1,721,031 research outputs found
Efficiency of Membrane Technology Activated Charcoal and a Clay Micelle Complex for the Removal of Ibuprofen and Mefenamic Acid.
No full textKinetic studies on the stability of two non-steroids anti-inflammatory drugs (NSAIDs), ibuprofen and mefenamic
acid, in pure water and activated sludge indicated that both pharmaceuticals were resistant to degradation for one
month. The efficiency of sequential advanced membrane technology wastewater treatment plant towards removal of
both drugs from wastewater was investigated. The sequential system included activated sludge, ultrafiltration
(hollow fiber membranes with 100 kDa cutoff, and spiral wound membranes with 20 kDa cutoff), activated carbon
column and reverse osmosis (RO). The overall performance of the integrated plant demonstrated complete removal
of ibuprofen and mefenamic acid from spiked wastewater samples. Activated carbon column was the most effective
component in removing these NSAIDs with a removal efficiency of 98.8% for both ibuprofen and mefenamic acid.
Batch adsorption of both NSAIDs by activated charcoal and a composite micelle (octadecyltrimethylammonium
(ODTMA)–clay (montmorillonite) was determined at 25 ̊C. The results revealed that both adsorptions fit Langmuir
isotherm with Qmax of 66.7 mg/g and 62.5 mg/g for ibuprofen using activated carbon and clay-micelle complex,
respectively, and with Qmax of 90.9 mg/g and 100.0 mg/g for mefenamic acid using activated charcoal and claymicelle
complex, respectively. These results suggest that an integration of ODTMA-clay-micelle complex column in
wastewater treatment plant is highly promising and can lead to an improvement of the removal efficiency of these
drugs from wastewater
A hplc-uv method for deteermination of three pesticides in water
Full text linkHPLC method is developed and validated for determination of three pesticides (abamectin, imidacloprid,
and -cyfluthrin) in water. These pesticides are used widely in agriculture for crops protection, and may be
leached to the groundwater. Reversed-phase method with C18 column (5 μm, 250mm × 4.6 mm inner
diameter) using a mobile phase consisting of acetonitrile/water (v:v = 4:1) at a flow rate of 1.5 mL/min and
UV detection at 220 nm was used. This method is validated according to new methods which include
accuracy, precision, linearity and range, limit of detection and limit of quantitation. The current method
exhibits good linearity over the range of 1-1000 ppb for abamectin, 0.5-1000 ppb for imidacloprid, and
0.4-1000 ppb for ß-cyfluthrin with r2 greater than 0.990. The percentage recovery of the method at three
concentration levels (5, 100, and 1000 ppb) is within 97.6 to 101.5% for the three pesticides. Relative
standard deviation of the area of six replicate injections of each pesticide at three concentration levels (5.0,
100.0, and 1000.0 ppb) was found to be less than 1% which reflect the precision of the method. Limit of
quantitation of the three pesticides using this method is low (1.0, 0.5, and 0.4 ppb) for abamectin,
imidacloprid, and -cyfluthrin, respectively which enables the determination of these three pesticides in
water at low concentration levels
Neue mixed-mode Polymermonolithe auf Methacrylatbasis hergestellt durch Komplexierung mit Cyclodextrinen und ihr Einsatz als stationäre Phasen in der Kapillar-Elektrochromatographie
No full textHighly crosslinked, macroporous mixed-mode monolithic stationary phases were synthesized for capillary electrochromatography (CEC). Free radical copolymerization was performed in aqueous solution with a cyclodextrin-solubilized hydrophobic monomer, a water-soluble crosslinker (piperazinediacrylamide), and a negatively charged monomer (vinylsulfonic acid) in bind silane-pretreated fused-silica capillaries. The prepared monolithic stationary phases were used for the separation of neutral hydrophobic (alkylphenones) and neutral polar (phenolic and nitrotoluene solutes) analytes by CEC. Chromatographic properties of the synthesized monoliths were studied with aqueous and non-aqueous mobile phases with hydrophobic and with polar analytes. Due to the amphiphilic nature of the polymers synthesized, the elution orders obtained correspond to the reversed-phase mode and to the normal-phase mode depending on the polarity of the mobile phase. However, observations made with polar solutes and polar mobile phase can only be explained by a mixed-mode retention mechanism. Comparison of retention data with those of a commercial octadecyl silica gel HPLC column reveals that the hydrophobicity of alkylphenones (expressed as methylene selectivity) of the monolithic capillaries prepared in this study is very similar to that of routinely used octadecyl silica gels.
The potential of methacrylate-based mixed-mode monolithic stationary phases bearing sulfonic acid groups for the separation of positively charged analytes (alkylanilines, amino acids, and peptides) by CEC is investigated. The retention mechanism of these charged solutes on these negatively charged mixed-mode stationary phases is investigated by studying the influence of mobile phase and stationary phase parameters on the corrected retention factor. Results show that both hydrophobic and ion-exchange interactions contribute to the retention of these analytes. The quantitative relationship between hydrophobic and ion-exchange interactions is investigated by comparing two different retention models for charged analytes on a mixed-mode stationary phase: the one site and the two-site model.Hochquervernetzte makroporöse monolithische stationäre Phasen wurden für die Kapillarelektrochromatographie (CEC) synthetisiert. Radikalische Copolymerisationen wurden in wässriger Lösung mit einem durch Cyclodextrin in Lösung gebrachten hydrophoben Monomer, einem wasserlöslichen Vernetzer (Piperazindiacrylamid) und einem negativ geladenen Monomer (Vinylsulfonsäure) in einer mit Bindsilan-modifizierten Kapillare durchgeführt. Die hergestellten monolithischen stationären Phasen wurden für die Trennung hydrophober Alkylphenone und weiter polarer Analyte (Phenole und Nitrotoluole) mittels CEC eingesetzt. Die chromatographischen Eigenschaften des synthetisierten Monolithen wurden mit wässrigen und nichtwässrigen mobilen Phasen über die Trennung der hydrophoben und der polaren Analyte ermittelt. Wegen der Amphiphilie des synthetisierten Monolithen entsprechen die erhaltenen Elutionsreihenfolgen sowohl dem Umkehrphasenmodus als auch dem Normalphasenmodus je nach Polarität der mobilen Phase. Jedoch können die Ergebnisse, die mit polaren Analyten und mit polarer mobiler Phase erhalten wurden, nur durch einen gemischtmodigen Retentionsmechanismus erklärt werden. Ein Vergleich von Retentionsdaten mit denen einer kommerziellen Octadecyl-Silicagel-HPLC-Säule zeigt, dass die Hydrophobizität (ausgedrückt als Methylenselektivität) der monolithischen Kapillaren in der gleichen Größenordnung liegt.
Von Interesse ist das Potential dieser monolithischen stationären Phasen mit kovalent immobilisierten Sulfonsäuregruppen für die Trennung von positiv-geladenen Analyte (Alkylaniline, Aminosäuren und Peptide) mittels CEC. Der Mechanismus der Retention dieser positiv-geladenen Analyte auf der negativ-geladenen stationären Phase wurde durch Erfassung des Einflusses der Zusammensetzung der mobilen Phase und der stationären Phase auf den korrigierten Retentionsfaktor untersucht. Die Resultate zeigen, dass sowohl hydrophobe Wechselwirkungen als auch Ionenaustausch zur Retention dieser Analyte beitragen. Das quantitative Verhältnis zwischen den hydrophoben und den Coulomb-Wechselwirkungen wurde untersucht, indem zwei unterschiedliche Modelle für die Wechselwirkung geladener Analyte mit der stationären Phase miteinander verglichen werden: das one-site-Modell und das two-site-Modell
Development and validation of a simple reversed-phase HPLC-UV method for determination of oleuropein in olive leaves
Full text linkAbstractA simple, precise, accurate, and selective method is developed and validated for the determination of oleuropein, which is the main phenolic compound in olive leaves. Separation was achieved on a reversed-phase C18 column (5 μm, 150 × 4.6 mm inner diameter) using a mobile phase consisting of acetonitrile/phosphate buffer pH 3.0 (20:80, v/v), at a flow rate of 1.0 mL/minute and UV detection at 280 nm. This method is validated according to the requirements for new methods, which include accuracy, precision, selectivity, robustness, limit of detection, limit of quantitation, linearity, and range. The current method demonstrates good linearity over the range of 3–1000 ppm of oleuropein, with r2 > 0.999. The recovery of oleuropein in olive leaves ranges from 97.7% to 101.1%. The method is selective, in that oleuropein is well separated from other compounds of olive leaves with good resolution. The method is also precise—the relative standard deviation of the peak areas of replicate injections of oleuropein standard solution is <1%. The degree of reproducibility of the results obtained as a result of small deliberate variations in the method parameters and by changing analytical operators has proven that the method is robust and rugged. The low limit of detection and limit of quantitation of oleuropein when using this method enable the detection and quantitation of oleuropein at low concentrations
Development and Validation of HPLC-UV Method for Determination of Bovine Serum Albumin and Myoglobin Proteins
Full text linkA simple HPLC with UV detection method is developed and validated for determination of
Bovine Serum Albumin and Myoglobin proteins in a standard solution of the two protein
as well as in a plasma spiked with theses two proteins. Separation was achieved on a
reversed-phase C18, 5.0 μm, 150mm × 4.6 mm inner diameter column using a mobile
phase consisting of solution A (900 mL of water, 100 mL Acetonitrile, 10 mL Trifluroacetic
acid) and solution B (900 mL of acetonitrile, 100 mL water, 10 mL Trifluroacetic acid) with
gradient elution of 5 to 50% of solution B in 15 minutes. This new method is validated in
accordance with requirements for new methods, which include accuracy, precision,
selectivity, linearity and range, robustness, limit of detection and limit of quantitation. The
method demonstrates good linearity over the range of 1-1000 ppm for the two proteins
with r2 greater than 0.998. The percentage recovery of the method is within 97.9 to
102.0% for the two proteins. Precision of this method reflected by relative standard
deviation of the area of six replicate injections of each protein at five concentration levels
(1.0, 100.0, 300.0, 500, and 1000.0 ppm) was found to be less than 2%. Limit of
quantitation of the two proteins is low which enables the determination of these proteins at
low concentration
Development and Validation of a Simple Reversed‑Phase HPLC‑UV Method for Determination of Malondialdehyde in Olive Oil
Full text linkA simple, precise, accurate and selective
method was developed and validated for determination
of malondialdehyde (MDA) in olive oil. Separation was
achieved on a reversed-phase C8 column using a mobile
phase consisting of methanol/0.8 % phosphoric acid
(10:90, v/v), at a flow rate of 1.0 ml/min and UV detection
at 220 nm. This method was validated according to
the requirements for new methods, which include accuracy,
precision, selectivity, robustness, a limit of detection,
limit of quantitation (LOQ), linearity and range. The current
method demonstrated good linearity over the range
of 0.5–1000 ppm of MDA with r2 greater than 0.999. The
recovery of MDA in olive oil ranged from 97.1 to 99.1 %.
The method was selective where MDA was distinctly separated
from other compounds of the oil with good resolution.
The method was also precise where the RSD of the
peak areas of replicate injections of MDA standard solution
were less than 1 %. The degree of reproducibility of
the results obtained as a result of small deliberate variations
in the method parameters and by changing the analytical
operators proved that the method is robust and rugged. The
low LOQ of MDA (0.5 ppm) using this method enables
quantitation of MDA at low concentration
Production and Characterization of Active Pectin Films with Olive or Guava Leaf Extract Used as Soluble Sachets for Chicken Stock Powder
No full textThe goal of this study was to improve the functionality of two pectin (PEC) edible films by incorporating olive leaf extract (OLE) or guava leaf extract (GLE). Different concentrations of OLE or GLE (0.1 and 0.2% w/v) were used, and 30% glycerol was added as a plasticizer. The obtained films were evaluated for their mechanical properties, antioxidant activity, thickness, color, opacity, permeability to gases and water vapor, moisture content, and moisture uptake. Soluble sachets were then prepared and filled with chicken stock powder. The results indicated that incorporating OLE or GLE into the PEC films significantly increased their opacity, greenness, and antioxidant activity, which increased from 8.5% in the control to 83.9% when 0.2% GLE was added. Additionally, the films had lower water vapor permeability than the control film. The moisture uptake of the films was also significantly increased when GLE was added. Furthermore, the developed sachets were tested in real-life scenarios, mirroring their intended usage in households. After being introduced to boiling water, the sachets rapidly dissolved within seconds. These results suggest that OLE or GLE, as natural additives, can be used to improve the functionality and activity of edible films
Berberine, a popular dietary supplement for human and animal health: Quantitative research literature analysis – a review
Full text linkBerberine is an alkaloid with a wide range of reported beneficial health effects. The current work provides an extensive literature analysis on berberine. Bibliometric data were identified by means of the search string TOPIC=(“berberin*” OR “umbellatine*”), which yielded 5,547 publications indexed in the Web of Science Core Collection electronic database. The VOSviewer software generated bubble maps to visualize semantic terms with citation results. The ratio of original articles to reviews was 13.6:1. The literature has been growing more quickly since the 2010s. Major contributing countries were China, the United States, India, Japan, and South Korea. Most of the publications appeared in journals specialized in pharmacology pharmacy, biochemistry molecular biology, chemistry, and plant science. Some of the frequently mentioned chemicals/chemical classes were alkaloid, palmatine, jatrorrhizine, coptisine, isoquinoline, and sanguinarine. The prevalent medical conditions under investigation included Alzheimer’s disease, cancer, diabetes, and obesity
Development and Validation of an HPLC-UV Method for Determination of Eight Phenolic Compounds in Date Palms
Full text linkA simple, precise, accurate, and selective method
was developed and validated for determination of
eight phenolic compounds (gallic acid,
p-hydroxybenzoic acid, vanilic acid, caffeic acid,
syringic acid, p-coumaric acid, ferulic acid, and
sinapic acid) in date palms. Separation was achieved
on an RP C18 column using the mobile phase
methanol–water with 2% acetic acid (18 + 82, v/v).
This method was validated according to the
requirements for new methods, which include
accuracy, precision, selectivity, robustness, LOD,
LOQ, linearity, and range. The method demonstrated
good linearity over the range 1–1000 ppm of gallic
acid, p-hydroxybenzoic acid, vanilic acid, caffeic
acid, and syringic acid with r2 greater than 0.99, and
in the range of 3–1000 ppm for p–coumaric acid,
ferulic acid, and sinapic acid with r2 greater than
0.99. The recovery of the eight phenolic compounds
ranged from 97.1 to 102.2%. The method is selective
because adjacent peaks of phenolic compounds
were well separated with good resolution. The
degree of reproducibility of the results obtained as
a result of small deliberate variations in the method
parameters and by changing analytical operators
proved that the method is robust and rugged
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