一测多评法测定白背叶中3个黄酮碳苷成分的含量

目的:建立一测多评法测定白背叶药材中3个黄酮碳苷成分葫芦巴苷Ⅱ、夏佛托苷和异夏佛托苷的含量,并验证其准确性及可行性。方法:采用高效液相色谱法,使用C_(18)色谱柱(4.6 mm×250 mm,5μm),柱温25℃,流动相为甲醇-0.1%乙酸水溶液,梯度洗脱,流速1.0 m L·min^(-1),检测波长336 nm。以葫芦巴苷Ⅱ为内参物,建立其与夏佛托苷和异夏佛托苷的相对校准因子,计算白背叶药材中夏佛托苷、异夏佛托苷的含量,实现一测多评。同时采用外标法测定白背叶药材中3个黄酮碳苷成分的量,比较计算值与测定值之间的差异,以验证一测多评法在测定中的准确性及可行性。结果:在一定线性范围内,葫芦巴苷Ⅱ与夏佛托苷、异夏佛托苷的相对校正因子分别为1.315、1.022。一测多评法测得6批样品中葫芦巴苷Ⅱ的含量范围为0.75~7.51 mg·g^(-1),夏佛托苷的含量范围为1.24~7.56 mg·g^(-1),异夏佛托苷的含量范围为1.03~5.99 mg·g^(-1),与外标法测定结果无显著性差异。结论:所建立的同时测定葫芦巴苷II、夏佛托苷和异夏佛托苷含量的一测多评法准确、可行,可用于白背叶药材的定量分析。

A possible mechanism for the formation of annual growth lines in bivalve shells

We report a unique shell margin that differed from the usual shell structure of Pinctada fucata.We observed empty organic envelopes in the prismatic layer and the formation of the nacreous layer in the shell margin.All the characteristics of the growing margin indicated that the shell was growing rapidly.To explain this anomaly,we propose the concept of "jumping development".During jumping development,the center of growth in the bivalve shell jumps forward over a short time interval when the position of the mantle changes.Jumping development explains the unusual structure of the anomalous shell and the development of annual growth lines in typical shells.Annual growth lines are the result of a discontinuity in the shell microstructure induced by jumping development.