发展,因其快速准确的结构鉴定等优点而逐渐发展成为水果等天然产物风味物质结构鉴定的重要技术手段之一.水果中的风味物质主要为游离态挥发性香气成分、半挥发性有机物、以及以键合态存在的有机物[1,2],系统的检测体系研究报道不多,本文以芒果为例,结合SPME、固相萃取(SPE)以及酶解技术开发系统分析风味物质的前处理体系,优化GC-MS条件,快速、全面的分析风味物质,为我国西部地区丰富天然水果资源的进一步开发利用起探索性指导作用.     

Application of DLLME to Isolation and Concentration of Non-Steroidal Anti-Inflammatory Drugs in Environmental Water Samples

Dispersive liquid–liquid microextraction (DLLME) coupled with liquid chromatography-tandem mass spectrometry detection was applied for determination of selected anti-inflammatory pharmaceuticals: ibuprofen, ketoprofen, naproxen and diclofenac. Development of DLLME procedure included optimisation of several important parameters such as kind and volume of extracting and dispersive solvents as well as sample pH. Under optimised conditions a two-step extraction with sonication was used. Chloroform was applied as the extracting and acetone as dispersing solvent. Calibration curves ranges were 1–500 μg L^?1 for naproxen and ibuprofen and 0.25–500 μg L^?1 for ketoprofen and diclofenac with correlation coefficients at least 0.997. Limits of quantitation were from 0.5 to 10 ng L^?1. The developed analytical method was employed for determination of ibubrofen, ketoprofen, naproxen and diclofenac in river and tap water samples. The results showed that DLLME is a simple, rapid and sensitive analytical technique for the pre-concentration of trace amounts of pharmaceuticals in environmental water samples.     

流动注射在线预富集—同步扫描荧光法分析水样中痕量多环芳烃

建立了苯并［ａ］芘和的流动注射在线预富集－同步扫描荧光检测法，方法简便快速。苯并［ａ］芘和的测定下限分别为０２μｇ／Ｌ和００４μｇ／Ｌ。测定的相对标准偏差分别为：７１１％和７５４％。用于实际水样的测定，苯并［ａ］芘的回收率为９０％～１０３３％，为１０３３％～１１６７％，结果满意。     

Determination of Hg(II) in Environmental Water Samples Using DLLME Method Prior to GC-FID

Mercury exists in two forms in environment, inorganic salts and organic compounds. Determination of mercury is very important, due to its health effects. In the present research, diphenylation of mercury using phenylboronic acid as a derivatization reagent was used for the determination of Hg(II) in real water samples. A simple, rapid and cheap method named dispersive liquid–liquid microextraction was used for the extraction of analyte under the following conditions: extraction solvent 16 μL of carbon tetrachloride, disperser solvent 1 mL of ethanol and sample volume 5 mL. Under the optimal conditions, the enrichment factor for diphenylmercury was 931 and the limit of detection calculated on the basis of five replicates was 0.004 μg mL⁻¹. The repeatability of the method expresses as relative standard deviation was 5.1 (n = 6). The linear range was between 0.01 and 10 μg mL⁻¹. The performance of the proposed technique was evaluated for the determination of mercury in different environmental water samples.

     

Determination of Hg(II) in Environmental Water Samples Using DLLME Method Prior to GC-FID

Mercury exists in two forms in environment, inorganic salts and organic compounds. Determination of mercury is very important, due to its health effects. In the present research, diphenylation of mercury using phenylboronic acid as a derivatization reagent was used for the determination of Hg(II) in real water samples. A simple, rapid and cheap method named dispersive liquid–liquid microextraction was used for the extraction of analyte under the following conditions: extraction solvent 16 μL of carbon tetrachloride, disperser solvent 1 mL of ethanol and sample volume 5 mL. Under the optimal conditions, the enrichment factor for diphenylmercury was 931 and the limit of detection calculated on the basis of five replicates was 0.004 μg mL^?1. The repeatability of the method expresses as relative standard deviation was 5.1 (n = 6). The linear range was between 0.01 and 10 μg mL^?1. The performance of the proposed technique was evaluated for the determination of mercury in different environmental water samples.     

综合性实验——纯净水与果汁瓶材料的剖析

设计了一个高分子材料与工程专业的综合性教学实验。利用FT-IR、UV-Vis和DSC三种方法,对生活中常见的纯净水瓶(PET)和果汁瓶(PP)材料进行了剖析,确认出两种材料的组成,合理解释了当沸腾后的热水倒入纯净水瓶时,瓶体会明显变软、变形,而果汁瓶不发生变形的原因。该实验加深了学生对常用高分子材料结构与性能的认识,已应用在三届学生的专业实验教学中,教学效果良好。     

重氮偶合表面增强拉曼光谱快速分析椰汁中西维因

基于水解西维因/重氮偶合反应生成具有拉曼增强信号偶氮化合物的方法,以具有核壳结构的Au@SiO2纳米颗粒(由约55 nm的Au核和约1~2 nm的SiO2壳层组成)为增强基底,建立了偶氮化合物间接测定西维因含量的新方法,并对反应条件和测试方法进行了优化。在优化条件下,方法的线性范围为5.0~100.0 mg/L,检出限为1.7 mg/L。方法应用于椰汁中西维因的检测,回收率为100.4%~105.1%,相对标准偏差(RSD)为2.8%~4.9%。该方法简便快速、成本低、样品用量少,可实现现场的快速检测。     

分散液相微萃取-石墨炉原子吸收光谱法测定水样中痕量铅

基于分散剂乙醇(0.5mL)和萃取剂四氯化碳(30μL)的协同作用,可使水样(5.0mL)中痕量铅(Ⅱ)与吡咯烷基二硫代氨基甲酸铵(APDC,0.012g·L-1)所形成的螯合物,在pH 7.0及55℃的条件下迅速借分散液相微萃取(DLLME)进入四氯化碳的液滴中,从而达到样品中痕量铅的分离与富集。其含量用连续光源石墨炉原子吸收光谱法予以测定。铅的线性范围在1.00~40.00μg·L-1之间,其检出限(3s/k)为0.15μg·L-1。应用本法测定了自来水和河水中痕量铅,加标回收率在96.8%~105%之间,测定值的相对标准偏差(n=10)均小于5%。     

Determination of Low-Level Ethylenediaminetetraacetic Acid in Water Samples by Ion Chromatography with Ultraviolet Detection

A convenient and sensitive ion chromatographic (IC) method for the analysis of ethylenediaminetetraacetic acid (EDTA) in water samples was proposed. Using a fast reversible reaction of free EDTA and metal–EDTA complexes into Fe(III)–EDTA complex in the presence of Fe(III) ions, sample solutions were applied to an ion-exchange column using a mobile phase (pH 2.3), which was composed of 100 μM Fe(III) chloride and 5 mM methanesulfonic acid. The addition of Fe(III) solution (100 μL) containing 10 mM Fe(III) chloride and 0.5 M methanesulfonic acid to the sample solution (10 mL) permitted the injection of a large volume (400 μL) of sample, which allowed for greater sensitivity. The proposed IC method gave a highly linear (r ² > 0.999) calibration curve ranging 0.005–1.0 μM EDTA and had a limit of detection of 1.5 nM. High repeatability (RSD < 2.1%) and recoveries (88–108%) were also obtained. With this method, total EDTA level in raw and drinking waters were analyzed successfully.     

果汁中有机磷农药残留的动态液相微萃取/气相色谱法检测

应用动态液相微萃取与气相色谱联用技术建立了果汁中3种有机磷农药(敌敌畏、甲基对硫磷、对硫磷)的快速分析方法.考察了萃取溶剂、溶剂体积、萃取次数、水样pH值以及离子强度对液相微萃取的影响.3种有机磷农药的线性范围均为40 ～400 μg·L-1,富集倍数22.3 ～51.5,回收率80% ～120%,相对标准偏差2.0% ～8.1%,检出限12.2 ～20.6 μg·L-1.     

竹炭固相萃取/气相色谱-质谱联用对环境水样中16种多环芳烃的测定

以竹炭为固相萃取吸附材料,考察了其对环境水样中16种多环芳烃的吸附富集能力,采用DB-35MS弹性石英毛细管色谱柱对16种多环芳烃进行分离,气相色谱-质谱联用法对多环芳烃进行定性及定量分析.结果表明,1 000 mg竹炭作为固相萃取吸附剂,10 mL二氯甲烷作为洗脱剂,上样速率5 mL/min,水样中甲醇体积分数为15%的条件下,16种多环芳烃有较好的回收率,竹炭固相萃取柱的穿透体积大于500 mL,通过实验比较竹炭的萃取回收率优于商品化的C18固相萃取柱.16种多环芳烃的质量浓度在10 ～500 ng/L范围内与峰面积的线性关系良好(苯并(k)荧蒽,苯并(a)芘,二苯并(a,h)蒽,苯并(g,h,i)苝为25 ～500 ng/L),相关系数为0.983 6 ～0.998 4.方法的检出限为0.6 ～8.0 ng/L,实际水样的加标回收率为67% ～113%,相对标准偏差为2.1% ～11.3%.通过对白沙河河水的分析表明,该方法能够满足实际水样的测定,竹炭可以作为固相萃取材料应用于水中16种多环芳烃的分析测定.     

Determination of Allura Red and Tartrazine in Food Samples by Sequential Injection Analysis Combined with Voltammetric Detection at Antimony Film Electrode

An antimony film electrode prepared on‐line and installed as part of a sequential injection system, was used as an electrochemical detector to determine azo dyes in food samples. The influence of several flow variables were evaluated using a central composite design. In optimal conditions, the linear range of the calibration curve varied from 1–5 µM, with a limit of detection limit of 0.3 µM. The relative standard deviation of analytical repeatability was <5.0 %.The method was validated by comparing the results obtained with those provided by HPLC; no significant difference were seen.     

微波等离子体原子发射光谱法(MP-AES)测定果汁中的常量元素

介绍了使用配有Agilent 4107氮气发生器的Agilent 4200微波等离子体原子发射光谱法(MPAES)分析果汁样品中的钙、镁、钠和钾等常量元素的分析方法,在分析两种质量控制(QC)测试材料时,加标回收率在90%~110%,6h中所有四种元素的相对标准偏差(RSD)均小于4%。与火焰原子吸收光谱法(FAAS)相比,MP-AES的等离子体源在检出限和线性动态范围等性能方面有所改善,MP-AES无需使用可燃性气体,也无需使用昂贵又费时的改性剂和电离抑制剂,对标准物质的测定结果与标准值基本一致。4200 MP-AES将是替代火焰原子吸收仪器的理想选择。     

配位聚合物固相萃取/气相色谱-质谱联用法测定环境水样中的6种多环芳烃

制备了一种二维的[Zn(benzotriazole)2]n配位聚合物,并经过XRD、SEM及元素分析法的表征,将其用于富集萃取环境水样中的6种重质多环芳烃,该配合物对于含多苯环的化合物显示出较强的吸附力。实验中分别对填料用量、淋洗剂、洗脱剂的种类及用量、穿透体积等参数进行考察,并将其与同等上样量及加标量的C18固相萃取小柱进行对比,建立了水样中6种多环芳烃的气相色谱-质谱联用检测方法。结果表明,使用200mg[Zn(benzotriazole)2]n配合物作为固相萃取填料,以10%甲醇为淋洗剂,0.5mL丙酮和5mL二氯甲烷作为洗脱剂,在上样体积为200mL、流速为4mL/min的条件下,6种多环芳烃均具有较高的回收率。荧蒽(Flan)、苯并(b)荧蒽(BbF)、苯并(g,h,i)芘(BghiP)的质量浓度在20～1000μg/L范围内,苯并(k)荧蒽(BkF)、苯并(a)芘(BaP)、茚并(1,2,3-Cd)芘(InP)在10～500μg/L范围内与峰面积呈良好线性关系,相关系数为0.9968～0.9993。方法的检出限为0.45～10.7ng/L,加标回收率为77%～112%,相对标准偏差为3.8%～8.5%。结果表明,该方法具有成本低、灵敏度高等特点,能够满足实际水样中6种多环芳烃的测定要求。     

Determination of Tetracyclines in Water Samples Using Liquid Chromatography with Fluorimetric Detection

A liquid chromatographic method with fluorimetric detection is proposed for the determination of trace levels of oxytetracycline, tetracycline, chlortetracycline and doxycycline in water samples. The analytes are preconcentrated by solid phase extraction using reversed phase polymeric cartridges and acetonitrile as eluent. Preconcentration factors up to 125 can be obtained. The chromatographic separation is performed on a polymeric column with a gradient elution program using mobile phases based on mixtures of acetonitrile and 0.01 mol L^?1 oxalic acid aqueous solution at a flow rate of 1.2 mL min^?1. Tetracyclines are post-column derivatized with a reagent solution consisting of 0.1 mol L^?1 Mg(II) at pH 9 at a flow rate of 0.6 mL min^?1. The highly fluorescent Mg(II) chelates are detected at λ _ex = 374 nm and λ _em = 499 nm. The detection limits of the whole process are in the low μg L^?1 level. The proposed method has been applied to the analysis of spiked natural water samples, and recovery rates higher than 80% have been obtained.     

流动注射-毛细管电泳直接紫外测定环境水中硝酸根和亚硝酸根

采用流动注射与毛细管电泳联用（FI-CE）接口进行自动连续采样。对检测波长、电渗流改性剂浓度、载流中四硼酸钠浓度、载流PH、载流流速及采样环体积等条件进行优化，并对环境水样中常见阴离子的干扰进行研究，建立了同时测定水中硝酸根和亚硝酸根的方法。在采样量为50μl时硝酸根和亚硝酸根的检出限（3σ）分别为0.2和0.4mg/L；峰高RSD分别为1.6%和2.0%(20mg/L,n=25)，峰面积RSD分别为1.7%和1.6%(20mg/L,n=25)，采样频率为60/h。用本法测定井水水样的结果与离子色谱法一致。水样中加入10mg/L硝酸根和亚硝酸根的回收率为98%-108%。     

Solid-Phase Extraction and LC with Fluorescence Detection for Analysis of PAHs in Rainwater

The efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) from rainwater by solid-phase extraction (SPE) with three different types of cartridge, and analysis by high-performance liquid chromatography with fluorescence detection, are discussed in this paper. Three cartridges were investigated but only one was suitable. After equilibration in a desiccator for 65–80 h or in ambient air for 90–100 h the SPE cartridges were activated with 5 mL dichloromethane then 5 mL 2-propanol. The volume of sample passed through the cartridges was 50 mL; after loading of the sample the cartridges were dried under vacuum for approximately 20 min by application of a pressure of 15 mbar to the SPE manifold. The PAHs were eluted with 5 mL dichloromethane–hexane, 50:50 (v/v). The flow rate used for conditioning, sample loading, and elution was 2.5 mL min⁻¹, achieved by application of a pressure of 6 mbar. For analysis of PAHs in rainwater, recovery was between 67 and 99%, the relative standard deviation varied between 2 and 5%, and the detection limits of the method were less than 16.9 ng L⁻¹ for several PAHs. These optimum conditions were used for analysis of rainwater collected between June 2002 and May 2003 at two sites in Alsace (eastern France) and 17 PAHs were quantitatively determined. Concentrations varied between 1.6 and 968.1 ng L⁻¹.     

LC-Fluorescence Detection of Abamectin, Ivermectin, Doramectin, and Eprinomectin in Rabbit Feces

A simple multi-residue method was developed for the simultaneous determination of abamectin, ivermectin, doramectin, and eprinomectin in rabbit feces. Samples were extracted with acetonitrile, cleaned up with a C18 solid-phase extraction cartridge, and analysed by LC with fluorescence detection after derivatization. Abamectin, ivermectin, doramectin, and eprinomectin were detected at levels of 2–500 ng g^?1; the average recoveries ranged from 73.2 to 99.6% with relative standard deviations of 2.5–11.3%. The limits of detection were 0.1–0.4 ng g^?1.