Application of Total Error Strategy in Validation of Affordable and Accessible UV-Visible Spectrophotometric Methods for Quality Control of Poor Medicines

In the framework of fighting against the poor quality medicines sold in developing countries using classical analytical methods easily accessible in those countries, four UV-Visible spectrophotometric methods for one antimalarial (quinine) and two antibiotics (amoxicillin and metronidazole) have been developed and validated according to the total error strategy using the accuracy profiles as a decision tool. The dosing range was 2 - 10 μg/mL (for quinine sulfate in tablet), 4 - 12 μg/mL (for quinine bichlorhydrate in oral drop-metronidazole benzaote in oral suspension) and 15 - 35 μg/mL (for amoxicillin trihydrate in capsule). The validated methods were then applied in determining the content of some analogous medicines sold in the Democratic Republic of Congo. Thus, the proposed UV-Visible spectrophotometric methods are simple and suitable to quantify quinine, amoxicillin and metronidazole in different pharmaceutical forms.

IMPROVEMENT OF FLUORIMETRIC AND UV－VISIBLE SPECTROPHOTOMETRIC ASSAY METHODS FOR MEASURING NITRIC OXIDE AND／OR EDRF IN BLOOD

The increasing importance of endothelium-derived relaxing factor(EDRF),which has now been identified as nitric oxide (NO),has been underscored by the eltlcidation of its role'in a growing number of normal and pathophysiological processes. Therefore techniques for detection of nitric oxide should serve as useful tools in defining the role of nitric oxide to these processes.We have improved a simple, sensitive assay methods for determination of nitric oxide in blood, tissue, and other body fluids both by fluorometric and by ultraviolet-visible spectrophotometric measurements. Data obtained by floores cence and by UV-visible assay were correlated well (r=0. 9938, P<0. 0001 ).Linearity:0.1￣ 100μmol/L,r =0.9996,P<0.0001. The minimum detection limit were < 10pmol/L. Within-and between-run CVs were 2. 48%and 4. 62% (n = 10),respectively.Reference values for healthy adults(n=40) were(9.82 ± 1. 57) pmol/L. In conclusion:the methods is sensitive, specific,and precise. It is fairly rapid and simple to perform andrequires no pretreatment of sample, i. e., plasma and urine.The value can be obtained by fluorimeter and/or UV-visible spectrophotometer.The present method is sufficiently rapid and simple to make this a practical choice for many laboratories.

Study on superoxide and hydroxyl radicals generated in indirect electrochemical oxidation by chemiluminescence and UV-Visible spectra

The generation and transformation of radicals on the cathode of indirect electrochemical oxidation were studied by chemilumines- cence(CL)and UV-Visible spectra in the reactor with a salt bridge that connected the separated chambers.The CL intensity of 4×10^(-9)mol/L luminol on the cathode with bubbling oxygen was about seven times that of the intensity without it,which was because of the generation of reactive oxygen species(ROS).The existence of ROS,especially the generation of the superoxide radical,coul...

Characterization on the Exfoliation Degree of Graphite Oxide into Graphene Oxide by UV-visible Spectroscopy

The exfoliation degree of graphite oxide into graphene oxide plays an important role in the massive production method of reduced graphene oxide. It is significant to find a simple and feasible method to analyze the exfoliation degree of graphite oxide. In the present work, graphite oxide was synthesized by a modified Hummers method, and then graphene oxide colloids were obtained by exfoliation of graphite oxide dispersed in de-ionized water. UV-visible spectroscopy was used to characterize the absorption of the graphene oxide colloids, and the concentration of graphene oxide colloids indicated by absorption area of UV-visible spectra was studied. Results show that there is a relatively stable relationship between them, indicating that UV- visible spectroscopy is a potential method for analyzing the exfoliation degree of graphite oxide into graphene oxide.

Fast-speed self-powered PEDOT:PSS/α-Ga_(2)O_(3)nanorod array/FTO photodetector with solar-blind UV/visible dual-band photodetection

Theα-Ga2 O_(3)nanorod array is grown on FTO by hydrothermal and annealing processes.And a self-powered PEDOT:PSS/α-Ga_(2)O_(3)nanorod array/FTO(PGF)photodetector has been demonstrated by spin coating PEDOT:PSS on theα-Ga_(2)O_(3)nanorod array.Successfully,the PGF photodetector shows solar-blind UV/visible dual-band photodetection.Our device possesses comparable solar-blind UV responsivity(0.18 mA/W at 235 nm)and much faster response speed(0.102 s)than most of the reported self-poweredα-Ga_(2)O_(3)nanorod array solar-blind UV photodetectors.And it presents the featured and distinguished visible band photoresponse with a response speed of 0.136 s at 540 nm.The response time is also much faster than the other non-self-poweredβ-Ga_(2)O_(3)DUV/visible dual-band photodetectors due to the fast-speed separation of photogenerated carries by the built-in electric field in the depletion regions of PEDOT:PSS/α-Ga_(2)O_(3)heterojunction.The results herein may prove a promising way to realize fast-speed self-poweredα-Ga_(2)O_(3)photodetectors with solar-blind UV/visible dual-band photodetection by simple processes for the applications of multiple-target tracking,imaging,machine vision and communication.

IN－SITU FTIR AND UV－VISIBLE－NEAR－IR SPECTROELECTROOHEMICAL STUDIES OF MIXED－VALENCE ISOPOLYANION Mo＿6O＿（19）￣（3－） IN APROTIC MEDIA

In the paper, we have studied the mixed-valence isopolyanion by cyclic voltammogram, in-situ UV-Visible-Near-IR and FTIR spectroelectrochemical methods in aprotic medium,such as methylene chloride.A number of hetero-- and iso--polyanions of molybdenum are re(luci})leto a series of mixed-valeDce compounds containing Mow and Mo t'. f 1 1These species exhibit intervalence transfer bands. This description ofthe electronic structure corresponds to cia88 H syetems in Robinand Day'8 classification of mixed--valence compounds t21. The electrochemical methods can prepare the mixed--valence compounds in which laceetructure of the parent oxidized form is generally retained. [31 In--situepectroelectrochemical studies have many advantages for product identification and for mechanistic studies of transition metal complexes in solution. t.1 Among theme are small electrolysis volumee that yield shortelectrolysis times, rapid time response for the measurement or kineticparameters, and the rapid in--situ generation of reactive species withBtable properties that preclude isolation [51.The cyclic voltammogram indicates that the (TBA).Mo.O.. undergoestwo reductione, which are labeled ac reactions 1--2 and corre6pond tothe electron transfers given in eq. 1-- 2.Mo.O.g-- + e * Mo.O.g--' E./2=--0.690V -----------------------------(1)Mo.O.S-- + e - Mo.O.:-- ac- other products E.,.=--1.650V------(2)

UV–visible spectral characterization and density functional theory simulation analysis on laser-induced crystallization of amorphous silicon thin films

The effect of laser energy density on the crystallization of hydrogenated intrinsic amorphous silicon （a-Si：H） thin films was studied both theoretically and experimentally. The thin films were irritated by a frequency-doubled （λ= 532 nm） Nd：YAG pulsed nanosecond laser. An effective density functional theory model was built to reveal the variation of bandgap energy influenced by thermal stress after laser irradiation. Experimental results establish correlation between the thermal stress and the shift of transverse optical peak in Raman spectroscopy and suggest that the relatively greater shift of the transverse optical （TO） peak can produce higher stress. The highest crystalline fraction （84.5%） is obtained in the optimized laser energy density （1000 mJ/cm2） with a considerable stress release. The absorption edge energy measured by the UV- visible spectra is in fairly good agreement with the bandgap energy in the density functional theory （DFT） simulation.

Interaction between DNA with Complex of Eu^(3+)-Rutin by UV-Visible Spectroscopy and Electrochemistry

The interaction of Eu^3＋-rutin with CT DNA was studied by UV-visible spectroscopy and electrochemistry. All experimental results indicate that the complex binds to DNA by the electrostatic mode and the groove binding mode. Information such as intrinsic binding costant （ k = 1. 426 × 104 mol·L^-1 ）, and binding numbers （ n = 2）, were determined by cyclic vohammetry and differential pulse vohammetry at glass carbon electrode. Interaction between Eu^3＋ with rutin was also studied by UV-visible spectroscopy.

Determination of the Biodiesel Content in Petrodiesel/Biodiesel Blends: A Method Based on Uv-Visible Spectroscopy and Chemometrics Tools

In this work, we developed an analytical method based on UV-visible spectroscopy to determine the concentration of biodiesel from African palm in blends of petrodiesel. Seventy-five samples with biodiesel concentrations between 0-100 wt% were prepared. The spectral fingerprints that were obtained from the analysis of the samples by UV-visible spectroscopy were used to build predictive model using PLS regression. The predictive ability of the models was evaluated through statistical parameters: the standard error of calibration (SEC), the standard error of validation (SEV), the correlation coefficient of calibration (r Cal) and validation (r Val), the ratio (SEC/SEV), the coefficient of determination R2, the paired data Student’s t-test, cross-validation and external validation. The results indicate that the PLS model predicts the concentration of biodiesel from African palm with high precision in mixtures with petrodiesel. The method developed in this study can be applied to determine the concentration of biodiesel African palm in mixtures of petrodiesel in a more rapid and economical way. Moreover, this method has less analytical errors and is more environmentally friendly than the conventional methods.

非诺贝特酸胆碱缓释胶囊生产设备的UV法清洁验证

为验证清洁操作完成后生产设备表面非诺贝特酸的残留量是否低于安全指标,建立了紫外可见分光光度法测定擦拭棉签的提取溶液中非诺贝特酸的含量。使用286 nm检测波长,1 cm吸收池,50%甲醇的溶剂。非诺贝特酸在0.95~14.25μg/mL浓度范围内线性关系良好。316不锈钢板、有机玻璃和硅胶的取样回收率分别为82.2%、75.8%、76.9%,RSD分别为9.47%、4.41%、4.06%。方法回收率为101.5%,RSD为1.05%。该UV法可用于生产设备上非诺贝特酸胆碱缓释胶囊残留物的清洁控制分析。

New Preparation Method of Visible Light Responsive Titanium Dioxide Photocatalytic Films

We report a new and simple preparation method of the visible light responsive Titanium dioxide (TiO2) photocatalytic films using sol-gel method and ultraviolet light (UV) irradiation. Proposed films were prepared on fused silica plates using titanium tetra-isopropoxide, urea, 2-methoxyethanol, water and UV irradiation. The 650°C-annealed films were carbon-containing anatase type TiO2, not carbon-doped ones. The prepared films absorbed visible light with wavelengths longer than 400 nm. Also, organic dyes were effectively photodegradated by visible light irradiation in the presence of these films.

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.

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。

紫外分光光度法测定歧化松香中去氢枞酸含量的干扰因素研究

利用液相色谱仪、制备液相色谱仪、气相色谱质谱联用仪,对歧化松香(DR)中去氢枞酸(DA)紫外光谱测定方法的干扰因素进行了详细研究。测定的市售不同省份的5个样品中有2个主要干扰物质,进一步定性,确定干扰物质1为6,8,11,13-枞四烯酸(ATA),干扰物质2为混合物,主要检出物为去氢枞醛(D)和枞酸(AA)。采用二阶导数光谱法和偏最小二乘(PLS)法对紫外光谱数据进行分析,以消除去氢枞酸紫外分光光度法的干扰,结果表明:PLS法比二阶导数光谱法误差更小,能够同时消除多种干扰因素,使测试结果更加接近真实值。

壳聚糖-魔芋葡甘聚糖复合絮凝剂在印染污水处理中的应用

利用改性-交联的方法制备壳聚糖/魔芋葡甘聚糖复合絮凝剂,以亚甲基蓝为例,对印染废水进行处理。探究了壳聚糖/魔芋葡甘聚糖复合絮凝剂的用量、吸附时间以及pH值对印染污水吸附率的影响。结果表明:在常温条件下,亚甲基蓝溶液初始浓度为8.0 mg/L,溶液PH为9,壳聚糖/魔芋葡甘聚糖复合絮凝剂的投加量为0.3 g,吸附时间72 h,亚甲基蓝溶液吸附率达到98.90%。

酰基膦氧化物光引发剂在UV光聚合法合成高吸水树脂中的应用

介绍了Irgacure 819、Irgacure 1800和Irgacure 1700三种新型的酰基膦氧化物光引发剂,用紫外-可见分光光度等方法探讨了其结构及光分解的机理。这三种高效的光引发剂可用于紫外光(UV)光聚合法合成聚丙烯酸-丙烯酸铵高吸水树脂。对曝光时间和光引发剂含量对树脂的吸水性能的影响进行了综合比较。以Irgacure1700为光引发剂,UV光聚合法合成的高吸水性树脂,其吸水率最高可达835mL/g,交联率达到94.5%。

可见/近红外联合UVE-PLS-LDA鉴别压榨和浸出山茶油

山茶油是我国特有的优质食用油,而压榨山茶油营养品质优于浸出山茶油。采用可见/近红外光谱技术对压榨和浸出山茶油进行鉴别研究。在350～1 800nm波段范围内采集压榨和浸出山茶油样本的透射光谱,利用无信息变量消除(UVE)方法进行波长变量优选,剔除无用波长变量,并应用偏最小二乘-线性判别分析(PLS-LDA)建立鉴别分类模型。最后,利用鉴别分类模型对未参与建模的26个预测集样本进行鉴别。研究结果表明,UVE-PLS-LDA是一种有效的鉴别分类方法,所建立的鉴别分类模型能较好地对压榨和浸出山茶油进行鉴别,校正集和预测集样本的鉴别正确率均为100%。因此,可见/近红外光谱联合UVE-PLS-LDA方法鉴别压榨和浸出山茶油是可行的。

连续流动分析仪测定碳酸氢钠提取土壤有效磷的方法优化与研究

为了提高土壤有效磷的检测灵敏度和检测效率,对《土壤有效磷的测定碳酸氢钠浸提-钼锑抗分光光度法》(HJ 704-2014)及《森林土壤的测定》(LY/T 1232-2015)中碳酸氢钠提取有效磷的检测方法进行了优化。设计了连续流动分析仪试剂配制方案及试剂流路,探讨了浸提方式、振荡速度、浸提温度、浸提时间及检测波长等实验条件对测定结果的影响,考察了方法的线性范围、检出限、精密度及准确度等参数,并比较了分光光度法与连续流动分析仪法检测结果。结果表明,在880 nm波长下,优化后的连续流动分析仪法检测碳酸氢钠浸提的有效磷的线性范围为0~3.00 mg/L,相关系数R2>0.999,检出限为0.004 mg/L,变异系数<5.0%,测定参比物质NSA 2[有效磷认定值(36±6)mg/kg]、NSA 4[有效磷认定值(14.5±2.6)mg/kg]、标准物质ASA-3a[有效磷认定值(29±3)mg/kg]分别为35.9、12.5和28.1 mg/kg,均在认定值范围内,可以准确测量有效磷低的土壤。优化后的连续流动分析仪法检测碳酸氢钠浸提土壤中有效磷含量具有自动进样、在线除气泡、在线恒温显色检测、试剂用量少及环境友好等优点,且实验周期短,测得数据的灵敏度、精密度和准确度良好,优势突出,可为第三次全国土壤普查高效准确测量碳酸氢钠浸提有效磷含量提供技术依据。