超声提取-气相色谱法测定土壤1,9-癸二醇

Determination of 1,9-Decanediol in Soil with Ultrasonic Extraction-Gas Chromatography

1,9-癸二醇是由水稻根系分泌物中发现的一种新型生物硝化抑制剂,在农业生产中可提高氮肥利用率,减少氮素损失。为建立一套超声波提取-气相色谱检测土壤中1,9-癸二醇的方法,分别对超声波提取条件(提取剂、提取次数、液料比、超声时间)和气相色谱检测参数(进样口温度、检测器温度、升温程序)进行研究。结果表明,超声波提取土壤1,9-癸二醇的最佳方法为甲醇作为提取剂超声提取1次,液料比40 mL·g-1,超声时间30 min。气相色谱Agilent 8890测定1,9-癸二醇的最佳条件为进样口温度250℃;氢火焰离子化检测器(FID)温度310℃;升温程序:初始柱温60℃,保持2 min,以20℃·min^(-1)的速率升至150℃,然后以3℃·min^(-1)的速率升至180℃,保持2 min,最后以20℃·min^(-1)的速率升至270℃。在最佳提取和测定条件下,不同浓度1,9-癸二醇的加标回收率为90.58%~94.55%。超声提取-气相色谱法检测限低、灵敏度和精密度高,快速高效、重复性好,为今后1,9-癸二醇的实际应用工作奠定了基础。

【Objective】The application of biological nitrification inhibitors(BNIs)is considered an important new strategy to reduce nitrogen loss from agricultural systems.Recently,a new BNI,1,9-decanediol,has been identified in rice root exudates and the substance is found to be contributive to improvement of nitrogen(N)-use efficiency(NUE)and reduction of N2O emissions in agriculture.In order to evaluate its stability and effect in soil,an efficient,fast and accurate extraction and detection method needs to be developed.Thus,this study was oriented to develop a method of using ultrasonic extraction-gas chromatography(GC)to determine 1,9-decanediol in soil.【Method】Soil samples were collected from a paddy soil at Yixing(31°17′N,119°54′E),Jiangsu Province of China for extraction of 1,9-decanediol using different methods,including different extractants(water,acetonitrile,methanol,acetone,ethyl acetate,dichloromethane,hexane,and petroleum ether),different liquid to solid ratios(varying in the range of 10-50 mL·g-1),different durations of ultrasonic processing(in the range of 10-50 min),different frequency of extraction(in the range of 1-3 times),and different gas chromatography detection parameters,including inlet temperature(in the range of 200-280℃),detector temperature(in the range of 260-320℃),and four heating procedures for optimization.Spike recovery of the substance in soil was determination relative to its concentration(10,100 and 1000 mg·kg^(-1)).【Result】Results show that:(1)the method of ultrasonic extraction using methanol as extractant,40 mL·g-1 in liquid/solid ratio,and going only one round that lasted 30 min was the optimal one;(2)In using the Agilent 8890 gas chromatographer to determine the substance,the optimal conditions were 250℃at the inlet,310℃at the FID detector,60℃in the column kept for the first 2 min,and then raised up to 150℃at 20℃·min^(-1) and to 180℃at 3℃·min^(-1),kept for 2 min.and in the end,raised to 270℃at 20℃·min^(-1);(3)under such conditions,determination of 1,9-decanediol,10-100.00μg·mL^(-1) in concentration exhibited good linearity,standard curve of y=26.81x-9.678(R^(2)=0.999),detection limit of 0.03μg·mL^(-1),recovery rate of 93.99%-96.91%,intraday precision 1.78%and interday precision of 1.52%;and(4)under such optimal extraction and determination conditions,the spike recovery rate of 1,9-decanediol in soil samples,regardless of concentration,varied in the range of 90.58%-94.55%with relative standard deviation(RSD)varying in the range of 0.30%-3.41%.【Conclusion】This method,low in detection limit,high in sensitivity and precision,and good in reproducibility,and this experiment may lay down a foundation for evaluation of stability and environmental impacts of 1,9-decanediol in agricultural soils,and provide a good reference for developing methods for extracting other BNIs in soil in future.