Stability-indicating spectrophotometric and densitometric methods for determination of aceclofenac

Three methods were developed for the determination of aceclofenac in the presence of its degradation product, diclofenac. In the first method, third-derivative spectrophotometry (D₃) is used. The D₃ absorbance is measured at 283 nm where its hydrolytic degradation product diclofenac does not interfere. The suggested method shows a linear relationship in the range of 4-24 µg mL^-1 with mean percentage accuracy of 100.05±0.88. This method determines the intact drug in the presence of up to 70% degradation product with mean percentage recovery of 100.42±0.94. The second method depends on ratio-spectra first-derivative (RSD₁) spectrophotometry at 252 nm for aceclofenac and at 248 nm for determination of degradation product over concentration ranges of 4-32 µg mL^-1 for both aceclofenac and diclofenac with mean percentage accuracy of 99.81±0.84 and 100.19±0.72 for pure drugs and 100.17±0.94 and 99.73±0.74 for laboratory-prepared mixtures, respectively. The third method depends on the quantitative evaluation of thin-layer chromatography of aceclofenac using chloroform:methanol: ammonia (48:11.5:0.5 v/v/v) as a mobile phase. Chromatograms were scanned at 274 and 283 nm for aceclofenac and diclofenac, respectively. The method determined aceclofenac and diclofenac in concentration ranges of 2-10 and 1-9 µg spot^-1 with mean percentage accuracy of 100.20±1.03 and 100.14±0.98 for pure drugs and 99.77±0.74 and 100.07±0.78 for laboratory-prepared mixtures, respectively. This method retains its accuracy in the presence of up to 80% degradation product for the studied drug.

The suggested procedures were checked using laboratory-prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparation. The validity of the proposed methods was further assessed by applying a standard addition technique. The obtained results agreed statistically with those obtained by the reported method.     

电芯粉中总锰的测定

本文提出了一种简便的处理方法,使乙炔黑转化成二氧化碳排出,并利用指示剂准确地指示终点,用氧化还原滴定法测定电池电芯粉中总锰含量。     

极弱酸碱的pH滴定法研究

深入讨论了pH滴定法滴定极弱酸碱的原理、方法和应用,对10种不同极弱酸碱进行了广泛的测定,测定结果相对误差一般在0.2％左右,相对标准偏差在0.2％左右,达到化学分析要求。pH滴定法具有简便、价廉、快速和通用的优点,为直接滴定极弱酸碱和化学分析仪器化开辟了新的途径。     

硅石的抗爆裂性和还原性能测定

介绍了测定硅石抗爆性和还原性能的方法 ,并对测定结果进行了分析讨论。硅石的抗爆性和还原性能取决于硅石的晶粒度 ,晶粒小抗爆率高 ,还原性能好。生产得出 ,冶炼 75 %硅铁时 ,1 2 5MVA电炉使用抗爆率为 87%左右的硅石可获得较好的技术经济指标。     

土壤样品中氚水的测定

本文介绍了土壤中氚水的测定方法，主要包括真空解析与冷凝、制样和液闪测量等步骤。当分析１２０ｇ湿度为２０％的土壤时，方法回收率为９６．７％，探测下限为０．７０Ｂｑ／ｋｇ。     

分光光度法测定蜂王浆中的锗含量

研究含锗蜂王浆产品中锗含量的测定方法，并用分光光度法建立经验方程：Ｃ＝４７．１５Ａ５１０＋４。７８。     

水中~(46)Sc 的测定

本文介绍了一种水中~(46)Sc 的分析方法。水中~(46)Sc 用 Fe(OH),浓集,磷酸三丁酯(TBP)萃取,苦杏仁酸沉淀纯化,最后在800℃下灼烧成氧化钪测其β放射性。本方法钪的化学回收率为(90.8±2.8)%,放化回收率为(89.8±3.8)%,一些有关核素的去污因子在10~3—10~5之间。     

Determination of the topology of a directed network

We consider strongly-connected, directed networks of identical synchronous, finite-state processors with in- and out-degree uniformly bounded by a network constant. Via a straightforward extension of Ostrovsky and Wilkerson's Backwards Communication Algorithm [Proc. 14th Annual Symp. on Principles of Distributed Computing, 1995], we exhibit a protocol which solves the Global Topology Determination Problem, the problem of having a root processor map the global topology of a network of unknown size and topology, with running time O(ND) where N represents the number of processors and D represents the diameter of the network. A simple counting argument suffices to show that the Global Topology Determination Problem has time-complexity which makes the protocol presented asymptotically time-optimal for many large networks.     

高含量铜、钴、钼精矿试样中铁的分析测定

试样经硝酸-氯酸钾饱和溶液分解，于盐酸溶液中，用氢氧化铵-氯化铵沉淀分离。在强盐酸溶液中用二氯化锡溶液还原铁的三价离子，过量的二氯化锡用碘酸钾、硫酸银氧化还原，以二苯胺磺酸钠为指示剂，用重铬酸钾标准溶液滴定。     

RP—HPLC测定N—苯基—2,6—二氯苯胺合成反应的终点

目的:建立高效液相色谱法测定N—苯基-2,6-二氯苯胺合成反应的终点。方法:采用Shim-PackCLS-ODS色谱柱(15cmX6mm,5μm);甲醇—水(80:20)为流动相;紫外检测波长254nm。结果:N—苯基—2,6-二氯苯胺与2,6-二氯苯胺在3.22~9.67μg范围内呈良好的线性关系。平均回收率为100.6%,RSD二1.8%。结论:方法简单可行,迅速准确。