气相色谱-微池电子捕获检测器分析茶叶中杀螟丹的残留

介绍了一种快速、灵敏、可靠的适用于茶叶样品中杀螟丹残留量的气相色谱分析方法。茶叶样品经过0.05 mol/L盐酸溶液提取,液-液分配净化,在碱性条件下用正己烷萃取提取液中的杀螟丹,用毛细管气相色谱法-微池电子捕获检测器（μ-ECD）测定杀螟丹的残留量。结果表明：样品的添加回收率为70.2%~92.0%,相对标准偏差小于10%,方法的检测低限为0.01 mg/kg,符合农药残留分析的要求。     

杀螟丹和异杀螟丹及其降解产物的薄层层析分离和残留量测定方法

杀螟丹是一种新型杀虫剂,商品名Cartap,学名S,S’-[2-(二甲氨基)三甲撑]-双-硫赶氨基甲酸酯盐酸盐,动物毒性:LD_(50)250毫克/公斤。 在合成杀螟丹时,还将生成少量异杀螟丹。在一定条件下,二者将分别降解生成相应的沙蚕毒和异沙蚕毒。 关于杀螟丹的残留最分析方法,Nishi等在1970年已有报道。是以稀酸提取杀螟丹后,转     

亲水作用色谱-串联质谱法测定茶叶中杀螟丹农药残留量

采用亲水作用色谱-串联质谱(HILIC-MS/MS)测定茶叶中的杀螟丹农药残留。样品经乙腈-甲醇-乙酸(93:5:2)提取,C18固相萃取(SPE)或GCB与C18分散固相萃取(d-SPE)净化。以乙腈-10mmol/L乙酸铵为流动相,ZIC-HILIC色谱柱分离,电喷雾电离(ESI),多反应监测模式(MRM)质谱检测。结果表明,基质效应随着茶叶种类、样品质量的变化而变化。杀螟丹在0.005～0.5mg/L范围内线性关系良好(r2≥0.998),方法的定量下限(LOQ)为0.008mg/kg(绿茶)和0.005mg/kg(红茶)。采用绿茶和红茶基质进行1倍、5倍、10倍LOQ 3个水平的加标回收率实验,测得回收率为70%～89%,相对标准偏差(RSD)低于6%。该方法灵敏、准确,满足茶叶中杀螟丹农药残留检测的要求。     

对氨基苯甲酸修饰的金纳米粒子比色法检测水样中痕量杀螟丹

采用柠檬酸钠还原法合成粒径为13nm的金纳米粒子(AuNPs),并在其表面修饰上对氨基苯甲酸(PABA-AuNPs)。实验发现,当杀螟丹存在时,在一定的pH条件下,杀螟丹能够诱导PABA-AuNPs聚集,使AuNPs溶液从酒红色变成蓝色。据此,以对氨基苯甲酸修饰的AuNPs为探针,建立了快速检测杀螟丹的比色方法。通过优化得到最佳条件为:杀螟丹与PABA-AuNPs反应平衡时间4min,缓冲溶液pH=5.5。在优化条件下,检测杀螟丹的线性范围为0.08~0.7mg/L,检测限为0.02mg/L。该方法具有简单、快速、灵敏、选择性好等优点,应用于环境水样中的杀螟丹的检测,加标回收率在101%~107%之间,相对标准偏差为2.1%~4.7%。     

杀螟硫磷在离子液体修饰预处理玻碳电极上的电化学行为及测定

采用滴涂法制备了离子液体(IL)修饰预处理玻碳电极(IL/PGCE),建立了一种用于高效检测杀螟硫磷(FNT)的方法。利用循环伏安法(CV)对IL/PGCE进行了表征;通过方波伏安法(SWV)研究了杀螟硫磷在修饰电极上的电化学行为,并利用扫速研究了杀螟硫磷在IL/PGCE上的反应过程;讨论了pH值、预处理电位和时间、修饰剂含量、富集电位和时间等影响传感器性能的重要参数。在最优条件下,修饰电极对杀螟硫磷展现出较好的电化学响应,在0.001～1μg·L^-1和1～100μg·L^-1的范围内,峰电流与杀螟硫磷浓度之间呈现良好的线性关系。该方法具有较好的重现性和抗干扰能力,能够用于实际样品中杀螟硫磷的检测,样品回收率为89.6%～125.5%。     

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.     

液下单液滴微萃取/快速气相色谱-质谱联用法测定蔬菜中多种有机磷农药残留

建立了液下单液滴微萃取/快速气相色谱-质谱联用测定蔬菜中多种有机磷农药残留的方法,并对前处理条件进行了优化。采用液下单液滴微萃取技术对样品进行萃取和浓缩,以快速气相色谱-质谱(GCMS)分离检测,内标法定量。在优化条件下,治螟磷、甲拌磷、异稻瘟净、甲基对硫磷、皮蝇磷、马拉硫磷、毒死蜱、水胺硫磷和喹硫磷9种有机磷农药的色谱峰分离良好,相关系数均不低于0.995 8,检出限为0.32~0.91μg/kg,加标回收率为83.2%~134.5%,相对标准偏差(n=5)为3.4%~16.5%。该方法样品前处理简单,分析快速,灵敏度高,能够应用于蔬菜中这9种有机磷农药残留的检测。     

基于电剥离石墨烯传感器伏安法检测杀螟硫磷

以石墨片为原料,在硫酸铵电解液中利用电化学剥离的方法制备了一种石墨烯（eGr）。将该材料修饰到玻碳电极（GCE）表面构建了电化学传感器,利用该传感器探究了杀螟硫磷的电化学行为。对缓冲溶液pH、电极修饰量等实验条件进行了优化。结果表明：该电极具有较大的活性比表面积以及良好的电子转移速度,对杀螟硫磷具有良好的电催化氧化作用。通过线性扫描伏安法检测了杀螟硫磷,其线性响应浓度在1～100μmol/L之间,检出限为70 nmol/L。该传感器可应用于河水中杀螟硫磷的残留分析,回收率为97.2%～100.3%。     

杀螟硫磷微胶囊剂有效成分含量的测定

用RW试剂将水介质中游离的杀螟硫磷萃取,用气相色谱法测定出微胶囊内的杀螟硫磷有效成分含量。该法解决了“总有效成分”和“游离有效成分”的分离与测定问题。样品测定结果的相对标准偏差为0．82％（n=6）,回收率为91．7％-101．6％。     

超声波辅助分散液相微萃取-气相色谱联用分析菌核净

将超声波萃取(USE)与分散液-液微萃取(DLLME)联合,利用气相色谱-电子捕获检测(GC-ECD),建立了一种高灵敏度检测水体中菌核净的新方法。对萃取的条件进行优化,选定萃取条件为:在5 mL样品中,注入1 mL丙酮和0.1 mL的四氯化碳混合液,20 Hz超声10 min,振荡混匀后高速离心5 min,移出下层溶剂低温吹干以丙酮定容自动进样分析。在优化条件下,样品的富集倍数可达50倍,检出限为0.001μg/mL,对采于蔬菜地边的水样进行加标回收率实验,平均回收率在81%以上,相对标准偏差在4.3%~7.6%之间,方法可满足水样中菌核净农药残留的检测要求。     

Residues and dissipation of guadipyr in rice ecological system

A modified QuEChERs method with liquid chromatography-tandem mass spectrometry for analysis of guadipyr residue and dissipation in rice matrices, paddy soil and paddy water was developed and validated. Mean recoveries and relative standard deviations in paddy soil, paddy water, rice plant, rice straw, rice hull and husked rice matrices at three spiking levels were 83.1–116.5% and 1.6–9.5%, respectively. The half-life of guadipyr was determined in 2 years at three different field sites in China via a dissipation experiment. The half-lives of guadipyr in paddy water were 0.22–0.37 days, 0.24–3.33 days in paddy soil and 0.44–1.90 days in rice plant. The terminal residues of guadipyr ranged from ND (concentrations of guadipyr were below limit of detection) to 50 μg kg^?1 in paddy soil, 10–470 μg kg^?1 in rice hull, ND70 μg kg^?1 in husked rice and ND to 110 μg kg^?1 in rice straw. The results would be helpful in fixing maximum residue limit of guadipyr, a new insecticide, in rice.     

Highly sensitive and selective two-photon sensing of cartap using Au@Ag core-shell nanoparticles

A highly sensitive and selective two-photon sensing scheme for detection of cartap was developed by using Au@Ag bimetallic core-shell nanoparticles. Cartap was found to induce the aggregation of Au@Ag nanoparticles and up to 700-fold enhancement in two-photon photoluminescence. Huge enhancement in two-photon photoluminescence allows achieving a detection limit of as low as 0.0062 mg/kg, which is better than the conventional colorimetric methods. This two-photon sensing scheme has a broad dynamic range and displays excellent selectivity in detection of cartap against over other ten kinds of commonly used insecticides.     

高效液相色谱法分析水稻和稻田中的氯硝柳胺乙醇胺盐残留

建立了高效液相色谱(HPLC)测定水稻和稻田中氯硝柳胺乙醇胺盐残留量的分析方法。稻田水和稻秆样品中的氯硝柳胺乙醇胺盐残留用碱性乙酸乙酯直接提取;而稻田土壤、糙米和谷壳样品则先经碱性乙醇提取,再用乙酸乙酯进行萃取。萃取物经弗罗里硅土柱净化后,经Welchrom C18柱分离,采用紫外检测器检测,外标法定量。在0.01～10.00 mg/L范围内,氯硝柳胺乙醇胺盐的峰面积与其质量浓度间呈良好的线性关系,相关系数为0.9998。在稻田水、土壤、稻秆、糙米和谷壳中添加0.01～5.00 mg/kg的氯硝柳胺乙醇胺盐,其平均回收率为93.47%～100.9%,相对标准偏差为1.46%～5.82%,符合农药残留量分析与检测的技术要求。该方法简便、快速,灵敏度高,重现性好,可用于环境系统中氯硝柳胺乙醇胺盐残留量的分析与检测。     

超高效液相色谱-串联质谱法测定水稻基质中阿维菌素残留量

建立了超高效液相色谱-串联质谱法(UPLC-MS/MS)测定水稻基质中阿维菌素残留量,考察了基质效应,并对实际样品进行了检测.稻田土、稻壳、糙米和稻杆经乙腈振荡提取,稻田水经乙酸乙酯液液分配提取后,用C18固相萃取小柱或弗罗里硅土柱净化,采用UPLC-MS/MS正离子扫描测定残留的阿维菌素.稻田土、稻田水和糙米的3种添加浓度(1.0,10.0和100 μg/kg或μg/L)的平均回收率为84％～107％,相对标准偏差为4.7％～13.6％.稻壳和稻杆的2档添加浓度(10.0和100 μg/kg)的平均回收率为90％和103％,相对标准偏差为8.4％～12.9％.本方法在稻田水、糙米和稻田土中的检出限为0.3μg/kg在稻壳和稻杆中检出限为3.0 μg/kg,低于欧盟和日本在稻米中制定的阿维菌素最大残留限量值.阿维菌素在2.0～100 μg/L范围内线性关系良好( r＞ 0.999).     

Validation of QuEChERS-based UPLC-MS/MS method for determination of quinoid niclosamide (LDS) residue in water,soil and rice samples

A sensitive, rapid and easy analytical method was validated for the determination of quinoid niclosamide (LDS) molluscicide in water, rice and soil using a QuEChERS extraction procedure and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection. The LDS was extracted by using acetonitrile and then cleaned up by using dispersive solid-phase extraction with florisil and C18 sorbents. The determination of the target compound was achieved in less than 3 min using an electrospray ionisation source in negative mode. The overall average recoveries for this method in water, rice and soil matrix at three fortified levels ranged from 82.54 to 99.9%, with relative standard deviations in the range of 1.51 to 4.86% (n = 5). The calculated limits of detection were lower than 0.1 µg kg^?1 and quantification was 5 µg kg^?1; these values were much lower than the maximum residue levels established by the Australian standard (0.01 mg kg^?1). The results of the method validation confirmed that this proposed method is convenient and reliable for the determination of LDS molluscicide in water, rice and soil samples.     

Monitoring of the pesticide diazinon in soil, stem and surface water of rice fields.

Diazinon is an organophosphorus insecticide (OPP) that is used as a pesticide for Chilo suppressalis (WLK) (Lep., Pyralidae) in rice fields. The extraction of diazinon from soil and the stems of rice plants has been carried out by microwave-assisted extraction (MAE) and the results compared with ultrasonic extraction (USE). The best parameters for MAE are hexane-acetone (8:2 v/v) as a solvent, a 2.5 min extraction time, and 20 ml of the solvent volume. Also, surface-water samples of the rice fields were extracted by solid phase extraction (SPE) using a C18 disc. The optimum conditions of SPE were a sample volume of 750 ml, a pH of 7 and high ionic strength of water. The extracted samples were analyzed by gas chromatography-mass spectrometry (GC-MS). The relative standard deviation (RSD) and regression coefficients related to the linearity were <3.5% (n = 5) and 0.99, respectively. The limit of detection (LOD) is 0.1 ng ml(-1) with selected ion monitoring (SIM) at 137 m/z. The average recoveries of diazinon in soil and stem samples by MAE and surface-water by SPE were 98% (+/-3), 94% (+/-5) and 87% (+/-3), respectively. In June, the concentration of diazinon in soil and stem samples of the rice plants in Guilan province is high (55 ng ml(-1)) and in September is low (2 ng ml(-1)). In surface-water samples, the results are converse. In November, diazinon can not be detected in soil, stem or surface-water samples. Diazinon is degraded to diethylthiophosphoric acid. Also, three microorganism genera (Pseudomonas sp, Flavobacterium sp and Agrobacterium sp) have been found to degrade diazinon in soil and surface water.     

大米中多种残留农药的固相萃取-气相色谱-质谱分析

建立了一种同时测定大米中有机氯、有机磷、氨基甲酸酯和拟除虫菊酯等4类农药残留量的分析方法。通过比较二氯甲烷、三氯甲烷、乙腈、乙酸乙酯和不同比例的己烷-丙酮混合溶剂等8种溶剂的提取效果,选择以二氯甲烷为提取溶剂;以Florisil固相萃取小柱净化,通过以不同比例的己烷-丙酮作洗脱溶剂,发现体积比为4∶1的己烷-丙酮的洗脱效果最佳,在选定的洗脱条件下,样品的净化效果良好;用气相色谱-质谱测定,以保留时间、选择离子及其相对丰度定性,以外标法定量。以低限加标样品的3倍信噪比确定方法的检出限(LODs),以两个添加水平测定样品的回收率和相对标准偏差(RSD)。该方法的检出限达到μg/kg水平;除敌敌畏、乐果、pp′-DDT等几种农药外,大多数农药的加标回收率在75%和120%之间,RSD均低于10.4%,r≥0.992。该方法简便、快速、灵敏,能够满足同时测定大米中多种类残留农药的要求,可以作为大米中农药多残留的例行分析和确证分析的方法。     

基于QuEChERS提取方法优化的液相色谱-串联质谱法测定蔬菜中51种氨基甲酸酯类农药残留

采用气相色谱-质谱（GC-MS）全扫描结合NIST谱库检索方法分析6种蔬菜（番茄、青刀豆、大葱、青花菜、姜、胡萝卜）提取液中的基质干扰物,以蒸发残渣重量法探讨乙二胺N-丙基硅烷（PSA）、十八烷基硅烷（C18）及两者组合对6种蔬菜提取液基质干扰物的净化效果及吸附机理,考察了原创QuEChERS方法及AOAC 2007.01方法对蔬菜中51种氨基甲酸酯类农药提取的适用性,并建立了液相色谱-串联质谱法测定蔬菜中51种氨基甲酸酯类农药残留的方法。结果表明,C18与PSA组合进行分散固相萃取的净化效果最好;AOAC 2007.01方法适用于二氧威以外的50种农药残留的提取,而原创QuEChERS方法对二氧威残留的提取可获得满意结果。经电喷雾正离子电离及多反应监测模式来测定目标化合物,采用基质匹配标准溶液曲线法进行定量。结果表明：51种农药在6种基质中3个添加水平（10、20、100 μg/kg）的回收率为58.4%~126%,相对标准偏差为3.3%~26%;以信噪比（S/N）≥10计,久效威及杀螟丹的定量限（LOQ）为50 μg/kg,其他49种农药的LOQ为0.2~10 μg/kg。本文方法有效、灵敏,适用于不同蔬菜基质中51种氨基甲酸酯类农药残留的测定。     

气相色谱-质谱法检测食品中残留的丙炔氟草胺

建立了多种食品中丙炔氟草胺残留量的气相色谱-质谱检测方法。样品采用乙腈或乙酸乙酯提取,经旋转蒸发去除提取液后,用乙腈-甲苯（体积比为3∶1）溶解残渣,经氨基固相萃取柱净化,净化液由气相色谱-选择离子监测质谱测定,外标法定量。方法的线性范围为0.02～1.0 mg/L,多种食品基质中的平均回收率为79.4%～101%,相对标准偏差(RSD)为0.242%～7.15%(n=10),检测限均为0.01 mg/kg。该方法灵敏度高,选择性好,可作为多种食品中丙炔氟草胺残留量的常规检测方法。     

Streamlining sample preparation and gas chromatography–tandem mass spectrometry analysis of multiple pesticide residues in tea

In this work, a new rapid method for the determination of 135 pesticide residues in green and black dry tea leaves and stalks employing gas chromatography coupled to tandem mass spectrometry (GC–MS/MS) with a triple quadrupole was developed and validated. A substantial simplification of sample processing prior to the quantification step was achieved: after addition of water to a homogenised sample, transfer of analytes into an acetonitrile layer was aided by the addition of inorganic salts. Bulk co-extracts, contained in the crude organic extract obtained by partition, were subsequently removed by liquid–liquid extraction using hexane with the assistance of added 20% (w/w) aqueous NaCl solution. The importance of matrix hydration prior to the extraction for achieving good recoveries was demonstrated on tea samples with incurred pesticide residues. For most of the analytes, recoveries in the acceptable range of 70–120% and repeatabilities (relative standard deviations, RSDs) ≤20% were achieved for both matrices at spiking levels of 0.01, 0.1 and 1 mg kg⁻¹. Under optimised GC–MS/MS conditions, most of the analytes gave lowest calibration level ≤0.01 mg kg⁻¹, permitting the control at the maximum residue levels (MRLs) laid down in Regulation (EC) No 396/2005. The developed method was successfully applied to the determination of pesticide residues in real tea samples.