Ruckstandsanalyse von Pyrethroid-Insecticiden in Getreide, Mahlerzeugnissen und Brot

Zusammenfassung Beschrieben wird ein Verfahren zur Rückstandsanalyse von 8 Pyrethroid-Insecticiden bis zu Gehalten von 2–5 g/kg. Man extrahiert dazu Getreide, Mahlerzeugnisse oder Brot mit Acetonitril/Wasser (2+1) und schüttelt den Extrakt nach Verdünnen mit Petroläther aus. Die Petroletherphase wird durch Gelchromatographie an Bio-Beads S-X3 und mit einer kleinen Florisilsäule gereinigt. Die GC mit dem ECD an einer unpolaren SE-30-Capillarsäule trennt auch die Isomeren der Wirkstoffe voneinander. Versuche mit Cyfluthrin, Cypermethrin, Deltamethrin, Fenvalerat und Permethrin zeigten, daß sich die Gehalte in Roggen und Weizen während der Lagerung kaum änderten. Die Verluste beim Vermahlen und Backen waren gering. Die Pyrethroide gewährleisten also einen dauerhaften Schutz vor Insektenbefall, hinterlassen aber nennenswerte Rückstände in den Getreidemahlerzeugnissen und Broten.

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Residual analysis of pyrethroid insecticides in cereal grains, milled fractions and bread

Summary A procedure is described for the residual analysis of eight pyrethroid insecticides at levels of 2–5 g/kg. Residues are extracted from cereal grains, flour or bread with a mixture of acetonitrile/water (2 + 1) and are partitioned into petroleum ether. Clean-up is performed by gel permeation chromatography on Bio-Beads S-X3 and an additional Florisil column. Electron capture gas liquid chromatography on a non-polar SE-30 capillary column separates the isomers of the compounds. Under the conditions used in the experiments with cyfluthrin, cypermethrin, deltamethrin, fenvalerate, and permethrin, the compound levels in rye and wheat did not decrease significantly. Losses during milling and baking were small. Consequently, pyrethroid insecticides remain effective in grain stored over a long period of time. However, considerable residues result in the milled fractions as well as in different types of bread.

     

Improved sensitive determination method for bromate in bread

An effective clean-up procedure was developed to determine trace levels of bromate in bread by high-performance liquid chromatography with post-column flow reactor detection. Bromate was extracted from bread with deionized pure water. After centrifugation, the supernatant was filtered through a paper filter. The filtrate was filtered through a 0.2 micron nylon filter and chloride ion was removed by an IC-SP M Ag cartridge column or On-Guard Ag cartridge column. The eluate was applied to an Oasis MAX anion exchange cartridge column. The column was washed with 20% acetic acid and water. Bromate was then eluted with 0.5% sodium nitrate solution. The eluate was determined by HPLC with post column flow reactor detection. The method had a quantitation limit of 2 ng/g in bread products. Recoveries of bromate from bread ranged from 68 to 72% at a spiked bromate level of 2-10 ng/g.     

Analysis of glyphosate residues in cereals using liquid chromatography-mass spectrometry (LC-MS/MS)

A fast and specific method for the determination of glyphosate in cereals is described. The method is based on extraction with water by ultrasonication. The samples are cleaned up and separated by high-performance liquid chromatography on a polystyrene-based reverse-phase column (clean-up) in series with an ion chromatography column (separation) using NaHCO₃ as eluent. A micro-membrane suppressor was inserted after the separator column to remove the Na⁺ ions before detection by electrospray ionization mass spectrometry in the negative-ion mode. In MS/MS, mode the following transitions were monitored m/z 168 →150 (glyphosate) and 170 →152 (internal standard 2-¹³ C¹⁵N-glyphosate) for quantification. The mean recovery was 85% (n=32) at spiking levels from 0.03 to 0.33 mg kg^-1. From 1998 to 2001, from the analysis of about 50 samples per annum, a reduction in the glyphosate residues was observed owing to a Danish trade decision not to use grain with glyphosate residues for milling or bread production.     

Determination of Pyrethroid Insecticides in Crude and Canned Vegetable Samples by Supercritical Fluid Chromatography

A supercritical fluid chromatography method for the determination of seven pyrethroid insecticides (allethrin, resmethrin, phenothrin, permethrin, tetramethrin, cypermethrin, deltamethrin) and one of their common metabolites, phenoxybenzyl alcohol, in whole and peeled potatoes and mixed vegetables was developed. The efficiencies of the two extraction techniques, supercritical fluid extraction and microwave-assisted extraction, for the extraction of pyrethroids from vegetable samples were also compared. The retention times of various pyrethroids ranged from 8.4 to 22.9 min, while all of the peaks were well-resolved and distinctly identified. The limits of detection of pyrethroid insecticides ranged between 0.31 and 0.54 ppm, whereas the limits of detection of phenoxybenzyl alcohol was 0.62 ppm. The recoveries of pyrethroid insecticides from whole potatoes, peeled potatoes, and mixed vegetables ranged as 93.83–99.8%, 92.3–105.8%, and 93.67–102.7%, respectively, with the use of supercritical fluid extraction. The corresponding recovery ranges while using microwave-assisted extraction were 94.2–102%, 96.6–101.2%, and 96–103.2%. These findings suggested that supercritical fluid chromatography was a sensitive and rapid technique for the analysis of pyrethroids in complex matrices, such as vegetables, fruits, and other agricultural products.     

固相萃取-气相色谱法检测蔬菜中8种菊酯类 农药残留

目的建立一种固相萃取-毛细管柱气相色谱方法,可以同时检测蔬菜中8种菊酯类农药残留。方法蔬菜样品匀浆后,经正己烷/丙酮(V:V=50:50)提取,Florisil固相萃取柱净化,HP-5毛细管气相色谱柱进行分离,GC-ECD进行定性及定量分析。结果 8种菊酯类农药残留的色谱图分离效果良好,线性相关系数均大于0.995,方法检出限在0.0025~0.02 mg/kg之间。8种菊酯类农药的添加水平为0.025~2 mg/kg,回收试验表明该方法平均回收率在73.6%~97.0%之间,相对标准偏差小于5%。结论该方法样品处理简单、仪器配置要求较低、净化效果好、易于推广使用,适合蔬菜中多种菊酯类农药残留的检测和安全监控。     

DETERMINATION OF BENZOIC AND SORBIC ACID IN TURKISH FOOD USING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

Benzoic and sorbic acid levels in different brands of jam, candied chestnut, carbonated drink, pickle, black table olive, green table olive, wholemeal/brown bread and white bread, which are available on the Turkish market, were determined by high-performance liquid chromatography with diode array detector (235–254 nm). Chromatographic separation was achieved with a C18 column and acetate buffer (pH 4.74)–methanol mixture (70:30) as a mobile phase. The levels of benzoic and sorbic acid in the analyzed samples were in the range of not detected to 662 mg/kg or L, and not detected to 432 mg/kg or L, respectively. Only one sample (jam) presented a preservative although not permitted by the legislation enforced in Turkey. The levels of preservative in the other samples were determined in legal limitations. According to the results, the utilization of benzoic and sorbic acid is lower than the certain legal limitations permitted by legislation to be used.

PRACTICAL APPLICATIONS

The amount of the sorbic and benzoic acid used as preservatives during food processing is important for consumer health. Determination of the amounts of the preservatives mentioned above will be possible in a short period of time (11 min) with the methods used in this study (high-performance liquid chromatography). According to the results obtained from study and data about food consumption, daily intake amount of these preservatives (benzoic and sorbic acid) will be able to be defined in Turkey, separately.     

Analysis of polychlorinated biphenyls, pyrethroid insecticides and fragrances in human milk using a laminar cup liner in the GC injector

 Since 1970 the State Laboratory of Basle City has been periodically analyzing human milk from the region (the latest in 1998/99) as a bioindicator for the environmental load of organochlorine pesticides [1, 2]. The analysis of human milk is very complex including several clean-up steps and is therefore time consuming. The focus is mainly on organochlorine pesticides, polychlorinated biphenyls (PCB), and nitro-musk compounds; analytes which are easily detectable with gas chromatography and electron capture detection (ECD). Our aim was to minimize the clean-up steps for the analysis of ECD sensitive substances. Furthermore, analytes insensitive to EC detection that require MS detection, such as polycyclic musk substitutes, were of interest. With the help of a specially designed GC liner in the vaporizing injector of the gas chromatograph, the laminar cup liner, we have considerably reduced the time and effort in the sample preparation. With the described clean-up procedure we analyzed 53 human milk samples from the region of Basle for PCB, pyrethrins, and pyrethroid insecticides and fragrances (nitro-musk compounds and polycyclic musk substitutes). While PCB showed a general downward trend in mean concentrations since 1980, residues of the polycyclic musk substitutes galaxolide and tonalide were detectable in almost every sample (e.g., 73 μg/kg fat of HHCB, 74 μg/kg fat of AHTN). Pyrethrins and pyrethroid insecticides were detected only at low concentrations between 0.03 and 0.46 mg/kg fat. Received: 28 September 1999 / Revised version: 2 May 2000     

大米中氨基甲酸酯类农药的多残留检测

介绍一种大米中11种氨基甲酸酯类杀虫剂及其代谢产物的多残留快速测定方法。乙腈提取样品中农药。氨基固相萃取柱净化，甲醇和二氟甲烷（v／v，1／99）洗脱。液相色谱柱后衍生荧光检测器检测。对大米样品进行添加回收率实验，分别添加0．1mg／kg、0．5mg／kg、2mg／kg，回收率在71．9％-98．2％之间，变异系数为2．78％～10矧名。     

拟除虫菊酯类农药通用人工抗原的合成与鉴定

根据拟除虫菊酯公共结构设计合成一种拟除虫菊酯通用半抗原,所有中间体及半抗原经电喷雾电离质谱(ESI-MS)、红外光谱(IR)和核磁共振(1H NMR)鉴定确定结构.通过活化酯法将通用半抗原与钥孔血蓝蛋白(KLH)偶联制备出免疫原,紫外吸收法鉴定表明免疫原偶联成功,研究为建立拟除虫菊酯多残留免疫分析方法奠定了基础.     

Levels of ochratoxin A in wheat and maize bread from the central zone of Portugal

Ochratoxigenic fungi are natural contaminants of cereal and the produced toxins are harmful to humans and animals. Ochratoxin A (OTA) is among the most important mycotoxins, and the International Agency for Research on Cancer (IARC) classifies it as possibly carcinogenic to humans (group 2B). A total of 61 samples of bread from the central zone of Portugal were analysed for OTA by liquid chromatography (LC) with fluorescence detection (FD). For confirmation two procedures were applied, methyl ester derivatization with boron trifluoride-methanol and liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS). As far as we know, this is the first report where on-line LC/electrospray ionization (ESI) tandem mass spectrometry (MS/MS) was used for OTA analysis in bread. Limits of detection (LOD) and quantification (LOQ) were 0.015 and 0.03 ng/g, using LC-FD, and 0.03 and 0.09 ng/g by LC-MS/MS. The incidence of OTA was 12.9% and 70.0% for wheat and maize bread, respectively. The highest OTA levels were obtained for maize bread, having one sample exceeded the European maximum limit established for OTA in cereal products. The estimate daily intake (EDI) was below the tolerable daily intake.     

基于电化学技术的Ⅱ型拟除虫菊酯分子印迹膜的研制

拟除虫菊酯类农药残留造成的安全问题已受到越来越广泛的关注,开发快速检测技术可为农副产品中拟除虫菊酯类农药残留的监控提供技术支持。本实验以邻氨基酚为功能单体,以Ⅱ型拟除虫菊酯农药结构类似物间苯氧基苯甲酸为模板分子,采用循环伏安法电聚合技术在玻碳电极表面聚合形成可检测含间苯氧基苯甲酸结构的Ⅱ型拟除虫菊酯农药的分子印迹膜,用于Ⅱ型拟除虫菊酯类农药的检测研究。5 min可完成对农药的响应,其响应电流变化值与一定浓度范围内的溴氰菊酯、氰戊菊酯、甲氰菊酯、氯氟氰菊酯呈良好的线性关系,相关系数r分别为0.991、0.992、0.992、0.990,精密度分别为2.20%、2.80%、2.50%、2.12%,检出限在0.01mg/kg~0.30 mg/kg之间。对加标红桔、贡桔和椪柑样品进行检测,准确性高。     

金针菇中6种拟除虫菊酯类农药多残留的测定

建立联苯菊酯、甲氰菊酯、高效氯氟氰菊酯、高效氯氰菊酯、氰戊菊酯和溴氰菊酯6种拟除虫菊酯类农药在金针菇中的多残留分析方法。样品以乙腈为提取溶剂,弗罗里硅土柱层析净化,气相色谱-电子捕获法测定。该检测条件下,联苯菊酯、甲氰菊酯和高效氯氟氰菊酯在0.005～0.50mg/L、高效氯氰菊酯、氰戊菊酯和溴氰菊酯在0.01～1.00mg/L的范围内具有良好的线性关系,线性方程的决定系数大于0.996。添加回收实验结果表明,供试农药在添加量范围平均回收率为85.54%～102.27%,变异系数为1.24%～9.58%,联苯菊酯、甲氰菊酯和高效氯氟氰菊酯的最低检测限为5μg/L,高效氯氰菊酯、氰戊菊酯和溴氰菊酯的最低检测限为10μg/kg。该方法的准确性、精确性和灵敏度均满足农药残留分析的要求。     

烟草中拟除虫菊酯类农药残留分析技术研究进展

为方便相关研究人员了解烟草中拟除虫菊酯类农药残留的分析方法,对近年来烟草中拟除虫菊酯类农药的检测方法进行了文献调研和系统总结.结果表明:①目前对此类农药残留分析技术的研究主要集中在样品前处理技术、分析仪器的选择和分析条件的优化方面.②样品前处理技术方面,QuEChERS提取结合多元SPE小柱净化进行烟草样品的前处理,在...     

基于气相色谱法的含脂羊毛中4种拟除虫菊酯药物残留测定

为了研究建立气相色谱－电子捕获检测器测定含脂羊毛中4种拟除虫菊酯杀虫剂残留的国家标准方法。在空白含脂毛中分别添加4个浓度水平（0.06 μg/g、0.30 μg/g、2.00 μg/g、5.00 μg/g）的4种拟除虫菊酯农药混标,以正己烷+乙醚（体积比2:1）为提取溶剂,中性氧化铝固相萃取柱和弗罗里硅土柱净化,以4 ml正己烷+乙酸乙酯（体积比95:5）进行洗脱,气相色谱－电子捕获检测器测定,外标法定量。结果显示：4种农药的最小检出量分别为0.020 μg/g、0.060 μg/g、0.024 μg/g和0.030 μg/g,平均回收率79.4%~101.2%,相对标准偏差1.20%~3.08%,分离良好,干扰峰少,结果准确,且操作简便、快捷,溶剂使用量小、符合环保要求。     

气相色谱法测定食品中DMF

用已酸已酯作提取剂,柱层析法分离提取样品中的DMF,气相色谱法直接测定提取液中的DMF。方法回收率为96.45%～97.96%,RSD为1.80%。应用本方法测定面包等烘烤食品中的DMF,具有操作简单、灵敏度高、重现好等特点。     

Determination of residues of organochlorine insecticides and polychlorinated biphenyls in cereals, feeds and water

A semimicro method for the quantitative determination of chloro-organic insecticides (COI) and polychlorinated biphenyls (PCB) in cereals, feed-pellets and water is presented. The extraction of the active compounds is carried out with n-hexane or dichloromethane. The extracts of cereals and pellets are purified by column chromatography with aluminum oxide. A silicagel column is used for the separation of the compounds into COI as well as PCB and hexachlorobenzene. The determination of the active compounds is carried out by gas chromatography using an electron capture detector. Recoveries range between 70 and 108%, except for beta-endosulphan.     

High-performance liquid chromatography multiresidue method for the determination of N-methyl carbamates in fruit and vegetable juices

A rapid multiresidue method has been developed for the analysis of N-methylcarbamate insecticides (oxamyl, methomyl, propoxur, carbofuran, carbaryl, and methiocarb) in fruit and vegetable juices. The method is based on the adsorption of the N-methyl carbamates in Florisil and the subsequent extraction of pesticides using a low volume of acetone. Residue levels in juice were determined by reversed-phase high-performance liquid chromatography with fluorescence detection after postcolumn derivatization. The separation of carbamates is performed on a C8 column with water-methanol as mobile phase. Recovery studies were performed at 500-, 100-, and 10-ng/ml fortification levels, and average recoveries obtained for carbamates ranged from 79 to 109%, with relative standard deviations between 1.4 and 9.9%. The method was found to be linear over the range assayed from 10 to 1,000 ng/ml, and the detection limits for carbamates varied from 0.8 to 1.9 ng/ml.     

QuEChERS-气相色谱法测定葡萄酒中6种杀虫剂

目的建立QuEChERS-气相色谱法测定葡萄酒中6种杀虫剂残留的分析方法。方法样品经乙腈提取后,提取液采用QuEChERS前处理后上机测定。优化的色谱条件为:DB-1石英毛细管柱(0.53 mm×1.50μm,30m),采用程序升温分离,火焰光度检测器检测,采用外标法定量。结果在优化的条件下,6种杀虫剂在0.01~1.50μg/mL范围内线性良好,相关系数(r)均大于0.999,定量限为0.02~0.025 mg/kg, 6种杀虫剂平均回收率为81%~115%,相对标准偏差(relative standard deviation, RSD)在0.870%~7.29%(n=3)之间。结论该方法具有操作简便、快速、准确的特点,适用于葡萄酒中6种杀虫剂残留痕量分析。     

UPLC-MS/MS测定葡萄酒中3种双酰胺类杀虫剂

建立了葡萄酒中氰虫酰胺、氯虫苯甲酰胺、氟苯虫酰胺等3种双酰胺类杀虫剂残留量的超高效液相色谱-串联质谱(UPLC- MS/MS)检测方法。葡萄酒中的3种双酰胺类杀虫剂经乙腈提取后,用GCB/NH2固相萃取柱净化,以乙腈-5 mmol/L乙酸铵-甲酸作为流动相,梯度洗脱,通过UPLC-MS/MS进行测定。结果表明,3种双酰胺类杀虫剂在质量浓度1～20 μg/L范围内呈良好的线性关系,相关系数(R)≥0.999 5,方法检出限＜1.0 μg/kg;以1.0 μg/kg、2.0 μg/kg、10 μg/kg为添加水平,平均回收率在76.3%～91.1%之间,相对标准偏差(RSD)为3.9%～9.8%。表明该方法快速简便、净化效果好、准确度较好、精密度较高,可应用于葡萄酒中3种双酰胺类杀虫剂的同时测定。     

Simultaneous evaluation of neonicotinoids in cotton seed cake using reverse phase high‐performance liquid chromatography

BACKGROUND: The cotton crop accounts for more than 52% of total insecticide usage in India. Neonicotinoids, being newer insecticides, have found greater use in the northern region. In this study a rapid and sensitive high‐performance liquid chromatography method was developed for measuring neonicotinoid residues in cotton seed cake (CSC). The method involves the extraction of three neonicotinoids from CSC with acetonitrile/water (80:20 v/v), followed by liquid–liquid partitioning and column clean‐up prior to injection. RESULTS: Recoveries at 0.5–2 µg g^?1 spiking levels varied from 95.60 to 79.50% for imidacloprid, from 92.89 to 84.00% for acetamiprid and from 96.96 to 88.36% for thiacloprid. Minimum detectable levels using this method were 5, 10 and 20 ng g^?1 for imidacloprid, acetamiprid and thiacloprid respectively. CONCLUSION: The method developed in this study allows rapid and reliable measurement of the insecticides imidacloprid, acetamiprid and thiacloprid in CSC. Copyright © 2009 Society of Chemical Industry