Bromocresol Green Dye Research Articles

Choice of assay affects serum albumin measurements in HIV patients: A comparison of bromocresol green and bromocresol purple dye binding methods

Background: Dye-binding assays – bromocresol green (BCG) and bromocresol purple (BCP) –are widely used for serum albumin measurement. Differences between the results reported by these assays can have important clinical implications. There are limited studies elucidating the differences between the results of two assays in HIV patients. We aimed to determine whether the choice of assay affects serum albumin measurements in HIV patients. Materials and Methods: Hundred newly diagnosed HIV patients were included in the study. The subjects were followed up for 6–12 months after initiating ART. Hundred HIV-negative healthy controls matched for age and body mass index were taken as controls. Serum albumin and three acute phase proteins (APPs) (Alpha-1 acid glycoprotein, C-reactive protein, ceruloplasmin) were measured. Serum albumin measurement was done by both BCG and BCP dye binding methods. Paired t-test was used to compare the groups. Results: The concentration of APPs reduces with ART indicating reduced inflammation, and is lowest in the control group. The difference in serum albumin concentrations measured by the two dye binding methods reduces with reduction in APPs. The study further indicates that the BCG method gives higher values of serum albumin as compared to BCP method in the presence of other proteins in the sample. Conclusion: The choice of albumin assay affects the serum albumin assessment of HIV patients. We recommend that the BCP assay be used to measure serum albumin in HIV patients, particularly in patients not on ART.

Isolation, characterization and optimizations of laccase producer from soil: A comprehensive study of application of statistical approach to enhance laccase productivity in Myrothecium verrucaria NFCCI 4363

The aim of this work was to find the optimal cultivation conditions of Myrothecium verrucaria NFCCI 4363 to enhance its laccase productivity. Interactive effect of twelve physicochemical parameters were determined and optimized by Plackett-Burman Design (PBD) and Box-Behnken Design (BBD). After statistical experimental performance, significant factors were determined and confirmed as yeast extract, 0.3%; temperature, 25 °C; ABTS, 0.5 mM; MgSO4, 1.5 mM and CuSO4, 0.5 mM. Laccase productivity of M. verrucaria NFCCI 4363 in optimized media was 1415.77 ± 42.34 U/L, more two times increased than unoptimized condition. Stable and optimal conditions of the produced laccase was determined as pH 5, 20 °C and pH 6, 50 °C, respectively. Therefore by statistical approach optimal values of cultural parameters were achieved. Moreover, crude laccase showed more than 70% decolorization potential of bromothymol blue, bromocresol green and bromocresol purple dyes in absence of any of the mediators.

Effect of temperature and composition of mixed solvent media on the interaction of bromocresol Green dye with cetylpyridinium chloride

The study of dye-surfactant interaction is very important in achieving an optimal dyeing process in textile industries. Conductivity measurements of the cationic surfactant cetylpyridinium chloride (CPC) in the presence of bromocresol green dye (BCG) in various solvents were performed, in order to provide insight into the interaction between BCG and CPC. Three critical micelle concentrations (cmc) were observed over the studied CPC concentration range. The observed cmc values of the BCG + CPC system were found to change significantly as a function of BCG concentration. The cmc values of the BCG + CPC system showed U-shaped variation, with increasing temperature in aqueous and propanol media, while decreasing monotonically in ethanol media. The concentration of additives (ethanol, propanol, and propylene glycol) also affected the cmc values significantly. The values of counterion binding (β) were also found to be dependent on the temperature and concentration of additives. Different thermodynamic parameters, e.g. Gibbs free energy (), enthalpy (), and entropy () changes, as well as their transfer properties associated with micellization of the BCG + CPC system, were determined. The ΔH o m and ΔS o m values reveal the presence of hydrophobic, ion-dipole, or dipole-diploe interactions amongst employed constituents.

Influences of alcohol and diol on the aggregation behaviour, modes of interaction and the thermodynamic properties of the mixture of bromocresol green dye and sodium dodecyl sulphate at numerous temperatures

The aggregation of the mixture of anionic surfactant – sodium dodecyl sulfate (SDS), and an anionic dye – bromocresol green sodium salt (BCG) was investigated by conductometric technique in water and alcoholic/diolic media within a temperature range of 300.55–320.55 K (with 5 K interval). The observed critical micelle concentration (cmc) decreases with surging of the concentration of BCG, following the same trend for β value. In presence of additives (ethanol, propanol, and ethylene glycol), the cmc value decreases up to a certain concentration and then the cmc values start enhancing with increasing concentration in all the cases. With the increased additive percentage, the β values continually decrease. Again, the cmc value increases gradually with the increase of temperature both in water and aq. additives media. The free energy of studied aggregation phenomena is negative which experiences an augmentation with the escalation of temperature. The increased negative value of free energy at elevated temperature indicates that the process becomes more spontaneous at a higher temperature. The and values reveal that the probable interaction forces between BCG and SDS are hydrophobic, ion-ion, as well as electrostatic interactions.

Flipped Quick-Response Code Enables Reliable Blood Grouping.

Accurate and rapid blood typing plays a vital role in a variety of biomedical and forensic scenarios, but recognizing weak agglutination remains challenging. Herein, we demonstrated a flipping identification with a prompt error-discrimination (FLIPPED) platform for automatic blood group readouts. Bromocresol green dye was exploited as a characteristic chromatography indicator for the differentiation of plasma from whole blood by presenting a teal color against a brown color. After integrating these color changes into a quick-response (QR) code, prompt typing of ABO and Rhesus groups was automatically achieved and data could be uploaded wirelessly within 30 s using a commercially available smartphone to facilitate blood cross-matching. We further designed a color correction model and algorithm to remove potential errors from scanning angles and ambient light intensities, by which weak agglutination could be accurately recognized. With comparable accuracy and repeatability to classical column assay in grouping 450 blood samples, the proposed approach further demonstrates to be a versatile sample-to-result platform for clinical diagnostics, food safety, and environmental monitoring.

Plasma Total Thiols and Total Thiol/Albumin Ratio in Patients Suffering from Depression

Introduction: Increased oxidative stress has been reported in patients who suffer from depressive disorders. Albumin acts as a target for plasma protein oxidation during oxidative stress. The plasma thiols act as significant in vivo antioxidants. Major SH-groups are found on the surface of albumin molecules. Since depressive disorders are related to oxidative stress. Only a few studies have been done that correlate plasma total thiols with major depressive disorder. The authors intended to draw a relationship between oxidative stress, thiols and major depressive disorder by estimating total plasma thiols and calculating the ratio of thiol/albumin. The study may throw some light in understanding whether the use of anti-oxidant supplements to counter oxidative stress in depressed patients. Aim: The aims was to estimate plasma thiols, albumin and obtain a plasma thiol/albumin ratio in people suffering from depression and compare the levels with the control group. Materials and Methods: This case control study was conducted in Kasturba Medical College, Manipal. Plasma thiols were estimated using Ellman’s method. Plasma albumin levels were estimated using Bromo-cresol green dye binding method. Mann- Whitney U test was used for analysing the data for total thiols and thiol/albumin ratio. A p-value <0.05 was considered significant. Results: The study group was made up of 43 (22 males and 21 females) patients and the control group was made up of 40 (18 males and 22 females) healthy controls. Plasma thiol levels and the plasma total thiol/albumin ratio were significantly elevated (p-value=0.00036) in cases (depression) as compared to that of the controls. Conclusion: Plasma total thiols can be used as an early marker for understanding the risk for major depressive disorders and also be used as a prognostic indicator in the follow up of patients suffering from major depressive disorder who are under treatment.

Biosorption of Bromo-based Dyes from Wastewater Using Low-Cost Adsorbents: A Review

The dyes in the effluents discharged into water bodies, aimlessly, are displeasing aesthetically and pose hazards to aquatic communities. The use of adsorption process has been adopted for effective treatment of wastewater containing dyes. The removal of Bromophenol blue (BPB), Bromocresol green (BCG), Bromocresol purple (BCP), and Bromothymol blue (BTB) dyes (a family of triarylmethane dyes) through adsorption process using several cheaply available non-conventional agricultural-waste based adsorbents was reviewed in this report. The gaps in the treatment trend further indicate the prospect of adapting various lignocellulose and other biogenic materials for the removal of Bromo-based dyes from wastewater.

Design of pH Responsive Textile as a Sensor Material for Acid Rain.

The chemical composition of rainwater can serve as an indicator of the excess of acidifying air pollutants. The pH value of rainwater in the presence of sulphur dioxide and nitrogen oxides, the precursors of acid rain, falls below pH 5.6, which is the limit value for acid rain. In this research, the tailoring of halochromic textile was examined for the design of a functional textile that can serve as a sensor and inform the wearer about the presence of pollutants in the air by means of an immediate colour change. For this purpose, a polyamide 6 fabric was dyed with the pH-sensitive Bromocresol green dye, which causes a colour change below pH 3.6 (yellow) and above pH 5.4 (blue). In addition, the dyed polyamide 6 fabric was treated with a water and oil repellent finish. Colour and colour change before and after immersion of unfinished and finished dyed samples in buffer solutions with different pH values were evaluated spectrophotometrically using the CIELAB colour space. The colour fastness to rubbing, washing, and light, and the water and oil repellency of the dyed fabrics were determined according to valid SIST EN ISO standards. The results showed that the unfinished dyed polyamide 6 fabric undergoes a reversible colour change faster and more clearly than the finished dyed polyamide 6 fabric. The dyed polyamide 6 fabric had good colour fastness to rubbing and domestic and commercial laundering, while the colour fastness to light was poor. In addition, the dyed polyamide 6 fabric was pH-sensitive, despite dye degradation under xenon light, regardless of whether it was finished.

Serum albumin and total protein level as plausible marker for diagnosis of protein energy malnutrition in children under age 5 years

Background: The circulating concentration of transport protein, traditionally albumin, has been used to define protein deficiency. However, few studies have been conducted to see if there is any correlation between serum total protein and albumin levels in children with PEM. Hence the study was planned to estimate serum total protein, serum albumin levels in children with PEM and healthy controls.Methods: All the children were divided in two groups. Case Group A consist of 250 children with protein energy malnutrition and control Group B consist of healthy 250 children. Venous blood of amount 3 ml was collected with full aseptic precautions. The blood was collected in the EDTA vacutainer and test tube. Serum total protein was estimated by Biuret method, serum albumin was estimated by Bromocresol green dye method (BCG dye).Results: When the mean serum levels of albumin levels and the total protein levels were measured in the controls as well as case groups, there was decrease in levels in case group as compared to control group. This difference of decrease when evaluated statistically it was found to be statistically significant. When the albumin/globulin ratio was calculated in both the groups, it was found to be statistically lower in case group as compared to control group. PEM children have low serum total protein and albumin levels as compared to healthy controls (p<0.001), this is probably due to decreased intake of proteins and reduced biosynthesis. PEM children have lower hemoglobin levels as compared to healthy controls; this is probably due to deficiency of iron and other micronutrients, which is often found in a child with malnutrition.Conclusions: Early diagnosis and prompt management of PEM and its complications can prevent development of permanent physical and mental retardation.

Impact of impurities in bromocresol green indicator dye on spectrophotometric total alkalinity measurements

Abstract. Due to its accurate and precise character, spectrophotometric pH detection is a common technique applied in measurement methods for carbonate system parameters. However, impurities in the used pH indicator dyes can influence the measurements quality. During our work described here, we focused on impacts of impurities in the pH indicator dye bromocresol green (BCG) on spectrophotometric seawater total alkalinity (AT) measurements. In order to evaluate the extent of such influences, purified BCG served as a reference. First, a high-performance liquid chromatography (HPLC) purification method for BCG was developed as such a method did not exist at the time of this study. An analysis of BCG dye from four different vendors with this method revealed different types and quantities of impurities. After successful purification, AT measurements with purified and unpurified BCG were carried out using the novel autonomous analyzer CONTROS HydroFIA® TA. Long-term measurements in the laboratory revealed a direct influence of impurity types and quantities on the drift behavior of the analyzer. The purer the BCG, the smaller was the AT increase per measurement. The observed drift is generally caused by deposits in the optical pathway mainly generated by the impurities. However, the analyzers drift behavior could not be fully overcome. Furthermore, we could show that a certain impurity type in some indicator dyes changed the drift pattern from linear to nonlinear, which can impair long-term deployments of the system. Consequently, such indicators are impractical for these applications. Laboratory performance characterization experiments revealed no improvement of the measurement quality (precision and bias) by using purified BCG as long as the impurities of the unpurified dye do not exceed a quantity of 2 % (relationship of peak areas in the chromatogram). However, BCG with impurity quantities higher than 6 % provided AT values which failed fundamental quality requirements. In conclusion, to gain optimal AT measurements especially during long-term deployments, an indicator purification is not necessarily required as long as the purchased dye has a purity level of at least 98 % and is free of the named impurity type. Consequently, high-quality AT measurements do not require pure but the purest BCG that is purchasable.

Application of Modified Agricultural Waste in the Adsorption of Bromocresol Green Dye

Background: The adsorptive removal of anionic dye (Bromocresol green) from aqueous solution was investigated using activated carbon prepared from rice husk.
 Place of Study: The research work took place at Nnamdi Azikiwe Univeristy Awka, Nigeria.
 Methods: The rice husk which was obtained from rice mills in Awka was activated with tetraoxophosphoric acid and carbonized in a furnace. The adsorption process was investigated by varying the contact time, temperature, dosage, pH and initial concentration in a batch process. Five isotherm models (Langmuir, Freundlich, Temkin, Halsay and Harkin-Jura) were employed in the equilibrium studies. Thermodynamics and kinetics of the adsorption were carried out.
 Results: The result indicated that increase in contact time, adsorbent dosage and temperature increased the percent uptake of the Bromocresol green dye. Maximum percentage adsorption of about 93% was obtained. Langmuir and Harkin-Jura isotherm models best described the equilibrium data of the adsorption process. Pseudo second-order kinetic model best correlates the kinetics of the experimental data. The thermodynamic study showed that the Gibbs free energy (ΔG), enthalpy change (ΔH) and entropy change (ΔS) were –2.541 kJ/mol, -7.401 kJ/mol and –15.52 kJ/mol K respectively.
 Conclusion: This work has shown that activated carbon prepared from rice husk can be used in adsorptive removal of bromocresol green dye from solution and that the adsorption process was spontaneous and exothermic.

Electronic Structure, Morphological Aspects, and Photocatalytic Discoloration of Three Organic Dyes with MgWO4 Powders Synthesized by the Complex Polymerization Method

Heterogeneous photocatalytic (PC) degradation of organic dyes in aqueous solution with semiconductor oxides has been very effective in relation to conventional methods for the wastewater treatment. In this paper, MgWO4 powder was synthesized by the complex polymerization method and heat-treated at 900 °C for 2 h. Their structure, morphology and optical behavior were characterized by different techniques. First-principles quantum mechanical calculations based on the DFT in the B3LYP level was employed to obtain their electronic band structure (EBS) and density of state (DOS). Moreover, we have investigated the PC properties for the discoloration of three organic dyes. XRD patterns indicate that MgWO4 powders present a monoclinic structure. FE-SEM and TEM images showed that these powders are composed of several nanoparticles. UV–Vis spectrum displays an optical band gap of 4.33 eV, while EBS calculation showed a direct band gap value of 4.49 eV. DOS data revealed that the main orbitals involved in the electronic structure are O-2p orbitals in the valence band and W-5d orbitals in the conduction band. Finally, it was obtained the best PC activity of MgWO4 powders with discoloration of 84% for bromocresol green dye, while the discoloration for methyl orange and rhodamine B dyes were 56% and 29%, respectively. The electronic structure, morphology and photocatalytic properties of MgWO4 powders synthesized by complex polymerization method calcinated at 900 °C for 2 h have been explained for the first time.

Estimation of serum albumin and serum total protein levels in children with protein energy malnutrition

Background and Aim: Protein energy malnutrition (PEM) continues to be a major public health problem throughout the developing world. PEM is associated with reduced synthesis of plasma proteins. The present study has been conducted to study the effect of PEM on plasma protein levels.Materials & Methods: The study included children of age group 1-5 years. Two hundred fifty children with PEM were included as cases and 250 healthy children were enrolled as controls. Details were collected in predesigned proforma. Serum total protein by biuret method, serum albumin by bromocresol green dye method and hemoglobin was estimated using auto analyzer. The parameters were compared among cases and controls.Results: Mean hemoglobin, serum total protein, serum albumin levels and A/ G ratio were significantly low in PEM children (cases) as compared to controls. Conclusion: PEM children have low serum total protein and albumin levels as compared to healthy controls. This is probably due to decreased intake of proteins and reduced biosynthesis. PEM children have lower hemoglobin levels as compared to healthy controls; this is probably due to deficiency of iron and other micronutrients, which is often found in a child with malnutrition.

Fe/Co-chalcogenide-stabilized Fe3O4 nanoparticles supported MgAl-layered double hydroxide as a new magnetically separable sorbent for the simultaneous spectrophotometric determination of anionic dyes

Magnesium-aluminum layered double hydroxide (MgAl-LDH) supported on Fe3O4–SiO2 which stabilized and modified by CoS-FeS chalcogenide was prepared and characterized by FT-IR, XRD, FE-SEM, EDS and, VSM analysis. Subsequently, this prepared material was applied in a dispersive solid-phase extraction (DSPE) system for simultaneous preconcentration and determination of trace levels of disulfine blue (DSB) and bromocresol green (BCG) anionic dyes from aqueous solutions which method was followed by UV–vis spectrophotometry detection. Central composite design (CCD) was applied to optimize the contribution of operational parameters including pH, sorbent dosage, sonication extraction time, type, volume and eluent concentration on system performance. Under optimized conditions, detection and quantification limits were obtained to be 0.033 mg L−1 and 0.109 mg L−1 for DSB and 0.037 and 0.123 mg L−1 for BCG, respectively, as well as, good linearity was obtained. This novel and interesting extraction approach seem to be fast and efficient procedure for the extraction of anionic dyes from aqueous samples. The kinetics and the adsorption isotherms of dyes reveal their rapid adsorption, following a with a pseudo-first-order kinetics and Freundlich adsorption isotherm model.

Residual lignin from biomass pretreatment for 2G ethanol production as an adsorbent in dye removal

Liquid waste from some industrial activities generates a serious environmental impact due to the presence of dyes. However, during the production process of second-generation ethanol, a lignin-rich residue is generated, which may be able to absorb the dyes in the waste. The goal of this work was to test the potential of lignin as a dye-removal adsorbent. Two quantities of precipitated lignin (200 and 500 mg) were tested as adsorbents by contact with Methylene Blue, Eriochrome Black T, and Bromocresol Green dyes. Kinetics curves for the adsorption capacity (Q) of lignin quantities were constructed and the percentage of removal of each dye was calculated. The Q of the three dyes increased with contact time and was higher in the 200-mg treatment; however, the strongest dye removal was presented by the 500-mg treatment. The maximum removal achieved was 84.77% with 500 mg lignin in the methylene blue solution and the minimum was 21.32% with 200 mg in the Bromocresol green solution. Therefore, it is concluded that lignin has potential as an adsorbent, as increased quantities are more efficient in removing dyes.

Noninvasively Imaging pH at the Surface of Implanted Orthopedic Devices with X-ray Excited Luminescence Chemical Imaging.

Implanted medical device-associated infections are a leading cause of fixation failure, and early diagnosis is the key to successful treatment. During infection, acidosis near the implant plays a role in antibiotic resistance and low pH is a potential infection indicator. Herein, we describe a pH sensor which attaches to the implants to noninvasively image local pH with high spatial resolution. The sensor has two layers: a scintillator layer which emits 620 and 700 nm light upon X-ray irradiation and a pH indicator layer containing bromocresol green dye that absorbs 620 nm luminescence in neutral/basic pH and passes 700 nm light at all pHs. We also developed a dedicated imaging system capable of scanning relatively large specimens through thick tissues. A focused X-ray beam irradiates one spot on the sensor, and the 620to 700 nm peak ratio is measured to determine the local pH; images are acquired by scanning the X-ray beam across the surface and measuring the pH point-by-point. The sensor was covered with varying thickness slices of chicken breast tissue (0-19 mm) to evaluate how the tissue affects the peak intensity and ratio. Thick tissues attenuated both 620 and 700 nm light, with more attenuation at 620 nm than 700 nm. Although this spectral distortion shifted the pH calibration curve, the effect could be corrected for using a scintillator film region with no pH indicator layer as a spectral reference. The sensor was attached to an orthopedic plate affixed to a human cadaveric tibia and imaged through tissue. This approach provides both high spatial resolution from focused X-ray excitation and surface chemical specificity from the indicator dye, providing a tool for imaging local pH through tissue.

Modification of hyperbranched hemicellulose polymer and its application in adsorbing acid dyes

The paper presented a new, non-pollution macromolecule of adsorbing acid dyes, and developed the adsorption mechanism on the basis of effect between the modified groups of hyperbranched hemicellulose polymer and acid dyes. The modified hyperbranched hemicellulose polymer (HHP) with a large number of terminal carboxyl groups and hydroxyl groups was synthesized by hemicellulose maleate and dihydroxymethyl propionic acid. The degree of substitution, kinematic viscosity and thermal stability of HHP was determined. In SEM images, the HHP exhibited the pores and cross-linked structure which were good help for dye adsorption. When the HHP was applied in adsorbing Methyl red dye, Bromocresol green dye and Bromophenol blue dye, it exhibited higher adsorption capacity. The adsorption capacity changed with different adsorbent dosage, pH, temperature and ionic strength, and the optimal adsorption capacity for Methyl red dye, Bromocresol green dye and Bromophenol blue dye could reach 825 mg/g, 675 mg/g and 912 mg/g respectively. The adsorption mechanism, adsorption isotherm and adsorption diffusion mode were demonstrated by Pseudo-order model, Langmuir model, Intraparticle diffusion model and Memberance diffusion model respectively. The adsorption data possessed better correlation with Pseudo-second-order model, Langmuir model and Intraparticle diffusion model. The adsorption isotherms and thermodynamic date indicated the processes of HPP2 adsorbing three acid dyes were endothermic. The N2-adsorption/desorption isotherms of HPP2 revealed the hyperbranched hemicellulose polymer filled the pore in clusters, and its adsorption process met with monolayer adsorption.

The effect of warming kidney and dredging collaterals on the clinical effect and urinary C5b-9 in patients with idiopathic membranous nephropathy

Objective To observe the effect of the method of warming kidney and dredging collaterals on the clinical effect and the content of urine C5b-9 in patients with idiopathic membranous nephropathy with spleen kidney yang deficiency and blood stasis. Methods A total of 60 idiopathic membranous nephropathy patients with spleen kidney yang deficiency and blood stasis type were randomly divided into the conventional western medicine treatment group (control group), Jingui-Shenqi pill and Taohong-Siwu decoction plus conventional western medicine treatment group (treatment group), 30 cases in each group. The Scr was detected by deproteinized alkaline picric acid method, and BUN was detected by rate method, and serum albumin (ALb) was detected by bromocresol green dye binding method, and 24 hours urinary protein was measured by pyrogallol red colorimetry, and the double antibody sandwich ELISA method was used for detection of urinary C5b-9. Results The Jingui-Shenqi pill combined with Taohong-Siwu decoction plus conventional western medicine treatment has obvious curative effect on patients. The total effective rate was 83.3 in the treatment group (25/30), and the control group was 60% (18/30). After treatment, the Alb (33.5 ± 7.95 g/L vs. 28.8 ± 6.10 g/L, t=2.569) in the treatment groupwas significantly higher than that in the conventional treatment group (P<0.01). While the 24 h urine protein (2.40 ± 0.92 g/24 h vs.3.60 ± 2.3 g/24 h, t=2.653), the contents of C5b-9 in urine (42.5 ± 17.50 ng/mg vs.71 ± 25.2 ng/mg, t=5.088) in the treatment group were significantly lower than those in the conventional treatment group (P<0.01). Conclusions The method of warming kidney and dredging collaterals can improve the clinical symptoms, improve serum albumin level, reduce the 24 hour urine protein and urinary C5b-9 content of idiopathic membranous nephropathy of spleen and kidney yang deficiency and blood stasis type. Key words: Glomerulonephritis, membranous; Syndrome of yang deficiency of spleen and kidney; Syndrome of static blood blocking collaterals; Tao Hong Si Wu Tang; Jingui-Shenqi pill; Urinary albumin excretion rate; Urine C5b-9

Spectrophotometric determination of Rivaroxaban in bulk drug and oral dosage formulation

A simple, rapid, cost effective and extractive UV-Vis spectrophotometric method has been developed for the determination of Rivaroxaban (RIV) in bulk drug and pharmaceutical formulation. It was based on UV-Vis spectrophotometric measurements in which the drug made a complex with bromocresol green dye (BCG) in acidic medium and give stable pale yellow colored complex which exhibits absorption maximum at 416 nm. Beer’s law was obeyed in the concentration range of 2 - 40 ?g /ml. This method was tested and validated for various parameters according to ICH guidelines. The proposed method was successfully applied for the determination of RIV in oral formulation. The results demonstrated that the procedure is accurate, precise and reproducible (relative standard deviation &lt; 2 %). As it is simple, cheap and less time consuming, it can be suitably applied for the estimation of RIV in dosage forms in quality control labs.

Synthesis and characterization of Keggin-type polyoxometalate/zirconia nanocomposites—Comparison of its photocatalytic activity towards various organic pollutants

Heteropolyacid supported ZrO2 nanocomposites has been prepared through wet impregnation method with the intention to improve the photodegradation performance under UV light. The material consist of mixed monoclinic and cubic ZrO2 phase and orthorhombic Keggin type 12- phosphotungstic acid(PTA) with different ratios. The phase structure, chemical composition and oxidation state of the elements tungsten (W), zirconia (Zr) were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). In addition, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Diffuse Reflectance Ultraviolet–Visible Spectroscopy (DRS-UV–Vis) were carried out to confirm the presence of functional group and optical absorption properties. Surface area of the synthesized composite was analyzed by BET analysis and morphology was confirmed using high resolution scanning electron microscopy (HR-SEM) and high resolution transmission electron microscopy (HR-TEM) and the results reveal that PTA is chemically bonded to zirconia support which confirms that the sample was synthesized successfully. The heterogeneous photocatalytic activity of the composites were studied by using aqueous solution of various organic pollutants such as methylene blue (MB), methyl orange (MO), rhodamine B (Rh-B), crystal violet (CV), bromo cresol green (BCG) dyes, 4- Nitrophenol and 2,4- Dichlorophenoxy acetic acid under UV light illumination. It is found that each dye needs different specific ratio of nanocomposite to degrade efficiently at a given time interval.