Characterization and Purity Determination of Trans (±) 1,2-Diaminocyclohexane Platinum (Iv) Tetrachloride Using Liquid Chromatography With A Platinum Selective Detector

Abstract

An important aspect of drug development is the reliable determination of the purity of a bulk drug substance. In the case of Trans (±) 1,2-Diaminocvclohexane Platinum (IV) Tetrachloride, classical techniques such as differential scanning calorimetry and phase solubility analysis cannot be used because of the compound's poor tabulation of the fractions (percent) of platinum contained in each peak as measured with d.c. plasma and a corresponding response factor for the UV detector. the power of the d.c. plasma detector in producing unequivocal information on the platinum-containing species and its application in elucidating the data obtained with the UV detector is well demonstrated in this case.     

Role of analytical techniques for characterisation of advanced and high purity materials

High purity metals and other advanced materials are extensively employed in various applications connected with electronics, solar energy conversion, superconductors, shape memory alloys and other industrial applications of importance. In many of these applications, the properties are affected by the nature and concentration of impurities present in the material. The use of modern analytical techniques for chemical and surface characterization is highly beneficial for the evaluation of such materials for various critical applications. The sophisticated chemical analysis techniques like AAS, GFAAS, ICPAES, ICPMS, NAA and DPASV helps in chemical characterization which together with surface analytical techniques like XPS provides complete evaluation of the material for various applications.     

Analysis of doxycycline by capillary electrophoresis

Summary Doxycycline is a semi-synthetic broad spectrum antibiotic with improved serum half-lie. Potential impurities are 4-epidoxycycline, 6-epidoxycycline, 4,6-epidoxycycline, metacycline and 2-acetyl-2-decarboxamidodoxycycline. Method development has been undertaken to investigate the potential of capillary electrophoresis for the analysis of doxycycline. The influence of buffer type, buffer pH and concentration was systematically examined, then that of capillary temperature and applied voltage. All the potential impurities could be separated at 15 °C on a 44 cm × 50 μm I.D. fused silica capillary (effective length to detector, 38 cm) with sodium carbonate (70 mM) - EDTA (1 mM), pH 10.50, as background electrolyte and with a voltage of 12 kV. The relative standard deviation was 2.2 % for doxycycline. The limit of detection and quantification for doxycycline were 0.2 and 0.4 %.     

Handling undetected and low-level components in purity determination

Impurities expected to be present at low levels in a high-purity material may go undetected or be measured with near-zero values. This complicates assessment and reporting of uncertainty, and in particular can lead to underestimation of uncertainty, anomalies in estimating degrees of freedom, and coverage intervals, which extend outside the feasible range for the measurand. These issues are considered and appropriate remedies are suggested. Papers published in this section do not necessarily reflect the opinion of the Editors, the Editorial Board and the Publisher.     

Determining the purity of samples from natural products by coupling HPLC and CCD spectrometry

Isolation and identification of natural products is a very important and active research field. However, establishing the purity of the samples during the isolation process is quite difficult, especially when the retention times are similar for two desired components in HPLC. Although some technologies, e.g. MS and NMR, offer effective ways of obtaining purity information about the samples, the expensive instrumentation required or the off-line nature of coupling (generally speaking) make purity analysis somewhat inconvenient. In this paper, an on-line analytical system coupling HPLC and a CCD spectrometer for determination of purity for each eluate was developed in a thin layer spectrometric cell. The effectiveness of the system was demonstrated by differentiating Tanshinone I, Tanshinone IIA, and their mixture. The time-resolved UV-Vis spectra promptly revealed significant differences between the three samples while conventional single wavelength detection (CSWLD) could not. The system was then used to distinguish two steroid compounds which behaved as a single component in CSWLD. The compounds were isolated from a Chinese marine invertebrate animal, a marine annelid, Arenicola cristata, referred to here as Stimpson. The method reported here provided an efficient, convenient, fast, and inexpensive approach holding promise for on-line determination of the purity of samples isolated from natural products.     

高纯氟化锂的分析

本文叙述了适于作超低损耗金属氟化物光纤材料的高纯氟化锂的方法研究。其分析方法为：氟化锂样品经硝酸溶解，重复蒸发除去大部分Ｆ＾－，以石墨炉原子吸收标准加入法直接测定过渡金属，Ｆｅ，Ｃｏ，Ｃｕ，Ｎｉ含量，制得了四种对光纤质量影响最大的过渡金属杂质的含量均低于０．０００１％的氟化。方法的相对标准偏差为Ｆｅ，４２％，Ｃｏ，１６．８％，Ｎｉ８．８％，Ｃｕ６．９％。     

杂交稻种宜香725纯度的可见-近红外反射光谱鉴定

提出了一种基于可见-近红外光谱技术快速、无损鉴定杂交稻种纯度的新方法.以FieldSpec(R)3地物光谱仪采集纯度在90%～99%范围内的杂交稻种(宜香725)光谱数据90份,随机分成校正集(75份)和检验集(15份).根据其在380～2 400 nm的反射光谱,以偏最小二乘算法(PLS)建立了回归模型,并比较了不同光谱预处理方法对模型的影响.分析表明采用一阶导数结合标准归一化处理能最有效地提取光谱信息,此时PLS模型校正集决定系数与检验集决定系数分别为0.988 4与0.922 7,校正标准误差(SEC)与预测标准误差(SEP)分别为0.002 5与0.006 6.将经一阶导数结合标准归一化处理后的光谱进行PCA降维,以前20个主成份(含原始光谱86.09%的特征信息)为输入变量,建立杂交稻种纯度鉴定的BP-ANN模型.分析表明BP-ANN模型校正集决定系数与检验集决定系数分别为0.995 2与0.936 9,SEC与SEP分别为0.001 7与0.006 1,具有比PLS模型更高的精度.结果表明以可见-近红外技术进行杂交稻种纯度的快速、无损鉴定是可行的,且PCA结合BP-ANN是一种优选方法.     

双光子非共振作用系统中纯度和密度算符间距的演化

研究了双光子非共振作用系统中纯度和密度算符间距的特性.讨论了相干光场与激发态二能级原子作用时失谐量对纯度和密度算符间距演化的影响.数值计算表明:失谐量对末态与初态的间距和原子与光场的缠结有调制作用.     

A novel method for immediate post-purification purity determination of fractions collected during high-throughput purification

Following purification, the fractions of purified samples typically are analyzed to determine the relative purities of each fraction. We report a novel technique for performing post-purification analysis immediately after each preparative LC/MS run. The Single Pass Compound Purification and Analysis System (SPACPASS) samples and stores a representative aliquot from the fraction while it is being collected. Demonstrated for '1:1' fraction collections, this method of fraction purity assessment streamlined sample processing by reducing post-purification sample handling. For 97% of the collected fractions, this technique provided relative purities to within +/-5% when compared with more traditional post-purification analysis.     

MPCVD金刚石的Raman光谱分析

用微波等离子体化学气相淀积法（MPCVD）在Si基片上生长了金刚石薄膜，通过对其进行Raman光谱分析，一次表征了金刚石的结构，纯度及应力状况等材料性能，同时并研究了生长过程中微波功率与金刚石性质的关系。研究表明，微波等离子体化学气相溶积法生长的金刚石薄膜，除了金刚石成分的生长外，还会有部分非金刚石成分的生长，金刚石的纯度与微波功率的关系不明显，另外此种方法生长的金刚石薄膜主要表现为张应力。