Ml Of NaOH Research Articles

Enzymatic Activity of Lactoperoxidase in the Colostrum of Cows in different lactations

In order to evaluate the activity of the lactoperoxidase enzyme (LPO), in colostrum and milk at the first month of lactation, the characterization of colostrum in cows was carried out from the first day postpartum and during the first month of lactation, in first, second, third and more lactations for six (06) months, the parameters were analyzed: acidity, pH, temperature, qualitative detection of the lactoperoxidase enzyme, quantifying the volume of the LPO activity. Descriptive statistics were applied using the STATISTIX 4.0 package (1985-1992) and one-way nonparametric statistics Kruskal – Wallis test for the levels First, second, third and more lactations and for the characterized parameters, using the SAS-STAT statistical system, to know the independence of the variables under study. It was found that the acidity is high and varies in a decreasing manner as follows: 37.68; 27.13 and 26.13 ml of NaOH O.1N/100ml. respectively, the pH was observed below that of milk, ranging between 5.0 and 6.2 (equiv/L). The enzymatic activity registered values of up to 182.89 U/lt., considered low compared to milk in the first month of lactation; from one to more than three lactations, according to the values found: 383.9, 394.39 and 753.54 U/ml respectively. It is concluded that the enzymatic activity is low in colostrum and then increases, until reaching the values of normal milk in the first month of lactation. The independence of each parameter (variable) in colostrum was also verified.

Evaluation of Stability and TLC Fingerprinting of the Artemether Component in Artemether-Lumefantrine Combination Suspension Formulations Available in Nigeria Pharmaceutical Market

Aim: Artemether is the main component of the artemisinin-based combination therapy (ACT), used in the management of malaria infection caused by Plasmodium falciparum. Hence, its stability and conformation to pharmacopeia standards are necessary for use. The study aimed to review the first-order derivative spectrophotometric method for simultaneous estimation of artemether and its derivatives in pure and combined formulations, and their stability profiles, then develop a simple, precise, and fast technique for their rapid physicochemical analysis.
 Methodology: Thin-layer chromatographic (TLC) Fingerprinting principles were used in the analysis. Artemether and its derivatives were spotted on the TLC chromatograms after adding 25 mL of the suspension to a mixture of 100 mL of distilled water and 4 mL of NaOH, extracting the mixture with 60 mL of dichloromethane (DCM), drying, and sonicating the residue with 20 mL of the solvent. It was centrifuged, and the clear supernatant was spotted on the TLC plates.
 Results: The color test results revealed the presence of the artemether compound in the reference standard as well as the six brands of suspensions (A, B, C, D, E, and F) utilized in the study. Artemether melting point was obtained between 86 - 89 °C; within the International Pharmacopeia specified range. The chromatograms of Artemether and derivatives showed Rf values of 0.25 (impurity A), 0.3 (artenimol impurity B), 0.35 (impurity C), 0.4 (α-artemether: impurity D), and 0.55 (artemether).
 Conclusion: The devised method can be applied to the routine quality control analysis of artemether-lumefantrine suspension in addition to existing analytical techniques.

Microbiota Properties and Texture of Rice Flour Bread with Pineapple Starter

Changing the ingredients also can change the properties of the bread. In this study, bread was made using rice flour and sourdough. Sourdough with Lactic Acid Bacteria (LAB) and yeast can also be added with pineapple starter to help microbiota growth. The study aimed to determine the amount of microbiota produced from sourdough with pineapple addition and its effect on the texture of rice flour bread. Pineapples with water and sugar were fermented to make pineapple starter. Pineapple starter is then used in sourdough making and fermented around 3-6 days. The mature sourdough was used in bread making. The addition of pineapple, in the form of a starter, made the pineapple sourdough (PS) have lower pH and higher titratable acidity (TA), total Lactic Acid Bacteria (LAB), and total yeast than sourdough without the addition of pineapple starter or wheat sourdough (WS). The pH and TA of PS at the peak were 3.25 and 2.67 mL of NaOH. The total LAB of PS at the peak was 9.27 Log CFU/g, and the total yeast was 9.30 Log CFU/g. PS reached its peak on the third day, while wheat sourdough (WS) reached it on the sixth day. The pineapple sourdough bread (PSB) had the lowest specific volume, and the highest texture properties compared to control bread (CB) and wheat sourdough bread (WSB), but there is no significance different. The addition of pineapple starter can fasten the fermentation time of sourdough and made the bread less brittle than CB.

Quantitative analysis and degradation mechanisms of different protein degradation methods.

The abrasive debris produced by wear test of artificial joints in vitro is encapsulated by proteins in serum lubricants, which hinder the characterization of debris analysis. One of the key issues of isolating wear debris from serum is degrading the proteins wrapping the wear debris. In this article, the proteins in calf serum were degraded by a strong alkali, a strong acid, and an enzyme. The residual concentration of proteins in calf serum was detected by UV absorption. Quantitative analysis of protein degradation and the protein degradation rate was proposed, following treatment with different degradation reagents and different incubation times. The results showed that when 10 mL of 25% volume calf serum was added with 40 mL of NaOH and incubated at 65°C for 24 h, the protein degradation rate reached a maximum of 95.52%. The protein degradation rate in the solution ranged from 31.86% to 71.64% when a different volume of 37% HCl was added and incubated at 60°C. The highest protein degradation rate was 94.98% in the protease degradation solution. When the protein degradation rate is less than 70%, the particles were coated by protein. When the protein degradation rate was more than 95%, there was no protein coating around the particles. The three protein degradation methods have different processes and protein degradation rates. A suitable method for protein degradation can be selected according to these practical applications.

PM 7/121 (2) ‘Candidatus Liberibacter africanus’, ‘Candidatus Liberibacter americanus’ and ‘Candidatus Liberibacter asiaticus’

Specific scopeThis Standard describes a diagnostic protocol for ‘Candidatus Liberibacter africanus’, ‘Candidatus Liberibacter americanus’ and ‘Candidatus Liberibacter asiaticus’.1This Standard should be used in conjunction with PM 7/76 (5) Use of EPPO diagnostic protocols.Specific approval and amendmentFirst approved in 2014–09. Revised in 2021–04.

Cold coffee beverages extracted by cold and hot methods: Composition and sensory acceptance by youngers

Brazil is the second largest coffee consumer in the world, however, the participation of the young public in this market is not very expressive. The objective of this study was to evaluate the impact of non-sensory (packaging color, information, and images) and brewing methods (hot or cold extraction) on the acceptance of cold coffee beverages by young consumers. A coffee:water ratio of 1:10 (w:v) and infusion during 4 min and 24 h was used for both hot and cold extractions, respectively. Hot extraction was performed at 95 °C, then cooled in a refrigerator and served at 6 to 10 °C, the same temperature that the cold extraction was performed and served. The beverages were characterized by composition and extraction yield. The packaging of the beverages was designed aiming to appeal to the young Brazilian public (15 to 24 years old), and it was used for the Expectation Evaluation. The type of extraction (hotor cold) produced beverages with differences in composition but with similar acceptance. Except for pH (average value of 5.1), the beverages differed in all the studied parameters. Hot-extracted beverages (iced coffees) had higher contents of caffeine, chlorogenic acids, and melanoidins (92.9, 258.2, and 360.8∙10-6 kg 100 mL-1, respectively); they also presented higher acidity (3.4 mL of NaOH 20 mL-1) as well as higher yield compared to the cold-extracted beverages (cold brews). The use on product labels of brown and black colors, coffee bean images, and the inclusion of information regarding the beverages (extraction method, consumption temperature, non-addition of sugar) generated a positive expectation that was assimilated by the young public. In conclusion, both proposals of cold coffee beverages (by hot or cold extraction) were well accepted considering their sensory and non-sensory aspects. Key words: Caffeine; CGA; Coffea arabica; melanoidins; packaging.

Coffee brews composition from coffea canephora cultivars with different fruit-ripening seasons

PurposeThe purpose of this paper is to evaluate the contents of bioactive compounds and/or that of interest for the brew quality (trigonelline, caffeine, total chlorogenic acids and melanoidins), acidity and antioxidant activity (AA) of roasted coffee brews produced with Coffea canephora.Design/methodology/approachCoffee samples corresponded to three cultivars – Diamante ES8112, ES8122 “Jequitibá,” and Centenária ES8132 – with different fruit-ripening seasons (early, medium and late, respectively). The study evaluated five genotypes from each cultivar and coffees were cultivated in two sites, a total of 30 samples.FindingsThe average contents on the coffee brews varied from 1,176 to 1,452 µg mL−1 for caffeine; from 206 to 413 µg mL−1 for trigonelline; from 528 to 942 µg mL−1 for total chlorogenic acids; from 6.8 to 7.8 mg mL−1 for melanoidins; showing total titratable acidity between 1.15 and 1.79 mL of NaOH 0.1 mol L−1 by 20 mL of the brew. AA varied from 6.78 to 8.80 mg of TROLOX mL−1, correlating positively with the contents of caffeine, total chlorogenic acids, melanoidins. Fruit-ripening seasons had no effect on coffee brew composition and AA.Originality/valueThe results presented provide not only a unique analysis of coffee brew from genotypes developed to improve the good agricultural practice and brew quality, but also relevant information that can be extended for research in coffee composition and for the coffee industry.

Bulk etch rate for PADC CR-39 at extended concentration range of NaOH mixed with ethanol and etchant viscosity study

Bulk etch rate of PADC CR-39 detector in a mixture of NaOH and ethanol alcohol aqueous solution of (8 ml of NaOH + X ml of ethanol: X = 0, 1, 2, 3) at 70 °C was determined using fission track diameter method. Wide range of NaOH concentration, never covered before, from 2 to 30 N was studied. Higher NaOH concentrations and ethanol increase the detector etching rate dramatically leading to a reaction rate far from equilibrium. Arrhenius and multi hit equations are no longer hold and therefore a need for new equations is arise. Viscosity of (NaOH + ethanol) in such wide concentration range was also studied at different temperatures to explain the reaction rate. Many efforts and different fitting equations were used to manipulate the data. Some of these equations are statistically as well as chemically rejected and finally three equations seem to read the data quit well are suggested.

Distribution and formation of degradation products of 14C-quinclorac in five tropical soils

ABSTRACT Quinclorac is an extremely persistent herbicide in the environment. However, information regarding the degradation of this herbicide in the soil is missing. Thus, the objective of this study was to evaluate the behavior of quinclorac in five tropical soils of contrasting textures by quantifying the extracted residue with formation of metabolites, bound residue and mineralization to 14CO2. The herbicide was applied at the dose of 15.1 Bq per biometric vial. For mineralization, 10 mL of NaOH were used, with weekly analyses of radioactivity in the liquid scintillation spectrometer, up to 240 days after application (DAA). Extractions were performed using NaOH and acetone. Thin Layer Chromatography (TLC) plates were used for the separation of the extracted residue in quinclorac and its metabolites. After the extraction, the soils were burned in a biological oxidizer to quantify the bound residue. Half-life (DT50) ranged from 57.7 to 266.5 days and five metabolites were found. The mineralized 14CO2 ranged from 12.5 to 25.6%, extracted residue from 104.3% to 23.3% and the bound residue from 3.6 to 49.5%. Quinclorac showed high persistence in the soil, which could cause carryover in subsequent crops and reach non-target organisms, but this depends on the physicochemical characteristics of each soil.

USING POTENTIOMETRIC ACID-BASE TITRATION TO DETERMINE PKA FROM MANGOSTEEN PERICARPS EXTRACT

One of the uses of acid-base indicators is to show the end point of the titration, so the accurate determination of acidity constant and pH range of indicators needs to be done. This study aims to determine the acidity constant (pKa) of mangosteen pericarp extract and its accuracy as an indicator of acid-base titration. Determination of pKa was done by a simple potentiometric titration method. The titration data were plotted in three graphs, i.e., pH, ΔpH/ΔV (the (the first derivative), and Δ2pH/ΔV2 (the second derivative) versus titrant volume to determine the equivalence point of the titration. The accuracy test was carried out by comparing the volume of oxalic acid used to titrate NaOH solution using the indicator of mangosteen pericarp extract and phenolphthalein indicator. The result showed that the equivalence point was found on the titrant volume of 8.6 mL and a measured pH of 9.84. so the pKa value of mangosteen pericarp extract was 7.20, and the pH range was 6.20 to 8.20. the average volume of oxalic acid used to titrate 5 mL of NaOH using phenolphthalein as the indicator was 5.2 mL while the titration used mangosteen pericarp extract was 5.23 mL. The accuracy of mangosteen pericarp extract was 99.42%. By the result, it can be concluded that potentiometric titration can be used as a simple way to determine the acidity constant of mangosteen pericarp extract. Moreover, the mangosteen pericarp extract can be used as an alternative acid-base titration indicator to substitute the common acid-base titration in the laboratory.

Extraction of triclosan and methyltriclosan in human fluids by in situ ionic liquid morphologic transformation

Herein, we established an ionic liquid (IL)-based liquid-solid transformation microextraction (IL-LTME) combined with HPLC-UV detection for the simultaneous determination of triclosan (TCS) and its methylated product, methyltriclosan (MTCS), in human fluids. The IL-LTME method was based on an in situ metathesis between hydrophilic IL and ion-exchange salt to form a solid hydrophobic IL. According to the above principle, a hydrophilic IL, [C12MIM]Br, was selected as the extractant, and NH4PF6 as ion-exchange salt. The prominent advantages of the newly developed method are: (1) the in-situ reaction between the extractant [C12MIM]Br and ion-exchange salt NH4PF6 changed the IL from hydrophilic to hydrophobic that avoiding the stick of ionic liquid on the tube wall; (2) bubbling with NH3 greatly increased the contact area between IL-extractant and analytes resulting in improved extraction recovery; and (3) solidification of the [C12MIM] PF6 provided a good separation and avoided the use of specialized equipment. A series of main parameters were optimized by single-factor screening and central composite design as follows: 0.9 mL of NaOH, 2.0 min of second ultrasonically time, 10 min of centrifugation time, 21 mg of extractant [C12MIM]PF6, 2.4 min of ultrasonic time, 65 mg of NH4PF6 and 13.8 min of cooling time. Under the optimized conditions, the limits of detection for TCS and MTCS were 0.126–0.161 μg L−1 in plasma samples, and 0.211–0.254 μg L−1 in urine samples, respectively. The extraction recoveries for TCS and MTCS were in the range of 94.1–103.8%. The intra-day and inter-day precisions were 1.00–4.74% and 1.02–5.21%, respectively. In general, the IL-LTME method is environment-friendly, time-saving, economical, high efficient and robust with low detection limits and high recoveries. Thus, the newly developed method has excellent prospects for sample pretreatment and analysis of trace TCS and MTCS in blood and urine samples.

Extraction of gelatin from catfish bone using NaOH and its utilization as a template on mesoporous silica alumina

Gelatin extraction from catfish bone using NaOH and its utilization as a template on a synthesis of mesoporous silica-alumina had been investigated. The extraction was prepared by immersing 25 g catfish bone in 125 mL of NaOH in concentration of 0.0; 0.05; 0.10; 0.15 and 0.20 M for 24 h, then washing with demineralized water until pH 7, followed by immersed the bone into 125 mL of 1 M HCl for 1 h, then washed using demineralized water into pH 5. To produce gelatin the bone was refluxed with 100 mL demineralized water at 70°C for 5 h then evaporated at 50°C. The dry gelatin was characterized using FTIR and electrophoresis (SDS-PAGE). The best performance of gelatin was produced by NaOH 0.10 M. The gelatin consists of amide A, B, I, II, III and molecular weight of 25-200kDa. Silica and Alumina material prepared from Lapindo mud extraction. Dry Lapindo mud crushed and filtered until pass 100 mesh, then reflux using 6 M HCl (1:4 w/V) at 90°C for 5h then filtered. The filtrate was consisting alumina solution adding with 6 M NaOH (2/3 V/V) them filtered. The filtrate then injected by CO2 gas for 30 minutes and filtered, the residue was calcined at 500°C for 5h. The residual of Lapindo mud dried and refluxed with 6 M NaOH (1:4 w/v) at 90 °C. After 5h filtered and the filtrate added by HCl to pH 8 and filtered, the residual then dried. The Si and Al were then analyzed by XRF and consist of silica and alumina for 99.1 and 87.73%, respectively. Silica-alumina was prepared using silica and alumina extracted from Lapindo mud. 6 g of SiO2 and 2 g of NaOH was immersed in 62 mL of demineralized water then added with alumina solution (0.204 g alumina in 30 mL demineralized water). The gelatin solution (5 g gelatin in 70 mL demineralized water) was dropped into the silica-alumina while stirring at 50°C for 4 h and aging for 24 h. The synthesized silica alumina was analysed using FTIR and surface area analyser. The FT-IR spectra indicated the TO4 (T=Si, Al) vibration at wave number of 1049.28 and 1103.23 cm-1. The synthesized silica-alumina showed mesoporous characters with a pore diameter of 41.18 nm and surface area of 32.76 m2/g

Avaliação do processo produtivo de polvilho azedo em indústrias de Santa Catarina

Resumo O polvilho azedo apresenta um sabor típico, com características diferentes do amido nativo de mandioca. É utilizado, por exemplo, na produção de biscoitos e de pães de queijo, produtos de grande aceitação sensorial no Brasil. Nas últimas décadas, o polvilho perdeu mercado nacional, devido, principalmente, à falta de padrão de suas características tecnológicas, bem como pela substituição deste amido naturalmente modificado por amidos quimicamente modificados, como o modificado por ácido. O presente trabalho teve como objetivo avaliar as condições do processo produtivo de polvilho azedo em polvilharias de Santa Catarina e caracterizar as amostras coletadas nessas unidades. As amostras apresentaram umidade variando de 11,12 a 15,06 g.100 g–1, pH de 3,11 a 4,82, acidez total titulável de 1,66 a 7,05 mL de NaOH 1 mol.L–1/100 g, volume específico de 5,15 a 10,93 mL.g–1, além das diferenças observadas quanto às concentrações de ácidos orgânicos, propriedades de pasta e outras propriedades de expansão. Os resultados confirmaram a falta de padronização envolvida nas etapas da produção do polvilho azedo, sendo que as condições de fermentação e a secagem são as mais críticas para a qualidade do produto final.

Injectable bone regeneration biomaterial with analgesic properties

Event Abstract Back to Event Injectable bone regeneration biomaterial with analgesic properties Ahmed E. Al Subaie1, 2, Marco Laurenti1, Iskandar Tamimi1, Laura S. Stone3, Magali Millecamps3, Jake Barralet1 and Faleh Tamimi1 1 McGill University, Faculty of Dentistry, Canada 2 University of Dammam, College of Dentistry, Saudi Arabia 3 McGill University, Edwards Centre for Research on Pain and Faculty of Dentistry,, Canada Introduction: Bone regeneration procedures require invasive and painful interventions. Bone fixation for instance involve invasive incision through skin and muscle to expose bone in order to place fixation plates. Pain management in bone regeneration interventions is limited to the use of drugs such as non-steroidal anti-inflammatories, opioids, acetaminophen and local anesthetics. However, these drugs have several limitations; non-steroidal anti-inflammatories delay bone healing and increase the risk of gastrointestinal diseases[1],[2]. Opioids are controlled drugs, and have major side effects such as constipation and addiction[3]. Acetaminophens are usually not effective in moderate or severe bone pain. Local anesthetics are relatively the most effective and have the least side effects, however they are limited by their short duration of action[3]. Due to the issues raised above, a bone regeneration biomaterial that can relief pain and be applied through minimal invasive procedures could bring a paradigm shift to the field of orthopedic and craniofacial interventions. Recently, we have shown that sodium magnesium phosphate nanocrystals (gel) are osteoinductive, thixotropic colloidal suspension and can be injected through high gauge needles (unpublished work) and therefore can be used for minimal invasive interventions. In this study, we investigated how this gel can control the release of local anesthetic (mepivacaine) in-vitro and in-vivo with the ultimate goal of developing an injectable bone regeneration biomaterial with analgesic property. Materials and Methods: The gel was prepared by dissolving 85 mg of Mg(OH)2 in 2.2 mL of H3PO4 1.5 M and subsequent addition of 3.8 mL of NaOH 1.5 M under vigorous stirring. The resulting colloidal suspension was centrifuged, and the supernatant was discarded. Different concentrations of mepivacaine were dissolved in the gel for drug release by placing them in Pur-L-Lyzer dialysis kit, incubated in 30mL of PBS at 37Co. The PBS was changed and analyzed with UV-Vis spectroscopy at different time points (0-168) hours in order calculate the amount of drug released. The analgesic action of the mepivacaine with gel was assessed in-vivo using the mouse-hindpaw-model. Twelve mice were assigned into four groups (n=3, each); saline, mepivacaine, gel and gel+mepivacaine. Each mouse received a single injection of the assigned treatment (5 μL subcutaneously) into the planter surface of the hindpaw. Sensitivity to thermal stimuli was tested using radiant heat at different time points (15-120 minutes). Results and Discussions: The gel was able to control the release of mepivacaine for up to 24 hours. Higuchi and Korsmeyer-Peppas models indicated that mepivacaine was release by diffusion. The mepivacaine released by the gel presented no change in its molecular structure as shown by UV-Vis spectra, indicating that the drug was compatible the gel (figure 1). Radiant heat test showed that the gel loaded with mepivacaine provides analgesia and the analgesic action of mepivacaine was prolonged by the gel (figure 2). Conclusion: The bone regeneration biomaterial described here can be injected through high gauge needle and provide analgesia. This biomaterial could minimize the invasiveness of bone regeneration procedures, shorten the healing period and mobilization time while eliminating the need for systemic drugs for pain management. McGill University, Faculty of Dentistry; University of Dammam, College of Dentistry; Saudi Arabian Cultural Bureau

Erosive Effect of Different Soft Drinks on Enamel Surface in vitro: Application of Stylus Profilometry

Objective: To assess the erosive potential of various soft drinks by measuring initial pH and titratable acidity (TA) and to evaluate enamel surface roughness using different exposure times. Materials and Methods: The initial pH of the soft drinks (group 1: Coca-Cola; group 2: orange juice; group 3: Cedevita; group 4: Guarana, and group 5: strawberry yoghurt) was measured using a pH meter, and TA was measured by titration with NaOH. Enamel samples (n = 96), cut from unerupted human third molars, were randomly assigned to 6 groups: experimental (groups 1-5) and control (filtered saliva). The samples were exposed to 50 ml of soft drinks for 15, 30 and 60 min, 3 times daily, during 10 days. Between immersions, the samples were kept in filtered saliva. Enamel surface roughness was measured by diamond stylus profilometer using the following roughness parameters: R_a, R_q, R_z, and R_y. Data were analyzed by one-way ANOVA, Tukey's post hoc and Student-Newman-Keuls post hoc tests. Results: The pH values of the soft drinks ranged from 2.52 (Guarana) to 4.21 (strawberry yoghurt). Orange juice had the highest TA, requiring 5.70 ml of NaOH to reach pH 7.0, whereas Coca-Cola required only 1.87 ml. Roughness parameters indicated that Coca-Cola had the strongest erosion potential during the 15 min of exposure, while Coca-Cola and orange juice were similar during 30- and 60-min exposures. There were no significant differences related to all exposure times between Guarana and Cedevita. Strawberry yoghurt did not erode the enamel surface regardless of the exposure time. Conclusion: All of the tested soft drinks except yoghurt were erosive. Erosion of the enamel surfaces exposed to Coca-Cola, orange juice, Cedevita, and Guarana was directly proportional to the exposure time.

Peat Soil Humic Acid Immobilization on Silica Gel and Its Application as an Adsorbent for the Selective Adsorption of Copper

A new type of adsorbent based on the immobilization of humic acid (HA) extracted from tropical peat soil taken in Sambutan village, East Kalimantan, Indonesia, on silica gel (SG) was synthesized and then applied as an adsorbent for the selective adsorption of Cu(II) in the presence of Ca(II). The extraction of HA was performed by the recommended procedure of International Humic Substances Society (IHSS). The immobilization was begun with purification of SG in HCl 1:1 and followed by activation at temperature 110°C for 24 hours. The activated silica gel (4 g) was suspended into 40 mL of NaOH 0.01 M, and into this suspension, 60 mL of NaOH 0.01 M containing 4 g HA was then poured and stirred for 24 hours to allow immobilization of HA on SG. This immobilization produced an adsorbent (SG-HA) with the content of HA was 13.05%(w/w), and this immobilized HA was stable in the acidity range of pH 1.0 to 8.0. The application of SG-HA to selectively adsorb Cu(II) from the solution containing Ca(II) could be achieved at medium acidity that equivalent to pH 4.0 to 5.0. At pH 5, the adsorption rate constant of Cu(II) on SG-HA was 0.027 min-1, while that of Ca(II) on SG-HA was only 0.004 min-1. Similar to the adsorption rate constant, the adsorption capacity and energy of SG-HA for Cu(II), i.e. 0.21 mmol/g and 26.63 kJ/mol, respectively, were also higher than those for Ca(II), i.e. 0.07 mmol/g and 24.87 kJ/mol, respectively. Compared to SG, the immobilization of HA on SG resulted enhancement of the rate constant, capacity, and energy of adsorption. By using SG, the rate constant, capacity, and energy of adsorption of Cu(II) were 0.001 min-1, 0.10 mmol/g, and 21.34 kJ/mol, respectively. [DOI: 10.1380/ejssnt.2006.602]

A New Type of Adsorbent Based on the Immobilization of Humic Acid on Chitin and Its Application to Adsorb Cu(II)

Synthesis of a new type of adsorbent has been conducted by immobilizing peat soil humic acid (HA) on chitin isolated from crab shell waste. The adsorbent was then applied to adsorb Cu(II) in aqueous medium. The HA was extracted from peat soil of Gambut District, South Kalimantan, Indonesia; while the chitin was isolated from marine crab shell waste of seafood restaurants. The extraction of HA was performed by the commonly used alkaline extraction in NaOH 0.1 M solution, and the isolation of chitin was conducted through deproteination using NaOH 3.5%(w/v) and followed by removal of inorganic impurities using HCl 1 M. The extracted HA and the isolated chitin were characterized by Fourier Transform Infra Red (FT-IR) spectroscopy. Parameters investigated in this study consisted of method of HA immobilization on chitin, stability test of the immobilized HA, as well as rate, capacity, and energy of adsorption. The FT-IR spectra revealed the presence of main functional groups of COOH and OH (phenolic- and alcoholic-OH) in HA, and those of NH, C=O, CH3, and OH groups in chitin. The immobilization of HA on chitin was successfully done by reacting gelatinous chitin (40 g) in 250 mL of HCl 0.5 M and solution of HA (4 g) in 500 mL of NaOH 0.5 M. This immobilization produced an adsorbent of humic acid immobilized on chitin (Chitin-HA) with the content of HA was 1.98%(w/w). The HA immobilized was stable in the acidity range of pH 3.0 to 11.0. At the acidity giving maximum adsorption, i.e. pH 4, the first order rate constant, capacity, and energy of adsorption of Cu(II) on the HAC were 4.6 × 10-4 min-1, 0.282 mmol/g, and 20.35 kJ/mol, respectively. Compared to the adsorption of Cu(II) on chitin, the first order rate constant and capacity of adsorption of Cu(II) on the Chitin-HA were, respectively, 1.24 and 1.42 time higher; while the adsorption energy was 0.90 time smaller. [DOI: 10.1380/ejssnt.2006.46]

Adsorption of Fluoride, Phosphate, and Arsenate Ions on a New Type of Ion Exchange Fiber

A new type of ion exchange fiber for the removal of fluoride, phosphate, and arsenate ions has been developed. A batch adsorption technique for investigating adsorption kinetic and equilibrium parameters and determining pH adsorption edges is applied. It is shown that the adsorption properties of the ion exchange fiber for fluoride, phosphate, and arsenate ions depend on the pH value and anion concentration. The adsorption of arsenate on the sorbent reaches a maximum of 97.9% in the pH value range of 3.5 to 7.0. The adsorption percentage of phosphate is more than 99% in the pH range of 3.0 to 5.5. The adsorption of fluoride on the ion exchange fiber is found to be 90.4% at pH 3.0. The Freundlich model can describe the adsorption equilibrium data of fluoride, arsenate, and phosphate anions. The sorption of the three anions on the ion exchange fiber is a rapid process, and the adsorption kinetic data can be simulated very well by the pseudo-second-order rate equation. The column performance is carried out to assess the applicability of the ion exchange fiber for the removal of fluoride, phosphate, and arsenate ions from synthetic wastewaters with satisfactory removal efficiency. The desorption experiment shows that fluoride ion sorbed by the fiber column can be quantitatively desorbed with 5 mL of 0.50 mol/L NaOH at elution rate of 1 mL/min, and 30 mL of NaOH is necessary for the quantitative recovery of phosphate and arsenate ions.

Determination of donepezil, an acetylcholinesterase inhibitor, in human plasma by high-performance liquid chromatography with ultraviolet absorbance detection

A simple and sensitive high-performance liquid chromatographic (HPLC) method with UV absorbance detection is described for the quantification of donepezil, a centrally and selectively acting acetylcholinesterase inhibitor, in human plasma. After sample alkalinization with 0.5 ml of NaOH (0.1 M), the test compound was extracted from 1 ml of plasma using isopropanol–hexane (3:97, v/v). The organic phase was back-extracted with 75 μl of HCl (0.1 M) and 50 μl of the acid solution was injected into a C 18 STR ODS-II analytical column (5 μm, 150×4.6 mm I.D.). The mobile phase consisted of phosphate buffer (0.02 M, pH 4.6), perchloric acid (6 M) and acetonitrile (59.5:0.5:40, v/v) and was delivered at a flow-rate of 1.0 ml/min at 40 °C. The peak was detected using a UV detector set at 315 nm, and the total time for a chromatographic separation was ∼8 min. The method was validated for the concentration range 3–90 ng/ml. Mean recoveries were 89–98%. Intra- and inter-day relative standard deviations were less than 7.3 and 7.6%, respectively, at the concentrations ranging from 3 to 90 ng/ml. The method shows good specificity with respect to commonly prescribed psychotropic drugs, and it could be successfully applied for pharmacokinetic studies and therapeutic drug monitoring.

Determination of risperidone and its major metabolite 9-hydroxyrisperidone in human plasma by reversed-phase liquid chromatography with ultraviolet detection

A simple and sensitive high-performance liquid chromatographic (HPLC) method with UV absorbance detection is described for the quantitation of risperidone and its major metabolite 9-hydroxyrisperidone in human plasma, using clozapine as internal standard. After sample alkalinization with 1 ml of NaOH (2 M) the test compounds were extracted from plasma using diisopropyl ether–isoamylalcohol (99:1, v/v). The organic phase was back-extracted with 150 μl potassium phosphate (0.1 M, pH 2.2) and 60 μl of the acid solution was injected into a C 18 BDS Hypersil analytical column (3 μm, 100×4.6 mm I.D.). The mobile phase consisted of phosphate buffer (0.05 M, pH 3.7 with 25% H 3PO 4)–acetonitrile (70:30, v/v), and was delivered at a flow-rate of 1.0 ml/min. The peaks were detected using a UV detector set at 278 nm and the total time for a chromatographic separation was about 4 min. The method was validated for the concentration range 5–100 ng/ml. Mean recoveries were 98.0% for risperidone and 83.5% for 9-hydroxyrisperidone. Intra- and inter-day relative standard deviations were less than 11% for both compounds, while accuracy, expressed as percent error, ranged from 1.6 to 25%. The limit of quantitation was 2 ng/ml for both analytes. The method shows good specificity with respect to commonly prescribed psychotropic drugs, and it has successfully been applied for pharmacokinetic studies and therapeutic drug monitoring.