茶碱标准物质的研制与定值

建立了茶碱标准物质的制备和定值方法.将市售茶碱原料纯化、干燥、混匀后.分装成500瓶样品.随机抽取其中11瓶做均匀性检验.经F检验和T检验.结果表明在95%置信范围内样品的均匀性良好;稳定性检验按短期稳定性(1月)和长期稳定性(12月)分别进行,长期稳定性结果通过了T检验,表明在20℃条件下茶碱的稳定期不少于12个月....

Development and Certification of Theophylline Certified Reference Material

A methodology regarding preparation and certification of certified reference material(CRM) of theophylline was presented.The CRM was prepared by repeated recrystallization and drying at 80 ℃ in vacuum condition for 5 h.According to analysis procedure of homogeneity,11 bottles of sample were randomly taken from 500 bottles,in which one bottle was measured for ten times,the other ten bottles were respectively measured for one time,and the results were validated by F-test and T-test statistical methods.The stability inspection was carried on the short-term(one month) and the long-term(12 months),and the results indicated that the period for theophylline of storage was 12 months at 20 ℃.The purity of theophylline were determined by two methods e.g.mass balance method and differential scanning calorimetry(DSC) method,based on different principles.The qualitative and quantitative analysis of impurities were respectively performed by liquid chromatography ion trap-time of flight mass spectrometry(LC-IT TOF) and high performance liquid chromatography with diode array detector(DAD).The content of water in theophylline was measured by Karl-Fischer titrator with drying oven using methanol as solvent.Volatile material in theophylline was determined by temperature gravity analysis(TGA).The determination of losses on drying ash was carried out by the routine method.The uncertainty of mass balance method and DSC methods were respectively evaluated.The result showed that the certified result was 99.80% and expanded uncertainty was 0.14%(k=2).