SPME/GC-MS鉴别地沟油新方法(Ⅱ)

采用固相微萃取/气相色谱-质谱(SPME/GC-MS)方法测定地沟油中的微量杂质成分,通过对各种纯正植物油中的内源性微量成分与不同地区地沟油中的外源性杂质成分的对比分析,以及对地沟油中杂质成分来源的分析,确定了广州、贵州、深圳、北京等地区地沟油的特征成分,并作为鉴别指示成分。该方法灵敏度高、特征性强,在卫生部组织的地沟油检测盲样考核中,对阳性样品判断的准确率高达95.5%。     

基于固相微萃取技术的GC-MS法快速检测地沟油

ACF-SPME与GC-MS联用,优化的测定地沟油的最佳条件为:称取0.025g样品,加入0.005g Na2SO4,在120℃下萃取50 min,色谱解析1 min。实验发现不同来源的地沟油和不同品牌的植物类食用油均可以检测到2-十九烷酮,且地沟油中的含量远高于植物油;所有油类均含有庚醛,其含量与其他物质成比例增加或减少。提出用M值指标来判断地沟油的方法。即M=(H2/H1)2,其中H2表示2-十九烷酮的峰高,H1表示庚醛的峰高。结果表明:不同品牌植物油的M值均低于40,而地沟油远高于40,最高可达339.07。M值法适用于泔水油来源的地沟油的判断。     

地沟油检测技术研究进展

地沟油非法加工用作食用油,对人体健康有很大的危害,建立地沟油鉴别国家标准是当前亟需解决的难题。对地沟油检测方法的研究报道进行了综述及评价,并对未来地沟油鉴别研究方向进行了展望。     

A Novel Method for the Identification of Gutter Oils Using SPME/GC - MS ( Ⅱ )

采用固相微萃取/气相色谱-质谱(SPME/GC- MS)方法测定地沟油中的微量杂质成分,通过对各种纯正植物油中的内源性微量成分与不同地区地沟油中的外源性杂质成分的对比分析,以及对地沟油中杂质成分来源的分析,确定了广州、贵州、深圳、北京等地区地沟油的特征成分,并作为鉴别指示成分.该方法灵敏度高、特征性强,在卫生部组织的地沟油检测盲样考核中,对阳性样品判断的准确率高达95.5％.     

市场

7种方法难让地沟油现形行政部门很无奈据21世纪网报道,工商局、质检中心、环保局三方人士均表示,即使依靠各种仪器方法,地沟油仍然难以检测。地沟油不是一种产品,其来源复杂,成分不定。现在的7种检测方法只是对地沟油里面存在的多环芳烃、重金属,胆固醇等单一指标进行检测,而地沟油经过高温加热、水洗、     

地沟油检测的新方法

地沟油——城市下水道里悄悄流淌的垃圾。然而,有淘者对其进行加工,摇身变成餐桌上的“食用油”。这种被称作“地沟油”的三无产品,其主要成分仍然是甘油三酯,却又比真正的食用油多了许多致病、致癌的毒性物质。一旦食用“地沟油”,会破坏人们的白血球和消化道黏膜,引起食物中毒,甚至致癌。所以“地沟油”是严禁用于食用油领域的。近期,地沟油事件越闹越凶,各个检测单位都开始开展了地沟油的检测,由于基质复杂,方法指标众多,成为了检测的难题。     

活性炭纤维-固相微萃取-气相色谱/飞行时间质谱法鉴别地沟油与植物油

采用活性炭纤维-固相微萃取(ACF-SPME)与气相色谱/飞行时间质谱(GC/TOFMS)联用技术检测地沟油与植物油中挥发性游离脂肪酸的含量,通过色谱峰分析脂肪酸含量的变化,建立了鉴别地沟油的新方法。检测出6种挥发性脂肪酸:戊酸、己酸、辛酸、壬酸、棕榈酸和硬脂酸;地沟油中棕榈酸的含量远高于植物油中的含量,而己酸含量基本不变。据此提出了地沟油检测指标,即A值指标=棕榈酸的峰面积/己酸的峰面积:地沟油的A值大于0.8,而植物油的A值均小于0.8。通过实验证明了不同纤维、不同品牌植物油对A值没有影响,通过模拟加热食用油实验表明了A值指标的可靠性,适用于煎炸老油的鉴定。     

科普实验教学项目:地沟油-膨润土去污皂的制备及去污率测定*

本科普实验设计以地沟油和膨润土为主要原料,通过皂化反应制备地沟油-膨润土去污皂,主要包括简化地沟油纯化流程、优化皂化反应配方、美化产品,实验的观赏性和互动性强。在此基础上,通过制作科普视频、宣传手册、举办体验活动等方式,全面立体地向公众展现地沟油纯化过程、皂化现象及其背后的化学原理等。     

地沟油、花生油和调和油中微量元素含量差异的研究

应用电感耦合等离子体原子发射光谱法(ICP-AES)测定了地沟油与普通食用油中Na,Mg,Al,P,Ca,Fe,Zn和Pb等元素的含量,并对这些测量数据进行了对比分析。油样进行微波消解后,ICP-AES能直接测定处理液中的上述8种元素含量;地沟油中的Zn和Pb等重金属元素的含量并不比普通食用油高;而Mg,Al,P和Ca元素的含量,在地沟油、花生油和调和油之间却存在明显差异。花生油中P元素的含量明显高于在地沟油和调和油中的含量;调和油中的M g和Ca含量均明显比地沟油高,而调和油中Al的含量明显高于花生油。上述结果可以作为区分这3类油品的辅助信息。     

基于地沟油的洗衣液合成及性能研究

以地沟油为原料,经磺化并提纯,获得棕色胶质地沟油磺酸钠盐,采用傅里叶变换红外光谱确定合成化合物特征基团,并对其水溶液的电导率和表面张力进行测定。在此基础上,与脂肪醇聚氧乙烯醚硫酸钠(AES)、脂肪醇聚氧乙烯醚(AEO-9)等辅助材料采用正交试验进行复配,获得一种环保型洗衣液。以该洗衣液对油污布洗涤效果对配方进行优化,最后得到一种以地沟油为原料制备的性能优良的洗衣液。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

探究“铁的锈蚀条件”实验创新设计

设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。