气相色谱-质谱法分析乳制品中的三种乳化剂

运用气相色谱-质谱(GC-MS)联用技术,建立了乳制品中的乳化剂单棕榈酸甘油酯、单油酸甘油酯和单硬脂酸甘油酯分析新方法.乳制品中目标物用二氯甲烷提取,经硅烷化试剂(BSTFA+1％TMCS)进行衍生,对提取及衍生化条件进行了优化.在优化条件下,单棕榈酸甘油酯、单油酸甘油酯和单硬脂酸甘油酯分别在1～20 mg/L、5～1...     

超高效合相色谱-质谱法快速分离测定4种单脂肪酸甘油酯

采用超高效合相色谱-质谱(UPC² -MS)技术,建立了一种快速分离植物油单脂肪酸甘油酯中单软脂酸甘油酯、单硬脂酸甘油酯、单油酸甘油酯和单亚油酸甘油酯4种单甘酯的测定方法。以葵花籽油为原料,通过脂肪酶催化甘油解反应制备单甘酯。样品用正己烷/异丙醇(体积比7:3)溶解,采用超临界CO₂-甲醇/乙腈(体积比1:1)梯度洗脱,经ACQUITY UPC² BEH 2-EP(100 mm×2.1 mm,1.7 μm)色谱柱分离,通过质谱检测器在正离子电喷雾模式下对目标化合物进行分析,外标法定量。结果表明,4种单甘酯化合物在线性范围内线性关系良好,线性相关系数(R²)均大于0.9983;目标物的检出限(S/N≥3)为0.036~0.093 mg/L;3个加标水平下的回收率在88.50%~110.00%之间,相对标准偏差为1.01%~4.04%。本方法具有检出限低、分析速度快、分离效果好、分析成本低等优点,为脂肪酸酯类物质的分离测定提供了新的色谱技术平台。     

超高效合相色谱-质谱法快速检测植物油脂中5种脂肪酸含量

建立了一种超高效合相色谱-质谱(UPC2-MS)技术快速检测植物油脂中棕榈酸、硬脂酸、油酸、亚油酸、亚麻酸5种常见脂肪酸的方法。样品用正己烷溶解后,采用超临界CO2-甲醇/乙腈(体积比,1∶1)梯度洗脱,经ACQUITY UPC2BEH 2-EP(2.1 mm i.d.×100 mm,1.7μm)色谱柱分离,通过质谱检测器对目标化合物进行分析,外标法定量。结果表明,5种脂肪酸在0.5~100 mg/L范围内具有良好线性(相关系数不小于0.998 5);在3个加标水平下,样品的回收率为90.5%~105.4%,相对标准偏差为0.8%~2.9%;方法的检出限(S/N≥3)为0.07~0.26 mg/L。相比于其他方法,本方法简单快速,分离效果好,且无需对脂肪酸样品进行衍生化,为UPC2技术在油脂相关分析领域的进一步应用和研究提供了参考。     

超高效合相色谱-质谱法快速检测工业油酸中5种常见的脂肪酸

采用超高效合相色谱-质谱(UPC2-MS)技术,建立了工业油酸中5种常见的脂肪酸(软脂酸、硬脂酸、油酸、亚油酸和亚麻酸)的快速检测方法。样品用正己烷溶解,采用超临界CO2-甲醇/乙腈(1∶1,V/V)梯度洗脱,经Acquity UPC2BEH 2-EP色谱柱(100 mm×2.1 mm,1.7μm)分离,通过质谱检测器在负离子电喷雾模式下对目标化合物进行分析,外标法定量。通过对UPC2-MS条件的优化,5种脂肪酸在3 min内实现有效分离,目标物在0.5~100 mg/L范围内具有良好的线性(相关系数大于0.9985);在3个添加水平下,5种脂肪酸的回收率在89.3%~106.7%之间,相对标准偏差为0.8%~3.0%;方法检出限(S/N≥3)为0.07~0.26 mg/L。实际样品分析结果表明,本方法不但简单快速,分离效果好,而且无需对脂肪酸样品进行衍生化,同时为UPC2在油脂类相关领域的研究与开发提供一种快速有效的检测方法。     

毛细管气相色谱/质谱法测定柑籽中的脂肪酸

用乙醚/正已烷混合溶剂萃取柑籽中的脂肪酸甘油酯,用KOH-CH_3OH法甲酯化,以毛细管色谱/质谱/计算机法测定其脂肪酸组成,共检出7种脂肪酯,其中以棕榈酸(35.48%)、油酸(26.6%)及亚油酸(27.27%)为主。     

气相色谱法测定面包中三种单甘油酯含量

建立了气相色谱法检测面包中3种单甘油酯(单辛酸甘油酯、单癸酸甘油酯和单月桂酸甘油脂)含量的分析方法。样品以二氯甲烷-正己烷(1∶1)提取,提取液经浓缩后,用正己烷饱和乙腈萃取,气相色谱测定,外标法定量。3种单甘油酯在20～1 000 mg/L范围内呈良好线性,相关系数(r)大于0.999。3种单甘油酯的定量下限分别为35.2、23.3、12.8 mg/kg,加标回收率为81.1%～95.7%,相对标准偏差(RSD)为2.9%～8.8%。该法操作简便、灵敏度高、重现性和选择性好,可用于面包中3种单甘油酯的检测。     

无溶剂体系中脂肪酶催化合成单甘酯的研究

以自制铜绿假单胞菌脂肪酶为催化剂,通过无溶剂法棕榈油甘油解反应催化合成了单脂肪酸甘油酯,实验结果表明：适宜加酶量为500u/g棕榈 油,甘油相适宜水含量为3％－4．5％,适宜加酶量为500u/g棕榈油,甘油与棕榈油的摩尔比为（2．0－2．5）：1,最佳反应温度为38－42度,在此温度区间内适宜反应时间为24h,临界反应温度为44度,程序降温和批次加酶更有利于反应,产物中单甘酯含量可增大10－20％,实验条件下反应48h后单甘酯含量可达65％,脱酶后达77％。     

液相色谱-大气压化学电离质谱分析鉴别地沟油中的氧化成分

采用液相色谱-大气压化学电离质谱(HPLC-APCI-MS)方法,分析了食用油脂和地沟油的甘油三酯(TAG)组成。采用C18色谱柱,乙腈-丙酮为流动相,梯度洗脱,APCI正离子模式检测。应用本方法检测了15个地沟油和11个食用油样品,结果表明,地沟油中存在三亚油酸甘油酯(LLL)、二亚油酸单油酸甘油酯(LOL)、二亚油酸单亚麻酸甘油酯(LLnL),二油酸单亚油酸甘油酯(OOL)等甘油三酯的5种亚油酰基氧化产物。采用偏最小二乘法判别分析(PLS-DA)化学计量学方法,分析建立了地沟油和正常食用油的判别模型,实现了正常食用油和地沟油区分,模型正确判别率96.2%。在判别模型中,含有亚油酸环氧化物的TAG分子对判别贡献率较大,该类化合物可作为地沟油区别于正常油脂的标志成分。     

高效液相色谱法同时测定食品中6种对羟基苯甲酸酯

建立了同时检测食品中6种对羟基苯甲酸酯的高效液相色谱-二极管阵列检测器( HPLC-DAD)定量分析方法.样品用乙腈提取,经LC-C18固相萃取柱净化,采用Agilent C18色谱柱分离,甲醇/水溶液梯度洗脱,二极管阵列检测器检测,外标法定量.结果表明:6种对羟基苯甲酸酯在1.0～500.0 mg/L范围内线性关系良好(r≥0.9997);检出限为0.0016～0.0081 mg/L(S/N=3);6种对羟基苯甲酸酯各添加水平在经表面处理的新鲜蔬菜、水果、醋、碳酸饮料及牛奶,食品馅料中的回收率为85.1％～95.4％;相对标准偏差为3.6％～10.9％.     

Using Lipase Modified Screen-printed Electrode as Glyceryltrioleate Biosensor

制备了用于快速检测三油酸甘油酯的脂肪酶修饰丝网印刷电极(SPE)电化学传感器单元.用循环伏安法(CV)和计时电流法(CC)研究了三油酸甘油酯在脂肪酶修饰SPE上的电化学行为,确定了测定甘油酯的最优条件,建立了测定三油酸甘油酯浓度的电化学方法.其中CV法的线性范围为0.01～5 g,L-1,检出限为2.5 mg· L-1; CC法的线性范围为0.001～5.50 g·L-1,检出限为0.2 mg· L-1.以CV法考察样品的加标回收率,6个葵花籽油样品的加标回收率为94％ ～ 105％.     

Die quantitative Bestimmung isomerer Monoglyceride

Ohne Zusammenfassung     

Zur Analyse technischer Monoglyceride mit Perjodat

Ohne Zusammenfassung     

Monoglyceride and Diglyceride Production Through Lipase-Catalyzed Glycerolysis and Molecular Distillation

Distilled glycerides are obtained through distillation of the system mono-diglycerides which is produced from the esterification reaction between a triglyceride with glycerol. In this work, monoglycerides (MG) and diglycerides (DG) are produced through lipase-catalyzed glycerolysis of soybean oil using Candida antarctica B in a solvent-free system. To separate the products of the reaction in order to obtain essentially MG and an oil of DG, it is necessary to use a suitable process in order to preserve the stability of the components and to keep the products free of inappropriate solvents. So, after 24 h of enzymatic reaction, the mixture of acylglycerols and fatty acids was distilled into a centrifugal molecular distiller, since it provides a free solvent and lower temperature environment to increase the desired product concentration. Starting from a material with 25.06% of triglycerides (TG), 46.63% of DG, 21.72% of MG, 5.38% of free fatty acids (FFA), and 1.21% of glycerol, the MG purity in the distillate stream was 80% at evaporator temperature (T _E) equal to 250 °C and feed flow rate (Q) equal to 10.0 mL/min. At these conditions, the MG recovery was 35%. The material collected in the residue stream presented DG-enriched oil with TG unhydrolyzed, residual MG, and low acidity (29.83% of TG, 53.20% of DG, 15.64% of MG, and 1.33% of FFA), which is suitable to replace TG oil in the human diet.     

甘油单油酸脂/水立方液晶体系流变性质的研究

Monoglyceride (MO) can form various liquid crystalline phases spontaneously in the presence of various amount of water at room temperature. The appropriate compositions from binary phase diagram of MO/H2O were selected to form cubic phases. The selected systems were studied at different salt concentrations and pH value using rheological methods. There was a weak effect of salt on viscoelastic properties of cubic phases formed from MO/H2O system. Hexagonal phase was formed when pH value was decreased or increased. The viscoelasticity of cubic phases was different from that of hexagonal liquid crystals. Rheological properties of MO/H2O cubic phases were stable at pH and salt concentration similar to physiological condition.     

Thermoresponsive Dual-Structured Gel Emulsions Stabilized by Glycyrrhizic Acid Nanofibrils in Combination with Monoglyceride Crystals

Responsive dual-structured emulsions and gel emulsions have attracted more and more attention due to their complex microstructures, on-demand responsive properties, and controlled release of active cargoes. In this work, the effect of monoglyceride (MG)-based oil phase structuring on the formation and stability, structural properties, and thermoresponsive and cargo release behavior of gel emulsions stabilized by glycyrrhizic acid (GA) nanofibrils were investigated. Owing to the formation of GA fibrillar networks in the aqueous phase and MG crystalline networks in the oil phase, a stable dual-structured gel emulsion can be successfully developed. The microstructure of the dual-structured gel emulsions largely depended on the concentration of MG in the oil phase. At low MG concentrations (1–2 wt%), the larger formed and lamellar MG crystals may pierce the interfacial fibrillar film, inducing the formation of partially coalesced droplets. In contrast, at high MG concentrations (4 wt% or above), the smaller MG crystals with enhanced interfacial activity can lead to the formation of a bilayer shell of GA nanofibrils and MG crystals, thus efficiently inhibiting the interfacial film damage and forming a jamming structure with homogeneously distributed small droplets. Compared to pure GA nanofibril gel emulsions, the GA−MG dual-structured gel emulsions showed significantly improved mechanical performance as well as good thermoresponsive behavior. Moreover, these stable GA−MG gel emulsions can be used as food-grade delivery vehicles for encapsulating and protecting hydrophobic and hydrophilic bioactive cargoes. They also have great potential as novel and efficient aroma delivery systems showing highly controlled volatile release. The dual-structured emulsion strategy is expected to broaden the applications of natural saponin GA-based gel emulsions in the food, pharmaceutical, and personal care industries.     

The Antiviral Activity of Caprylic Monoglyceride against Porcine Reproductive and Respiratory Syndrome Virus In Vitro and In Vivo

Porcine reproductive and respiratory syndrome (PRRS) is a disease with a major economic impact in the global pig industry, and this study aims to identify potential anti-PRRSV drugs. We examined the cytotoxicity of four medium-chain fatty acids (MCFAs) (caprylic, caprylic monoglyceride, decanoic monoglyceride, and monolaurin) and their inhibition rate against PRRSV. Then the MCFAs with the best anti-PRRSV effect in in vitro assays were selected for subsequent in vivo experiments. Potential anti-PRRSV drugs were evaluated by viral load assay, pathological assay, and cytokine level determination. The results showed that caprylic monoglyceride (CMG) was the least toxic to cells of the four MCFAs, while it had the highest PRRSV inhibition rate. Then the animals were divided into a low-CMG group, a medium-CMG group, and a high-CMG group to conduct the in vivo evaluation. The results indicated that piglets treated with higher concentrations of caprylic monoglyceride were associated with lower mortality and lower viral load after PRRSV infection (p < 0.05). The pulmonary pathology of the piglets also improved after CMG treatment. The levels of pro-inflammatory cytokines (IL-6, IL-8, IL-1β, IFN-γ, TNF-α) were significantly downregulated, and the levels of anti-inflammatory cytokine (IL-10) were significantly upregulated in the CMG-treated piglets compared to the positive control group (p < 0.05). Taken together, the present study revealed for the first time that caprylic monoglyceride has strong antiviral activity against PRRSV in vitro and in vivo, suggesting that caprylic monoglyceride could potentially be used as a drug to treat PRRS infection.     

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.