溴虫腈在土壤的残留动态

通过超临界流体萃取技术结合气相色谱法,研究了土壤中溴虫腈的残留降解动态。正交试验L9(33)结果表明,在流量25~27 m3.h-1,夹带剂甲醇1 mL.g-1样品时,最佳萃取条件为压力25 MPa,温度39℃,时间30 min。超临界萃取试验结果表明,主要影响因素对溴虫腈回收率的影响高低程度依次为萃取温度,萃取时间,萃取压力。验证试验表明,在上述最佳萃取条件下,溴虫腈添加量为10μg、100μg、200μg时,回收率分别是105.00%、80.33%、102.33%,变异系数分别是7.32%、4.58%、4.95%。降解动态试验表明溴虫腈在土壤中的消解动态方程为Ct=0.097 2e-0.4501 t,R2=0.973 7,t1/2=2.4 d。溴虫腈10%悬浮剂(商品名除尽)在推荐剂量50 mL.(667 m2)-1或100 mL.(667 m2-)1使用2~3次,3~7 d后在土壤中残留量为6.44~23.58μg.kg-1,消解速度较快,属于易降解农药,可合理使用于无公害蔬菜生产。     

油松种子醇溶蛋白提取剂比较

采用乙醇、尿素、2氯乙醇、2巯基乙醇等配成的不同浓度和成分的提取剂提取了山西太岳龙门口、陕西洛南、辽宁千山和河北雾灵山4个不同油松种群的种子醇溶蛋白;用酸性聚丙烯酰胺凝胶电泳(APAGE)对蛋白提取液进行分析.条带数目反映所提取醇溶蛋白的数量,谱带颜色深浅反映不同提取剂得到的某种醇溶蛋白的量.结果表明,不同提取剂提取的醇溶蛋白图谱存在明显差异.由1%2巯基乙醇和12%尿素组成的复合提取剂提取效果最佳,其次是由20%2氯乙醇、1%2巯基乙醇和12%尿素组成的复合提取剂.提取的醇溶蛋白的电泳图谱可以用于油松种群的遗传多样性分析和系统演化的研究.图1表2参11     

纳米纤维固相萃取-气相色谱法分析海水中狄氏剂与多氯联苯

随着纳米技术的发展,纳米纤维作为固相萃取材料受到广泛的关注,其高比表面积可以提供数量巨大的作用位点,使得萃取容量大且效率高,在环境中有机污染物的分离富集方面具有良好的应用前景.本文采用聚苯乙烯纳米纤维固相萃取对海水中狄氏剂与7种PCBs进行分离富集,通过考察海水盐度与pH对纳米纤维分离富集效果的影响,优化萃取实验条件,建立纳米纤维固相萃取气相色谱分析海水中狄氏剂与7种PCBs的方法.     

二(2-乙基己基)磷酸络合萃取邻氨基苯酚的研究

以二(2-乙基己基)磷酸(D2EHPA)为萃取剂,研究稀释剂种类、萃取剂浓度、溶液的初始pH值、溶液中甲(乙)醇等因素对邻氨基酚(OAP)稀溶液分配比(D)的影响.结果表明:溶液的初始pH值在7左右时,D有最大值;D值随二(2-乙基己基)磷酸浓度的增大而提高,且在极性环境要优于惰性环境;甲(乙)醇是影响萃取结果的主要因素.     

水稻中氟虫双酰胺及其代谢产物的超高效液相色谱残留分析方法

采用超高效液相色谱法分析了氟虫双酰胺及其代谢产物在田水、土壤、稻秆、糙米和稻壳中的残留.水样以乙酸乙酯为萃取溶剂,液-液分配净化;土壤样品以丙酮为提取剂,液-液分配净化;水稻样品经乙腈提取,NH2-Carb柱净化.对水稻和环境中的氟虫双酰胺及其代谢产物进行不同水平的添加回收率实验,方法的回收率在78.2%—104.8%之间,相对标准偏差为1.1%—4.4%.氟虫双酰胺及其代谢产物的最小检出量在0.004—0.02 ng,其在稻田水中的最低检测浓度为0.0008—0.0009 mg.L-1,在土壤、稻秆、糙米、稻壳中的最低检测浓度为0.001—0.003 mg.kg-1.     

工业污染源复杂废水体系的水质剖析方法

叙述了对工业污染复杂废水体系进行剖析的方法和程序。经过在不同pH下,用不同极性溶剂萃取及XAD树脂吸附提取后,废水中96％以上的有机污染物可以得到提取和富集。逐级萃取后对水相进行COD值检测,可以得知在不同条件下,有机污染物被从水中提取和富集的程度。将萃取物在硅胶层析柱上进行预分离,可以使含量悬殊的化合物按类别得以分离。经预分离后的萃取相,进一步用毛细管气相色谱和色-质谱进行分析鉴定,对其中主要的污染物,选择合适的色谱条件进行定量分析。应用此法对煤气化废水进行剖析,从中测出三百余种有机、无机污染物,并对其中主要类别化合物进行了定量分析。     

P204f(D2EHPA)萃取分离回收催化剂母液中钴、锰

石油化工和化纤工业中大量使用钴,锰催化剂,应及时从各种废液中回收、再生,本文在25±1℃下研究了D_2EHPA-煤油从硫酸盐介质中萃取分离钴(Ⅱ)、锰(Ⅱ)的工艺,考察了萃取剂浓度、平衡pH值、相比对萃取的影响,求取了较适宜的工艺条件,利用五级逆流萃取模拟试验将钴、锰浓度比从1:1.5提高到1000:1,加入洗涤段后,又可获得金属含量比为1000的纯锰溶液,初步探索了用先进的液膜萃取新技术从溶液中分别富集、分离钴(Ⅱ)、锰(Ⅱ)的方法,找出了体系pH值对液膜萃取的影响,提出了从PTA氧化母液中回收废催化剂,萃取分离钴、锰,再生制备醋酸钴、醋酸锰和其他含钴、锰精细化工产品的工艺。     

磁性介孔硅胶萃取剂的制备及萃取性能研究

合成了C18基团修饰的磁性介孔硅胶材料,并利用该材料建立了磁性固相萃取-色谱分析方法,测定了几种环境水样中酞酸酯类(PAEs)污染物的含量.结果表明,该材料具有较大的比表面积(273 m.2g-1)和饱和磁通量(29 emu.g-1),对水样中痕量的PAEs有较强的萃取能力,而且萃取剂的磁分离特性使得萃取操作更为方便、快捷.在优化条件下,30 mg萃取剂在40 min内即可从500 mL水样中萃取痕量PAEs,回收率可达80%以上.此外,该萃取剂在处理复杂环境样品时仍能保持较强的萃取能力,环境水样中4种PAEs的检测限可达15.6—32.5 ng.L-1,加标回收率为62%—109%,相对标准偏差为2%—8%.     

有机膦萃取分离制革污泥淋滤液中Cr和Fe

采用磷酸二(2-乙基己基)酯(D2EHPA)和磷酸三丁酯(TBP)为萃取剂,萃取分离制革污泥淋滤液中的Cr3 与Fe3 .结果表明,在pH 2.2时,采用5?EHPA-正己烷萃取体系,Fe3 的萃取率达到99%,有效地分离了制革污泥淋滤液中的Fe3 和Cr3 .以5 mol·l-1的盐酸作为反萃剂反萃负载有机相,20min时的反萃率可以达到90%左右.以TBP和 D2EHPA为萃取剂萃取分离Cr3 与Fe3 时,降低了污泥淋滤液中Fe3 的萃取率,这是由于TBP的加入降低了D2EHPA的有效浓度.同时TBP的加入阻碍了萃取物分子和反萃剂的接触,降低了Fe3 的反萃率.     

稻田样品中丁虫腈及其代谢产物的残留分析方法

建立了固相萃取-气相色谱法同时测定稻田环境样品中丁虫腈及其代谢产物的残留分析方法,即:稻田水样品以二氯甲烷萃取,水稻土样品以丙酮提取后再经乙酸乙酯萃取,稻株样品以乙腈提取后用CarbonNH2固相萃取小柱净化,然后均用气相色谱-电子捕获检测器(GC-ECD)检测。结果表明,稻田水中丁虫腈及其代谢产物的最低检测质量浓度均为0.01 mg·L-1,土壤和水稻植株中目标物最低检测质量含量为0.015 mg·kg-1。在该方法条件下,当添加水平为0.05～1.0 mg·L-1(或mg·kg-1)时,稻田水、土壤和水稻植株中丁虫腈及其代谢产物的平均回收率为75.1%～109.2%,变异系数为1.0%～7.9%。     

茶多酚对三丁基锡诱导的小鼠氧化损伤的保护作用

为研究茶多酚对三丁基锡诱导的小鼠氧化损伤是否具有保护作用,采用灌胃方法,对雄性小鼠进行TBT染毒, 然后分别用不同剂量的茶多酚进行保护．结果表明,茶多酚保护组小鼠肝组织活性氧(ROS)活性和丙二醛(MDA)含量均明显低于TBT对照组;彗星实验发现茶多酚保护组小鼠淋巴细胞尾长较正常,而尾相与TBT对照组相比没有显著改变．电镜观察结果表明茶多酚保护组胸腺细胞核和线粒体损伤明显减轻．因此茶多酚对TBT诱导的氧化损伤具有一定的预防作用,并且对细胞核损伤也有一定的保护作用．茶多酚对TBT所引起的细胞核损伤的保护作用机制可能是抑制脂质过氧化反应,防止细胞氧化损伤,从而保护DNA．     

施用碱渣对茶园土壤酸度和茶叶品质的影响

开展田间小区试验研究了不同施用量条件下碱渣对酸化茶园土壤的酸度和茶叶品质的影响.结果表明,施用碱渣可以显著提高土壤pH、土壤交换性盐基和盐基饱和度,降低土壤交换性酸和交换性铝含量,并使土壤中钙、镁养分保持合理比例.施用碱渣提高了茶叶中茶多酚、儿茶素、咖啡碱、氨基酸和叶绿素含量,降低了茶叶中铅含量,使茶叶品质得到改善.碱渣施用量为4 500 kg·hm-2时,可将土壤pH值调节至5.51,达到最适合茶树生长的酸度条件,该条件下生产的茶叶品质也最佳,茶叶茶多酚、儿茶素、咖啡碱、氨基酸和叶绿素含量分别比对照提高22.5%、27.8%、34.9%、69.0%和52.1%,而Pb含量下降51.2%.     

赤红壤地区茶叶施用有机无机复肥的效果初探

本试验比较了三种不同Ｎ／Ｋ２Ｏ的有机无机复肥和进口复肥在赤红壤茶园上的施用效果．结果表明，施用有机无机复肥能促进茶树生长，增大茶芽密度．提高茶叶产量，增加茶叶的茶多酚和氨基酸含量；且能增加土壤有机质含量，平衡土壤养分．有机无机复肥中的Ｎ／Ｋ２Ｏ对其肥效的发挥有重要作用，Ｎ／ｋ２Ｏ值以４．５为宜．     

从顽拗植物荔枝中提取基因组DNA技术的研究

针对荔枝体内含有大量影响ＤＮＡ提取质量的多酚等次生代谢物质的特点,在常规ＳＤＳ和ＣＴＡＢ提取方法的基础上做了技术改进,即在核裂解之间先破碎细胞,将存在于细胞质中次生物质除去后再裂解细胞核,同时加入活性炭以吸咐杂质反复清洗几次后加入核型解液释放基因组ＤＮＡ,纯化之后经外观和电泳检测,以及Ｄ２６０ｎｍ和Ｄ２８０ｎｍ比值的测定,限制性内切酶反应,ＰＣＲ扩增的结果表明,用改进方法提取的ＤＮＡ无论在纯度上还     

Assessment of lead (Pb) and cadmium (Cd) in 10 samples of Iranian and foreign consumed tea leaves and dissolved beverages

The tea bush (Comellia sinensis) is grown commercially in a large number of countries. Tea is a beverage, which consists of processed and dried tea leaves and is one of the most popular global drinks. Tea contains some heavy metals, such as Pb and Cd, which exert adverse effects on human health. The aim of this study was to determine the Pb and Cd levels in tea leaves and in the solution following dissolution in boiling water. In order to assess Pb and Cd in Iranian consumed tea, 10 tea samples were analyzed for metal concentration in tea leaves and boiled water solutions. For tea leaf analysis, the samples (5 g) were oven dried, ash dried in a cold oven, cooled at room temperature and then 2 mL nitric acid were added to the samples and the acid were evaporated on hot plate. For tea solution analysis, tea (5 g) was added to 250 mL of boiling distilled water and after filtering, the liquid was collected as tea solution. The results show that the average concentration of Pb and Cd in Iranian tea leaves was 9.73 and 0.67 mg kg^?1 and in foreign tea leaves 2.5 and 0.53 mg kg^?1, respectively. Shariat and Golkis representing Iranian, and Red Shahrzad and Ahmad representing foreign tea, showed the highest and lowest concentration respectively of Pb. Bamdad and Shariat representing Iranian, and Black Sedaghat and Ahmad representing foreign tea, showed the highest and lowest levels of Cd, respectively. The results showed that the longer the time of dissolution of the tea, the higher concentration of Pb and Cd in tea solution. In order to control Pb and Cd levels in tea, the type of water used in agriculture and quality of soil needs to be regulated.     

Influences of charcoal and bamboo charcoal amendment on soil-fluoride fractions and bioaccumulation of fluoride in tea plants

High levels of fluoride in tea plants pose a potential health risk to humans who drink tea. It has been demonstrated that tea plant fluoride is closely related to the available fluoride in soil. But approaches that could be used to regulate the availability of fluoride in soil have been rarely seen. This study aims to investigate how the addition of charcoal and bamboo charcoal affected soil fluoride availability and bioaccumulation of fluoride in tea plants. In a microcosm experiment, tea plants were grown in the tea garden soil mixed with different amounts of charcoal and bamboo charcoal [that is, 0.5, 1.0, 2.5, and 5.0?% (w/w)]. Soil-fluoride fractions and fluoride accumulated in tea plants were determined using the sequential extraction and ion selective electrode method. Obtained results showed that both charcoal and bamboo charcoal additions significantly enhanced the concentrations of Fe/Mn oxide-bound fluoride, but significantly reduced the concentrations of water-soluble and exchangeable fluoride (p?相似文献   

吸烟烟气对鼠肺细胞膜的损伤和茶多酚的保护作用

本文以香烟气相物质作用鼠肺细胞膜为模型,用脂肪酸自旋标记物5-DOXYL和16DOXYL分别研究膜浅层和深层的动态性质受气相烟的影响,并用紫外可见分光光度法研究气相烟对膜脂的作用。结果发现,在实验的气相烟流量下,香烟气相物质能引发鼠肺细胞膜的脂质过氧化,并且使膜浅层的流动性增大。但对膜深层的动态性质没有明显的改变,如果在鼠肺细胞中预先加入粗晶态或粉态茶多酚。则肺细胞的过氧化和膜的动态性质改变受到抑制,而且这种抑制作用与茶多酚浓度呈量效关系,而茶多酚本身对膜浅层无明显作用,但对膜深层的流动性有一定影响,而且两种茶多酚的作用相似。     

Fluoride in Ceylon tea and its implications to dental health

The purpose of this study was to assess the fluoride content of Ceylon Tea, which is a popular beverage throughout the world. The fluoride content of tea infusions prepared from different grades of tea leaves collected from different parts of the tea-growing regions (25 samples) of Sri Lanka was measured using a fluoride-selective electrode. Fluoride leaching was found to vary from 0.32 to 1.69 mg F/l, but there were no significant differences in terms of fluoride leaching between tea from different tea-growing regions or between tea of different grades. Dental fluorosis is widespread throughout the dry zone of Sri Lanka, and drinking water has traditionally been considered to be the main contributory factor to the development of fluorosis. However, diet, the consumption of tea in particular, may also contribute to the manifestation of dental diseases.     

Optimization of methyl orange removal from aqueous solution by response surface methodology using spent tea leaves as adsorbent

The effective disposal of redundant tea waste is crucial to environmental protection and comprehensive utilization of trash resources. In this work, the removal of methyl orange （MO） from aqueous solution using spent tea leaves as the sorbent was investigated in a batch experiment. First, the effects of various parameters such as temperature, adsorption time, dose of spent tea leaves, and initial concentration of MO were investigated. Then, the response surface methodology （RSM）, based on Box- Behnken design, was employed to obtain the optimum adsorption conditions. The optimal conditions could be obtained at an initial concentration of MO of 9.75 mg·L-1, temperature of 35.3℃, contact time of 63.8 min, and an adsorbent dosage 3.90 g· L-1. Under the optimized condi- tions, the maximal removal of MO was 58.2%. The results indicate that spent tea leaves could be used as an effective and economical adsorbent in the removal of MO from aqueous solution.     

红壤坡地茶园蒸腾及其影响因子研究

用整株容器法研究了红壤坡地茶园的蒸腾作用 ,结果显示 :(1)茶园蒸腾速率具有明显的早晚低、中午高的日变化特征 ,但在不同的日期蒸腾速率日变化曲线存在一定差异。 (2 )蒸腾速率受诸多田间小气候因子的影响 ,相关分析及多元逐步回归分析表明 ,气温与净辐射是影响茶园蒸腾作用的 2个主要气象因子。 (3)蒸腾速率与叶片气孔导度关系密切 ,且随着气孔导度的增加 ,蒸腾速率增大。最后探讨了植物蒸腾驱动力及其抑制的可能性及气孔行为的调节与水分利用。