Simultaneous determination of dissolved organic nitrogen, nitrite, nitrate and ammonia using size exclusion chromatography coupled with nitrogen detector

Accurate quantification of dissolved organic nitrogen (DON) has been a challenge due to the cumulative analytical errors in the conventional method via subtracting dissolved inorganic nitrogen species (DIN) from total dissolved nitrogen (TDN). Size exclusion chromatography coupled with an organic nitrogen detector (SEC-OND) has been developed as a direct method for quantification and characterization of DON. However, the applications of SEC-OND method still subject to poor separations between DON and DIN species and unsatisfied N recoveries of macromolecules. In this study, we packed a series of SEC columns with different lengths and resin materials for separation of different N species and designed an independent vacuum ultraviolet (VUV) oxidation device for complete oxidation converting N species to nitrate. To guarantee sufficient N recoveries, the operation conditions were optimized as oxidation time ≥ 30 min, injection mass (sample concentration × injection volume) < 1000 µL × mg-N/L for macromolecular proteins, and neutral pH mobile eluent. The dissolved O₂ concentration in SEC mobile phase determined the upper limit of VUV oxidation at a specific oxidation time. Compared to conventional HW50S column (20 × 250 mm), HW40S column (20 × 350 mm) with mobile phase comprising of 1.5 g/L Na₂HPO₄·2H₂O + 2.5 g/L KH₂PO₄ (pH = 6.85) could achieve a better separation of DON, nitrite, nitrate, and ammonia. When applied to river water, lake water, wastewater effluent, groundwater, and landfill leachate, the SEC-OND method could quantify DON as well as DIN species accurately and conveniently even the DIN/TDN ratio reached 0.98.     

大气中挥发性苯系物的Carbotrap吸附气相色谱法

本文研究以Ｃａｒｂｏｔｒａｐ作吸附剂，在常温采集大气中挥发性苯系物，直接采用热脱附气相色谱分析。对新型吸附剂Ｃａｒｂｏｔｒａｐ的采样－脱附－分析精度，回收率，突破体积等作了试验。本法具有灵敏度高，操作简单，不需复杂的样品预处理，色谱峰好，吸附剂可反复使用等优点。可对大气中１０－９级苯系物进行测定，ＲＳＤ≤３．５％。     

大气中苯乙烯的气相色谱法测定

采用活性炭管吸附大气中基苯乙烯，以二硫化碳洗脱，以溴水加成后，用气相色谱电子捕获器测定苯乙烯的二溴加成物。本方法适合于检测多种污染物共存的大气中痕量苯乙烯。其线性范围为０．０１５－０．７４ｎｇ，最低检出浓度为０．００１ｍｇ／ｍ＾３；重现性实验的变异系数为２．３％：当活性炭管吸附苯乙烯在２．９μｇ时，回收率为９０％，吸附苯乙烯０．２９μｇ时，回收率为７２％。     

胜利石油局配气站噪声治理

本文对配气站管网系统作了噪声源分析，提出了在节流降压阀下游加装消声器，对管道作重点隔声包扎和简易隔声包扎、加装阀门局部隔声罩的方案。方案实施后，管网噪声由１２１ｄＢＡ降至８０ｄＢＡ，效果十分显著。     

一个填埋场的气体排放控制系统的建立及其从中得到的几点启示

介绍位于纽约州北汉姆斯特城的ＰｏｒｔＷａｓｈｉｎｇｔｏｎ城市固体废弃物填埋场填埋气体的排放、监测和处理系统及其有关测试数据和从中得到的启示．     

轻烧镁窑烟尘污染治理技术的筛选与应用

利用煤气发生炉生产煤气，烧结轻烧镁，具有产品质量高，大幅度削减烟尘排放量，节约能源等优点，该项技术具有广泛的推广价值，本文较详细地介绍了辽宁省轻烧镁窑烟尘污染治理技术的典型，具有同类技术的国内先进水平．     

煤气洗涤废水的处理研究

本研究对特难处理的煤气洗涤废水，采用混凝──电化学氧化处理，可获得良好的处理效果．其ＣＯＤ、油、酚分别由１０３２２ｍｇ／Ｌ、１５０００ｍｇ／Ｌ、１５７０ｍｇ／Ｌ降至２８９ｍｇ／Ｌ、１００ｍｇ／Ｌ、０．５ｍｇ／Ｌ．去除率分别为９７．２％，９３．３％，９９．９７％．     

饮用水中五种有机磷农药的快速检测法

本文介绍了使用Ｗａｔｅｒｓ ＯＡＳＩＳ－ＨＬＢ固相萃取小柱从水中分离富集敌百虫、敌敌畏、乐果、甲基对硫磷，对硫磷五种有机磷农药的快速检测法。     

含硫化合物的气相色谱检测响应特性研究

利用气相色谱（配炎焰光度检测器）对二硫化碳（ＣＳ２）、甲硫醇（ＣＨ３ＣＨ）、甲硫醚（ＤＭＳ）和二甲二硫醚（ＤＭＤＳ）４种含硫物质进行了分析检测，着重讨论了气相色谱仪的各项参数对几种含硫物质响应和分离效果的影响。结果表明：该分析对含硫气体的最小检测浓度达到ｐｐｂ级。在各项参数中，色谱柱温度在Ｎ２压力对各含硫物质响应和分离度影响最大，汽化室和检测器温度及空气压力对它们的影响相对较小。     

Immediate prenatal diagnosis of Zellweger syndrome by direct measurement of very long chain fatty acids in chorionic villus cells

We report a gas chromatographic-mass spectrometric method which allows the very long chain fatty acids content of trophoblastic tissue to be directly measured in samples collected by biopsy between 8 and 11 weeks of gestation. This method has been successfully applied to the detection of fetal Zellweger syndrome in two pregnant women who had previously delivered affected infants. In one of them, increased concentrations of C26:0 (0.254 versus 0.108±0.035 μ/mg proteins) and C24:0 (1.32 versus 0.815±0.325 μ/mg proteins) in trophoblast indicated that the fetus had Zellweger syndrome, a diagnosis confirmed by pathological findings after abortion. In the second case, the pregnancy was allowed to proceed, on the basis of normal concentrations of very long chain fatty acids in trophoblastic tissue, and its outcome was actually a healthy newborn.