First-order Derivative Spectrophotometry for the Determination of Vitamin C in Medicament

A novel method for the determination of vitamin C（Vc） is proposed in this article. After the reaction with Folin-Ciocalteau reagent at ambient temperature, Vc solution was scanned at 750--1100 nm, and its first-order derivative spectrum were obtained from the original spectrum. The values of derivative selected at 995 nm were used for determination. It was proved that Vc could quickly react with Folin-Ciocalteau reagent within 5 min and the product was quite stable for a long time. The conditions required for this method is not very complicated, its precision and accuracy are similar to those of the iodometric titration described in Chinese Pharmacopoeia, and the limit of detection is 0.312 μg/mL. The determination of the results of vitamin C tablet, pill, and injection demonstrates that this method has wide pharmaceutical applications.

Spectrophotometric Determination of Water-Soluble Hexavalent Chromium and Determination of Total Hexavalent Chromium Content of Portland Cement in the Presence of Iron (III) and Titanium (IV) Using Derivative Ratio Spectrophotometry

A rapid, reliable and accurate method for the determination of hexavalent chromium in Portland cement is developed. The proposed method includes direct spectrophotometric determination of Cr (VI) in Portland cement with 1, 2, 5, 8 Tetrahydroxyanthraquinone, (Quinalizarin, QINZ) at pH 1.5. The European Directive (2003/53/EC) limits the use of cements so that it contains no more than 2 mg.Kg-1 of water-soluble Cr (VI). The absorbance at 565 nm due to Cr (VI)-QINZ complex is recommended for the determination of water-soluble Cr (VI) in Portland cement. The quantification of Cr (VI) released from cement when mixed with water is performed according to TRGS 613 (Technical Rules of Hazardous Substances). The validity of the method is thoroughly examined and the proposed method gives satisfactory results. A derivative spectrophotometric method has been developed for the determination of total Cr (VI) in Portland cement in the presence of Fe (III) and Ti (IV). The hexavalent chromium complex formed at pH 1.5 allows precise and accurate determination of chromium (VI) over the concentration range 0.05 to 3.0 mg.L-1of chromium (VI). The validity of the method was examined by analyzing several Standard Reference Material (SRM) Portland cement samples. The MDL (at 95% confidence level) was found to be 25 ng/mL for chromium (VI) in National Institute of Standards and Technology (NIST) cement samples using the proposed method.

Estimation of the galanthamine using derivative spectrophotometry in bulk drug and formulation

Two simple, rapid, accurate, precise, reliable and economical spectrophotometric methods have been proposed for the determination of galanthamine hydrobromide (GH) in bulk and pharmaceutical formulation. First method is zero order UV spectrophotometry and second is 1st derivative zero crossing spectrophotometry. The developed methods have shown best results in terms of linearity, accuracy, precision, LOD and LOQ for bulk drugs and marketed formulations. Absorbance was measured at 287 nm for zero order and 277.4 nm for first derivative. It obeyed Lambert-Beer’s law in the range of 30-80 μg mL-1. Both methods have good linearity (r2 = 0.9997) and accuracy found to be 100.5% and 101.2% for both methods respectively.

Simple and sensitive method for the determination of trace amounts of thorium using a benzoquinone derivative

A novel simple, sensitive, rapid, direct, and spectrophotometry-based procedure was investigated to determine Th(IV) at trace amounts. The new method is based on Th(IV) chelation with 3,6-dichloro-2,5-dihydroxy-l,4-benzoquinone(DDBQ). The reagent reacts with Th(IV) in 0.1 M HCl to form an orange 1:2 complex. The stability constant value is 6.62×10~4 for the Th(IV)complex. The Th(IV)-DDBQ obtained shows one peak with a maximum at about 346 nm. The chelate forms immediately and the absorbance remains stable for over24 h. Beer's law was obeyed in the concentration range0–10 μg mL^(-1). The molar absorptivity and Sandell's sensitivity were 4.4×10~4 L mol^(-1)cm^(-1) and 0.0053 μg cm^(-2), respectively. Different analytical parameters were tested in detail. Interfering ion(cations and anions) effects were tested. Methods for Th(IV) determination by second and third-derivative spectrophotometry were also introduced at about 344 and 341 nm, respectively. These two derivative orders offer the feature of sensitivity without the necessity for solvent extraction,heating, or pre-concentration steps. Finally, the methods were successfully utilized for Th(IV) determination in monazite, environmental water, and wastewater samples.

DIRECT DETERMINATION OF NEODYMIUM AND ERBIUM IN RARE EARTH MIXTURE BY DERIVATIVE SPECTROPHOTOMETRY

The absorption spectra of 4f electron transitions of the complexes of neodymium and erbium with 8-hydroxyquinoline-5-sulphonic acid in the presence of diethylamine and ethanol have been measured by normal and third-derivative spectrophotometry. Their molar absorptivities are 70.7 l.mol^(-1).cm^(-1) for Nd and 62.5 l.mol^(-1).cm^(-1) for Er. They are 7.6 times and 14.9 times greater than those of corresponding chlorides, respectively. Use of the third-derivative spectra both eliminates the interference of Ce(Ⅳ) and increases the sensitivity for Nd and Er. Beer,s Law was obeyed from 0-10 ug/ml of Nd and Er. The method has been applied to the determination of neodymium and erbium in rare earth mixtures.

淫羊藿红外光谱特征分析与总黄酮、还原糖及总酚含量测定

通过分析和比较淫羊藿和箭叶淫羊藿的红外光谱特征,测定两种淫羊藿的总黄酮、还原糖及总酚含量,为淫羊藿的质量控制提供科学依据。本文利用傅里叶红外光谱扫描仪获得淫羊藿和箭叶淫羊藿的红外光谱原始图,并进一步将图谱进行二阶导数处理,通过紫外-可见分光光度法、二硝基水杨酸法及FolinCiocalteu法测定了两种淫羊藿中总黄酮、还原糖及总酚的含量。在400~4000 cm^(-1)范围内寻找到10个专属于淫羊藿的红外吸收特征峰,16批淫羊藿样品中富含总黄酮、还原糖及总酚,含量最高分别可达到96.79、6.61和35.55 mg/g,淫羊藿间含量存在差异。原始平均红外光谱及其二阶导数红外图谱相结合,有助于淫羊藿的整体质量控制以及有效成分定性分析研究。

一阶导数分光光度法测定复方氯霉素洗剂中氯霉素的含量

目的 :建立复方氯霉素洗剂中氯霉素的含量测定方法。方法 :采用一阶导数分光光度法 ,样品不经分离处理直接测定复方氯霉素洗剂中氯霉素的含量 ,检测波长为 2 98nm。同时与外指示剂法比较。结果 :线性范围为 5～ 4 0mg·L-1,r =0 .9998,平均回收率为 10 0 .1% ,RSD为 1.96 %。结论 :本法可消除其他组分的干扰 ,优于外指示剂法 ,简便易行 。

比光谱-导数-紫外分光光度法同时测定水中硝酸根和亚硝酸根

利用二元混合物的混合光谱与其中某一组分光谱的比值对波长求导，可达到分辨重叠光谱的目的。本文研究了用比光谱-导数-紫外分光光度法同时测定水样中NO3-和NO2-，以“减法技术”求导，兼具导数光度法能消除低频背景和高频噪声干扰及线性回归法分辨能力强的优点。方法避免了一般光度法需加入试剂而可能引起的误差。在pH7～9条件下测量203um～219um的光吸收值，用比光谱-导数技术处理，同时测定合成试样中0～4mg／L的NO3-和NO2-，6次测定相对标准偏差＜7％，加入回收率在95％～101％之间。讨论了干扰离子的影响及消除，并与P-矩阵法作了比较。方法已用于井水、雨水及湖水中NO3-和NO2-的同时测定。

紫外导数光谱法直接测定含油污水中的苯胺类

在ｐＨ为２．５的盐酸介质中，用紫外四阶导数光谱法直接测定含油污水中的苯胺类，不需要预蒸馏、萃取、显色等繁杂过程。苯酚、石油类、悬浮物、硫化物等均不干扰测定。含油污水中苯胺类测定的结果与禁乙二胺偶氮比色法的测定结果基本吻合。本方法检出限低、回收率好、操作简便。适用于油矿区污水中苯胺类的监测。

利培酮片的一阶导数分光光度测定

采用一阶导数分光光度法测定利培酮片的含量。以甲醇为溶剂 ,浓度在 5～ 40 μg/ml范围内 ,浓度 C与 2 5 4nm和 2 78.5 nm导数光谱峰谷间的振幅 D呈线性关系 ,r=0 .996 6。平均回收率为 99.91% ,RSD为 0 .0 5 %。

氧氟沙星凝胶剂的一阶导数分光光度测定

采用一阶导数分光光度法直接测定氧氟沙星凝胶剂的含量，能消除其它组分的干扰。方法简便，快速准确，平均回收率９９．９％，ＲＳＤ为０．７％。

组合导数光度法同时测定钼与锡的研究

本文利用“组合导数分光光度法”,在表面活性剂CTMAB存在的强酸性介质中,以邻-氯苯基萤光酮(oCl-PF)作显色剂,对钼、锡的同时测定进行了详细研究。本方法不仅灵敏度高于单波长光度法,而且解决了重迭谱带相互干扰的问题。对合金钢和铜合金中微量钼、锡进行测定,结果令人满意。

青黛超临界提取物中靛蓝和靛玉红的含量测定研究

目的 :本文采用磺化—紫外分光光度法及一阶导数紫外分光光度法 ,对青黛药材及青黛超临界提取物进行含量测定。方法 :样品经磺化反应后 ,用零阶光谱在 6 2 3nm波长处测定靛蓝的含量 ,用一阶导数紫外分光光度法在 4 82nm波长处测定靛玉红的含量。结果 :靛蓝的线性范围为 1 14～ 5 32 μg·ml- 1,r=0 9999,平均回收率为 10 1 0 6 % ,RSD为 1 2 7% ,靛玉红的线性范围为 0 5 2～ 5 2 μg·ml- 1,r =0 9999,平均回收率为 10 1 80 % ,RSD为 0 75 % ,放置 8h对含量测定无影响。结论 :测定数批青黛药材及青黛超临界提取物样品 ,其靛蓝含量测定与药典法测定结果无显著差别。

阳离子交换树脂一阶导数分光光度法测定盐酸环丙沙星脂质体包封率

目的测定盐酸环丙沙星脂质体的包封率。方法用阳离子交换树脂分离脂质体和游离的盐酸环丙沙星 ,采用一阶导数分光光度法 ,消除磷脂对药物的干扰 ,测定脂质体中盐酸环丙沙星的含量 ,计算包封率。结果阳离子交换树脂对溶液中盐酸环丙沙星的吸附率达到 1 0 0 % ,对空白脂质体和盐酸环丙沙星的物理混合物中盐酸环丙沙星的吸附率大于 97 6 %。含量测定方法的线性范围为 4～ 1 4mg/L ,回收率在 98 1 2 %～ 1 0 0 5 8% (n =5 ) ,日内与日间RSD均小于 1 81 % ,加样回收率为 1 0 0 4 3% (RSD =1 0 8% ,n =6 )。结论此方法简便、可行。

导数光谱法同时测定人发中微量铜和锌

研究了以５－Ｂｒ－ＰＡＤＡＰ作显色剂，利用三阶导数光谱法，在碱性介质中同时测定铜和锌．该法测定铜、锌的表观三阶导数摩尔吸光系数分别为１．０×１０３和３．０×１０５，同时解决了谱带相互重叠干扰问题．对人发中铜和锌进行测定。

导数光谱法测定微乳中维生素C的含量

目的 :探讨微乳中药物的测定方法。方法 :分别利用二阶及三阶导数光谱测定了维生素C(VitC)的O/W及W/O型微乳中VitC的含量。结果 :平均回收率及精密度分别达到 98.1% ,RSD % =0 .6 2 (n =12 ) ;99.0 % ,RSD % =0 .5 2 (n =12 )。结论 :该法简便 ,适合VitC微乳的含量测定。为保证结果可靠 。

复方中药喉咽清水蜜丸的研制及其体外溶出度的研究

目的：研究喉咽清水蜜丸的制剂工艺及质量标准，并通过体外溶出度探讨自研样品处方和工艺的可行性。方法：按照中药制剂方法研制水蜜丸，照中国药典1995年版要求测定溶出度，用二阶导数光谱法测橙皮苷含量来确定水蜜丸的溶出曲线。结果：所制水蜜丸符合药典要求。结论：喉咽清水蜜丸的处方和工艺是可行的。

利巴韦林滴眼液的一阶导数分光光度测定

采用一阶导数分光光度法直接测定利巴韦林滴眼液的含量。样品不需特殊处理，操作简便，结果准确。平均回收率为９９．５％，ＲＳＤ为０．１６％。

比光谱-导数分光光度(计算)法同时测定邻硝基酚、间硝基酚或对硝基酚二元混合物的含量

运用比光谱 -导数分光光度 (作图 )法的基本原理 ,推导了比光谱 -导数分光光度 (计算 )法同时测定二元混合物含量的基本公式 ,研究了邻、间硝基酚 ,邻、对硝基酚和间、对硝基酚的三种二元混合物含量的同时测定 ,取得了满意结果。另外 ,还比较了单位质量浓度的除数因子与一般除数因子在测量该 3种二元混合物时的方法灵敏度 ,证明用单位质量浓度溶液标准光谱作除数因子时灵敏度较高。

导数分光光度法测定矿石中的金

研究了在聚乙烯醇存在下，ｐＨ３．２的缓冲溶液中金与钼酸盐和罗丹明Ｂ显色后的一阶导数吸收光谱，结果表明，一阶导数吸收光谱的摩尔吸光系数是２．０３×１０６，较基本光谱的灵敏度提高３４倍。服从比尔定律范围为０～０．２ｍｇ／Ｌ。以聚醚型聚胺酯泡沫塑料分离共存离子，对矿石中金进行测定并与氢醌容量法进行对照实验，两方法绝对偏差≤０．１６ｍｇ／Ｌ，结果令人满意。