固相微萃取技术的原理及应用

本文所介绍的固相微萃取技术是一项无溶剂样品制备方法，其原理是利用分析组分在样品基质提取与提取剂中的分配不同，从而达到分离目的，具有简便，经济，不使用溶剂等优点，并且能做到提取，净化浓缩和ＧＣ上进样分析同步完成，本文还对固相微萃取的装置，工作程序及应用作了介绍。     

Modelling penetration of plant cuticles by crop protection agents and effects of adjuvants on their rates of penetration

A theory of cuticular penetration of crop protection agents (CPAs) is presented, which incorporates properties of cuticles and cuticular waxes as well as properties of active ingredients and adjuvants. Based on this theory, two models are developed which are analytical in the sense that they help to quantify and understand (i) differences in permeability among cuticles from different species, (ii) effects of properties of CPAs on permeabilities of cuticles and rates of uptake and (iii) the effects of adjuvants on properties of cuticles and rates of uptake of CPAs. The models can be used to predict rates of uptake of CPAs as affected by properties of cuticular waxes, active ingredients and adjuvants. However, before this can be done, a constant, two parameters and at least two variables must be estimated. Properties of cuticles are accounted for by the constant D⁰/Δx and the parameter β′. The former, the ratio of the mobility of a hypothetical molecule having zero molar volume (D⁰x) divided by the path length (Δx) across the cuticle, has the dimension of velocity (ms^?1) and is independent of the solubility of the CPA. The latter is a measure of size selectivity of the cuticle. Differences in permeabilities of cuticles from different species increase with increasing size of active ingredients due to size selectivity (β′). Removing cuticular waxes from Citrus cuticles increased D⁰/Δx by a factor of 2042, while β was not affected. Differential solubility of CPAs is considered part of the driving force and at least two different partition coefficients are needed to account for differences in solubilities in cuticular waxes, cutin, water and the formulation residue on the surface of the cuticles. Adjuvants are solvents in the formulation residue on the leaf surface once the carriers (water and other volatile solvents) have evaporated and certain adjuvants also act as accelerators; they penetrate the cuticle and increase D⁰/Δx. Thus, accelerators increase rates of uptake and this effect depends on two factors, (i) the intrinsic activity of the accelerator and (ii) rate of penetration into the cuticle, because the active ingredients follow the accelerator front across the cuticle. Since accelerators penetrate from the formulation residue into the cuticle, the volume of the formulation residue decreases with time. This maintains high concentrations of CPAs in the formulation residue and, thus, maximum driving forces and rates of penetration. To utilise fully this dual accelerator effect, it is necessary to match velocities of penetration of accelerators and active ingredients accurately.     

Application of Solid Phase Micro‐Extraction (SPME) to the analysis of pesticide residues in vegetables

Solid Phase Micro‐Extraction (SPME) is a new analytical technique, based on capturing the analytes by adsorption onto an organic phase coating a glass fibre, and subsequent direct desorption into the injector of a gas chromatograph. This technique has been successfully applied in the analysis of organic contaminants in water, giving linear responses and, in some cases, high sensitivities. The present paper reports data about the application of SPME to the analysis of pesticide residues in a vegetable matrix, testing over nearly one hundred active compounds, with two types of adsorbent phase (polydimethylsiloxane and Carbowax/divinylbenzene). A vegetable matrix spiked with pesticides was analyzed by SPME and by a traditional multi‐residue method; recoveries were determined and compared for the two cases. The behaviour of the analytical response by SPME was studied in the range 0.01–1 mg kg⁻¹ by adding increasing amounts of given pesticide mixtures to the vegetable matrix. The procedure was further tested by analyzing real samples, and gave some difficulties in recovering the whole amount of some of the residues present (in comparison with the traditional method). The SPME method was then improved by pre‐extracting with acetone and sonicating before the extraction/adsorption step. The results obtained were satisfactory (some certified matrices were also tested) with good accordance between the two methods. Nevertheless some active compounds showed very low responses or remained undetectable by SPME in our experimental conditions. © 2000 Society of Chemical Industry     

Effect of hot water treatment on peach volatile emission and Monilinia fructicola development

The effect of hot water treatment (HWT) to control peach brown rot was investigated. Peaches were dipped in water at 60°C for 60 s and artificially inoculated with Monilinia fructicola conidia. HWT failed to control brown rot if applied before inoculation and microscopic observations revealed a stimulatory effect on germ tube elongation of M. fructicola conidia placed immediately after HWT on the fruit surface, compared to the control. The influence of fruit volatile emission due to HWT was performed on the pathogen conidia exposed to the headspace surrounding peaches. The results showed an increase of M. fructicola conidial germination ranging from 33 to 64% for cultivars Lucie Tardibelle and Red Haven heat‐treated peaches, respectively, compared to the control. The volatile blend emitted from heat‐treated fruit was analysed by solid‐phase microextraction/gas chromatography‐mass spectrometry (SPME/GC‐MS) and proton transfer reaction‐time of flight‐mass spectrometry (PTR‐ToF‐MS). Fifty compounds were detected by SPME/GC‐MS in volatile blends of cv. Lucie Tardibelle peaches and significant differences in volatile emission were observed among heated and control fruit. Using PTR‐ToF‐MS analysis, acetaldehyde and ethanol were detected at levels 15‐ and 28‐fold higher in heated fruit compared to unheated ones, respectively. In vitro assays confirmed the stimulatory effect (60 and 15%) of acetaldehyde (0·6 μL L^?1) and ethanol (0·2 μL L^?1) on M. fructicola conidial germination and mycelial growth, respectively. The results showed that volatile organic compounds (VOCs) emitted from heat‐treated peaches could stimulate M. fructicola conidial germination, increasing brown rot incidence in treated peaches when the inoculation occurs immediately after HWT.     

Composition of essential oil of Chinese Chenopodium ambrosioides and insecticidal activity against maize weevil, Sitophilus zeamais

BACKGROUND: In a screening programme for new agrochemicals from Chinese medicinal herbs, Chenopodium ambrosioides L. was found to possess strong fumigant activity against the maize weevil Sitophilus zeamais (Motsch.). Essential oil of C. ambrosioides was obtained by hydrodistillation, and the constituents were determined by GC‐MS analysis. The active compounds were isolated and identified by bioassay‐directed fractionation. RESULTS: Five active compounds [(Z)‐ascaridole, 2‐carene, ρ‐cymene, isoascaridole and α‐terpinene] were isolated and identified from the essential oil from Chinese C. ambrosioides. The LC₅₀ values (fumigation) of the crude essential oils and the active compound (Z)‐ascaridole against S. zeamais adults were 3.08 and 0.84 mg L^?1 air respectively. The LD₅₀ values (contact toxicity) of the crude essential oil and (Z)‐ascaridole against S. zeamais adults were 2.12 and 0.86 µg g^?1 body weight respectively. CONCLUSION: The findings suggested that the essential oil of Chenopodium ambrosioides and its main active constituent, (Z)‐ascaridole, may be explored as a natural potential fumigant. Copyright © 2011 Society of Chemical Industry     

嘧菌酯·苯醚甲环唑PBS/PLA微球的结构表征与释放性能

以PBS/PLA共混物为复合载体,嘧菌酯和苯醚甲环唑为包埋有效成分,聚乙烯醇(PVA-1788)为分散剂,采用溶剂挥发法制备了嘧菌酯·苯醚甲环唑PBS/PLA微球。通过光学显微镜、扫描电子显微镜、Nicolet 6700型傅立叶变换红外光谱仪、高效液相色谱(HPLC)等表征复配农药微球的性质,采用透析袋法测定其缓释性能。结果表明,所得的嘧菌酯·苯醚甲环唑PBS/PLA微球中嘧菌酯的载药量和包埋率分别为14.30%、85.06%,苯醚甲环唑的载药量和包埋率为9.47%、90.18%,且微球球形规整,平均粒径为7.20μm。嘧菌酯·苯醚甲环唑PBS/PLA微球具有良好的缓释性能,并且2种活性成分的释放量之比与其最佳复配比接近,可以达到增效目的。     

Ovicidal,larvicidal and juvenilizing activity of a picolinephenoxyanilide against Cydia pomonella

N‐(4‐phenoxyphenyl)‐2‐pyridinecarboxamide (1) was synthesized from commercially available materials and its ovicidal and larvicidal activity against Cydia pomonella (L) was tested. The compound showed a LC₅₀ of 0.98 mg ml⁻¹ when eggs less than 24 h were sprayed using a Potter Tower, but it had no effect when eggs older than this were sprayed. The compound did not have larvicidal activity when larvae were treated with 1200 µg g⁻¹. However, the larval head capsules were smaller than those in the controls when treated at this concentration. To assess its possible juvenile‐hormone‐like activity, the compound was topically applied to young pupae of Tribolium confusum duVal, where it produced clear juvenilization effects, which were dependent on the applied dose. © 2000 Society of Chemical Industry     

Insecticidal activity against Aedes aegypti of m-pentadecadienyl-phenol isolated from Myracrodruon urundeuva seeds

BACKGROUND: Myracrodruon urundeuva Fr. Allemao is a common tree in the Caatinga that has been widely used for various medical purposes. Previous studies showed that the ethanol seed extract of M. urundeuva has potent activity against the larval stage of the dengue vector Aedes aegypti. Given this potential insecticidal activity, bioguided separation steps were performed in order to isolate the active compound(s). RESULTS: The isolation process resulted in only one active chemical compound, identified by infrared spectroscopy and mass spectrometry as m-pentadecadienyl-phenol. This compound presented potent larvicidal and pupicidal activity (LC₅₀ 10.16 and 99.06 µg mL⁻¹ respectively) and great egg hatching inhibitory activity (IC₅₀ 49.79 µg mL⁻¹). The mode of action was investigated through observations of behavioural and morphological changes performed in third-instar larvae treated with m-pentadecadienyl-phenol solution after 1, 6, 12, 16 and 20 h of exposure. Some changes were observed as flooding of the tracheal system, alterations in siphonal valves and anal gills and lethargy, probably caused by the strong anticholinesterasic activity reported previously. CONCLUSION: The compound isolated from M. urundeuva seeds, m-pentadecadienyl-phenol, showed potent activity against immature stages of dengue vector, Ae. aegypti, being considered the main larvicidal principle. Copyright © 2012 Society of Chemical Industry     

Volatile analogues of penconazole and their activity against the take-all fungus,Gaeumannomyces graminis var. tritici

Eight new sterol biosynthesis-inhibiting fungicides, structurally related to penconazole and having vapour pressures up to 118 mPa, were synthesised. Their toxicities to the cereal take-all fungus, Gaeumannomyces graminis var. tritici, on agar were measured; intrinsic activities were measured after incorporating the compounds into the agar and vapour activities were measured after their evaporation from glass and from moist soil. Vapour activity following evaporation from soil was shown to be a function of both the intrinsic activity of the compound and its partition coefficient between the air and moist soil (K_as). The latter is itself a function of vapour pressure, 1-octanol/water partition coefficient (K_ow) and the soil type. The compound most active as vapour from soil in the in-vitro test, 1-(pyridin-3-yl)-2-(4-flurorophenyl)pentane, was ineffective against take-all in wheat in a pot test in which the inoculated soil was treated unevenly, providing further evidence that the redistribution of fungicides in moist soil occurs predominantly via the water phase rather than the vapour phase.     

Fumigant toxicity of volatile natural products from Korean spices and medicinal plants towards the rice weevil,Sitophilus oryzae (L)

The fumigant toxicity of various volatile constituents of essential oils extracted from sixteen Korean spices and medicinal plants towards the rice weevil, Sitophilus oryzae L (Coleoptera: Curculionidae), was determined. The most potent toxicity was found in the essential oil from Mentha arvensis L var piperascens (LC₅₀ = 45.5 µl litre^?1 air). GC–MS analysis of essential oil from M arvensis showed it to be rich in menthol (63.2%), menthone (13.1%) and limonene (1.5%), followed in abundance by β‐pinene (0.7%), α‐pinene (0.6%) and linalool (0.2%). Treatment of S oryzae with each of these terpenes showed menthone to be most active (LC₅₀ = 12.7 µl litre^?1 air) followed by linalool (LC₅₀ = 39.2 µl litre^?1 air) and α‐pinene (LC₅₀ = 54.9 µl litre^?1 air). Studies on inhibition of acetylcholinesterase activity of S oryzae showed menthone to have a nine‐fold lower inhibitory effect than menthol, despite menthone being 8.1‐fold more toxic than menthol to the rice weevil. Different modes of toxicity of these monoterpenes towards S oryzae are discussed. © 2001 Society of Chemical Industry     

不同残膜量对土壤水分运移的影响及模拟

为解决绿洲区残膜污染,结合已有研究,根据农田残膜量与覆膜年限的关系,设计了9种残膜量处理(0、50、80、132、160、264、396、792、1 320 kg·hm~(-2)),利用室内土柱模拟试验,对不同处理的土壤水分湿润锋运移距离、运移速率、累积蒸发量、蒸发速率、土壤含水率进行监测分析并进行模型模拟,探究残膜量对土壤入渗和蒸发的影响以及模型模拟精度。结果表明:随着残膜量增加,湿润峰运移距离呈减小趋势,较CK减少2.76%～8.66%(P0.05),0～5 h内的平均运移速率较CK减少0.4%～19.5%(P0.05),总体呈幂函数降低趋势;随残膜量增加,累积蒸发量逐渐减小,较CK减少5.04%～38.92%(P0.05),蒸发速率呈降低趋势,而随着蒸发时间增长,蒸发速率也呈幂函数降低趋势;各残膜处理0～10 cm土层土壤平均含水率比10～20 cm土层降低1.51%～3.08%(P0.05),残膜破坏了土壤水分分布的均衡性。通过评价模型的结果显示,各处理拟合结果的决定系数R~2均大于0.988。随着残膜量的增加,RRMSE值出现差异,CRM值趋近0,CE值出现波动变化,模型拟合的结果呈现先变好后变差。     

Diflubenzuron: Some aspects of its ovicidal and larvicidal mode of action and an evaluation of its practical possibilities

Diflubenzuron, 1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea, possesses larvicidal and ovicidal activities. On larvae it acts mainly as a stomach poison, yet it sometimes exhibits important contact activity. Though all instars can be controlled, older instars are generally less susceptible than younger ones. Histological inspections of Leptinotarsa decemlineata larvae revealed that after ending exposure to the compound, distortions in newly deposited cuticular layers decreased gradually. Ovicidal effects resulted from direct contact of diflubenzuron with eggs or from contamination of females by contact or feeding. Electron microscopic observations of embryos of Leptinotarsa decemlineata, contaminated via the female, also showed disturbed cuticule formation, suggesting a similar activity of the compound in larvae and in eggs. Spraying the eggs of Leucoptera scitella shows the compound to be mainly ovidical at a rate of 100 mg litre^?1, whilst with lower concentrations (10 and 1 mg litre^?1) the young larval instar will be killed. The levels of cross-resistance to diflubenzuron as a larvicide are low and the compound can be used effectively in the field against populations that are highly resistant to conventional insecticides. Laboratory and field results, based on larvicidal and ovicidal activities of diflubenzuron, are discussed in respect of species belonging to the Diptera, Lepidoptera, Coleoptera, Acarina (Phyllocoptruta oleivora) and Hemiptera (Eurydema oleraceum and Psylla piri).     

Design,synthesis and acaricidal activity of novel strobilurin derivatives containing pyrimidine moieties

BACKGROUND: The intermediate derivatisation method based on bioisosteric replacement led to the discovery of the lead strobilurin compound 5a. To produce new strobilurin analogues with improved activity, a series of substituted pyrimidines were synthesised and bioassayed. RESULTS: The compounds were identified by ¹H NMR, IR, MS and elemental analysis. The highly active compound 5g was studied by X‐ray diffraction. Preliminary bioassays demonstrated that some of the title compounds exhibited excellent acaricidal activity against Tetranychus cinnabarinus (Boisd.) at 10 mg L^?1. The relationship between structure and acaricidal activity is reported. CONCLUSION: The present work demonstrates that strobilurin derivatives containing pyrimidine moieties can be used as possible lead compounds for developing novel acaricides. Copyright © 2010 Society of Chemical Industry     

Efficacy of plant metabolites of imidacloprid against Myzus persicae and Aphis gossypii (Homoptera: Aphididae)

The metabolism of the chloronicotinyl insecticide imidacloprid is strongly influenced by the method of application. Whilst in foliar application most of the residues on the leaf surface display unchanged parent compound, most of the imidacloprid administered to plants by soil application or seed treatment is metabolized more or less completely, depending on plant species and time. The present study revealed that certain metabolites of imidacloprid which have been described in crop plants are highly active against aphid pests in different types of bioassays. Some of these metabolites showed a high oral activity against the green peach aphid (Myzus persicae), and the cotton aphid (Aphis gossypii). The aphicidal potency of the metabolites investigated was weaker in aphid dip tests than in oral ingestion bioassays using artificial double membranes. The most active plant metabolite was the imidazoline derivative of imidacloprid. The LC₅₀ values of this metabolite for M. persicae and A. gossypii in oral ingestion bioassays were in the lower ppb-range, i.e. 0·0044 and 0·0068 mg litre^-1, respectively. Most of the other reported metabolites showed much weaker activity. Compared to imidacloprid, the imidazoline derivative showed superior affinity to housefly (Musca domestica) head nicotinic acetylcholine receptors, while all other metabolites were less specific than imidacloprid. It seems possible that, after seed treatment or soil application, a few of the biologically active metabolites arising are acting in concert with remaining levels of the parent compound imidacloprid, thus providing good control and long-lasting residual activity against plant-sucking pests in certain crops. © 1998 SCI.     

Rodent tissue residue and secondary hazard studies with bromadiolone1

A series of toxicological, residue, secondary hazard, and environmental fate studies were completed with bromadiolone. The compound was eliminated rapidly after ingestion by Rattus norvegicus and Mus domesticus. In R. norvegicus, 75% of the bromadiolone was eliminated within 4 days. Dead rodents collected from field trials using bromadiolone had residue levels of 1.92 in R. rattus, 1.17 in M. domesticus, and 0.49 ppm in Spermophilus beecheyi. The LD50 for bromadiolone in beagle dogs was calculated at 8.1 mg kg^-1 (10.7 for males and 6.3 mg kg^-1 in females). The approximate LD50 in Canis latrans was 10 mg kg^-1. Dietary LC50 determination compound in Putorius putorius furo was 9.8 ppm. Secondary hazard studies showed the rodenticide to have little potential to snakes and birds of prey if used properly. Field tests with grain and pelleted baits over 21 days demonstrated that the active ingredient degraded by 78 and 45%, respectively.     

松脂二烯在植物叶片表面的成膜性能

为明确松脂二烯 (pinolene) 提高农药田间防效的机理,研究了其在植物叶片表面的成膜性能。以红叶石楠和山核桃为试材,分别将3%噻虫啉微囊悬浮剂和2%甲氨基阿维菌素苯甲酸盐微乳剂与松脂二烯桶混后喷施到植物叶片上,通过电镜及光合测定仪,观测了松脂二烯对农药药液在叶片表面的成膜形态及其对光合作用的影响;通过人工模拟降雨和氙灯光照,研究了松脂二烯抗雨水冲刷能力和抗光解能力。结果表明:添加松脂二烯的农药颗粒表面均有一层明显的油状包被。在不同雨水冲刷时间段,添加松脂二烯的噻虫啉处理组植物叶片上的农药保持量均显著高于对照组;松脂二烯和甲氨基阿维菌素苯甲酸盐混用,能显著降低甲氨基阿维菌素苯甲酸盐的光分解速率;松脂二烯叶片成膜致其光合速率下降5.16%,但与对照无显著差异。本研究结果表明,松脂二烯和农药混用,可增加农药有效成分在植物叶片上的成膜性,且对植物光合作用影响较小,可有效减少农药受雨水冲刷损失和光解速率,延长农药持效期。     

High Performance Thin Layer Chromatography (HPTLC) profile of an insecticidal compound of <Emphasis Type="Italic">Trochus radiatus</Emphasis> and assessment of mucus-associated bacterial extracts

The current study is based on the screening of novel insecticides from new sources that have not being exploited hitherto. The major objectives of this research work were to extract marine molluscs, Lambis lambis, Trochus radiatus and Chicoreus ramosus, from Tuticorin coastal waters using different solvents to test their insecticidal properties and partially purify the active components. The ethyl acetate extracts of L. lambis and T. radiatus showed 100% mortality of Sitophilus oryzae, at a concentration of 200 μg ml⁻¹. The LC₅₀ values for ethyl acetate extracts of L. lambis, T. radiatus and C. ramosus were found to be 67.08, 348.86 and 571.42 μg ml⁻¹, respectively. With regard to bacterial metabolites, at a concentration of 200 μg ml⁻¹ the ethyl acetate extract of A3 was able to elicit an activity of 40% and that of strain A1 – 20%. The LC₅₀ values of the bacterial metabolites were also investigated. Upon chromatographic separation of active ethyl acetate extracts of T. radiatus, the 100% methanol column-purified fraction was found to have an activity of 30% at a concentration of 10 μg against S. oryzae. The purity of the partially pure active compound was observed to be 72.78% on analysis with high pressure thin layer chromatography.     

二甲戊灵和乙氧氟草醚在生姜上的残留分析及土壤中的消解动态

建立了气相色谱-质谱联用（GC-MS）同时测定二甲戊灵和乙氧氟草醚在生姜、茎秆和土壤中残留量的分析方法,并采用该方法研究了两种农药在土壤中的消解动态及在土壤和生姜中的最终残留。样品前处理采用QuEChERS法,经乙腈提取,姜块和茎秆提取液分别用N-丙基乙二胺（PSA）和石墨化碳黑（GCB）净化,土壤提取液用弗罗里硅土柱净化,选择离子监测模式（SIM）扫描,外标峰面积法定量。结果表明:当添加水平为0.01~0.5 mg/kg时,二甲戊灵在生姜、茎秆和土壤中的回收率分别为91%~100%、90%~98%和86%~100%,相对标准偏差（RSD）分别为3.2%~3.7%、2.7%~4.2%和3.2%~5.1%;乙氧氟草醚在生姜、茎秆和土壤中的回收率分别为90%~95%、86%~91%和85%~95%,RSD分别为2.4%~4.4%、3.9%~5.5%和2.3%~4.9%;样品中二甲戊灵和乙氧氟草醚的定量限（LOQ）均为0.01 mg/kg。二甲戊灵在土壤中的消解半衰期在12.5~20.5 d之间,乙氧氟草醚在18.8~25.6 d之间。采用33%二甲戊灵乳油和24%乙氧氟草醚乳油混剂分别按推荐剂量（有效成分693 g/hm2和72 g/hm2）和高剂量（有效成分1 039 g/hm2和108 g/hm2）于种植后施药1次,在生姜收获期的姜块中均未检出二甲戊灵和乙氧氟草醚残留。研究结果可为二甲戊灵和乙氧氟草醚在生姜上的合理使用及其最大允许残留限量（MRL）标准制定提供参考。     

Assessing the risk of pesticide environmental impact in several Argentinian cropping systems with a fuzzy expert indicator

BACKGROUND: The introduction of transgenic soybean (Glycine max, L.) varieties resistant to glyphosate (GR soybeans) has rapidly expanded in Argentina, increasing pesticide use where only grasslands were previously cultivated. The authors compared an estimate of environmental risk for different crops and active ingredients using the IPEST index, which is based on a fuzzy‐logic expert system. For IPEST calculations, four modules are defined, one reflecting the rate of application, the other three reflecting the risk for groundwater, surface water and air. The input variables are pesticide properties, site‐specific conditions and characteristics of the pesticide application. The expert system calculates the value of modules according to the degree of membership of the input variables to the fuzzy subsets F (favourable) and U (unfavourable), and they can be aggregated following sets of decision rules. IPEST integrated values of ≥ 7 reflect low environmental risk, and values of < 7 reflect high risk. RESULTS: Alfalfa, soybean and wheat showed IPEST values over 7 (low risk), while maize had the lowest IPEST values (high risk). Comparing active ingredients applied in annual and perennial crops, atrazine and acetochlor gave the highest risks of environmental contamination, and they are mainly used in maize. Groundwater was the most affected compartment. CONCLUSIONS: Fuzzy logic provided an easy tool combining different environmental components with pesticide properties to give a simple and accessible risk assessment. These findings provide information about active ingredients that should be replaced in order to protect water and air from pesticide contamination. Copyright © 2010 Society of Chemical Industry     

气相色谱-氮磷检测器测定草甘膦在土壤和苹果中的残留量

建立了简单、灵敏的土壤及苹果中草甘膦残留量的气相色谱检测方法。土壤样品用2 mol/L 的氨水提取,经三氟乙酸酐(TFAA)和三氟乙醇(TFE)衍生化后,由配有氮磷检测器的气 相色谱(GC-NPD)进行检测。土壤中草甘膦的最小检出量为9×10-12 g,最低检出浓度为0.02 mg/kg, 平均回收率及变异系数分别为84.4% ~94.0% 和7.46% ~10.40%。苹果样品则采用去离子水提取,经二氯甲烷液液分配和BIO-RAD AG 50W-X8阳离子交换柱净化后,再用TEAA和TFE衍生化,最后用GC-NPD检测,其中草甘膦的最小检出量(LOD)和最低检出浓度(LOQ)与土壤样品中的相同,平均回收率及变异系数分别为80.7% ~98.6%和9.3% ~11.8%。草甘膦的衍生化产物通过气相色谱-质谱联用仪(GC-MS)进行了确证。在北京昌平地区进行的消解动态和最终残留试验结果表明,以推荐高剂量(有效浓度)的1.5倍(2 025 g/hm2)施药,草甘膦在土壤中的半衰期为 9.2 d。两年的最终残留试验结果表明,无论是高浓度区(2 025 g/hm2)还是低浓度区(1 350 g/hm2),苹果收获时(距施药75 d),土壤和苹果样品中均未检出草甘膦。