毛细管气相色谱法测定清补凉中六六六、DDT的残留量

建立毛细管气相色谱法测定清补凉中六六六、滴滴涕(DDT)的残留量。用丙酮提取样品中残留的有机氯农药,石油醚萃取,萃取液以浓硫酸净化。采用HP-1石英毛细管色谱柱对清补凉中8种六六六、DDT的异构体进行了检测。结果表明,该法测定下限为2.45×10-14～1.15×10-12g,加标平均回收率为84.9%～98.6%,相对标准偏差为1.6%～4.5%。     

气相色谱法测定土壤中有机氯杀虫剂

建立了利用加速溶剂萃取和GC-ECD联用技术,对土壤中六六六、滴滴涕、艾氏剂、狄氏剂、硫丹Ⅰ、硫丹Ⅱ、硫丹硫酸盐内氯甲桥奈、内氯甲桥奈醋醛、七氯、环氧七氯17有机农药进行了分析,通过对回收率、重现性及精密度的测定,其实验具有操作简便,时间短,应用范围广的优点.     

滴滴涕单克隆抗体的制备及其评价

以滴滴涕(DDT)的特征部分为基础设计并合成了半抗原4-{4-[2,2,2-三氯-1-(4-氯-苯基)-乙基]-苯基}-丁酸(DDT-H1)、4-[4-(2,2,2-三氯-1-对甲苯基-乙基)-苯基]-丁酸(DDT-H2),并采用活泼酯法制备免疫原DDT-H1-BSA,以及混合酸酐法制备包被原DDT-H1-OVA、DDT-H2-OVA;用DDT-H1-BSA对小鼠进行免疫,通过细胞融合、筛选、克隆等步骤得到1株能稳定分泌DDT农药抗体的单克隆细胞株。细胞株经扩大培养后,注射小鼠体内产生腹水,并将其用辛酸-硫酸铵和protein A柱子纯化出单克隆抗体。其分泌的单克隆抗体免疫球蛋白亚类为Ig G1,单抗腹水的效价为1.68×105,亲和力Ka为5.238×1011L·mol-1,与其它几种代谢物有一定的交叉反应。在此基础上,利用获得的单抗研究建立DDT的间接竞争酶联免疫吸附检测法(ic ELISA)。结果表明,所建立的间接竞争ELISA方法的线性范围(IC20~IC80)为6.6~521.8 ng/m L,可用于检测农副产品、环境中残留的DDT及其代谢物。     

Comparative quantitative study of DDT and its metabolites in human milk by gas chromatography with electron capture and mass spectrometric detection

Summary Comparative analytical quantitation of DDE, DDD, and DDT in human milk, by gas chromatography with mass spectrometric and electron capture detection (GC-MS and GC-ECD) has been studied by use of 513 samples of milk from lactating mothers participating in a World Health Organization special study. Although Correlation between thep,p-DDE concentrations measured by GC-ECD and GC-MSD was excellent (r=0.950,P<0.0001) and correlation was significant and moderate forp,p-DDD andp,p-DDT, the best precision was obtained by use of GC-MS. This study has therefore demonstrated that GC-MSD is a useful tool for determining the concentration of DDT and its metabolites, because it enables simultaneous detection and confirmation.     

Determination of environmental organic pollutants with a portable optical immunosensor

A portable surface plasmon resonance (SPR) optical biosensor device is described as a direct immunosensing system to determine organic pollutants in natural water samples. Monitoring of organochlorine (DDT), organophosphorus (chlorpyrifos) and carbamate (carbaryl) compounds within the concentration levels stipulated by the European legislation, can be accomplished using this immunosensor. The lowest limit of detection (LOD) was obtained for DDT, at 20 ng L⁻¹, whilst 50 ng L⁻¹ and 0.9 μg L⁻¹, were achieved for chlorpyrifos and carbaryl, respectively. Matrix effects were evaluated for the carbaryl immunoassay in different water types with detection limits within the range of carbaryl standard curves in distilled water (0.9-1.4 μg L⁻¹). The covalent immobilization of the analyte derivative through an alkanethiol self-assembled monolayer (SAM) allowed the reusability of the sensor surface during more than 250 regeneration cycles. The quality of the regeneration was proved over a 1-month period of continuous working. The analysis time for a complete assay cycle, including regeneration, comprises 24 min. Our portable SPR-sensor system is already a market product, commercialized by the company SENSIA, SL. The size and electronic configuration of the device allow its portability and utilization on real contaminated locations.     

Aluminum Particles–air Detonation at Elevated Pressures

The effect of initial pressure on aluminum particles–air detonation was experimentally investigated in a 13 m long, 80 mm diameter tube for 100 nm and 2 μm spherical particles. While the 100 nm Al–air detonation propagates at 1 atm initial pressure in the tube, transition to the 2 μm aluminum–air detonation occurs only when the initial pressure is increased to 2.5 atm. The detonation wave manifests itself in a spinning wave structure. An increase in initial pressure increases the detonation sensitivity and reduces the detonation transition distance. Global analysis suggests that the tube diameter for single-head spinning detonation or characteristic detonation cell size would be proportional to (d ₀: aluminum particle size, p ₀: initial pressure). Its application to the experimental data results in m ~ O(1) and n ~ O(1) for 1 to 2 μm aluminum–air detonation, thus indicating a strong dependence on initial pressure and gas-phase kinetics for the aluminum reaction mechanism in detonation. Hence, combustion models based on the fuel droplet diffusion theory may not be adequate in describing micrometric aluminum–air detonation initiation, transition and propagation. For 2 μm aluminum–air mixtures at 2 atm initial pressure and below, experiments show a transition to a “dust quasi-detonation” that propagates quasi-steadily with a shock velocity deficit nearly 40% with respect to the theoretical C–J detonation value. The dust quasi- detonation wave can propagate in a tube with a diameter less than 0.4–0.5 times the diameter required for a spinning detonation wave.     

Pesticides in water and the performance of the liquid-phase microextraction based techniques. A review

The control of pesticides in surface, drinking and groundwater is nowadays a real necessity. In the European Community, their concentration must comply with the established parametric and environmental quality standards (EQSs). Regarding the new legislation, this article updates the information concerning the monitoring of pesticides and the technical specifications for their measurement in water samples where ultra-sensitive analytical methods are required. For some compounds, like pesticides, there is still a need to improve the performance of the existing methods. High sensitive techniques like gas chromatography tandem mass spectrometry (GC–MS/MS) and liquid chromatography coupled with mass spectrometry (LC–MS) have been developed. However, for most of the substances present at trace and ultra-trace levels the extraction and preconcentration steps are so far essential for their detection. Advances at a micro scale have been made and different types of microextractions are being developed. Liquid-phase microextraction (LPME) is an example. The study of this technique has increased in the last years and some innovations have been recently reported for pesticides water analysis. This article reviews the new developed LPME-based techniques and compares its performance with the analytical specifications established for pesticides water monitoring. The results show that LPME-based techniques can be a promising tool to improve the nowadays performance of methods used in pesticides water control.     

DDT在亚热带环境和农业生态的行为研究Ⅱ．DDT在水稻植株中的残留动态

￣（１４）Ｃ－ＤＤＴ示踪实验结果表明：地处广州亚热带地区的水稻，施用ＤＤＴ农药，在植株各器官中消失很快，整株总的ＤＤＴ的衰变常数是２９．４×１０￣（－２）／ｄ，半衰期（Ｔ＿（５０））为２３．６ｄ，残留量与施药时到收获期时间的长短和施药次数有关，实验证明：可溶态ＤＤＴ约占总残留量的７５％，约有２５％转化为结合态ＤＤＴ；水稻在收获前１５ｄ进行最后一次施用ＤＤＴ１０００ｍｇ／ｋｇ是安全的。     

BHC,DDT和B（a）P在内蒙古草地牧草中污染现状的初步调查

本文通过对内蒙古草地上优良牧草中，有机氯农药（６６６，ＤＤＴ）和苯并（ａ）芘（简写Ｂ（ａ）Ｐ），污染现状的调查，对四个地带性草地类型十个调查区域内１５４份牧草样品中，两项有害物质含量超标情况及分布进行了分析研究．结果表明：６６６、ＤＤＴ和Ｂ（ａ）Ｐ平均含量在草甸草原牧草中分别为０．０９２７ｍｇ／ｋｇ、０．００８６ｍｇ／ｋｇ、０．００５０ｍｇ／ｋｇ，在典型草原牧草中分别为０．０４５０ｍｇ／ｋｇ、０．００３０ｍｇ／ｋｇ、０．００５２ｍｇ／ｋｇ，在荒漠化草原牧草中分别为０．１００３ｍｇ／ｋｇ、０．００１５ｍｇ／ｋｇ、０．００５６ｍｇ／ｋｇ．在草原化荒漠牧草中分别为０．２５２９ｍｇ／ｋｇ、０．００００ｍｇ／ｋｇ、０．００５６ｍｇ／ｋｇ．全区草地上生长的１６种牧草中，两项有害物质均被检出，大部分含量都比较低，但个别样品含量很高，说明内蒙古草地环境已经受到一定程度的污染，应引起高度的重视．     

常武地区土壤中六六六、DDT的残留状况及残留规律

作者测定了1984.3—1985.1江苏常州及武进县土壤中六六六、DDT农药的平均残留浓度分别为109.4ppb,154。3ppb,并报道了它们在表层土壤及剖面层的残留规律;发现β—六六六的残留指数与土壤pH呈正相关。与土壤有机质呈负相关。同时估算了该地区土壤中六六六的残留浓度在6.2—12.3年后可下降到20ppb以下。