全自动固相萃取-气相色谱-质谱联用法测定油料 作物中2,4-二氯苯氧乙酸和2,4,5-三氯苯氧乙酸的残留量

目的建立全自动固相萃取-气相色谱-质谱联用法测定花生、大豆和芝麻3种油料作物中2,4-二氯苯氧乙酸和2,4,5-三氯苯氧乙酸的分析方法。方法样品经过二氯甲烷提取,衍生化反应,全自动固相萃取仪净化,DB-5MS毛细管色谱柱分离,选择离子扫描模式检测,外标法定量。结果 2种农药在线性范围内具有良好的线性关系,相关系数r≥0.999,定量限均低于0.010 mg/kg,添加的平均回收率在73.6%~100.8%之间,相对标准偏差在3.31%~7.68%之间。结论建立的方法样品前处理简单,净化过程实现了自动化操作,大大提高了工作效率。该方法灵敏度高、回收率好,适用于油料作物中2种农药的同时检测。     

Hydrophilic and hydrophobic sorption of organic acids by variable charge soils: effect of chemical acidity and acidic functional group

Sorption of organic acids by variable-charge soil occurs through both hydrophilic and hydrophobic sorption. In this study, the effect of chemical acidity and the type of acidic functional group on the relative contribution of hydrophilic and hydrophobic processes to sorption by a gibbsite-dominated and a kaolinite-dominated variable-charge soils was quantified by measuring sorption isotherms from different electrolytes (CaCl2, Ca(H2PO4)2, and KCl). The A1 soil is dominated by gibbsite whereas the DRC soil is primarily kaolinite. The organic acids investigated include five chlorinated phenols (pentachlorophenol, 2,3,4,6-tetrachlorophenol, 2,4,6-trichlorophenol, 2,4,5-trichlorophenol, and 2,4-dichlorophenol) with pKa values ranging from 4.69 to 7.85 and two acidic herbicides (2,4-D (pKa = 2.8) and prosulfuron (pKa = 3.76)) that contain carboxyl and urea functional groups, respectively. Anion exchange of chlorinated phenols and prosulfuron on both variable-charge soils as well as 2,4-D sorption on the A1 soil was linearly correlated to chemical acidity. The effective positive surface charge [AEC/(AEC + CEC)] and the anionic fraction of the organic acid in solution, which are both pH-dependent, were sufficient to estimate the contribution of anion exchange to organic acid sorption except for 2,4-D sorption by DRC soil. The latter was much greater than would be predicted from the pKa of 2,4-D. Calcium bridging between silanol edge group and 2,4-D was hypothesized and corroborated by differences in sorption measured from KCl and CaCl2 solutions. For predicting contributions from hydrophobic processes, a log-log linear relationship between pH-dependent octanol-water (Kow(pH)) and organic carbon-normalized sorption coefficients (Koc(pH)) appeared adequate.     

Determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in 2,4,5-trichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid-alkylesters and in the corresponding herbicide formulations (author's transl)]

A method is described for the determination of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) in 2,4,5-Trichlorophenoxyacetic Acid (2,4,5-T), 2,4,5-T-Akylesters and commercial herbicide formulations containing these substances. TCDD is extracted from alkaline solution with n-hexane and purified by column chromatography on silica gel and Florisil. TCDD is determined by gas-liquid chromatography with EC-detection. For TCDD-additions of 20 micron/kg to herbicide formulations recoveries of dioxin are 96--104%. The detection limit is about 5 microgram/kg 2,4,5-T.     

超高效液相色谱-质谱法测定豆芽中多菌灵、2,4-二氯苯氧乙酸、恩诺沙星残留

建立豆芽中多菌灵、2,4-二氯苯氧乙酸（2,4-dichlorophenoxyacetic acid,2,4-D）、恩诺沙星残留检测的超高效液相色谱-质谱的分析方法。样品经酸化乙腈提取,浓缩后经WAX小柱净化,采用Waters C18色谱柱分离,以甲醇和0.1%甲酸溶液为流动相进行梯度洗脱,采用电喷雾-正负离子多反应监测模式,外标法定量。在5～150 μg/L的质量浓度范围内,各种添加剂相关系数均大于0.999 0,该方法的检出限在0.5 μg/kg之间,定量限在1.5 μg/kg之间。添加5.0、10.0 μg/kg和25.0 μg/kg三个不同水平时,多菌灵、2,4-D、恩诺沙星的回收率在80.4%～97.8%之间,日内和日间相对标准偏差在1.25%～5.47%之间。该方法简单、灵敏度高、分析时间短,适用于多菌灵、2,4-D、恩诺沙星的测定。     

Formation and fate of bound residues from microbial biomass during 2,4-D degradation in soil

During organic contaminant degradation in soil, bound or nonextractable residues (NER) are formed. Part of these residues may be biogenic, because degrading microorganisms assimilate carbon derived from the pollutant and mineralized CO(2) to form cellular components for example, [fatty acids (FA) and amino acids (AA)], which are subsequently stabilized within soil organic matter (SOM). We investigated the formation and fate of FA and AA from biodegradation of (13)C(6)-2,4-D in soil and the incorporation of the (13)C-label into living biomass via (13)CO(2) fixation. After 64 days of incubation, (13)C-AA in SOM indicated that 44% of the initially applied (13)C(6)-2,4-D equivalents had been converted to microbial biomass and finally to biogenic residues. The intermediate maximum of (13)C-FA in SOM indicated a 20% conversion of (13)C(6)-2,4-D to biomass, but (13)C-FA decreased to 50% of that value whereas (13)C-AA in the SOM remained stable. We provide the first evidence that nearly all bound residues from 2,4-D are biogenic, containing natural microbial residues stabilized in SOM. Because of biogenic residue formation, the potential risk of bound residues from readily metabolized xenobiotics in soils is highly overestimated. Hence, the formation of biogenic residues must be considered in general when performing mass balances of pollutant biodegradation in soils.     

Relation of Chemical Structure to Plant Growth-regulator Activity in the Pineapple Plant: Retarding Senescence of Pineapple Fruit with Applications of 2,4,5-Trichlorophenoxyacetic Acid and 1-Naphthaleneacetic Acid

SUMMARY: The effectiveness of 1-naphthaleneacetic acid (SNA) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in markedly retarding further ripening of pineapple fruit and thus extending its marketable life as a fresh fruit has been demonstrated. The effects are evident at different stages of maturity and ripeness, different fruit densities, and from both pre-harvest and post-harvest applications. As little as 1 ppm of 2,4,5-T has noticeable effect, and 100 ppm appears optimum for senescence delay. For SNA, 500 ppm is an optimum level for dipping fruit. A brief wetting of the fruit is adequate. The crowns remain in better condition when not treated with growth regulator. Refrigeration can supplement the effect of the chemical in retarding senescence. Lower temperatures can retard some of the changes which even treated fruit will show, and the chemical can retard ripening changes that otherwise may take place, albeit slowly, under normal refrigeration of pineapple fruit.     

植物生长调节剂对番茄产量和品质的影响及膳食摄入风险评估

目的 明确不同植物生长调节剂赤霉酸、2,4-滴和噻苯隆对番茄产量和品质的影响, 掌握它们在番茄中的残留情况以及对不同人群的膳食摄入风险。方法 在番茄花期施用植物生长调节剂赤霉酸、2,4滴和噻苯隆各1次, 正常成熟期采摘, 分析不同植物生长调节剂处理对番茄产量和品质的影响及残留情况, 整合两年的番茄市场监测数据, 利用农药残留专家联席会议农药急性膳食风险摄入量计算法和@risk定量风险评估软件, 对番茄中3种植物生长调节剂残留在我国不同人群中的膳食摄入风险进行评估。结果 3种植物生长调节剂均可显著提高番茄的产量和品质(P<0.05), 其中噻苯隆效果最显著, 且产品中相应植物生长调节剂残留量较低, 平均值0.0042~0.0058 mg/kg; 3种植物生长调节剂在市场监测的300个样品中均有检出, 总检出率9.33%, 检出平均值0.034~0.069 mg/kg; 番茄中赤霉酸、2,4-滴和噻苯隆残留的短期膳食摄入量在0.00104~ 0.00658 mg/kg bw/d, 仅占相应每日急性参考剂量的0.60%~7.24%, 急性风险较低。结论 在番茄花期施用赤霉酸、2,4-滴或噻苯隆可显著提高番茄的产量和品质, 且产品中残留量低, 番茄中3种植调剂残留在不同人群中的膳食摄入风险均很低, 在可接受范围内。     

Bestimmung von 2,3,7,8-Tetrachlordibenzo-p-dioxin (TCDD) in 2,4,5-Trichlorphenoxyessigs?ure, 2,4,5-Trichlorphenoxyessigs?urealkylestern und daraus hergestellten Herbicid-Pr?paraten

Zusammenfassung Es wird eine Analysenmethode zur Bestimmung von 2,3,7,8-Tetrachlordibenzo-p-dioxin (TCDD) in 2,4,5-Trichlorphenoxyessigsäure (2,4,5-T), 2,4,5-T-Alkylestern und daraus hergestellten Herbicid-Präparaten beschrieben.TCDD wird aus alkalischer Lösung mit n-Hexan extrahiert und durch Sdulenchromatographie an Kieselgel und Florisil gereinigt. Die Bestimmung erfolgt gaschromatographisch mit Hilfe des ECD. Die Nachweisgrenze der Analysenmethode liegt bei 5 g/kg bezogen auf 2,4,5-T. Die Wiederfmdungsraten betragen 96–104% bei TCDD-Zusätzen von 20 g/kg zu Herbicid-Formulierungen.

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Determination of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) in 2,4,5-Trichlorophenoxyacetic Acid, 2,4,5-Trichlorophenoxyacetic acid-alkylesters and in the corresponding herbicide formulations

Summary A method is described for the determination of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) in 2,4,5-Trichlorophenoxyacetic Acid (2,4,5-T), 2,4,5-T-Akylesters and commercial herbicide formulations containing these substances. TCDD is extracted from a kaline solution with n-hexane and purified by column chromatography on silica gel and Florisil. TCDD is determined by gas-liquid chromatography with EC-detection. For TCDD-additions of 20 /kg to herbicide formulations recoveries of dioxin are 96–104%. The detection limit is about 5 g/kg 2,4,5-T.

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Diese Methode wurde im Auftrage der Biologischen Bundesanstalt für Land- und Forstwirtschaft, Fachgruppe für Chemische Mittelprüfung, Braunschweig, erarbeitet     

A rapid and low cost monitoring method for fluvalinate determination in honey

A simple analytical method for determining Fluvalinate residues in honey is described. Analyses were carried out by gas chromatography–electron capture detector (ECD), using a borosilicate glass column packed with 3% SP-2100. Fluvalinate residues were extracted from honey samples with n-hexane and acetic acid. Mean recoveries ranged from 98·1±6·9 to 101·9±7·6% with SD<10 after standard addition of 20, 50 and 500 μg. No interferences of other pesticides were detected. ECD responses were linear within the range studied of 10–50 pg of Fluvalinate with a coefficient of determination 0·994, and a detection limit of 3 mg kg⁻¹ was established. The use of a packed column allowed the exclusion of an expensive clean-up step. This fast, low-cost analytical method is adequate for monitoring studies of honey samples. © 1998 SCI.     

气相色谱法同时测定大豆中13种苯氧羧酸类除草剂的残留量

为检测大豆中的苯氧羧酸类除草剂残留,建立了大豆中13种苯氧羧酸类除草剂(对氯苯氧乙酸、对氯苯氧丙酸、苯氧丁酸、麦草畏、2甲4氯苯氧乙酸、2甲4氯苯氧丙酸、2甲4氯苯氧丁酸、2,4-滴、3,4-滴、2,4,5-涕、2,4,5-涕丙酸、2,4-滴丙酸、2,4-滴丁酸)多残留量的气相色谱检测方法。样品经过正己烷预除脂后用乙腈和50mmol/L盐酸混和液(体积比7 3)提取,提取液经过与乙腈饱和的正己烷液液分配除脂,阴离子交换柱净化后用五氟溴苄衍生化。衍生产物经硅胶柱净化后,采用气相色谱(GC)-电子捕获检测器(ECD)检测,外标法定量。13种苯氧羧酸类除草剂在质量浓度0.005～0.1mg/kg之间,与峰面积呈线性关系,相关系数为0.9954～0.9993;0.01和0.1mg/kg2个水平的加标回收率均在70%以上,相对标准偏差小于20%,方法的检测限(S/N≥3)满足主要贸易国最大残留限量要求。     

气相色谱仪电子捕获检测器的清洗方法

气相色谱仪电子捕获检测器是一个有选择性的高灵敏度的检测器,已成为目前在食品检验、动植物体中的农药残留量和环境检测领域中应用最多的检测器之一。电子捕获检测器对杂质十分敏感,放射源表面污染时,使放射源电离能力下降,从而使直流电压和恒频率方式的检测器基流下降或恒电流方式的检测器基频增高;另外,杂质可以直接俘获检测器中的电子,使基流下降或基频增高;两者最终均导致灵敏度降低。本研究总结了电子捕获检测器的清洗方法,氮气热清洗检测器可以除去轻微的化学污染;在室温条件下,甲醇清洗检测器可以除去石墨碎屑、色谱柱碎末;在检测条件下使用甲醇热清洗检测器可以降低噪音。     

基质固相分散-气相色谱法测定小麦中五种拟除虫菊酯类农药残留

建立小麦样品中5种拟除虫菊酯类农药残留同时进行测定的方法。以弗罗里硅土基质分散剂对小麦样品进行前处理,用气相色谱-电子捕获检测器测定,考察基质分散剂、洗脱剂和样品填料比对农药残留测定的影响。结果表明：5种拟除虫菊酯类农药的平均回收率均在85.5%～97.6%之间;其结果(n=5)的相对标准偏差(RSD)最大值为8.4%。这表明该方法是一种经济、快速、准确、重现性好的检测方法。     

QuEChERS前处理结合气相色谱电子捕获检测器检测果蔬中30种农药残留

目的 应用QuEchERS前处理法处理样品,建立了气相色谱-电子捕获检测器检测多种水果蔬菜中30种常见农药残留的分析方法。方法 用乙腈作为溶剂,分别采用无缓冲盐体系、醋酸缓冲盐体系和柠檬酸盐缓冲体系提取对蔬果中30种农药进行提取,用PSA进行净化后上机处理。结果 采用不加缓冲盐体系提取,经PSA净化的方法适用于本文所选30种农药的检测,将该方法用于黄瓜、西红柿、生菜、苔菜、包菜、胡萝卜、梨、草梅,苹果等蔬果中30种农残的检测,结果表明30种农药残留的回收率在75%-122%之间,相对标准偏差在1%-12%之间;结论 该方法准确、简单、快速、灵敏度高,可以满足日常农残快速筛选的检测要求。     

肉及肉制品中2,4-滴残留量的测定

在酸性条件下,以二氯甲烷提取肉组织中残留的2,4-滴及其钠盐,并转移至碱液中。用有机溶剂洗涤后在将其酸化,2,4-滴再用二氯甲烷提取。去除溶剂后用甲醇溶解定容,供液相色谱-串联质谱测定。MS-MS采用电喷雾负离子化方式电离,多离子反应监测方式检测。优化了MS-MS参数和液相色谱条件,检测限可达0.005 mg/kg,回收率、精密度、线性均满足农药残留分析的规定。     

苯氧羧酸类除草剂残留检测技术的研究进展

以2,4-D为代表的苯氧羧酸类除草剂,低浓度为保花保果生长调节剂,调节细胞生长及愈伤的分化、提高保鲜时间,高浓度为除草剂,该类除草剂难降解,易污染地下水,广泛、大量的应用会使植物产生畸形,影响人体中枢神经系统,具有潜在的致癌性和致突变性。因此,快速、灵敏、准确地检测出苯氧羧酸类残留是保证农产品、环境安全的重要手段,本文概述了苯氧羧酸类除草剂的前处理方法及不同检测方法在检测农产品、环境水样等样品中苯氧羧酸类除草剂残留的研究进展。综合对比了色谱法、联合技术、免疫法、纳米材料及传感器等检测方法在苯氧羧酸类检测中应用的优缺点,提出了未来检测小分子物质的发展趋势。     

聊城市市售豆芽菜中5种植物生长调节剂残留调查分析

目的 分析聊城市东昌府区市售绿豆芽和黄豆芽中6-苄基腺嘌呤、4-氯苯氧乙酸、2,4-二氯苯氧乙酸、吲哚乙酸、吲哚丁酸的残留情况。方法 样品采用QuEChERs方法提取, 用含有0.1%甲酸的5 mmol/L乙酸铵水(A)和甲醇(B)作为流动相进行梯度洗脱, 质谱采用多反应监测-信息依赖性采集-增强子离子扫描模式(multiple reaction monitoring-information dependent acquisition-enhanced product ion, MRM-IDA-EPI), 同时得到的子离子谱图用于谱图库检索进行定性确证分析。结果 绿豆芽和黄豆芽中均存在植物生长调节剂残留, 在所检测的20份样品中, 10份检出6-苄基腺嘌呤, 11份检出4-氯苯氧乙酸, 20份检出吲哚乙酸, 其他两项均未检出。阳性样品的谱图匹配度均高于70%。结论 市售豆芽中植物生长调节剂的滥用依然存在, 必须持续监测和控制豆芽中植物生长调节剂的残留, 谨防滥用植物生长调节剂给消费者健康带来的风险。     

分散固相萃取-气相色谱法快速测定茶叶中27 种常见含卤素农药残留

采用分散固相萃取-气相色谱法对茶叶中27 种含卤素农药残留量进行测定。经丙酮-正己烷（l∶1,V/V）提取后,直接加入无水硫酸钠、硅镁型吸附剂及活性炭净化,使用DB-17毛细管气相色谱柱、微电子捕获检测器,对茶叶中27 种含卤素农药残留量进行测定。该方法样品平均加标回收率为82.2%～113.4%,相对标准偏差为1.2%～6.0%;茶叶中27 种含卤素农药多残留检出限为0.005～0.075 mg/kg。     

Determination of bisphenol A in canned vegetables and fruit by high performance liquid chromatography

A high performance liquid chromatograph y (HPLC) method was developed for the determination of bisphenol A (BPA) that had migrated into canned fruit and vegetables. BPA was extracted with acetonitrile from the solid portion of canned food, and with an OASIS HLB cartridge from the aqueous portion, respectively. Both extracts were cleaned up on a Florisil cartridge. The HPLC separation was carried out on a Wakosil II 3C18 RS column (4.6 × 150mm) with acetonitrile-water (40:60, v/v) as a mobile phase with a flow rate of 0.8 ml/min. BPA was detectable by UV detector at 228 nm and determined with the similarity of chromatographic peak spectrum by multiwavelength detector (similarity index was 0.99 or above). The quantification limits were 10 ng/g for the solid portion and 5 ng/ml for the aqueous portion, respectively. BPA was mainly detected in the solid portion of canned food and found at the maximum level of 11 μg per can. To verify migration into the solid portion of canned food, a partitioning experiment was carried out.     

Determination of aryloxyphenoxypropanoic acid derivatives in crops treated with herbicidal sprays

A reproducible and sensitive gas chromatographic method has been developed for the trace analysis of fluazifop-butyl, haloxyfop-ethoxyethyl and quizalofop-ethyl as well as their main metabolites (corresponding acids analysed after conversion to methyl esters) in some fruits and vegetables treated with herbicidal sprays. Comparable detection limits (0.01 mg/kg) were achieved when mass fragmentography and/or the electron capture detector were employed. However, in the latter case, bromination of fluazifop esters had to be carried out prior to GC analysis. By means of the nitrogen-phosphorus detector, determination of residues at a level of 0.05 mg/kg was possible. The residue values found in strawberries, cabbages, cauliflower and carrots were used to discuss the degree of metabolic hydrolysis of parent esters, i.e. active ingredients of herbicides.     

关于气相色谱测定酿酒原料六六六和滴滴涕的探讨

现在人类对于农药的施用越来越广泛,尤其是有机农药大量施用,对环境造成严重的农药污染问题,成为对人体健康的严重威胁.国家标准GB/T 14551-2003《动、植物中六六六和滴滴涕测定的气相色谱法》中规定了六六六、滴滴涕残留量的测量方法,为确保酿酒原料中六六六、滴滴涕残留量测定方法在本实验室的适宜性和可靠性,本实验室用气...