建立了高效液相色谱-串联质谱法同时检测食品中尿素、缩二脲和双氰胺的方法。样品经水浸泡并混匀,加入乙腈沉淀蛋白,通过冷冻离心去除脂肪,取清液挥干后用1.0 mL 70%乙腈水溶液复溶、过膜。采用电喷雾负离子电离(ESI+)模式和多反应监控(...建立了高效液相色谱-串联质谱法同时检测食品中尿素、缩二脲和双氰胺的方法。样品经水浸泡并混匀,加入乙腈沉淀蛋白,通过冷冻离心去除脂肪,取清液挥干后用1.0 mL 70%乙腈水溶液复溶、过膜。采用电喷雾负离子电离(ESI+)模式和多反应监控(MRM)扫描模式,外标法定量。该方法在0.1～20.0 mg/L范围内线性关系良好,相关系数(r2)大于0.995。尿素、缩二脲和双氰胺的检出限分别为0.03、0.05、0.01mg/L,定量下限分别为0.08、0.10、0.03 mg/L。加标水平为5.0、10.0、20.0 mg/kg时,尿素、缩二脲和双氰胺的平均回收率为70%～99%,相对标准偏差为0.42%～8.0%。该方法简便、灵敏、精确,适用于食品中尿素、缩二脲和双氰胺的检测。展开更多
A laboratory scale experiment of composting in a forced aeration system using pig manure with cornstalks was carried out to investigate the effects of both phosphogypsum and dicyandiamide （DCD, C2 H4 N4 ） as additiv...A laboratory scale experiment of composting in a forced aeration system using pig manure with cornstalks was carried out to investigate the effects of both phosphogypsum and dicyandiamide （DCD, C2 H4 N4 ） as additives on gaseous emissions and compost quality. Besides a control, there were three amended treatments with different amounts of additives. The results indicated that the phosphogypsum addition at the rate of 10% of mixture dry weight decreased NH3 and CH4 emissions significantly during composting. The addition of DCD at the rate of 0.2% of mixture dry weight together with 10% of phosphogypsum further reduced the N20 emission by affecting the nitrification process. Reducing the phosphogypsum addition to 5% in the presence of 0.2% DCD moderately increased the NH3 emissions but not N20 emission. The additives increased the ammonium content and electrical conductivity significantly in the final compost. No adverse effect on organic matter degradation or the germination index of the compost was found in the amended treatments. It was recommended that phosphogypsum and DCD could be used in composting for the purpose of reducing NH3 , CH4 and N20 emissions.0ptimal conditions and dose of DCD additive during composting should be determined with different materials and composting systems in further study.展开更多
基金supported by the National Natural Science Foundation of China(No.40971177)the National Key Technology R&D Program(No.2012BAD14B01,2012BAD14B03)+1 种基金the Sino-German Cooperation Project of Recycling of Organic Residues from Agricultural and Municipal Residues in China(No.BMBF,FKZ0330847)the Chinese Universities Scientific Fund
文摘A laboratory scale experiment of composting in a forced aeration system using pig manure with cornstalks was carried out to investigate the effects of both phosphogypsum and dicyandiamide （DCD, C2 H4 N4 ） as additives on gaseous emissions and compost quality. Besides a control, there were three amended treatments with different amounts of additives. The results indicated that the phosphogypsum addition at the rate of 10% of mixture dry weight decreased NH3 and CH4 emissions significantly during composting. The addition of DCD at the rate of 0.2% of mixture dry weight together with 10% of phosphogypsum further reduced the N20 emission by affecting the nitrification process. Reducing the phosphogypsum addition to 5% in the presence of 0.2% DCD moderately increased the NH3 emissions but not N20 emission. The additives increased the ammonium content and electrical conductivity significantly in the final compost. No adverse effect on organic matter degradation or the germination index of the compost was found in the amended treatments. It was recommended that phosphogypsum and DCD could be used in composting for the purpose of reducing NH3 , CH4 and N20 emissions.0ptimal conditions and dose of DCD additive during composting should be determined with different materials and composting systems in further study.
