Development and application of LC–APCI–MS method for biomonitoring of animal and human exposure to imidacloprid

Imidacloprid (IMI) is a relatively new neuro-active neonicotinoid insecticide and nowadays one of the largest selling insecticides worldwide. In the present study a LC–APCI–MS based method was developed and validated for the quantification of imidacloprid and its main metabolite 6-chloronicotinic acid (6-CINA) in urine and hair specimens. The method was tested in biomonitoring of intentionally exposed animals and subsequently applied for biomonitoring of Cretan urban and rural population.     

Degassing of H/He, CFCs and SF6 by denitrification: Measurements and two-phase transport simulations

The production of N₂ gas by denitrification may lead to the appearance of a gas phase below the water table prohibiting the conservative transport of tracer gases required for groundwater dating. We used a two-phase flow and transport model (STOMP) to study the reliability of ³H/³He, CFCs and SF₆ as groundwater age tracers under agricultural land where denitrification causes degassing. We were able to reproduce the amount of degassing (R² = 69%), as well as the ³H (R² = 79%) and ³He (R² = 76%) concentrations observed in a ³H/³He data set using simple 2D models. We found that the TDG correction of the ³H/³He age overestimated the control ³He/³He age by 2.1 years, due to the accumulation of ³He in the gas phase. The total uncertainty of degassed ³H/³He ages of 6 years (± 2 σ) is due to the correction of degassed ³He using the TDG method, but also due to the travel time in the unsaturated zone and the diffusion of bomb peak ³He. CFCs appear to be subject to significant degradation in anoxic groundwater and SF₆ is highly susceptible to degassing. We conclude that ³H/³He is the most reliable method to date degassed groundwater and that two-phase flow models such as STOMP are useful tools to assist in the interpretation of degassed groundwater age tracer data.     

多孔镁铝复合氧化物对水溶液中Cr（VI）的吸附性能

摘要以镁盐、铝盐、纯碱和烧碱为原料制备了一种多孔镁铝复合氧化物（P—Mg3.1AlO4.6），其比表面积、平均孔径和总孔容分别为206．3m2／g、8．961nm和0．4208cm3／g。研究了这种多孑L材料对水溶液中cr（VI）的吸附性能，在25～45qC时，静态吸附量为82．32～141．7mg／g；当初始浓度100mg／L、流速5mL／min、床层高度10cm和pH=6时，半穿透时间、半穿透吸附量和饱和吸附量分别为406rain、49．28ing／g和51．30Ing／g；拟合参数及误差分析表明，cr（Ⅵ）在P—M敬。AIO4.6上的静态吸附过程符合Freundlich等温方程式和伪二级动力学方程，Yoon·Nelson模型能很好地预测cr（Ⅵ）在P—Mg3.1A104.6上的动态穿透曲线。     

亚超临界水技术在废旧尼龙6解聚中的应用

研究了尼龙6在亚超临界水中的解聚反应,以期为废旧尼龙6的回收利用提供技术参数.实验分别利用气质联用仪和紫外分光光度计对解聚后的液相产物进行定性和定量分析,并考察了不同的反应温度、反应压力和反应时间对液相产物收率的影响.结果表明,液相产物绝大部分为己内酰胺;解聚的最佳条件为370 ℃、25 MPa、60 min;己内酰胺最大收率为96%.通过动力学分析和Arrhenius关系计算,得出尼龙6亚超临界水解聚的活化能为64.4 kJ/mol.     

Cryptic 1p36.3/6q25.2 translocation in three generations ascertained through a foetus with IUGR and cerebral malformations

Here we describe a foetus with intrauterine growth retardation (IUGR), cerebral malformations and a 46,XY,der(1),t(1;6)(p36.3;q25.2) karyotype owing to a familial cryptic translocation segregating in three generations. A balanced translocation was present in the mother, the maternal uncle, the aunt and the grandmother. A female first cousin with dysmorphisms, hydrocephalus and mental retardation was a carrier of a partial trisomy 1p and a partial monosomy 6q. Multiple miscarriages were present in the family pedigree. Parents of the foetus had three other pregnancies: a male with a balanced translocation, and two foetuses with 1p36.3–pter monosomy and 6q25.2–qter trisomy. Copyright © 2003 John Wiley & Sons, Ltd.     

Adsorption characteristics and mechanism of Cr （Ⅵ） on chitoan-yttrium porous microsphere

以壳聚糖和Y2（OH）5NO3为原料通过乳液交联法制备了壳聚糖-钇（Ch—Y）复合微球,通过扫描电镜、透射电镜、X射线衍射、红外光谱等方法对其表面形貌、结构进行了表征.探讨了溶液的pH值、反应时间、投加量、离子初始浓度对其吸附性能的影响.研究结果表明,壳聚糖-钇（Ch—Y）复合微球在pH值为3的酸性环境中对Cr（Ⅵ）保持了较高的吸附能力,吸附容量为52.39mg·g-1,其吸附行为符合Langmuir吸附等温模型;通过吸附机理的研究,发现壳聚糖-钇（Ch—Y）对Cr（Ⅵ）吸附是化学吸附静电吸附协同氧化Cr（Ⅵ）离子作用来实现的.     

改性人造沸石处理含黄玉铬洁(Ⅵ张焕)祯地下水的实验研究

为了提高人造沸石对地下水中铬(Ⅵ)的去除能力,采用氯化铝对人造沸石进行改性。确定最佳改性条件:20%氯化铝溶液,液固比12 mL/g,室温下以180 r/min振荡改性8 h;最佳除Cr(Ⅵ)条件:pH值为4～8,液固比为33.3 mL/g,室温下水浴恒温振荡2 h。改性沸石对铬(Ⅵ)的吸附符合Langmuir及Freundlich等温线方程,由Langmuir吸附等温线可得其吸附容量为5.624 mg/g。在最佳反应条件下,水样中铬(Ⅵ)浓度可由5 mg/L下降到0.026 mg/L,低于0.05 mg/L,满足GB/T 14848—93《地下水环境质量标准》Ⅲ类标准。     

改性粉煤灰处理含铬(Ⅵ)地下水的实验研究

用硫酸改性的粉煤灰作为吸附剂,处理含铬(Ⅵ)为5mg/L地下水,最佳条件为:pH=2,液固比10000:3,25℃下反应3h。处理后水样铬(VI)浓度0.03mg/L,满足(GB/T 14848-93)《地下水环境质量标准》。在不改变原水pH条件下,增加粉煤灰用量,水样中铬(VI)浓度也可由5mg/L降至0.05mg/L。同时,吸附剂对铬(VI)的吸附符合Freundlich和Langmuir等温线。     

双表面活性剂修饰下纳米零价铁对水中Cr(Ⅵ)污染去除研究

为解决纳米级零价铁（nZVI）在环境中易团聚、易氧化的问题,强化其去除水中Cr（VI）的能力,选择非离子型表面活性剂聚乙烯吡咯烷酮（PVP）和阴离子表面活性剂油酸钠（NaOA）同时对nZVI进行修饰.同时,通过对比不同pH值、材料干湿状态、初始浓度及共存离子条件下的反应效果,结合材料的XRD和XPS表征、动力学实验和25℃等温线的拟合进行机理分析.结果表明：酸性条件有利于Cr（VI）的去除;材料的干湿状态对去除效率影响较大;材料去除水中Cr（VI）可在3 h内达到反应平衡,去除效率在90%以上,实验条件下最大去除量为183.1 mg·g^-1,反应过程符合准二级动力学模型及Langmuir模型;反应过程中Cr（VI）大部分转化为Cr（Ⅲ）.