Development a Spectrophotometric of Fe(Ⅲ), Al(Ⅲ) and Cu(Ⅱ) Using Eriochrome Cyanine R Ligand and Assessment of the Obtained Data by Partial Least-Squares and Artificial Neural Network Method-Application to Natural Waters

Simultaneous determination of heavy metal cations and accurate quantitative prediction of them are of great interest in analytical chemistry.This work has focused on a comprehensive comparison of partial least squares(PLS-1)and artificial neural networks(ANN)as two types of chemometric methods.For this purpose,aluminum,iron and copper were studied as three analytes whose UV-Vis absorption spectra highly overlap each other.Accordance with determined parameters(ligand concentration,pH,waiting times,the relationship between absorbance and concentration of metal ion effect and foreign ions)are provided and the optimum conditions.After establishing the optimum conditions for Fe^(3+),Al^(3+) and Cu^(2+) containing mixtures spectrophotometric determinations and the data calibration method of least squares(PLS-1)regression,and artificial neural network(ANN)methods were used.Chemometric methods are applied in a fast,simple,and the results are applicable.

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.

Extraction and Determination of Three Chlorophenols by Hollow Fiber Liquid Phase Microextraction - Spectrophotometric Analysis, and Evaluation Procedures Using Mean Centering of Ratio Spectra Method

A method termed hollow fiber liquid phase microextraction (HF-LPME) was utilized to extract three chlo- rophenols, 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6- trichlorophenol (2,4,6-TCP), separately from water. The extracted chlorophenols were then separated, identified, and quantified by UV-Vis spectrophotometry with photodiode array detection (UV-Vis/DAD). In the study, experimental con-ditions such as organic phase identity, acceptor phase volume, sample agitation, extraction time, acceptor phase NaOH concentration, donor phase HCl concentration, salt addition, and UV absorption wavelength were optimized. The statistical parameters of the proposed method were investigated under the selected con-ditions. The analytical characteristics of the method such as detection limit, accuracy, precision, relative standard deviation (R.S.D.) and relative standard error (R.S.E.) was calculated. The results showed that the proposed method is simple, rapid, accurate and precise for the analysis of ternary mixtures.

Developed New Procedure for Low Concentrations of Hydrazine Determination by Spectrophotometry: Hydrazine-Potassium Permanganate System

An indirect, sensitive and accurate method for the determination of trace amounts of hydrazine is described. In this proposed the spectrophotometric method is based on its reduction properties of hydrazine with a known concentration of potassium permanganate to reduce the colour. The absorbance of unreduced permanganate is measured the colour difference at different wavelengths 546 and 526 nm which show an absorption spectrum with hydrazine. Hydrazine can be determined in the range of 100 - 700 μg/ml with correlation coefficient of 0.999 and relative standard deviation 1%. The method is successfully applied for the determination of hydrazine in water streams in nuclear reactors/purex process/boiler water and polluted water samples.

Dynamic Microwave-assisted Extraction of Flavonoids from Radix Scutellariae

Dynamic microwave-assisted extraction（DMAE） of flavonoids from Radix Scutellarie was described in this article. A TM010 microwave resonant cavity was used as the energy coupler. Several parameters of DMAE, including concentration, flow rate, volume of the extraction solvent, and irradiation power, were optimized. The extraction was performed under the optimum conditions for the extraction of total flavonoids. The total flavonoids were determined by UV-Vis spectrophotometry. The main bioactive components, including baicalin, baicalein, and wogonin, were determined by HPLC. The extraction yields of the tlavonoids obtained by DMAE were compared with those obtained by pressurized microwave assisted extraction （ PMAE）, ultrasonic extraction （ UE ）, soxhlet extraction （ SE ）, and reflux extraction（ RE）, and these results indicate that DMAE is a good alternative method for the extraction of flavonoids from Radix Scutellade.

Mg and Ni Incorporated ZnO Diluted Magnetic Semiconductor for Magnetic and Photo-Catalytic Applications

Zinc oxide is recently being used as a magnetic semiconductor with the introduction of mag-netic elements.In this work,we report phase pure synthesis of Mg and Ni co-substituted ZnO to explore its structure,optical,magnetic and photo-catalytic properties.X-ray di raction analysis reveals the hexagonal wurtzite type structure having P63mc space group without any impurity phase.UV-Vis spectrophotometry demonstrates the variation in bandgap with the addition of Mg and Ni content in ZnO matrix.Magnetic measurements exhibit a clear boosted magnetization in Ni and Mg co-doped compositions with its stable value of bandgap corroborating the structural stability and magnetic tuning for its advanced applications in modern-day spintronic devices.Photo-catalytic measurements performed using methyl green degradation demonstrate an enhanced trend of activity in Mg and Ni co-doped compositions.

Determination of Total Anthraquinone and Free Anthraquinone in Different Processed Products of Rhubarb

[Objectives]The content of total anthraquinone and 5 free anthraquinones in different processed products of rhubarb were determined.[Methods]Using emodin as the reference,the concentration of 1%magnesium acetate methanol solution was used for color development,and the absorbance was measured at 516 nm wavelength;the mobile phase was methanol-0.1%phosphoric acid(76∶24)aqueous solution,the detection wavelength was set at 256 nm,the flow rate was 1.0 mL/min,the column temperature was 30℃,and the sample size was 10μL.[Results]The content of total anthraquinones in rhubarb was determined by UV spectrophotometry.The linear range was 0.98-23.52μg/mL,R2=0.9993,the average recoveries were 100.12%,99.66%and 99.15%,with RSDs of 1.58%,0.94%and 1.41%,respectively.The linear ranges of emodin,emodin,emodin,chrysophanol and emodin methyl ether were 0.0207-0.414(R2=0.9999),0.1721-3.442(R2=0.9996),0.0203-0.406(R2=0.9999),0.148-2.96(R2=0.9998)and 0.164-3.28(R2=0.9993),respectively.[Conclusions]The contents of total anthraquinones and free anthraquinones in different processed products of rhubarb were determined by UV spectrophotometry and HPLC.The method can be used for quality control of rhubarb and its different processed products.

Adaptation and Validation of a Proteolytic Activity Methodology Using Dye-Crosslinked Substrate Tablets

Enzymatic activities are important to be quantified in products as enzymatic cleaners, which are used in medical and surgical devices reprocessing. Enzymatic activities are critical for the proper chemical cleaning that intends to remove solid organic dirt from inaccessible sites. The most important enzyme for this purpose is the protease, which is able to dissolve the main dirt attached to medical and surgical instruments. In this context, this study contributes to the development of a new proteolytic activity quantification method and its validation. The methodology is based on colorimetry and uses a UV-Vis spectrophotometer to measure the substrate hydrolysis by the blue color intensity, employing Protazyme AK tablets as substrate.

Extraction Technology and Content Determination of Total Flavonoids from Traditional Chinese Medicine Yipichou

[Objectives]The research aimed to optimize extraction technology of total flavonoids from traditional Chinese medicine Yipichou,and establish methods of extraction and content determination of its medicinal materials.[Methods]Using reflux extraction method,total flavonoids of Yipichou were extracted.Via single-factor test,influence of extraction method,extraction solvent concentration,extraction volume and extraction time on content of total flavonoids from Yipichou was inspected.Using orthogonal test,extraction conditions were optimized,and optimal extraction technology of total flavonoids from Yipichou was obtained.[Results]The optimal extraction process of total flavonoids from Yipichou was as below:70%of methanol,1∶40 of solid-liquid ratio,and 1.0 h of reflux extraction time.[Conclusions]In the test,total flavonoids were extracted from Yipichou,with better repeatability,and stable and feasible method,which could provide certain scientific basis for studying quality standard of this medicinal material.

Quality Standard of Yi Herb Medicine Millettia dielsiana

[Objectives]The paper was to establish the quality standard of Yi herb medicine Millettia dielsiana.[Methods]Yi herb medicine M.dielsiana was qualitatively identified by microscopic identification and thin layer identification.The content of total isoflavones was determined by UV-Vis spectrophotometry,and the contents of moisture,total ash,acid-insoluble ash and extract were checked according to the method introduced in Chinese Pharmacopoeia(2020 edition).[Results]The microscopic identification features,including stone cells,fiber bundles,calcium oxalate square crystals,starch granules,pigment blocks,ducts,etc.,were distinct.A TLC method for identification of M.dielsiana was established.The contents of water,total ash,acid-insoluble ash and extract should be no more than 13%,no more than 7%,no more than 0.5%and no less than 6%in 10 batches of samples,respectively.The total isoflavones of M.dielsiana based on genistein(C_(15)H_(10)O_(5)) should be no less than 0.25%.The linear relationship of genistein was good in the range of 0.002-0.007 mg/mL(R^(2)=0.9996);the average recovery was 97.01%and the RSD was 2.62%.[Conclusions]The method is simple,accurate and well-reproducible,and can be used for the quality control of Yi herb medicine M.dielsiana.

Comparison of Different Processing Methods of Ziziphus jujuba Mill.

[Objectives]To study and compare the processing methods of Ziziphus jujuba Mill.[Methods]Z.jujuba was processed by seven methods:cleaning,yellowish frying,burnt frying,carbonized frying,moistening by hot sand,steaming,and boiling.Ultraviolet-visible spectrophotometry was used to determine the content of total flavonoids in each processed Z.jujuba.[Results]The content of total flavonoids measured by various processing methods was different.The content of total flavonoids in the processed Z.jujuba by moistening by hot sand was relatively high and the absorption peak spectrum was almost the same as that of the cleaned processed Z.jujuba and the rutin reference substance.[Conclusions]The moistening by hot sand is the optimal method for processing of Z.jujuba.

Nanoparticles of Palladium, Platinum and Silver:Incoporation into Perfluoro-Sulfonated Membrane MF-4SK and Ionic Nafion

The purpose of the investigation is the study of the physico-chemical properties and electro-catalytic characteristics of the Nafion and MF-4SK membranes with the author’s nanoparticles (A. Revina, 2008) incorporated into the perfluoro- sulphonated cationic membranes. An important advance in the creation of new nano-composite materials with poly-functional activity is the inclusion of nanoparticles of various metals (Pd, Pt, Ag) in these membranes. Polymer ion exchange membranes represent widely applicable materials in various areas of modern nanotechnologies. The obtained nanocomposites on the base of included nanoparticles have the perspective properties and polyfunctional activity for the applications.

Mutual influence of copper and paraquat on their adsorption in soil

Paraquat and copper (Cu) are commonly used and detected in soil.Therefore,it is important to understand their mobility in the environment.In this study,the competitive effects of paraquat and Cu on their adsorption in five representative Chinese soils were investigated using batch adsorption equilibrium experiments and spectroscopic analysis.The results showed that the adsorption of paraquat in soil varied with soil type and was positively correlated with both soil cation exchange capacity and organic matter content.Paraquat exerted a more remarkable suppression effect on the adsorption of Cu than Cu on the adsorption of paraquat.In the presence of 0.12 and 0.19 mmol L-1paraquat,Cu adsorption decreased by 16%and 22%in Heilongjiang soil and by 24%and37%in Jiangxi soil,respectively.In the presence of 0.1 and 0.2 mmol L-1Cu,paraquat adsorption decreased by 4%and 8%in Heilongjiang soil and by15%and 19%in Jiangxi soil,respectively.Exchange selectivity involving symmetric cation (paraquat2+and Cu2+) exchange is the probable basis for the suppression effect.The ultraviolet-visible absorption experiments suggested that the formation of Cu-paraquat complexes was unlikely to happen in a solution or at the soil surface.Copper K-edge X-ray absorption spectroscopy indicated that Cu in soil may have some water as hydration layers as the nearest neighbors,and each Cu atom was coordinated with five oxygen atoms.These findings greatly improve our knowledge of the molecular-scale adsorption mechanisms of paraquat and Cu in soil and can be used to predict the behavior,transport,and fate of paraquat and Cu in agricultural soils.

Resonance scattering spectroscopy of gold nanoparticle

The gold nanoparticles in diameter of 10-95 nm have been prepared by Frens procedure, all of which exhibit a resonance scattering peak at 580 nm. The mechanism of resonance scattering for gold nanoparticle has been considered according to the wave motion theory of nanoparticle in liquid. The principle of superamolecular interface energy band(SIEB) has been set up and utilized to explain the relationship between the diameter and colors for gold nanoparticle in liquid. A novel spectrophotometric ruler for the determination of the diameter has been proposed according to the relationship of the maximum absorption wavelength and diameter.