漫反射傅里叶变换红外光谱法测定维生素C制剂中抗坏血酸的含量

采用漫反射傅里叶变换红外光谱法(DRIFTS)测定维生素C制剂中抗坏血酸的含量。选择合适的分析峰1660~1680 cm–1,可排除其它成分的影响,吸光度与抗坏血酸的浓度呈良好线性关系。以镜面为背景,以75μm筛过筛后的KBr为稀释剂,用DRIFTS法分别测定了3种市售维生素C制剂中的抗坏血酸含量,测定结果分别为75.60%,9.80%,6.72%;相对标准偏差(n=6)分别为6.6%,4.9%,8.2%,与碘量法测定结果接近。样品加标回收率为94.0%。DRIFTS法测定维生素C中的抗坏血酸方法简便、准确,无试剂消耗,无废液产生,是非破坏和非污染的绿色分析方法。但其测定结果的精密度不如碘量法,而且其测定结果的准确程度受样品的性状限制,对于白色粉末或可研磨为粉末的样品分析结果准确度较高。     

仲景胃灵片中芍药苷的含量测定

采用SPE -高效液相色谱法测定仲景胃灵片中芍药苷的含量 ;以甲醇 -水 (体积比30∶70)为流动相 ,IntersilODS(3)柱 (250mm×4.6mm ,5μm)为固定相 ,流速为1mL/min,检测波长为230nm ;芍药苷的测定在11.55～92.40mg/L范围内线性关系良好 ,平均回收率为99.9% ,RSD为1.6% ;方法简单 ,灵敏度高 ,可用于仲景胃灵片中芍药苷的含量测定。     

铁(Ⅲ)置换氧化还原滴定法测定维生素C片剂及针剂中抗坏血酸

基于将测定抗坏血酸的碘滴定（药典）法和铁铵矾滴定法相结合,即先用铁铵矾基准物氧化碘化钾置换出相当量的12,再在维生素C药物溶液滴定中让相当量的12定量氧化抗坏血酸。合适的反应条件是：乙酸介质,碘离子过量,室温置暗处置换反应10min。将该法用于维生素C药物中抗坏血酸的测定,结果与药典法结果相符。     

粉末压片-X-射线荧光光谱法分析砂岩型铀矿制样中粘结剂用量的探讨

由于砂岩型铀矿的成矿特性,样品粉末的内聚力小,采用直接压片法有时难以成型,样片表面常见裂纹,上机测量易碎裂。混合压片法适应性强,制样成功率高,但常见的问题是样品经粘结剂稀释会影响元素的检出限及结果的准确性。本文对粉末压片-X射线荧光光谱法测定砂岩型铀矿地质样品时,前期制样中添加粘结剂的比例进行了研究。试验按照不同比例在铀矿石标准物质GBW04101、GBW04102中添加粘结剂,在扫描电镜下观察到随着粘结剂用量的增加样片表面的光滑度及致密度都呈上升趋势,在X-射线荧光光谱仪上对主量元素进行测定后发现X射线强度在粘结剂添加量大于0.2 g时明显下降,经与GBW04101、GBW04102标准值进行对比后优选出粘结剂与样品的最佳比例为1：20,在此比例下制成的样片光滑平整,不易碎裂,用粉末压片-X射线荧光光谱法进行测定,标准物质测定结果的相对误差为0.56%～6.76 %,相对标准偏差(RSD,n=12)为0.013 %～7.68 %,均达到了《地质矿产实验室测试质量管理规范》DZ/T 0130-2006的要求。本文为粉末压片-X射线荧光光谱法分析砂岩型铀矿地质样品提供了可靠的实验参考依据。     

Comprehensive chemical profiling and quantification of Shexiang Xintongning tablets by integrating liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry

Shexiang Xintongning tablet (SXXTN) is a traditional Chinese medicine (TCM) preparation for the treatment of coronary heart disease (CHD) angina pectoris. However, due to the complexity of the compounds in SXXTN, the active chemical components responsible for the therapeutic effect are still ambiguous. The purpose of our study was to characterize the chemical profile of SXXTN and quantify the representative chemicals. The high-performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-QTOF MS) method and gas chromatograph coupled with mass spectrometry (GC–MS) method were utilized to identify the chemical constituents of SXXTN. A total of 140 compounds including alkaloids, ginsenosides, organic acids, esters, triterpenes, phthalides and amino acid were identified in accordance with their retention times, accurate masses and characteristic MS/MS fragment patterns. Forty-four volatile components were characterized by GC–MS through NIST database matching. In the further research of quantitative analysis, 40 non-volatile compounds and 17 volatile compounds were determined and successfully applied for detecting in 7 batches of SXXTN samples by high performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (HPLC-QQQ MS) and gas chromatograph coupled with triple-quadrupole tandem mass spectrometry (GC-QQQ MS) in multiple reaction monitoring (MRM) mode, respectively. The quantitative methods were verified in linearity, precision, repeatability stability and recovery. The above results indicated that the established method was practical and reliable for synthetical quality evaluation of SXXTN. In addition, our study might supplement the chemical evidence for disclosing the material basis of its therapeutic effects.