Method Verification and Validation of Hydralazine Hydrochloride: Spectrophotometric Analysis in Pure and Pharmaceutical Formulations

The new method proposed is based on the formation of hydralazine-Bromophenol blue ion pair simply and without further extraction or heating. The ion pair was prepared in the presence of pH 3 citrate buffer forming a yellow-colored chromogen. A new maximum UV-visible band formed at 416 nm. The color was stable for more than 10 hours and obeyed Beer’s Law over the concentration range of 10 - 50 µg/mL. The calculated molar absorptivity and Sandell’s sensitivity were 1.01 × 104 L∙mol−1∙cm−1 and 0.0514 µg/mL, respectively. The elements of method validation stipulated by The International Conference on Harmonization [Q2 (R1)] were applied for hydralazine hydrochloride assay in pure and pharmaceutical tablet formulation. The average recoveries of the pure solution and the pharmaceutical formulation were 98.94% and 99.50%, respectively. The results were statistically compared by F-test, which indicates that the method can be precise and repeatable for both pure and pharmaceutical solutions. The method was found to be accurate, reproducible, and cost-effective, and validated for the assay of hydralazine in terms of the routine quality control.

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.

紫外吸收剂UV-1164的工艺开发

对紫外吸收剂UV-1164的合成工艺进行优化,以三聚氯氰为原料,一锅法合成关键中间体2-(2,4-二羟基苯基)-4,6-二(2,4-二甲基苯基)-1,3,5-均三嗪(TMⅡ),再与溴辛烷反应合成紫外吸收剂UV-1164。选取反应物物质的量比n溴辛烷∶n TMⅡ、反应时间、反应温度3个因素,利用正交实验对合成进行优化,得到最佳合成条件:反应物物质的量比n溴辛烷∶n TMⅡ为1∶1.2、反应时间为2 h、反应温度为70℃。对优化后的工艺进行放大实验,产率稳定,具有工业化应用潜质。

A Comparative Analysis of Caffeine Extraction Efficiency from Different Tea Varieties and Its Effect on Human Physiology: A Spectrophotometric Investigation

The current work imitates the trivial method which intricates the abstraction along with classification of caffeine accessible in variability of decoction shrubberies which are expended in two different states of India (Telengana & Uttar Pradesh). As per observation individuals of both the states are identical tender of consumption of tea. Abstraction progression tangled variability of stages which are discoursed in the work. In addition, the outcome of drinking of caffeine or the permitted ingestion of caffeine over tea has also been conferred through the work and linked the data with the literature data. In this study, we used a UV-visible spectrophotometer as well as liquid-liquid extraction method to determine the caffeine content in various tea samples. The significance of this study lies in the fact that accurate determination of caffeine content is essential for quality control and labeling of tea products. The UV-visible spectrophotometer method was found to be simple, reliable, and sensitive for the detection of caffeine in tea samples.

Rapid accuracy determining DNA purity and concentration in heavy oils by spectrophotometry methods

DNA analysis is the core of biotechnology applied in petroleum resources and engineering. Traditionally accurate determination of DNA purity and concentration by spectrometer is the first and critical step for downstream molecular biology research. In this study, three different spectrophotometry methods, BPM, NDTT and NPMTTZ were compared for their performance in determining DNA concentration and purity in 32 oil samples, and molecule methods like quantitative real-time PCR (qPCR) and high-throughput sequence were also performed to help assess the accuracy of the three methods in determining DNA concentration and purity. For ordinary heavy oil (OHO), extra heavy oil (EHO) and super heavy oil (SHO), the characteristics of high viscosity (η), density (ρ) and resin plus asphaltene content will affect the DNA extraction and UV determination. The DNA concentration was decreased as density increased: OHO (11.46 ± 18.34 ng/μL), EHO (6.68 ± 9.67 ng/μL) and SHO (6.20 ± 7.83 ng/μL), and the DNA purity was on the reverse: OHO (1.31 ± 0.27), EHO (1.54 ± 0.20), and SHO (1.83 ± 0.32). The results suggest that spectrophotometry such as BPM and NPMTTZ are qualitatively favorite methods as the quick non-consumable methods in determining DNA concentration and purity of medium oil and heavy oil.

Determination of Total Lignanoids in Tangjiangshenkang Granules by Two-Wavelength Ultraviolet Spectrophotometry

[Objectives] To establish a determination method for the content of total lignanoids in Tangjiangshenkang granules. [Methods] Two-wavelength ultraviolet spectrophotometry (TWBS) was used to scan arctiin control solution, chlorogenic acid control solution and Tangjiangshenkang granule test solution in the range of 200-400 nm. In the ultraviolet scanning diagram of arctiin reference solution, the maximum absorption wavelength of 280 nm was determined as the determination wavelength λ 1, the detection wavelength in the ultraviolet scanning diagram of chlorogenic acid reference solution ( λ 1=280 nm) was determined, and 350 nm was the reference wavelength λ 2;the content of total lignosides in Tangjiangshenkang granules was determined with arctiin as the reference substance. [Results] The precision, accuracy, and durability of this method were fine. The concentration of arctiin was linearly correlated with the absorbance difference in the range of 0.007 95-0.071 55 mg/mL ( r =0. 999 9). The average recovery of arctiin was 100.8%, and the RSD value was 1.04% ( n =6). Calculated as arctiin, three batches of Tangjiangshenkang granules contain no less than 20% of total lignosides. [Conclusions] The method has the advantages of simple operation, good accuracy, precision and reliable stability. It can be used as the content determination and quality control method of total lignosides in Tangjiangshenkang granules.

紫外吸收剂/环烷油对高寒区SBS沥青路面的性能影响

为提高沥青混合料在高寒高海拔地区路用性能,选择不同掺量的紫外吸收剂(UV-531)/环烷油(NPO)对SBS沥青进行复合改性,研究复合改性剂对SBS改性沥青及混合料路用性能的影响。结果表明,相比于原样SBS沥青,UV-531/NPO复合改性剂能显著提高SBS沥青的低温变形能力和感温性能,但会降低沥青的高温性能(延度增加117.6%,当量脆点和感温系数分别降低52.0%和11.9%,当量软化点降低2.3℃)。同时,复合改性剂能显著提高混合料的低温抗裂性能(弯曲劲度模量降低9.61%,最大弯拉应变提升11.20%),然而对其高温稳定性与水稳定性会产生一定程度消极影响。高寒高海拔地区主要考虑混合料的低温抗裂性,因此,UV-531/NPO复合改性沥青路面具有很大应用潜力。

水基炭黑-胶原蛋白纳米流体制备及稳定性实验

纳米流体由于其优异的光热转换性能,已成为新型太阳能集热介质的研究重点;但因其稳定性差、制备工艺复杂,未能在实际应用中得到推广。本文以去离子水为基液,通过两步法制备炭黑-胶原蛋白纳米流体。探究了材料添加顺序、胶原蛋白种类、超声时间、材料配比以及溶液pH等对纳米流体稳定性的影响。结果表明,制备水基炭黑-胶原蛋白纳米流体时,先分散炭黑再加入胶原蛋白可以提高其稳定性;猪皮胶原蛋白更适用于炭黑-胶原蛋白纳米流体的制备;超声45min,炭黑胶原蛋白质量配比为1/20,悬浮液pH在6.5~7.5之间制备得到的纳米流体稳定性较好。本研究有助于今后水基炭黑-胶原蛋白纳米流体产业化应用于太阳能光热转换领域。

UV-VIS测定医疗设备涂料中六价铬的含量

六价铬虽然被广泛使用在很多行业中,但它不仅是一种常见的致癌物质,而且对环境具有持久性的危害。因此针对医疗设备所使用的涂料,检测其中六价铬(Cr(VI))的含量具有非常重要的意义。文章通过碱性消解液对医疗设备涂料样品进行超声提取,然后在波长540 nm处,使用紫外可见分光光度法(UV-VIS)对样品提取液中的Cr(VI)含量进行检测。本方法的线性相关系数大于0.999,六价铬的检出限可达到0.002 89 mg/L,加标回收率为91.4%~94.5%,相对标准偏差为1.69%,重复性好,测量结果准确,精密度高,操作简单,为医疗设备生产企业的产品质量控制、生产分析、原材料筛选以及安全性评估提供了良好的检测手段。

运用UV-Vis法检测自来水氯消毒副产物的研究

该文建立在紫外可见分光光度法的基础上,对自来水末梢水中氯离子含量测定进行研究。着重介绍比浊分光光度法和比色分光光度法测量氯离子含量的基本原理,除此之外还介绍其他几种适合测量氯离子含量的方法,例如莫尔法、离子选择性电极法和离子色谱法。进行参数的优化实验和最佳实验条件的探究,最后得出最佳测量条件是样品浓度稀释10倍后取出2.5 mL,硝酸、硝酸银和乙二醇的最佳加入量分别为2.5、2、2 mL,在这样的条件下测得氯离子浓度与A之间存在良好的线性关系,线性回归方程为A=1.378 5c-0.001 4(r^(2)=0.994 2)。利用对二号标准溶液重复4次测定测量值分别为7.85、6.28、7.57、6.82 mg/L相对标准偏差为10%。该方法具有良好的精密度和准确度,能精准地检测水中不同浓度范围的氯离子含量,操作方便简单,从而能更好地进行在线或离线检测、控制用水中氯离子的含量。

光稳定剂UV-531的合成新方法

采用对甲苯磺酰氯和正辛醇为起始原料,先制备对甲苯磺酸正辛酯,再将其与2,4-二羟基二苯甲酮反应合成产物UV-531。研究了碱、温度、对甲苯磺酸正辛酯与2,4-二羟基二苯甲酮物质的量比对反应收率的影响。结果表明最优的反应条件是碳酸钾为碱,反应温度为80℃,对甲苯磺酸正辛酯与2,4-二羟基二苯甲酮物质的量比为1∶1.1,UV-531的收率为96.2%。

酸性红R在UV-类Fenton体系中的光降解实验

本论文选用了偶氮染料ARR为主要研究对象,研究它在UV-类Fenton体系中的光催化降解行为。采用紫外杀菌灯(λ≥254 nm)为光源,光化学反应实验在自制的光催化反应装置中进行。光照反应时间50 min,间隔相同时间取样,采用分光光度法检测ARR在光催化降解过程中的浓度变化,系统地研究了ARR的初始浓度、反应体系pH值、蒙脱土/H_(2)O_(2)配比、以及NO_(3)^(-)、EDTA、Cl^(-)、丙酮酸钠等对偶氮染料ARR光催化降解的影响。结果表明:在pH=3.0、66 mg/L的30%H_(2)O_(2)和浓度为1 g/L的蒙脱土条件下,ARR在UV-类Fenton体系可以获得较高的反应速率,NO_(3)-、丙酮酸钠对ARR的光催化降解有促进作用,而Cl^(-)、EDTA对ARR的光催化降解有抑制作用。

Studies of Ce(Ⅲ)-ALC-F Interacting with Herring Sperm DNA by Electrochemical, Fluorimetric and UV-spectrophotometric Method

Ce(Ⅲ)-ALC-F complex can react with hsDNA to form an electrochemically non-active supermolecular complex Ce(Ⅲ)-ALC-F-DNA in the buffer solution of (CH2)6N4(pH=4.9), which results in the decrease of the peak current of Ce(Ⅲ)-ALC-F. This method can be applied to determine DNA concentration. In addition, by using fluorimetric and UV-spectrophotometric methods with studies of denatured DNA and the effect of NaCl solution , it is also found that the binding mode is intercalation.

亚甲蓝分光光度法测定水中阴离子表面活性剂含量的方法改进

对亚甲蓝分光光度法(GB 7494—1987)测定水中阴离子表面活性剂含量进行了方法改进。以毒性相对较小的二氯甲烷取代三氯甲烷作为萃取剂,试管取代分液漏斗,利用振荡器进行萃取。结果表明:改进方法的最佳萃取时间为1.5 min,单个样品的分析时间在10 min以内;十二烷基苯磺酸钠标准曲线的线性范围在2.0 mg·L^(-1)以内,检出限(3s/k)为0.0297 mg·L^(-1);对十二烷基苯磺酸钠标准溶液重复测定6次,测定值的相对标准偏差(n=6)均小于9.0%;对空白样品进行加标回收试验,回收率为95.0%~99.1%。

双波长光度法测定热处理橡胶木中支链淀粉和直链淀粉的含量

橡胶木中直链淀粉和支链淀粉的组成比例直接影响淀粉的化学特性,橡胶木热处理过程中,淀粉发生不同程度热降解影响其比例发生变化,分析其含量变化将为热处理橡胶木热解机制研究提供理论基础.研究采用单因素法优化了提取方法参数,并建立了双波长光度法检测橡胶木中直链淀粉和支链淀粉含量的定量分析方法,检验了该分析方法的精密度、稳定性和加标回收率.结果表明,直链淀粉和支链淀粉的标准曲线方程分别为y=0.02499x-0.1136和y=0.00159x-0.0005,其回归系数R^(2)均为0.998,方法前处理样品简便、快速,分析方法稳定性好、灵敏度高,回收率稳定,适用于橡胶木中直链淀粉和支链淀粉含量的定量分析.分析比较了橡胶木素材及不同温度(125、155、185℃)热处理橡胶木中直链淀粉和支链淀粉的含量,橡胶木素材中支链淀粉含量远高于直链淀粉,质量比约为8∶1.随着热处理温度升高至155℃,直链淀粉含量出现明显下降,而温度升高至185℃,支链淀粉含量出现明显下降趋势.

三氯化钒还原-分光光度法测定海水中硝酸盐的含量

为解决铜镉柱还原法在测定海水中硝酸盐时的操作繁琐、耗时、毒性大、难以适应大批量样品的快速测定等问题,提出了题示方法。取5 mL样品(海水样品用水稀释至盐度不大于7)和1 mL还原剂(体积比5∶1∶1的10 g·L^(-1)三氯化钒溶液、40 g·L^(-1)磺胺溶液和1.0 g·L^(-1)盐酸萘乙二胺溶液的混合溶液)于10 mL试管中,于45℃的水浴锅中加热60 min,取出,置于冰水混合物中冷却5 min,在543 nm波长下测定体系的吸光度差值。结果表明:方法的硝酸盐还原率在95%以上;当样品盐度不大于7时,基本消除盐效应对测定的影响,可用于淡水和海水中硝酸盐的测定。硝酸盐的质量浓度在300.0μg·L^(-1)以内与对应的吸光度差值呈线性关系,检出限为1.0μg·L^(-1)。对50.0,200.0μg·L^(-1)的加标样品溶液进行准确度和精密度试验,测定值与已知值基本一致,测定值的相对标准偏差(n=10)小于0.50%。采用本方法与HY/T 147.1-2013测定实际海水样品,两种方法的测定结果具有一致性,不存在显著性差异。本方法降低了试剂对环境的污染,避免了铜镉柱制备和过柱操作,可用于海水中硝酸盐的快速、批量测定。

连续流动-钼酸铵分光光度法测定土壤全磷

利用硫酸-高氯酸湿法消解土壤,采用连续流动分析仪直接测定消解液磷酸根含量,建立了高通量测定土壤全磷的实验方法。方法检测限6.0 mg·kg^(-1),土壤样品的加标回收率为85%~100%。将该方法用于土壤标准物质(GBW07405、GBW07406a)全磷含量测定,结果准确,相对标准偏差(RSD)分别为3.5%、4.5%(n=3)。方法具备无需调节待测液pH值、分析速度快、消耗试剂少、结果准确可靠等优点,适用于大批量土壤全磷的测定分析。

加速老化的无铬鞣革中游离苯胺的FIA-UV法分析

采用流动注射分析-紫外光谱法(FIA-UV),基于苯胺与亚硝酸盐在酸性条件下发生的重氮化反应及其在碱性条件下的偶合显色反应,实现苯胺的有效检测.通过实验参数的优化,确定495 nm为最大吸收波长,建立了苯胺质量浓度在0.002~2.0 mg/L范围内与峰高具有良好线性关系的模型(R^(2)=0.9997),检出限为1.62μg/L,重复性(RSD)为0.71%.该方法在加速老化后皮革萃取液中的应用表现出97.8%~103.8%的加标回收率,相较国标法具有更优的抗干扰能力和更高的检测精度.成功建立的苯胺检测新方法,为无铬鞣革产品的质量控制及环境监测提供了重要的技术支持,有助于提高公共健康和环境保护水平.

乙酰丙酮分光光度法在室内甲醛检测中的应用

目的:为有效利用乙酰丙酮分光光度法,对室内甲醛含量进行检测。方法:通过控制样品采集、实验检测过程,验证乙酰丙酮分光光度法检测室内甲醛含量的回收率和精密度,并对6户住宅装修后的室内甲醛浓度进行检测。结果:吸光度和甲醛含量的线性回归方程为Y=0.00468X+0.000413,R^(2)=0.9998。乙酰丙酮分光光度法检测的3组5μg/mL甲醛标准溶液回收率范围为87.46%~97.28%,相对标准偏差(RSD)分别为:1.25%、0.90%、0.64%,都小于1.5%,重复性较好;6户住宅装修后的甲醛质量浓度满足国家标准,均小于0.08 mg/m^(3)。结论:乙酰丙酮分光光度法对于检测室内甲醛钠的结果良好可靠。

原子吸收光谱法测定苦瓜中微量金属元素的含量

用微波消解法对苦瓜进行预处理,采用火焰原子吸收光谱法测定了苦瓜中钙、镁、铁、锌四种微量金属元素的含量。在最佳条件下测得苦瓜中各金属元素的含量分别为Ca:3843.50μg/g,Mg:2545.492μg/g,Fe:93.3415μg/g,Zn:77.685μg/g;RSD为0.19%~0.85%;检出限为0.0020μg·mL^(-1)~0.0703μg·mL^(-1);相关系数为0.9927~0.9997;加标回收率为94.60%~102.92%,此方法简单、快捷、经济、有效。