Enzyme immunoassay for atrazine analysis in water and soil

Enzyme immunoassay (EIA) has been tested for the detection of atrazine in soil and water. EIA kits and atrazine-fortified samples were received from the International Atomic Energy Agency. Atrazine concentrations of about 0·01 μg litre^-1 could be detected and the central detection point was found at about 0·15 μg litre^-1 which is a reasonably sensitive region for atrazine. A validation study with spiked local water samples yielded acceptable results. No treatment was required for water samples. Extraction of atrazine from soil was done by simple shaking with methanol without any clean-up steps. Detection limits of 1×10^-2 μg litre^-1 for water and 5×10^-3 μg kg^-1 for soil were achieved. © 1998 SCI.     

Effects of different parameters on the removal of atrazine in a water environment by Aspergillus oryzae biosorption

Atrazine is the most extensively used herbicide in the agricultural and forestry sectors. Nevertheless, along with the increasing usage amount of Atrazine, its harm exposed gradually, the main problem is its residues in the environment. Microbial adsorption may effectively reduce the pollution caused by atrazine residue in the environment. In this study, a strain of fungi with the function of adsorbing atrazine was selected using microbial screening technology. According to its phenotypic characteristics and 18S rDNA gene sequencing, this strain was of the species genus Aspergillus and was named ECUST-TXZC2018. By studying the dynamic adsorption effect of this strain on atrazine, we found that this strain adsorbed atrazine after 36 hr at pH=5–7, and 20–30°C with more than 70% adsorption. These results demonstrated that ECUST-TXZC2018 had potential application ability to control atrazine residue pollution through the biosorption function.     

小麦植株和麦田土壤莠去津残留气相色谱分析方法研究

本研究确立了乙腈振荡提取、弗罗里硅土SPE小柱净化小麦植株和麦田土壤中莠去津残留样本的前处理方法,建立了柱程序升温、GC-NPD残留样品检测方法.结果表明,优化色谱条件下,莠去津的色谱保留时间为5.97 min,在0.105～54.0 mg/L浓度范围内,莠去津浓度与其色谱峰面积在GC-NPD上线性响应良好,回归方程为Y=38.79X-120.34(R2=0.998 8).莠去津在小麦植株和麦田土壤中0.05～1mg/kg的3个水平的加标回收率均大于75％,各添加水平3次平行测定值的RSD均小于7％.其准确度和精密度均符合农药残留分析的要求.该色谱条件下仪器的最低检出量为0.38 ng,方法的最低检出浓度为0.018 mg/kg(植株)和0.021 mg/kg(麦田土壤),此检测灵敏度可以满足该农药在小麦植株和麦田土壤中残留的定量检测要求.     

固相萃取-气相色谱法测定水体中29种农药的残留量

建立了水体中29种农药的固相萃取-气相色谱检测方法。以Envi-18固相萃取小柱提取水样中的各种农药,上样体积为200 mL,洗脱溶剂为正己烷-丙酮(1∶1,体积比)。在添加水平为0.1、1.0和10 μg/L时,水样中29种农药的添加回收率为60%~111%,相对标准偏差(RSD)为1.2%~6.4%,方法的检出限(LOD)为5~50 ng/L。所建立方法准确、灵敏、快速,符合水体中多种农药残留检测分析的要求,且对水体中低浓度残留农药的检测效果较好。     

臭氧水对黄瓜和青菜中6种有机磷农药残留的去除效果

考察了臭氧水浸泡处理对黄瓜和青菜上6种有机磷类农药残留的去除效果。发现臭氧水浸泡的去除效果优于自来水处理,在通臭氧30 min后,其对青菜和黄瓜中乙酰甲胺磷、二嗪磷、马拉硫磷、毒死蜱、喹硫磷和三唑磷的总去除率分别为26.4%~65.2%和22.7%~75.4%,净去除率分别为6.8%~17.3%和4.4%~45.4%。对6种农药在臭氧水中降解速率的研究表明,臭氧处理对残留农药的去除效果与果蔬种类、处理时间及残留物种类有关。     

高效液相色谱法测定噻唑锌在水、土壤及黄瓜中的残留

建立了采用高效液相色谱-二极管阵列检测器（HPLC-DAD）测定水、土壤和黄瓜中噻唑锌残留的方法。在碱性条件下先将噻唑锌转化为噻二唑（AMT）,采用外标法通过测定噻二唑的量来进行噻唑锌的定量分析。样品在40℃恒温振荡条件下,依次经Na2S转化及乙腈提取;过滤后调节混合液pH值至3,经乙酸乙酯液-液分配后,用HPLC-DAD及BDS Hypersil-C18色谱柱,以V（乙腈）:V（0.1%乙酸）=10:90为流动相,在313 nm波长下测定样品中的噻唑锌残留。结果表明:噻二唑在0.10~10 mg/L、噻唑锌在0.20~5.0 mg/L的质量浓度范围内线性关系良好（R2 > 0.999 5）,噻二唑的检出限（LOD）为0.05 mg/L。在0.2、1和5 mg/L添加水平下,噻唑锌在水中的平均回收率为100%~110%,相对标准偏差（RSD）为0.90%~6.4%;在0.05、0.5和5 mg/kg添加水平下,噻唑锌在土壤中的平均回收率为81%~98%,RSD为0.70%~2.8%;在0.05、0.5和2 mg/kg添加水平下,噻唑锌在黄瓜中的平均回收率为95%~102%,RSD为1.3%~4.2%。噻唑锌在水、黄瓜和土壤中的定量限（LOQ）分别为0.03 mg/L、0.05 mg/kg和0.05 mg/kg。本方法简单、准确、可靠,能满足农药残留分析的要求。     

Evaluation of spatial-temporal dynamics in surface water temperature of Qinghai Lake from 2001 to 2010 by using MODIS data

Lake surface water temperature(SWT) is an important indicator of lake state relative to its water chemistry and aquatic ecosystem,in addition to being an important regional climate indicator.However,few literatures involving spatial-temporal changes of lake SWT in the Qinghai-Tibet Plateau,including Qinghai Lake,are available.Our objective is to study the spatial-temporal changes in SWT of Qinghai Lake from 2001 to 2010,using Moderate-resolution Imaging Spectroradiometer(MODIS) data.Based on each pixel,we calculated the temporal SWT variations and long-term trends,compared the spatial patterns of annual average SWT in different years,and mapped and analyzed the seasonal cycles of the spatial patterns of SWT.The results revealed that the differences between the average daily SWT and air temperature during the temperature decreasing phase were relatively larger than those during the temperature increasing phase.The increasing rate of the annual average SWT during the study period was about 0.01℃/a,followed by an increasing rate of about 0.05℃/a in annual average air temperature.The annual average SWT from 2001 to 2010 showed similar spatial patterns,while the SWT spatial changes from January to December demonstrated an interesting seasonal reversion pattern.The high-temperature area transformed stepwise from the south to the north regions and then back to the south region from January to December,whereas the low-temperature area demonstrated a reversed annual cyclical trace.The spatial-temporal patterns of SWTs were shaped by the topography of the lake basin and the distribution of drainages.