Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a ...Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a coaxial needle. The effects of PLA concentration, stirring speed, injection rate of core and shell solutions, and polyvinyl alcohol(PVA) concentration on phase change properties were investigated. The thermal properties of microP CMs were characterized by differential scanning calorimetry(DSC). The capsules prepared under the optimal conditions are about 2 mm in diameter and show a latent heat of up to 122.2 J·g^(-1).展开更多
目的:以牛磺熊去氧胆酸和牛磺鹅去氧胆酸为指标,建立龙泽熊胆胶囊中熊胆粉的含量测定方法。方法:采用高效液相色谱串联蒸发光检测器,色谱柱为ChromCore AQ C 18(4.6 mm×250 mm,5μm),乙腈(A)-5 mmol•L^(-1)醋酸铵溶液(B)为流动相,...目的:以牛磺熊去氧胆酸和牛磺鹅去氧胆酸为指标,建立龙泽熊胆胶囊中熊胆粉的含量测定方法。方法:采用高效液相色谱串联蒸发光检测器,色谱柱为ChromCore AQ C 18(4.6 mm×250 mm,5μm),乙腈(A)-5 mmol•L^(-1)醋酸铵溶液(B)为流动相,梯度洗脱(0~40 min,25%A;40~50 min,25%A→29%A;50~80 min,29%A;80~100 min,29%A→40%A),流速1.0 mL•min^(-1),柱温30℃,ELSD漂移管温度110℃,氮流量2.5L•min^(-1)。结果:牛磺熊去氧胆酸进样量在1.069~9.57μg内、牛磺鹅去氧胆酸进样量在0.74046~7.40464μg内,进样量的对数与峰面积的对数呈良好的线性关系;仪器精密度、重复性、稳定性试验的RSD<2.0%;经低、中、高3个浓度的准确度试验考察,牛磺熊去氧胆酸的回收率为95.2%~97.7%,牛磺鹅去氧胆酸的回收率为91.9%~95.9%。测定样品42批次,牛磺熊去氧胆酸和牛磺鹅去氧胆酸的含量分别为0.18~0.43、0.10~0.44 mg•粒^(-1)。结论:本法适用于龙泽熊胆胶囊中熊胆粉的质量控制,可为完善龙泽熊胆胶囊的质量标准提供科学的依据。展开更多
基金Supported by the National Natural Science Foundation of China(21476065)the China National Tobacco Corporation
文摘Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a coaxial needle. The effects of PLA concentration, stirring speed, injection rate of core and shell solutions, and polyvinyl alcohol(PVA) concentration on phase change properties were investigated. The thermal properties of microP CMs were characterized by differential scanning calorimetry(DSC). The capsules prepared under the optimal conditions are about 2 mm in diameter and show a latent heat of up to 122.2 J·g^(-1).