高效液相色谱法测定食品中的甜蜜素

利用次氯酸钠将食品中的甜蜜素转化为N,N-二氯环己胺,以正己烷萃取后用高效液相色谱法测定。采用Extend-C18 5μm不锈钢柱,以甲醇-水(体积比为80：20)作流动相,二极管阵列检测器检测波长为314nm。甜蜜素的浓度在1～80μg／mL内与色谱峰面积成良好的线性关系,回收率为102．8％～103．0％,检出限为1μg／mL,测定结果的相对标准偏差为0．84％。     

Epoxidation of vinyl cyanides by calcium hypochlorite under catalyst- and solvent-free conditions

In this paper, epoxidation of a wide range of alkenes by calcium hypochlorite (Ca(OCl)₂) was investigated under catalyst- and solvent-free conditions. It was noticed that the highest yield was achieved with crushing, when the reaction was between vinyl cyanides and Ca(OCl)₂. The structure of the synthesized epoxides was confirmed by IR, ¹H and ¹³C NMR and elemental analysis. Short reaction times, the use of a simple experimental procedure, and reducing of energy consumption are other important advantages of our work that could be mentioned too.     

Reactions of chlorination with tert‐butyl hypochlorite (TBuOCl)

The chlorination reactions of nitrogenous organic compounds (2,2,2‐trifluoroethylamine, benzylamine, glycine, and dimethylamine) by tert‐butyl hypochlorite (^tBuOCl) were studied at 25 °C, ionic strength 0.5 M and under isolation conditions. The kinetic results obtained in the formation processes of the corresponding N‐chloramines in acid medium (pH = 5–7) are summarized in this paper. Kinetic studies showed a first order with respect to ^tBuOCl concentration. The chlorination reactions involving benzylamine, glycine and dimethylamine were all first order with respect to nitrogenous compound concentration and approximately ?1 order with respect to proton concentration. The reaction with 2,2,2‐trifluoroethylamine was more complex, and the order of reaction with respect to the amine varied with pH. Copyright © 2014 John Wiley & Sons, Ltd.