Determination of pyrimethanil and kresoxim-methyl in soils by headspace solid-phase microextraction and gas chromatography-mass spectrometry

A method using headspace solid-phase microextraction (HS-SPME) then gas chromatography–mass spectrometry with selected ion monitoring (GC–MS, SIM) has been developed for determination of trace amounts of the fungicides pyrimethanil and kresoxim-methyl in soil and humic materials. Both fungicides were extracted on to a fused-silica fibre coated with 85 m polyacrylate (PA). Response-surface methodology was used to optimise the experimental conditions. For soil samples the linear dynamic range of application was 0.004–1.000 g g^–1 for pyrimethanil and 0.013–1.000 g g^–1 for kresoxim-methyl. The detection limits were 0.001 g g^–1 and 0.004 g g^–1 for pyrimethanil and kresoxim-methyl, respectively. HP-SPME–GC–MS analysis was highly reproducible—relative standard deviations (RSD) were between 6.7 and 12.2%. The method was validated by analysis of spiked matrix samples and used to investigate the presence of pyrimethanil and kresoxim-methyl above the detection limits in soil and humic materials.     

2-甲氧基烟酸嘧霉胺盐晶体结构的研究

由嘧霉胺和2-甲氧基烟酸在乙醇介质中反应制得了化合物2-甲氧基烟酸嘧霉胺盐,经确证其晶体属于单斜晶系,空间群为P2(1)/n,a=1·0102(1)nm,b=0·7602(1)nm,c=2·3178(2)nm,β=96·74(2)°,V=1·7677(3)nm3,Dc=1·324g/cm3,Z=4,F(000)=744,μ=0·092mm-1,线性吸收系数μ(MoKα)=0·072mm-1。晶胞中不含结晶水,也不含配位水。每一个结构单元中有两个氢键,2-甲氧基烟酸嘧霉胺盐中不存在分子间氢键,主要靠范德华力在空间形成三维无限堆积结构。     

苯氧乙酸嘧霉胺盐的低温热容和热力学性质研究

用精密自动绝热量热计测定了苯氧乙酸嘧霉胺盐在81-380 K之间的低温热容. 结果表明, 该化合物在81-328 K之间无相变和热异常现象发生, 在328-354 K之间发生固-液熔化, 其熔化温度、摩尔熔化焓和摩尔熔化熵分别为(349.38±0.03) K, (34.279±10) kJ/mol和(98.13±0.05) J/（K·mol）. 根据热力学函数关系式计算出苯氧乙酸嘧霉胺盐在80-325 K之间以标准状态(298.15 K)为基准的热力学函数值.     

西番莲果中嘧霉胺残留的SPE-RP-HPLC降解分析

建立固相萃取-反相高效液相色谱法测定西番莲果中嘧霉胺的残留降解分析的方法.色谱柱为Shim-pack VP-ODS 150 mm×4.6 mm,流动相为甲醇:1％冰乙酸=90:10(V/V),流速为0.4 mL/min,进样量20μL.嘧霉胺在0.0760～21.20 mg/L(r=0.9964)范围内与峰面积呈良好线性关系,检出限为0.05 mg/L,嘧霉胺的回收率为85.6％～102.3％,相对标准偏差0.89％～2.7％.方法可作为西番莲果中嘧霉胺含量监测的控制方法.同时,还对嘧霉胺由西番莲果皮向西番莲果肉的迁移,在西番莲果体上的降解动态进行了测定.     

Application of an ultrasound-assisted surfactant-enhanced emulsification microextraction method for the analysis of diethofencarb and pyrimethanil fungicides in water and fruit juice samples

In this work, a simple, practical and environmentally friendly sample pre-treatment method, ultrasound-assisted surfactant-enhanced emulsification microextraction coupled with high performance liquid chromatography–diode array detector/electrospray ionisation mass spectrometry, was developed to determine diethofencarb and pyrimethanil residues in water and fruit juice samples. Tween 80 was used as an emulsifier and carbon tetrachloride was chosen as the extraction solvent, and no dispersive organic solvent was needed, which is typically required in common dispersive liquid–liquid microextraction methods. Several variables, such as the type and volume of extraction solvent and surfactant, extraction temperature and ultrasound extraction time were investigated and optimised. Under optimal conditions, the enrichment factors were 265 and 253 for diethofencarb and pyrimethanil, respectively. The limits of detection (LODs), calculated as three times the signal-to-noise ratio (S/N), were 0.01 μg L⁻¹ for both diethofencarb and pyrimethanil. The linearity of the method was obtained in the range of 0.05–2000 μg L⁻¹, with correlation coefficients of 0.9994–0.9998. The water (at fortified levels of 0.1 and 1.0 μg L⁻¹) and fruit juice samples (at fortified levels of 0.1 and 1.0 μg L⁻¹) were successfully analysed using the proposed method, and the relative recoveries were in the range of 88–114%, 93–111%, 86–117% and 94–101%, respectively.     

超高效液相色谱-串联质谱测定多种食品中抑霉唑、嘧霉胺、克百威、三唑磷、多菌灵的残留量

建立了超高效液相色谱-串联质谱法同时测定苦瓜、木瓜、菠萝、绿茶饮料等4种食品基体中抑霉唑、嘧霉胺、克百威、三唑磷、多菌灵的方法,对提取条件、净化条件、流动相、质谱条件进行了研究.待测样品直接用含1%冰乙酸的乙腈提取,乙二胺-N-丙基硅烷(PSA)吸附剂除杂,采用电喷雾离子源(ESI)、多反应监测正离子模式扫描,外标法定...     

Heat Capacity and Enthalpy of Fusion of Crystalline Pyrimethanil Decylate (C22 H33 N3 O2)

IntroductionPyrimidinamines are heterocyclic compounds withnovel biological activities[1].They have been applied tomedicine and pesticide syntheses for their importantphysiological-action[2,3].Compared with the free py-rimethanil,pyrimethanil salts have a reduced vapourpressure,which increases the persistence of the com-pounds on crops and they have increased activities inmany aspects.Pyrimethanil decylate(molecular formu-la:C22H33N3O2)is an important new compound.Itcan be synthesized by the…     

气相色谱-质谱联用法测定大蒜中的嘧霉胺、噻螨酮残留量

建立了大蒜中嘧霉胺、噻螨酮残留量的气相色谱-质谱联用(GC-MS)检测方法.大蒜样品经过微波处理,乙酸乙酯提取,硅胶柱净化,采用EI源、选择离子监测方式(SIM),并通过基质添加标准消除了基质效应.结果证明,方法定量下限噻螨酮为0.01 mg/kg,嘧霉胺为0.001 mg/kg,加标回收率范围73.5%～97.8%,相对标准偏差在2.3%～12.5%之间,该方法可实现快速、灵敏、准确的检测分析.     

Comparison of pyrimethanil-imprinted beads and bulk polymer as stationary phase by non-linear chromatography

A pyrimethanil-imprinted polymer (P1) was prepared by iniferter-mediated photografting a mixture of methacrylic acid and ethylene dimethacrylate onto homemade near-monodispersed chloromethylated polydivinylbenzene beads. The chromatographic behaviour of a column packed with these imprinted beads was compared with another column packed with irregular particles obtained by grinding a bulk pyrimethanil-imprinted polymer (P2). The comparison was made using the kinetic model of non-linear chromatography, studying the elution of the template and of two related substances, cyprodinil and mepanipyrim. Extension of the region of linearity, capacity factors for the template and the related substances, column selectivity, binding site heterogeneity, apparent affinity constant (K) and lumped kinetic association (k_a) and dissociation rate constant (k_d) were studied during a large interval of solute concentration, ranging between 1 and 2000 μg/ml. From the experimental results obtained, in the linearity region of solute concentration column selectivity and binding site heterogeneity remained essentially the same for the two columns, while column capacity (at 20 μg/ml, P1 = 23.1, P2 = 11.5), K (at 20 μg/ml, P1 = 8.3 × 10⁶ M⁻¹, P2 = 2.5 × 10⁶ M⁻¹) and k_a (at 20 μg/ml, P1 = 3.5 μM⁻¹ s⁻¹, P2 = 0.47 μM⁻¹ s⁻¹) significantly increased and k_d (at 20 μg/ml, P1 = 0.42 s⁻¹, P2 = 0.67 s⁻¹) decreased for the column packed with the imprinted beads. These results are consistent with an influence of the polymerisation method on the morphology of the resulting polymer and not on the molecular recognition properties due to the molecular imprinting process.