五种不同产地天仙子总生物碱的含量分析

应用紫外分光光度法，分别测定了５种不同产地（山西、宁波、辽宁、内蒙古、河北）天仙子中总生物碱的含量，其强吸收处在 ２１０ ｎｍ左右，被溶剂吸收覆盖，无法测量，加入溴甲酚绿使波长长移，可有效地排除试剂干扰，直接测定总生物碱含量。方法可靠、准确。平均回收率分别为９９．６７％，ＲＳＤ＝０．７０％；９７．６９％，ＲＳＤ＝２．４％；９９．５５％，ＲＳＤ＝０．５０％；１００．９％，ＲＳＤ＝３．３％；９８．７７％，ＲＳＤ＝１．４％。

UV enhanced gas–solid synthesis of chlorinated poly vinyl chloride characterized by a UV–Vis online analysis method

Dynamic characteristics of UV enhanced gas–solid PVC chlorination process were revealed by a UV–Vis spectral online analysis method. Experimental results showed an instantaneous increase of the chlorination rate as soon as UV light was affiliated, which demonstrated the intensified effect of UV radiation on PVC chlorination directly.Different affiliation methods of UV light were then studied, proving that continuous UV radiation could enhance the chlorination process significantly while intermittent UV radiation was able to initiate the chlorination reaction once it was conducted. Besides, experiments were carried out to study the influences of parameters on the chlorination process such as UV wavelength, chlorination temperature, partial pressure of chlorine gas and PVC raw materials. Among all the parameters, chlorination temperature and partial pressure of chlorine gas were testified as two key factors to determine the chlorination performance. Thermal analysis of CPVC products showed that their corresponding properties such as the glass transition temperature(Tg) and the homogeneity of chlorine distribution in polymer phase were improved with the increase of chlorine content.