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土壤中的有机物对于斥水性的研究具有重要的作用,但是目前关于内蒙古草原土壤的研究主要集中在有机碳上,而对土壤中有机物种类的研究很少。选取内蒙古锡林浩特市南部的牧草土壤样品,使用溶剂超声萃取的方法,对土壤中的有机物进行了分析。结果发现,石油醚的粗提物最少,异丙醇/氨水(7:3)的粗提物最多。粗提物经紫外、红外和GC-MS测定,结果表明用石油醚、异丙醇和甲醇作为萃取剂,得到的有机物主要为直链或环烃化合物,含量占总提取物的95%以上;氯仿及异丙醇/乙酸(7:3)和异丙醇/氨水(7:3)提取物除了含有直链或环烃化合物外,还含有酯、酰胺和甾类化合物,且甾类化合物在异丙醇/氨水提取物中含量相对最高。采用异丙醇/氨水对所有土壤样品进行萃取,发现NM1和NM7提取物中甾类化合物的含量较高,占总提取物的25%左右。异丙醇/氨水的粗取物用石油醚:乙酸乙酯(4:1)作洗脱剂,经柱层析分离主要得到A、B两部分;经GC-MS测定、质谱图库检索表明A为甾酮类物质,B为不含氧的甾烯类或者甾醇类物质。
Organics in soils play an important role in the study of water repellency, but at present, the research on grassland soils in Inner Mongolia mainly focuses on organic carbon, while few studies on the types of organic matter in soils. Soil samples from forage grass in the southern part of Xilinhot, Inner Mongolia, were selected and the organic matter in the soil was analyzed by ultrasonic extraction with solvent. The results showed that petroleum ether crude extract at least, isopropanol / ammonia (7: 3) crude extract the most. The crude extracts were determined by UV, IR and GC-MS. The results showed that petroleum ether, isopropanol and methanol as the extractants, the organic compounds were mainly linear or cyclic hydrocarbons, the content of which accounted for more than 95% of the total extract; chloroform And isopropanol / acetic acid (7: 3) and isopropanol / ammonia (7: 3) extracts contain esters, amides and steroids in addition to linear or cyclic hydrocarbon compounds, Propanol / ammonia extract content is relatively highest. All soil samples were extracted with isopropanol / ammonia and found that the NM1 and NM7 extracts contained high levels of steroids, accounting for about 25% of the total extract. The crude extract of isopropanol / ammonia water was separated by column chromatography using petroleum ether: ethyl acetate (4: 1) as the eluent. The main components A and B were obtained by GC-MS. Is a steroid, B is an oxygen-free steroid or a steroid.