北京市蔬菜、水果中有机磷农药残留现状调查

为了解北京市蔬菜、水果中有机磷农药残留情况，2002年在北京市抽检样品354件进行13种有机磷监测，其中蔬菜28l件，水果73件。检测结果显示7．6％的检品不符合国家标准。叶菜类(14，占9．3％)和根茎类(8，占17．4％)蔬菜的不合格率明显高于瓜菜、果菜类(2，占2．4％)蔬菜和水果(3，占4．1％)。13种有机磷检测出12种，其中禁用农药占53％。本市种植的蔬菜、水果与外埠进京产品的有机磷农药残留情况无显差别，超市、集贸市场、批发市场销售的产品的不合格率亦无显差别。     

Determination of atrazine residues in red wine samples. A conductimetric solution

The potential of a conductimetric immunosensor to detect residual amounts of atrazine in a complex matrix, such as red wine, is evaluated. The immunosensor presented is based on interdigitated μ-electrodes (IDμEs), immunoreagents specifically developed to detect atrazine, and antibodies labelled with gold nanoparticles. Due to the amplification of the conductive signal, produced by the presence of the gold particles, atrazine can be detected using simple and inexpensive direct current (DC) measurements. Then, sensors response is related to the atrazine concentration in the sample. Likewise, the presence of gold particles generates an increase in the intensity of the electric field between the electrodes. The time for assay completion, for 48 samples, was 5 h. Nevertheless, during the first hour (devoted to the incubation assays), the number of samples could be increased without prejudice the assay duration.     

大气压气相色谱电离源-串联质谱法测定蔬菜中23种农药残留

目的 建立蔬菜中23种农药的大气压气相色谱电离源-串联质谱检测方法。方法 采用丙酮提取蔬菜样品中的目标农药,多壁碳纳米管为净化材料,经DB-5MS色谱柱(30 m×0.25 mm,0.25 μm)分离,结合大气压气相色谱电离源技术,正离子多反应监测(MRM)模式进行检测,外标标准曲线法定量。结果 23种农药在0.01～20 μg/L范围内线性良好,相关系数(R²)均大于0.99,在蔬菜基质中23种农药的方法检出限和定量限分别为0.02～0.40和0.05～1.25 μg/kg,回收率为66.7%～110.7%,相对标准偏差(RSD)≤14.8%。结论 本方法具有良好的灵敏度、重现性和特异性,适用于蔬菜中多种农药残留的快速检测。     

Results from the monitoring of pesticide residues in fruit and vegetables on the Danish market, 1998?99

The objective of the Danish pesticide monitoring programme for fruit and vegetables was to check for compliance with the maximum residue levels in foods and to monitor the residue levels to assess the pesticide exposure of the Danish population. Sampling plans were designed based on previous findings and on food consumption data. Approximately 60% of the samples were selected on the basis of positive findings in samples from the previous 5 years. The remaining samples reflected the pattern of food consumption in Denmark. In addition, a rolling programme is maintained for commodities with a low consumption and no detected residues. Within each commodity, the sampling was random. Samples (n = 4150) of mainly fresh, conventionally grown fruit and vegetables were taken throughout the chain of suppliers including foodprocessing companies. Of the samples, 3% were frozen products and 2% were organically grown. Of the samples, 35% were of Danish origin, with 65% originating from other countries. Three accredited laboratories performed analyses of the samples using capillary gas chromatography, liquid chromatography and spectrophotometric methods. Results were registered online into a central database. Residues were found in 54% of the samples of fruit but only in 13% of the vegetables. Residues above the MRL were found in 4% of all samples of fruit and in 1% of vegetables.     

澳门地区市售叶类菜有机磷农药残留检测:2000～2003

目的了解澳门地区叶类菜残留有机磷农药的情况。方法2000年至2003年间分别于澳门各菜市场、街头摊贩、蔬果杂货店等地点抽取了共817件叶类菜样本,以检测有机磷农药残留水平。结果2000年至2003年度,叶类菜残留有机磷农药不合格率平均为73%、132%、131%、149%,历年不合格率呈上升趋势(AdjustedR2=0074,P=003)。除2002年外,每年从街头摊贩所取得样本之不合格率均比从菜市场所抽取者为高,且差异具统计学意义(P<005)。构成历年不合格样本的原因,主要是甲胺磷和马拉硫磷农药残留超逾标准所致;各类叶类菜样本中亦以通心菜样本中残留有机磷农药的检出之不合格率最高,约占通心菜样本总数四成。讨论考虑到“农场到餐桌”食物链的全过程,除了农场方面对农药的正确和安全使用需要回顾外,农药的生产管理,以至营销流通监管亦不能掉以轻心,政府和有关部门必须高度重视。     

Results from the monitoring of pesticide residues in fruit and vegetables on the Danish market, 2000-01

To check compliance with the maximum residue levels in foods and to monitor the residue levels to enable an evaluation of the exposure of the Danish population to pesticides, a monitoring programme for pesticides residues in fruit and vegetables was performed. Sampling plans were designed based on previous findings and on consumption data. Samples (n = 4404) of mainly fresh conventionally and organically grown fruit and vegetables were collected at wholesalers and importers and at food processing companies. Of the samples, 3% were frozen products and 5% organically grown. Of the samples, 34% were of Danish origin, with 66% from other countries. Two accredited laboratories performed analyses of the samples using capillary gas chromatography, liquid chromatography and a spectrophotometric method. Reporting levels were set at the lowest calibration level or at the limit of determination. Residues were found in 60% of the samples of fruit but in only 18% of the vegetable samples. Residues above the maximum residue levels were found in 6% of all samples of fruit and in 2% of the vegetable samples.     

Detection of sulphathiazole in honey samples using a lateral flow immunoassay

A lateral flow immunoassay (LFIA) was developed in the competitive reaction format and applied to test sulphathiazole (STZ) residues in honey samples. To prepare the assay test, a hapten conjugate and goat antirabbit antiserum as capture and control reagent, respectively, were dispensed on nitrocellulose membrane. Polyclonal antiserum against sulphathiazole was conjugated to colloidal gold nanoparticles and used as the detection reagent. The visual limit of detection (cut-off value) of the sulphathiazole LFIA was 15 ng/g, reaching qualitative results within 10 min. The assay was evaluated with STZ spiked honey samples from different geographical origins (n = 25). The results were in good agreement with those obtained from liquid chromatography separation and mass spectroscopy detection (LC–MS), indicating that the LFIA test might be used as a qualitative method for the determination of sulphathiazole residues without expensive equipment. The test was also highly specific, showing no cross-reactivity to other chemically similar antibiotics. To our knowledge, this is the only work where a development of LFIA tests for the detection of sulphathiazole residues is performed.     

Determination of pesticide residues in milk using a QuEChERS-based method developed by response surface methodology

Response surface methodology (RSM) was employed to optimise a rapid and easy sample preparation method for the determination of 14 different pesticide residues in milk. The recovery of each pesticide was investigated by a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe)-based method with respect to 3 variables, the amounts of sodium acetate (Na Acetate), primary secondary amine (PSA), and octadecylsilane (C₁₈). After optimisation, the maximum predicted recovery was the 99.73% rate for myclobutanil under the optimised conditions of 1.70 g Na Acetate, 600.00 mg PSA, and 489.96 mg C₁₈. The recovery rates of the other 9 hydrophilic pesticides were ranged from 82.01% to 98.84%. However, the recovery rates for the 4 lipophilic pesticides (2,4′-DDE, 4,4′-DDE, 2,4′-DDT, and 4,4′-DDT) were <80% because they were removed by C₁₈ along with the other fatty compounds. This method could be implemented in many laboratories to reduce inspection time and cost.     

臭氧降解蔬菜中农药残留机理与效果研究

研究了臭氧降解蔬菜中农药残留机理和效果。结果表明，臭氧对甲胺磷、氧化乐果、敌敌畏、对硫磷和溴氰菊酯均有较强的降解作用。甲胺磷降解速度最快，其次为溴氰菊酯、氧化乐果、敌敌畏、对硫磷。不同种类蔬菜中以叶菜中农药残留最易降解，其次为莱豆、果莱。经5min处理结果比较，臭氧与果蔬清洗剂对叶菜中农药残留的清洗效果相当，对茄果类蔬菜臭氧清洗效果优于果蔬清洗剂。     

Monitoring of pesticide residues in Egyptian fruits and vegetables during 1997

A total of 2318 domestic samples of different types of fruits and vegetables were collected from eight Egyptian local markets in six different regions of the country. All samples were examined for residues of 54 pesticides, including organophosphorus, organonitrogen, organohalogen and certain pyrethroides. However, dithiocarbamates were analysed in only 318 samples. Overall, 81.5% of the samples had no detectable pesticide residues. Of the contaminated samples, 18.5% contained detectable residues and 1.9% exceeded their maximum residue limits (MRLs). Root and leafy vegetables showed the lowest contamination rates (1.9 and 4.7%, respectively), slightly exceeding the MRLs in leafy vegetables. However, fruit samples showed a slightly higher proportion of contamination than vegetables (29 and 14.3%, respectively). Fruit also exhibited a higher level of violation than vegetables (2.3 and 1.9%, respectively). The contamination and violation rates were lower than the percentages recorded in previous years' monitoring studies. Dicofol and dimethoate were the most frequently occurring pesticide residues at 5.1 and 5.0%, respectively. Dimethoate showed higher violation levels (0.69%). However, dicofol showed a slight violation rate (0.09%) which indicates good agricultural practices for dicofol use. Dithiocarbamates residues were found in 21 of the 318 samples analysed, which when expressed as a percentage contamination was 6.6%, and only one sample exceeded the MRL.     

Determination of pesticide residues in wine using gas chromatography with nitrogen-phosphorus and electron capture detection

A multiresidue method employing an extraction step with ethyl acetate followed by clean-up using an Isolute silica column and determination using gas chromatography with nitrogen-phosphorus and electron capture detection was validated for a wide range of pesticide residues in white and red wine. Recoveries between 70 and 110% and relative standard deviations below 20% were obtained for nearly all target analytes using matrix-matched standards. Limits of detection based on three times the signal-to-noise ratio were in the range 0.002-0.01 mg l^-1 for most compounds. The chromatograms were generally free of interference peaks resulting from co-extractives, although a few were noted for red wine with nitrogen-phosphorus detection. Ninety-two wine samples collected in Greece and Yugoslavia during 2 consecutive years were screened for residues of 84 pesticides, 71% of which were registered for use on vines in one or both countries. A total of 20% of the samples were obtained from field trials, and of these, one Greek wine contained iprodione 0.3 mg l^-1 and six Yugoslavian wines, for which vinclozolin had been added to the must as part of a different study, contained residues of this pesticide. No residues were detected in any of the other samples.     

QuEChERS-气相色谱-质谱法对植物油中农药残留的快速检测

建立植物油中8种常见农药的快速检验方法。样品采用液液萃取提取目标物和初步净化后经改进的QuEChERS方法进行提取净化,提取液经GC-MS进行检测。结果表明,8种农药在大豆油中的检出限为0.004～0.015 mg/kg;在0.02、0.04、0.1、0.2 mg/kg添加水平的平均回收率分别为99%～113%、80.8%～101.5%、71.9%～91.7%、86.3%～103.6%;相对标准偏差(RSD,n=6)分别为6.1%～13.4%、4.3%～8.5%、3.5%～7.4%、3.4%～6.7%。本方法具有操作便捷、快速等特点,适用于植物油中8种农药残留的快速检测。     

Determination of fenhexamid residues in grape must,kiwifruit, and strawberry samples by enzyme-linked immunosorbent assay

Fenhexamid is a new-generation agrochemical extensively used nowadays to protect high valuable crops and fruits from fungus attacks. In this paper, the development of an indirect competitive immunoassay for the determination of fenhexamid residues in fruit samples is described. After optimisation of immunoreagent concentrations, the assay, based on monoclonal antibody FHo4#27, showed high sensitivity, and selectivity, with a limit of detection for fenhexamid standards in buffer of 0.04 μg/L. The influence of several physico-chemical factors, including pH, ionic strength, solvent tolerance, and matrix interferences on the analytical parameters of the standard curve was studied. For spiked liquid food samples like grape must, just a direct 1:50 dilution in water was sufficient to attain recoveries between 100% and 110%. For kiwifruit and strawberry samples, a double extraction procedure with methanol is proposed in this study, which afforded recovery values that ranged between 103% and 116%. The limit of quantification of the developed assay was 5 μg/kg for grape must, 10 μg/kg for kiwifruits, and 25 μg/kg for strawberries. The optimised assay was compared with a reference procedure based on liquid chromatography using incurred samples from the market, and an excellent correlation between both methods was found.     

Comparison of pesticide residues in composite samples and in individual units: the Swedish approach to sampling

The method used to take samples for residues testing in Sweden involves taking three subsamples of 1-2kg. These are split in two for laboratory analyses. Where required one of these laboratory samples can be used to determine the variability between individual units. Details of the variation in residues in individual units of a number of commodities are presented. The highest variability factors, around 600, expressed as the quotient of the maximum and the minimum residue, were found for methamidophos in peppers and monocrotophos in grapes.     

气相色谱-质谱法筛查测定浓缩果蔬汁中73种农药残留

对Qu ECh ERS前处理方法进行改进,建立了Qu ECh ERS结合固相萃取技术(SPE)作为样品前处理方法的浓缩果蔬汁中73种农药多残留的气相色谱-质谱(GC-MS)检测方法。样品用体积分数1%的醋酸乙腈溶液萃取,经Waters Sep-Pak Vac固相萃取柱净化,乙腈-甲苯(体积比为3∶1)洗脱后旋转蒸发浓缩,气相色谱-质谱分析。分别以定量限和4倍定量限浓度对橙汁、苹果汁、葡萄汁、白菜汁、胡萝卜汁5种空白浓缩果蔬汁样品进行添加回收率实验,方法的回收率为71.5%~103.1%,相对标准偏差为1.6%~19.8%。方法的检出限和定量限分别为0.005 0~0.075 0 mg/kg、0.016 7~0.250 0 mg/kg。该方法前处理简单快速、分析时间短,灵敏度、准确度和精密度均符合农药多残留检测技术的要求,适用于苹果汁、橙汁、葡萄汁、白菜汁、胡萝卜汁等浓缩果蔬汁中73种农药多残留的快速筛查与定量分析。     

Catalytic determination of traces of oxalic acid in vegetables and water samples using a novel optode

A new optode has been introduced for determination of oxalic acid. The optode sensing reagent is Victoria blue 4R which is immobilized on triacetylcellulose membrane. This reagent could be oxidized by dichromate in acidic media resulting in decoloration of the membrane. Oxalic acid has a strong catalytic effect on this reaction. The difference in absorbance of the immobilized form of Victoria blue 4R at 615 nm between uncatalyzed and catalyzed reactions (ΔA) is directly proportional to the concentration of oxalic acid. Oxalic acid can be determined in the concentration range of 2–180 μg ml⁻¹. The effect of different possible interfering species has been examined and was shown that the optode has a very good selectivity. The optode has been applied for the determination of oxalic acid in different real samples such as spinach, beet root, mushroom and river water with excellent recoveries.     

Determination of ultratrace levels of selenium in fruit and vegetable samples grown and consumed in Portugal

The selenium content in fruit and vegetable samples from two regions in Portugal were analysed using hydride generation atomic fluorescence spectrometry (HG-AFS) and radiochemical nuclear activation analysis (RNAA) – two analytical methods with very low limits of detection. The lower detection limits of HG-AFS, 3 μg kg⁻¹ and 8 μg kg⁻¹ (according to conditions used for digestion), and for RNAA, 10 μg kg⁻¹, meant that it was possible to determine selenium in samples previously analysed using the replicate sample instrumental nuclear activation analysis (RSINAA) with a higher detection limit associated.     

Quantification of organophosphate insecticides and herbicides in vegetable samples using the “Quick Easy Cheap Effective Rugged and Safe” (QuEChERS) method and a high-performance liquid chromatography-electrospray ionisation-mass spectrometry (LC-MS/MS) technique

A Quick Easy Cheap Effective Rugged and Safe (QuEchERS) extraction was developed and followed by selective analysis using a liquid chromatography-mass spectrometry method for the quantification of eighteen pesticides in vegetable samples. This method was accurate (?99.5%), and it exhibited limits of detection and quantification values in the 0.006-0.091 and 0.020-0.314 μg kg⁻¹ ranges, respectively. Furthermore, the coefficients of variations (?0.9999) were less than 1% at the low μg kg⁻¹ end of the method. Mean recoveries ranged between 94% and 102%, and relative standard deviations were below 10%. Based on these results, the methodology was proven to be highly efficient, robust, and suitable for monitoring the maximum residue limits (MRL) compliance of a wide range of commodity/pesticide combination. This method was successfully applied to the analysis of vegetable samples that were collected from different government farmers’ markets and street shops in urban areas. The presence of target pesticides was found in the range of 0.016 and 50.85 μg kg⁻¹.     

Application of a commercial immunoassay to the direct determination of insecticide imidacloprid in fruit juices

An ELISA was used to directly determine residual imidacloprid in fruit juices. Imidacloprid could be determined by only diluting samples without any pre-treatments such as filtration, centrifugation, and clean-up procedures. The ELISA enabled imidacloprid to accurately determine down to about 5 μg/L in apple and grape juice samples and down to about 20 μg/L in orange juice sample. Recovery and precision of the ELISA were evaluated by spiking fruit juice samples with imidacloprid in the 10–400 μg/L ranges. Coefficients of variation were lower than 20% in all cases, and average recoveries were 94.2%, 113.2%, and 104.2% for apple, grape, and orange juice samples, respectively. No false positive results were found. The results obtained with the proposed ELISA well correlated with the reference HPLC for each fruit juice sample (r > 0.99).     

Organochlorine pesticide residues in cow's milk from a tropical region of Mexico

A monitoring study was conducted to assess the magnitude of DDT [(1,1,1-trichloro-2,2-bis( p -chlorophenyl)ethane)] and HCH (hexachlorocyclohexane) contamination of bovine milk from the central tropical region of Mexico as the chemicals are extensively used in livestock and public-health programmes. Among pesticide residues analysed, the milk samples collected from Tlalixcoyan showed a mean level of γ-HCH (0.128 mg kg -1 ), which was significantly higher than residues in milk samples from Medellin (0.049 mg kg -1 ) and Paso San Juan (0.022 mg kg -1 ). The mean level of pp '-DDE in Medellin samples (0.039 mg kg -1 ) was significantly higher than in Paso San Juan (0.018 mg kg -1 ) and Tlalixcoyan (0.024 mg kg -1 ) milk samples. The pp '-DDT mean level from Medellin milk samples (0.089 mg kg -1 ) was significantly higher than the levels detected in the other two areas. The highest mean Σ-DDT level detected in Medellin samples (0.146 mg kg -1 ) was three times the FAO/WHO tolerance level. The highest acceptable daily intakes calculated for Σ-DDT were 0.017 μg kg -1 bw day -1 for adults and 0.530 μg kg -1 bw day -1 for infants; for γ-HCH residues, they were 0.021 μg kg -1 bw day -1 for adults and 0.666 μg kg -1 bw day -1 for infants, indicating that infants are more exposed to pesticide residues. Results indicate that cattle exposure to HCH and DDT results in high levels in dairy milk and a potential health risk for consumers.