目的建立气相色谱-质谱法(gas chromatography mass spectrometry,GC-MS)测定食品中合成香料3-乙酰基-2,5-二甲基呋喃的方法。方法样品用正己烷涡旋提取后过滤,含油脂样品采用冷冻过滤技术去除油脂和其他杂质,选用TG-5MS毛细管色谱柱(30...目的建立气相色谱-质谱法(gas chromatography mass spectrometry,GC-MS)测定食品中合成香料3-乙酰基-2,5-二甲基呋喃的方法。方法样品用正己烷涡旋提取后过滤,含油脂样品采用冷冻过滤技术去除油脂和其他杂质,选用TG-5MS毛细管色谱柱(30 m×0.25 mm,0.25μm),载气流速1 mL/min进行分离后进质谱分析。结果3-乙酰基-2,5-二甲基呋喃在0.005~10.000μg/L质量浓度范围内曲线线性良好,相关系数为0.9997;在不同基质及不同加标浓度下,加标回收率为80.16%~103.76%,相对标准偏差为1.83%~7.87%(n=6);3-乙酰基-2,5-二甲基呋喃在不同基质中的检出限均可达到1μg/kg,定量限均可达到3μg/kg。结论该方法简单、准确度高、灵敏度好,可以用于食品中3-乙酰基-2,5-二甲基呋喃含量的快速检测,为合成香料的安全使用和监管提供技术手段。展开更多
The reduction of oxygen consumption is a key factor to improve the energy density of underwater Stirling engine.A series of fundamental experiments are carried out to elucidate the spray characteristics of soybean oil...The reduction of oxygen consumption is a key factor to improve the energy density of underwater Stirling engine.A series of fundamental experiments are carried out to elucidate the spray characteristics of soybean oil/2,5-dimethylfuran(DMF)blended fuel in an underwater Stirling engine.Spray characteristics such as spray penetration,spray angle,spray area,and light intensity level under low injection and ambient pressures are obtained using image post-processing method.The results show that the effects of injection pressure,ambient pressure,and nozzle diameter on the transient spray characteristics of underwater Stirling engine are similar to those of diesel engine.However,in the steady spray process,the injection pressure has little effect on spray near angle,and the spray far angle increases with the increase of the injection pressure.Compared with the spray far angle at injection pressure of 3 MPa,the spray far angle at 5 MPa and 7 MPa increased by 11.38%and 18.14%respectively.The addition of DMF can obviously improve the atomization of soybean oil/DMF blended fuel.The spray angle of blended fuel in transient process increases with the increase of the DMF concentration.The spray near angle has exceeded that of diesel(46.21°)when the DMF volume fraction exceeds 25%.The spray far angle is equivalent to that of diesel when the DMF volume fraction reaches 75%.Moreover,the spray with gas ejection no longer keeps conical,the droplet diameter distribution is more dispersed,and the droplet diameter is smaller.展开更多
The interface between Au and support has attracted extensive interest because of its unique catalytic ability for hydrogen activation in catalytic hydrogenation/hydrogenolysis reactions.Herein,we create the Au-CoO-OV ...The interface between Au and support has attracted extensive interest because of its unique catalytic ability for hydrogen activation in catalytic hydrogenation/hydrogenolysis reactions.Herein,we create the Au-CoO-OV interface in the 1.0%Au/Co3O4-Rod-250 catalyst,which could dissociate H2 via the heterolytic way to yield rich hydride species and achieve excellent catalytic performance in the hydrogenolysis of biomass-derived 5-hydroxymethylfurfural(HMF)to 2,5-dimethylfuran(DMF).The XRD and HRTEM analyses show that Au nanoparticles are uniformly dispersed on CoO-OV surface and in situ DRIFTS spectra show the enhancement of heterolytic dissociation of hydrogen(signals of Au-D and O-D vibration)compared with bare CoO(Co3O4-Rod-250).This work provides insights for fabricating highly active Au-support catalysts for catalytic hydrogenation/hydrogenolysis reactions.展开更多
基金the Natural Science Foundation of Jiangsu Province(No.BK20220588)the Initial Scientific Research Fund of Yangzhou University(No.137012553)and the Public Welfare Technology Research Program of Zhejiang Province(Nos.LGG19E060001 and LGG 21E090001)。
文摘The reduction of oxygen consumption is a key factor to improve the energy density of underwater Stirling engine.A series of fundamental experiments are carried out to elucidate the spray characteristics of soybean oil/2,5-dimethylfuran(DMF)blended fuel in an underwater Stirling engine.Spray characteristics such as spray penetration,spray angle,spray area,and light intensity level under low injection and ambient pressures are obtained using image post-processing method.The results show that the effects of injection pressure,ambient pressure,and nozzle diameter on the transient spray characteristics of underwater Stirling engine are similar to those of diesel engine.However,in the steady spray process,the injection pressure has little effect on spray near angle,and the spray far angle increases with the increase of the injection pressure.Compared with the spray far angle at injection pressure of 3 MPa,the spray far angle at 5 MPa and 7 MPa increased by 11.38%and 18.14%respectively.The addition of DMF can obviously improve the atomization of soybean oil/DMF blended fuel.The spray angle of blended fuel in transient process increases with the increase of the DMF concentration.The spray near angle has exceeded that of diesel(46.21°)when the DMF volume fraction exceeds 25%.The spray far angle is equivalent to that of diesel when the DMF volume fraction reaches 75%.Moreover,the spray with gas ejection no longer keeps conical,the droplet diameter distribution is more dispersed,and the droplet diameter is smaller.
基金the National Natural Science Foundation of China(No.21832002)the Fund of the Science and Technology Commission of Shanghai Municipality,China(STCSM,No.10dz2220500).
文摘The interface between Au and support has attracted extensive interest because of its unique catalytic ability for hydrogen activation in catalytic hydrogenation/hydrogenolysis reactions.Herein,we create the Au-CoO-OV interface in the 1.0%Au/Co3O4-Rod-250 catalyst,which could dissociate H2 via the heterolytic way to yield rich hydride species and achieve excellent catalytic performance in the hydrogenolysis of biomass-derived 5-hydroxymethylfurfural(HMF)to 2,5-dimethylfuran(DMF).The XRD and HRTEM analyses show that Au nanoparticles are uniformly dispersed on CoO-OV surface and in situ DRIFTS spectra show the enhancement of heterolytic dissociation of hydrogen(signals of Au-D and O-D vibration)compared with bare CoO(Co3O4-Rod-250).This work provides insights for fabricating highly active Au-support catalysts for catalytic hydrogenation/hydrogenolysis reactions.
