速冻蔬菜中氯氰菊酯残留量的测量不确定度评定

依据GB/T 5009.146-2003《植物性食品中有机氯和拟除虫菊酯类农药多种残留的测定》方法,对速冻蔬菜中氯氰菊酯残留量的测量不确定度进行分析和评定。该测量过程所产生的测量不确定度主要来源于气相色谱仪引入的测量不确定度,其次是氯氰菊酯标准工作溶液引入的测量不确定度。标准溶液引入的测量不确定度则主要来源于标准溶液的稀释过程所产生的测量不确定度。     

膜渗透与离子色谱联用技术测定蔬菜中亚硝酸盐和硝酸盐

建立了膜渗析与离子色谱联用技术分析蔬菜等复杂基体中亚硝酸盐和硝酸盐的方法。蔬菜样品经沸水浴后,试样液通过膜渗析除去水溶性大分子杂质和颗粒,直接进入离子色谱分析。渗析池采用0.20μm的醋酸纤维为渗析膜,以水为接收液,分析柱为Metrosep A Supp4-250阴离子交换柱,以1.8mmol/L Na2CO3 1.7mmol/L NaHCO3为流动相,采用化学抑制电导检测。以20g称样计量,方法中NO2-、NO3-的检出限分别为0.075mg/kg和0.105mg/kg;实际样品的加标回收率分别为80.6%~98.7%和90.5%~114%;相对标准偏差(RSD)≤10%。本方法前处理简单,重现性好,准确度高。     

Decomposition of vegetables for determination of Zn,Cd, Pb and Cu by stripping voltammetry

A simple and accurate digestion method using nitric acid, perchloric acid and hydrogen peroxide has been developed for use in trace analysis for heavy metals in vegetables by differential pulse anodic stripping voltammetry. The recovery of the metals from the samples is lower if the hydrogen peroxide is omitted from the digestion mixture. Standard reference materials have been analysed satisfactorily by this method.     

微波消化技术在蔬菜微量元素测定中的应用

使用家用微波炉在聚四氟乙烯密闭罐中，用硝酸和过氧化氢分解脱水蔬菜胡萝卜粒，火焰原子吸收光谱法测定铜、铁、镁、镍、锌微量元素。方法快速、简便，灵敏度高，再现性好，相对标准偏差为0．2％～1．5％，回收率为95．0％～110．6％。     

Selection of a Representative Matrix for Calibration in Multianalyte Determination of Pesticides in Vegetables by Liquid Chromatography-Electrospray Tandem Mass Spectrometry

An analytical method for determining residues of twenty pesticides by liquid chromatography (LC) coupled to electrospray ionisation (ESI) tandem mass spectrometry (MS-MS) in eight commodities, cucumber, tomato, pepper, green bean, eggplant, zucchini, melon and watermelon, has been developed and validated. On one hand, calibration curves prepared in solvent were compared with calibration curves prepared in a blank matrix extract of each target matrix. On the other hand, calibration curves and recoveries for each commodity were compared. Cucumber was selected as potential reference matrix for the target vegetables.     

气相色谱-三重四极杆串联质谱法快速测定蔬菜水果中129种农药的残留量

采用QuEChERS方法结合气相色谱-串联质谱法(GC-MS/MS)建立了蔬菜、水果中129种农药残留同时检测的分析方法。试样用1%乙酸乙腈均质提取,采用混合型固相分散萃取剂净化后,用GC-MS/MS在多反应离子监测(MRM)模式下进行检测,外标法定量。结果表明,129种药物在一定的含量范围内线性关系良好,相关系数(r2)均大于0.98;不同基质在10 μg/kg添加水平下大部分农药的平均回收率为66.2%～124.7%,相对标准偏差(RSD)为0.9%～24.4%;方法的定量限(LOQ)为0.03～16.7 μg/kg。结果表明,该方法简便快速、灵敏可靠、经济有效,适用于蔬菜、水果中农药多残留的同时快速筛查测定。     

基于QuEChERS净化/气相色谱法测定蔬菜及水果中16种有机氯农药残留

该文建立了蔬菜及水果中16种有机氯农药残留的QuEChERS净化/气相色谱快速检测方法。样品经1%冰乙酸乙腈处理,QuEChERS净化,气相色谱分离后,以色谱峰保留时间定性,外标法定量。结果表明:16种有机氯农药在2.0~100μg/L质量浓度范围内的线性关系良好,相关系数均大于0.99,检出限为0.16~2.90μg/L,在4种基质(油菜、黄瓜、橙子、苹果)中的加标回收率为70.1%~119%,相对标准偏差(RSD)为0.23%~5.2%。与其它前处理方法相比,该方法简便、快速、准确、高效,可用于蔬菜及水果样品中有机氯残留的高通量快速筛查。     

Multiresidue analysis of pesticides with hydrolyzable functionality in cooked vegetables by liquid chromatography tandem mass spectrometry

It would be preferable for pesticide residues substituted by hydrolyzable functionality to be analyzed after cooking because their structures are apt to degrade during boiling and/or heating. A liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method for the quantitative determination of 44 pesticide residues with hydrolyzable functional group in five typical vegetable widely consumed in Republic of Korea is described. The sample clean‐up was carried out according to the method of Food Code No. 83 established by the Korea Food and Drug Administration (KFDA). Zorbox XDB‐C₁₈ column was selected for the analysis because of the best peak separation. The LC mobile phase consisted of water and 5 mm methanolic ammonium formate, which resulted in a peak shape with good symmetry at each run. Tandem mass spectroscopic (MS/MS) experiments were performed in ESI positive mode and the multiple reaction monitoring modes. A conventional matrix effect was modified to more comprehensive form 100γ_ij (%). A high matrix effect (相似文献   

Impact of sonolytic ozonation (O3/US) on degradation of pesticide residues in fresh vegetables and fruits: Case study of Faisalabad,Pakistan

High pesticide residues in fresh produce is a serious food safety issue. This study was aimed at assessing the pesticides residues in some important vegetables and fruits marketed in Faisalabad, Pakistan and the impact of sonolytic ozonation (O₃/US) treatment in removing these contaminants. From a short grower’s survey, five registered and mostly used pesticides (acetamiprid, carbendazim, imidacloprid, thiacloprid and thiamethoxam) were identified. A time optimization trial of O₃/US application (05, 10 and 15 min) on okra, showed that 10 min treatment significantly reduced three identified chemicals (thiamethoxam 100 %, imidacloprid and thiacloprid 97.17 %), without any adverse effect on its quality. In follow up trial, five fresh vegetables (cauliflower, chillies, cucumber, spinach and tomato) three fresh fruits (grapes, guava and peach) collected from three markets of Faisalabad, were pooled together to have uniform samples. Vegetables and fruits were treated with O₃/US for 10 and 6 min, respectively, along with control (simple tap wash) for determining the impacts on pesticides degradation. Samples were processed for extraction, clean up and analysis using HPLC-UV–Vis in isocratic mode. The data revealed the presence of five mentioned chemicals, with an accumulative mean residue of 9.006 and 1.921 µg/g in tested vegetables and fruits, respectively. After subjecting to O₃/US, the accumulative chemical residues were reduced to 3.214 µg/g (64.313 %) and 1.064 (44.6 %) in treated vegetables and fruits respectively. Irrespective of fresh produce, the mean residues of thiamethoxam, imidachloprid, acetamiprid and thiachloprid and carbendazim were reduced by 99.3 %, 52.6 %, 65.2 %, 87.3 % and 72% respectively. It was concluded that sonolytic ozonation treatment was effective in significant reduction of pesticide residues from vegetables and fruits and thus can be employed as a good food safety practice at culinary level to reduce the associated health hazardous risks.