液相色谱–串联质谱法测定甘蓝中4-羟基百菌清的残留量

建立液相色谱–串联质谱法测定甘蓝中4-羟基百菌清残留的方法。以乙腈提取样品中的4-羟基百菌清,采用电喷雾负离子源(ESI–)和多重反应监测(MRM)模式测定,基质匹配标准工作曲线法定量。结果表明,甘蓝中4-羟基百菌清的质量浓度与其色谱峰面积呈良好的线性关系(r=0.999),线性范围为1.0~100μg/L,方法检出限为0.31μg/kg,定量限为1.0μg/kg。在5,10,50μg/kg 3个添加水平下,方法的回收率为88.0%~91.4%,测定结果的相对标准偏差为4.6%~7.2%(n=6)。该法简单、准确、快速、灵敏,符合法规残留限量监测要求。     

气相色谱法同时测定荞麦中百菌清、三唑酮和拟除虫菊酯类农药残留量

采用气相色谱法同时测定荞麦中百菌清、三唑酮和拟除虫菊酯类农药残留量。样品经石油醚-丙酮(4+1)混合溶剂提取后,所得提取液经层析柱净化浓缩,于气相色谱(带电子捕获检测器)测定。百菌清、三唑酮和4种拟除虫菊酯类杀虫剂的线性范围均为0.02~5.0 mg.L-1,方法的检出限(3S/N)均小于0.02 mg.L-1。在三个标准加入水平下进行了回收率和精密度试验,所得回收率在80.4%~111.6%之间,相对标准偏差(n=8)小于8.0%。     

气相色谱-串联质谱法测定鱼肉中毒死蜱及其代谢产物3,5,6,-三氯-2-羟基吡啶的残留量

采用气相色谱-串联质谱法(GC-MS/MS)测定鱼肉中毒死蜱及其代谢产物3,5,6,-三氯-2-羟基吡啶(TCP)残留量。样品经1mol·L-1盐酸-乙腈(1+99)混合液提取,提取液于-20℃冷冻去除脂肪,浓缩近干,残渣用乙酸乙酯溶解后与N-甲基-N-叔丁基二甲基硅基三氟乙酰胺进行衍生反应,产物经净化后采用GC-MS/MS测定。毒死蜱和TCP的线性范围分别为2.0~2 000,1.0~1 000μg·L。鱼肉中毒死蜱和TCP的检出限(3S/N)分别为0.5,0.3μg·kg-1,测定下限(10S/N)分别为1.7,1.0μg·kg-1。加标回收率分别为84.6%~95.6%,73.8%~82.7%,测定值的相对标准偏差(n=6)分别小于10%,13%。     

中空纤维膜液相微萃取-气相色谱质谱法测定水中的百菌清

研究了用中空纤维膜液相微萃取-气相色谱质谱法测定水中的百菌清。通过实验确定最佳萃取条件为:萃取剂为甲苯,萃取剂用量3μL,水样体积10mL,萃取温度为45℃,萃取时间为15 min,搅拌速率为500 r/min,萃取后取1μL有机溶剂直接进样进行气相色谱质谱分离检测。在此条件下,百菌清的富集倍数为450倍,方法的线性范围为5~600μg/L,检出限为0.5μg/L。测定实际水样的加标回收率在92.3%~96.0%之间。该方法可以用于水中百菌清的快速检测。     

溶解态菲及其中间代谢产物1-羟基-2-萘甲酸的同时测定

运用导数-同步荧光光谱建立了快速同时测定溶解态菲(Phenanthrene,Phe)及其中间代谢产物1-羟基-2-萘甲酸(1-Hydroxy-2-naphthoic acid,1H2NA)的分析方法。所建方法同时测定Phe与1H2NA的线性范围分别为4.0~1.0×103μg/L和4.0~1.2×103μg/L,检出限分别为0.08μg/L和0.07μg/L,加标回收率分别为96.5%~105.3%和99.2%~106.5%,相对标准偏差均小于1.0%。该方法可应用于实验室条件下溶解态Phe微生物降解过程中Phe和1H2NA的测定,具备原位研究Phe降解过程中间代谢产物1H2NA的应用潜力。     

测定茶叶中二氯联苯的酶联免疫吸附分析新方法

建立了测定茶叶中痕量3,4-二氯联苯(PCB12)的间接竞争酶联免疫吸附分析(ELISA)新方法。工作曲线方程为I=62.01+17.55lgρ,相关系数为0.9833,方法灵敏度IC50(抑制率50%)时PCB12的质量浓度达到0.207μg/L,检出限IC20(抑制率为20%时)PCB12的质量浓度为4.0 ng/L,交叉率小于1.0%。对市售铁观音茶叶做简单前处理后,用ELISA方法检测。加标回收实验显示回收率为94.5%~112.4%,相对标准偏差为4.0%~12%。     

QuEChERS-UHPLC-MS/MS法测定烟草中硝苯菌酯EI北大核心CSCD

建立了Qu ECh ERS-UPLC-MS/MS测定烟草中硝苯菌酯(2,4-DNOPC)残留的方法。烟草样品采用改进的Qu ECh ERS技术提取,在碱性条件下超声水解后进样分析,采用负离子多反应监测(MRM)模式检测,通过测定2,4-DNOPC相应的水解产物2,4-二硝基-6-(1-甲基庚基)苯酚(2,4-DNOP)来计算烟草中硝苯菌酯残留量。结果表明,2,4-DNOPC质量浓度在0.001~0.5 mg/L范围线性关系良好,相关系数(r2)大于0.999,检出限为3μg/kg,2,4-DNOPC在烟草中的回收率为92.4%~100.5%,RSD为2.5%~3.3%。方法适用于烟草中硝苯菌酯残留量的检测。     

分散液相微萃取-气相色谱联用测定葡萄中百菌清、克菌丹和灭菌丹残留

采用分散液相微萃取与气相色谱-电子捕获检测联用技术建立了测定葡萄样品中百菌清、克菌丹和灭菌丹农药残留的新方法.对影响萃取和富集效率的因素进行了优化.萃取条件选定为在10 mL带塞离心试管中加入 5.0 mL葡萄样品溶液,并加入1.0 mL丙酮(分散剂),振荡摇匀后以5000 r/min离心5 min,然后将上层清液转移至另一离心试管中,加10.0 μL氯苯(萃取剂),分散混匀后再以5000 r/min离心5 min,萃取剂氯苯相沉积到试管底部,吸取1.0 μL萃取相直接进样分析.在优化的实验条件下,3种杀菌剂的富集倍数可达788～876倍;检出限在6.0～8.0 μg/kg(S/N=3∶ 1)范围内.以α-六六六为内标,测定3种杀菌剂的线性范围为10～150 μg/kg,线性相关系数在0.9990～0.9995范围内.本方法已成功应用于葡萄样品中百菌清、克菌丹和灭菌丹残留的测定,平均加标回收率在92.3%～106.1%范围内;相对标准偏差在4.5%～7.2%之间,结果令人满意.     

QuEChERS-UHPLC-MS/MS法测定烟草中硝苯菌酯

建立了Qu ECh ERS-UPLC-MS/MS测定烟草中硝苯菌酯(2,4-DNOPC)残留的方法。烟草样品采用改进的Qu ECh ERS技术提取,在碱性条件下超声水解后进样分析,采用负离子多反应监测(MRM)模式检测,通过测定2,4-DNOPC相应的水解产物2,4-二硝基-6-(1-甲基庚基)苯酚(2,4-DNOP)来计算烟草中硝苯菌酯残留量。结果表明,2,4-DNOPC质量浓度在0.001~0.5 mg/L范围线性关系良好,相关系数(r2)大于0.999,检出限为3μg/kg,2,4-DNOPC在烟草中的回收率为92.4%~100.5%,RSD为2.5%~3.3%。方法适用于烟草中硝苯菌酯残留量的检测。     

氨基甲酸酯类杀虫剂速灭威酶联免疫吸附分析方法研究

利用间-甲酚和β-丙氨酸合成了速灭威半抗原β-(间-甲基苯氧基羰基)氨基丙酸(HOM)。通过活泼酯法将HOM交联于牛血清白蛋白(BSA)和卵清蛋白(OVA)上;HOM-BSA为免疫原制备了速灭威的兔抗血清,ELISA法测得其效价高达1.28×106,交叉反应测定表明抗体方法特异性识别速灭威。对离子强度等影响因素进行了研究,确定了速灭威酶联免疫吸附分析方法(ELISA)的最佳工作条件,建立了定量测定速灭威的间接竞争ELISA方法,结果表明,该方法检测线性范围为1~10000μg/L;IC50为40.74μg/L;检出限为0.08~0.10μg/L;批内相对标准偏差为2.9%;批间相对标准偏差4.6%。土壤、稻谷和水中的平均添加回收率分别为80%、93.4%和107%。本研究建立了一种快速检测环境和农产品中速灭威残留的有效方法。     

Reliable enzyme immunoassay detection for chlorothalonil: fundamental evaluation for residue analysis and validation with gas chromatography

This work describes the analytical performance of the enzyme-linked immunosorbent assay (ELISA) for the fungicide chlorothalonil to effectively exploit as a simple and rapid detection system for pesticide residue on the scenes of the agricultural production and distribution. This ELISA represents the satisfactory analytical characteristics (I50 value, 0.34 ng/g; limit of detection, 0.052 ng/g) to detect chlorothalonil at the regulatory values or thereabout in a sample. Noticeable cross-reactivities were shown with two fungicides, fthalide (58.8%) and pentachloronitrobenzene (quintozene) (20.0%), and some non-agrochemicals such as tetrachloroterephthalonitrile (96.8%) and tetrachlorophthalonitrile (68.3%). The influence of three organic solvents (methanol, acetone, and acetonitrile) used as extractants for chlorothalonil residue was evaluated, with the result that methanol was the most suitable solvent for the ELISA, and the final concentration in the well could be up to 5% (v/v) without any negative influence on the ELISA. It has been possible to directly analyze chlorothalonil residue only by giving dilution of each sample extract with water prior to the ELISA analysis. The average recovery values from the spiked samples by the ELISA were between 101.7 and 113.6% with the average coefficients of variation between 2.6 and 5.9%. Although the results obtained from the ELISA correlated well with those from the reference GC/MS methods for all agricultural samples (r>0.98), the linear function inclined to the ELISA results because of loss during complex sample preparations for GC/MS analysis. Nevertheless, the results demonstrated that the proposed ELISA is a reliable, cost-effective, and rapid quantitative method for chlorothalonil residue.     

Single‐step modified QuEChERS for determination of chlorothalonil in shallot (Allium ascalonicum) using GC‐μECD and confirmation via mass spectrometry

A single extraction method was developed for chlorothalonil in shallot using gas chromatography with an electron capture detector (GC‐μECD). Samples were extracted with single‐step modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method using ethyl acetate as an extraction solvent. Significant matrix effects were observed, and the calibration curve was constructed from the matrix. The linearity of the analytical response across the studied range of concentrations (0.01–1.00 mg/L) was excellent, obtaining a correlation coefficient (r²) of 0.996. >0.996. Recovery studies were carried out on spiked shallot blank samples, at two concentration levels (0.4 and 2.0 mg/kg) with three replicates performed at each level. Mean recoveries of 97.2–104.9% with RSDs of 1.3–2.7% were obtained. The method is demonstrated to be suitable for the determination of chlorothalonil in shallot. The dissipation rates of chlorothalonil were described using first‐order kinetics, and its half‐life was 2.8 days. Based on the dissipation pattern of the pesticide residues, the pre‐harvest residue limit (PHRL) was also calculated. Residues were confirmed via mass spectrometry. Copyright © 2012 John Wiley & Sons, Ltd.     

Gas chromatographic determination of chlorothalonil and its metabolite 4-hydroxy-2,5,6-trichloroisophtalonitrile (HTI) in water

Summary A gas chromatographic method, with electron capture detection and mass spectrometric confirmation, is described for the determination of chlorothalonil and its metabolite 4-hydroxy-2,5,6-trichloroisophtalonitrile (HTI) in water samples. Water is saturated with sodium chloride and acidified to pH<2 with dilute sulfuric acid. After extraction with dichloromethane, HTI was methylated with diazomethane. The extract obtained was cleaned with basic alumina. Chlorothalonil and the methylated HTI-derivative were determined by gas chromatography with electron capture detection (GC-ECD) and confirmed by gas chromatography-mass spectrometry (GC-MS). The limit of detection, depending on the nature of the water samples is for both compounds between 0.01–0.03 g 1^–1 water. The average recovery in ground water is 87% for chlorothalonil and 82 % for HTI.     

头孢噻呋人工牛血清抗原的合成与原子力显微镜鉴定

采用N-羟基琥珀酰亚胺与双环己基碳酰二亚酰胺联用的方法将兽药头孢噻呋与牛血清白蛋白偶联,得到头孢噻呋人工牛血清抗原.通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS - PAGE)、电喷雾质谱( ESI MS)证实头孢噻呋人工牛血清抗原合成成功,计算得到头孢噻呋与牛血清蛋白的结合比约为8,并首次尝试将原子力显微镜(AFM...     

Comparison of Multicomponent Determination of Iprodione,Procymidone and Chlorothalonil by Partial Least Squares Modelling Using Spectrophotometric and High-Performance Liquid Chromatography Data

Abstract

A Partial Least Squares (PLS) calibration method was applied to the simultaneous determination of iprodione, procymidone and chlorothalonil in mixtures, by uv-vis absorption spectrophotometry and by high performance liquid chromatography (HPLC). Signals and first-derivative (¹D) signals were used to optimize the calibration matrices by the PLS-1 method. Quantitative results are presented for synthetic mixtures and for extracts from soil and groundwater samples. Significant improvements were achieved by using the PLS-1 method built with first-derivative chromatograms, in the determination of iprodione, procymidone and chlorothalonil in environmental samples.     

Dual‐Amplification of Antigen–Antibody Interactions via Backfilling Gold Nanoparticles on (3‐Mercaptopropyl) Trimethoxysilane Sol‐Gel Functionalized Interface

A new dual‐amplification strategy of electrochemical signaling from antigen–antibody interactions was proposed via backfilling gold nanoparticles on (3‐mercaptopropyl) trimethoxysilane sol‐gel (MPTS) functionalized interface. The MPTS was employed not only as a building block for the electrode surface modification but also as a matrix for ligand functionalization with first amplification. The second signal amplification strategy introduced in this study was based on the backfilling immobilization of nanogold particles to the immunosensor surface. Several coupling techniques, such as with nanogold but not MPTS or with MPTS but not nanogold, were investigated for the determination of carcinoembryonic antigen (CEA) as a model, and a very good result was obtained with nanogold and MPTS coupling immunosensor. With the noncompetitive format, the formation of the antigen–antibody complex by a simple one‐step immunoreaction between the immobilized anti‐CEA and CEA in sample solution introduced membrane potential change before and after the antigen–antibody interaction. Under optimal conditions, the proposed immunosensor exhibited a good electrochemical behavior to CEA in a dynamic concentration range of 4.4 to 85.7 ng/mL with a detection limit of 1.2 ng/mL (at 3 δ). Moreover, the precision, reproducibility and stability of the as‐prepared immunosensor were acceptable. Importantly, the proposed methodology would be valuable for diagnosis and monitoring of carcinoma and its metastasis.     

Convergent synthesis of a fully phosphorylated GPI anchor of the CD52 antigen

A fully phosphorylated GPI anchor (1) of the CD52 antigen was synthesized by a highly convergent strategy. After a trimannose and a phospholipidated pseudodisaccharide were prepared separately, they were coupled together to form the GPI core, which was then phosphorylated to introduce two phosphoethanolamine moieties in one step to afford CD52 GPI in its fully protected form. Finally, global deprotection of the product resulted in 1.     

Synthesis of trisaccharide-coated magnetic nanoparticles for antibody removal

An efficient strategy for the synthesis of blood group A trisaccharide antigen has been developed. Magnetic nanoparticles having Fe₃O₄-Silica core-shell structure were prepared and functionalized with the prepared blood group A trisaccharide antigen derivative, and its excellent removal ability toward anti-A antibody was explored.     

基于温度敏感水凝胶的雌二醇荧光免疫分析

雌二醇完全抗原(Ag)与异丙基丙烯酰胺(NIPA)共聚,可得水凝胶－抗原结合物(pNIPA－Ag),pNI－PA-Ag与游离的雌二醇(E₂)竞争有限的荧光标记的单抗McAb-F,利用水凝胶温度相变的性质,分离高分子免疫复合物,并测定其荧光信号.结果表明,游离E₂在10～625ng/mL范围内呈线性关系,样品的回收率为88.9%～102.0%.     

Pesticide residue levels in peppers cultivated in Souss Masa valley (Morocco) after multiple applications of azoxystrobin and chlorothalonil

Residue levels of azoxystrobin and chlorothalonil were determined in peppers grown in an experimental greenhouse. These two pesticides were selected on the basis of previous excesses of 26 and 24%, respectively, found in peppers samples cultivated in 2008 in eastern Morocco. The measurements were made over a 7 week period in which up to three successive treatments with azoxystrobin and a 4 week period in which up to three successive treatments with chlorothalonil were carried out. In all cases, plants were sprayed separately with azoxystrobin and chlorothalonil with application rates of active ingredients of 50 and 200?cc?hl^?1, respectively. Sampling was carried out at 0, 2, 4, 7, 12, 15 and 22 days for azoxystrobin and 0, 1, 3, 7, 8 and 10 days for chlorothalonil. Residue levels of azoxystrobin and chlorothalonil were determined by liquid–liquid extraction (LLE) and gas chromatography with electron-capture detector (GC-ECD). During the study, residue levels in the plantation ranged between 1.14 and 0.02?mg?kg^?1 for azoxystrobin and between 0.55 and 0.04?mg?kg^?1 for chlorothalonil. The application of an intensive washing process to the pepper samples did not lead to a significant reduction in the residue levels of either pesticide. Likewise, significant differences were not found between the residue levels in the ‘edible’ and ‘inedible’ parts of the peppers.