气相色谱法测定水中的三氯乙醛

建立了一种用气相色谱法测定水体中三氯乙醛的方法。水样先以石油醚萃取,除去高沸点化合物,加入氯化钠破乳,然后再用石油醚—乙醚混合溶剂(V/V=2:1)萃取3次,萃取液经色谱柱分离,用电子捕获检测器检测。最低检出浓度可达0.008 mg/L,线性关系良好(相关系数γ=0.992~0.998),一般共存物质不干扰测定。     

湖岸缓冲带反硝化作用的研究进展

反硝化作用是湖岸缓冲带去除硝酸盐的重要途径。湖岸缓冲带是联系陆地与湖泊生态系的纽带,不仅为许多动植物提供适宜生境,而且通过反硝化作用能去除地下水中的硝酸盐,提高湖泊水质。概述不同检测反硝化速率的方法,并对比各种方法的优点与缺点。阐述反硝化作用的影响因素：厌氧环境、有机碳、湖岸坡度、缓冲带坡度、pH与温度、硝酸盐浓度。介绍反硝化速率模型的研究开发状况。最后,提出了目前国内外反硝化研究中存在的不足及发展方向。     

实例分析卫生防护距离和大气环境防护距离设置条件

卫生防护距离、大气环境防护距离,其定义相近、设定途径相似,但两者又有不同。故在环境影响评价大气环境预测分析时对大气环境防护距离、卫生防护距离的概念极易混淆。本文以某县殡仪馆建设项目为例,详细分析建设项目设置防护距离的设置条件,帮助环评工作者理解防护距离设置原则,防止出现"在环境保护法规和导则要求下盲目划定、划大防护距离"的技术错误。     

Trends of air pollution in the Fichtelgebirge Mountains, Bavaria

We analyzed 13 years of hourly measurements of SO₂, NO_x, and O₃, at forest ecosystem research sites in SE Germany. A quasi-continuous data record was obtained by combining data sets from two locations. Before interpreting trends in the combined data set, we analyzed if the change of location introduced a systematic bias. We employed autocorrelation functions, Hurst statistics, complexity analysis, and recurrence quantification and found that the partial data sets exhibited no indication of the presence of any bias. For SO₂, we also compared the data from the forest sites with data obtained in nearby cities and also found no indications for any systematic effects. Applying nonparametric trend statistics we found a significant decrease of the SO₂. Most of the observed decrease is due to the reductions of SO₂ emissions in eastern Germany, but reductions in western Germany and the Czech Republic also played important roles. For O₃, we observed a significant increase, the causes of which are unclear from our data alone. No trend was identified for NO_x.     

汞在不同粒径大气颗粒物中的分布

采用DFG 1型五段分级采样装置及冷蒸汽原子荧光法 ,对北京市冬、春、夏和秋季不同粒径大气颗粒物 (分别为≤ 1 1μm ,1 1— 2 0 μm ,2 0— 3 3μm ,3 3— 7 0 μm和≥ 7 0 μm )中的汞进行分析 .结果表明 :北京大气颗粒物中汞的浓度在 0 6 0— 3 95ng·m-3 之间 ,冬季平均浓度为 2 85ng·m-3 ,远大于其它季节 ;大气颗粒物中的汞呈双峰分布 ,在≤ 1 1μm的细颗粒和粗粒径处各有一峰值 ;北京大气颗粒物中的汞主要分布在≤ 1 1μm的细颗粒中 ,不同粒径颗粒物中汞的分布随季节变化而变化 ,冬季各粒径颗粒物中汞的浓度比其它季节高 ;大气颗粒物中汞的质量中值粒径 (MMD )冬季为 0 71μm ,其它季节均大于1 0 μm ;北京大气颗粒物中的汞至少有 5 0 %可进入人体呼吸系统 ,且冬季最为严重     

垃圾堆肥场堆肥废气环境影响评价分析

垃圾堆肥场的建设将改变目前垃圾任意堆放的局面 ,堆肥产品可用于林业使垃圾得到无害化处理 ,并变废为宝。尽管如此在垃圾堆肥过程中还将释放出有害气体和垃圾渗透液等影响环境质量。针对堆肥所产生的大气污染物进行源强确定、扩散计算 ,分析其影响范围并推算卫生防护距离。     

水中氰化物突发性污染事故应急监测方法研究

旨在研究现场快速测定水中的氰化物。运用比色分析的朗伯 比尔定律和真空工艺设计 ,将复杂繁琐的实验室测试方法和操作程序有机地融合在测试管中。该测试管具有快速、简便和价格低廉等特点 ,测定范围为 0 0 0 5— 0 2 0mg/L。     

Application of water extract of slippery elm tree leaves as a natural reagent for selective spectrophotometric determination of trace amounts of molybdenum(VI) in environmental water samples

A novel spectrophotometric method for the determination of molybdenum(VI) by using a natural reagent, water extract of slippery elm tree leaves, is developed. Molybdenum(VI) reacts with this natural reagent to form an orange colored product. The formed product shows maximum absorbance at 418 nm with a molar absorptivity value of 0.57 × 10⁴ L mol^?1 cm^?1, and this method is linear in the 0.4–10 mg L^?1 concentration range. The detection limit value was found to be 0.0350 mg L^?1. The proposed method is simple, clean, low cost, selective, and sensitive. It was applied to the analytic samples with satisfactory results.     

Rapid liquid chromatographic analysis of Metoclopramide in pharmaceutical preparations

A sensitive, accurate and reproducible method for the analysis of metoclopramide, a gastrointestinal drug, has been described. An isocratic HPLC elution method was employed which requires about 10 minutes to be performed. The concentration of metoclopramide hydrochloride preparations was found to be 95.1 ±0.3% and 94.21 ±0.25% in tablet and injection formulations, respectively.