Hydraulic Activity in Synthetic and Commercial Slags

Slag, by itself, shows very little hydraulic activity. However, hydration is greatly accelerated by incorporation of the slag with Portland cement. This phenomenon is due to the activating role of calcium hydroxide released from the hydration of Portland cement. This study was aimed at finding other activators that will increase hydration in both synthetic and commercial slags. The effects of chemical composition and the aggregation state of the slag on the hydration process were also investigated. For the synthetic slags, the aggregation state was altered by different quenching techniques. The chemical composition was varied by synthesizing a series of slags. The degree of hydration was studied by developing a thermogravimetric analysis technique and the glass content was determined using microscopy. Minerals were determined using powder x-ray diffraction analysis

Preparation and characterization of hybrid molecularly imprinted polymer membranes for the determination of citrinin in rice

A new method for the determination of Citrinin (CIT) in rice samples by hybrid molecularly imprinted polymer (MIP) membrane prior to its quantification by high performance liquid chromatography with fluorescence detection (HPLC-FD) is described for the first time. Conventional extraction methods, such as liquid-liquid extraction (LLE) and solid phase extraction (SPE) produce large volumes of environmentally hazardous waste and the common sorbents used in SPE often suffered from low selectivity. Hybrid MIP membranes offer the advantage of combining the mechanical integrity of the support membrane and the selectivity of the imprinted polymer. These membranes offer large specific surfaces, providing relatively high imprinting sites per unit mass, and fine porous structures, resulting in accessibility of imprinting sites. Thus, MIPs for CIT with 1-naphthol as mimic template were prepared using divinylbenzene as crosslinker and naphthol methacrylate was hybridized into the polyethersulfone scaffold by phase inversion process. The prepared hybrid MIP membrane was characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Using the resultant hybrid MIP membranes as sample preparation for HPLC-FD of CIT, detection and quantification limits of 0.5 ng g-1 and 1.7 ng g-1, respectively, were obtained. The intra-day and inter-day precision expressed in %RSD ranged from 1.9-2.9% and 2.6-5.9%, respectively. The recoveries of CIT in rice spiked at 5, 25 and 100 ng g-1 ranged from 89.7-94.2%. Thus, the hybrid MIP membranes can be valuable material for the practical determination of CIT in rice extracts

Application Of A Flow-Through Triiodide Detector For The Rapid Determination Of Peroxide Value In Edible Oils.

Lipid oxidation constitutes a major quality problem in the processing and storage of fats and oils, and is a major contributor to food deterioration

Flow-Through Chloroquine Sensor And Its Applications In Pharmaceutical Analysis.

Poly(vinyl chloride) membrane electrodes that responded selectively towards the antimalarial drug chloroquine are described. The electrodes were based on the use of the lipophilic potassium tetrakis(4-chlorophenyl)borate as ionexchanger and bis(2-ethylhexyl)adipate (BEHA), or trioctylphosphate (TOP) or dioctylphenylphosphonate (DOPP) as plasticizing solvent mediator

STRUCTURE AND THERMAL STABILITY OF THE BENZO-15-CROWN-5 WITH LANTHANUM (III) BROMIDE COMPLEX

The reaction of benzo-15-crown-5 (C14H20O5) ligand with La(NO3)3.7H2O in the presence of HBr has resulted in the production of an exotic sandwich complex, [LaC28H36Br4O10][3Br]. The crystal system is triclinic with space group P1, a = 12.5834(14) Å, b = 13.5816(16) Å, c = 13.8403(16) Å, a = 70.751(2)°, b = 66.773(2)° and g = 67.631(2)°. The cation comprises of the lanthanum atom coordinated to two crowns via three oxygen atoms from each crown in a η3-sandwich fashion. The two phenyl groups of the crown are brominated. The La-OLigand bond lengths are between 2.857(7) and 2.949(7) Å. The trianion [3Br]3- is linear with Br-Br bond lengths of 2.518(2) and 2.560(2) Å respectively. The molecule is stabilized by intermolecular interactions of the type C-H...Br to form dimers and are arranged parallel to bc face.  Keywords: lanthanum, benzo-15-crown-5, hydrogen bonding, bromination, x-ray structur

2-Hydr­oxy-5-nitro­benzaldehyde 2,4-dinitro­phenyl­hydrazone

In the title compound, C13H9N5O7, one of the nitro groups is twisted away from the attached benzene ring by 16.21 (8)°. The dihedral angle between the two benzene rings is 4.63 (1)°. The mol­ecular structure is stabilized by intra­molecular N—H⋯O and O—H⋯N hydrogen bonds which generate an S(6) ring motif. The mol­ecules pack as layers parallel to the ab plane; mol­ecules of adjacent layers are linked into chains along the [101] direction through N—H⋯O hydrogen bonds

Molecularly imprinted silica gel incorporated with agarose polymer matrix as mixed matrix membrane for separation and preconcentration of sulfonamide antibiotics in water samples

Molecularly imprinted silica gel (MISG) was incorporated through dispersion in agarose polymer matrix to form a mixed matrix membrane (MMM) and was applied for the determination of three sulfonamide antibiotic compounds (i.e. sulfamethoxazole (SMX), sulfamonomethoxine (SMM), and sulfadiazine (SDZ)) from environmental water samples. Several important microextraction conditions, such as type of desorption solvent, extraction time, amount of sorbent, sample volume, pH, and effect of desorption time, were comprehensively optimized. A preconcentration factors of ≥ 20 was achieved by the extraction of 12.5 mL of water samples using the developed method. This microextraction-HPLC method demonstrated good linearity (1–500 μg L–1) with a coefficient of determination (R2) of 0.9959–0.9999, low limits of detection (0.06–0.17 μg L–1) and limits of quantification (0.20–0.56 μg L–1), good analyte recoveries (80–96%), and acceptable relative standard deviations (< 10%) under the optimized conditions. The method is systematically compared to those reported in the literature

Polyamines as chemical markers for the assessment of the infection of fusarium oxysporum F.Sp. Cubense in banana plants.

Fokus utama penyelidikan ini ialah untuk memperkembangkan kaedah analisis baru bagi penentuan (i) amina biogenik dan (ii) drug antidiabetis, metformin. Satu kaedah baru untuk penentuan lapan amina biogenik iaitu histamina, putresina, kadaverina, tiramina, spermina, spermidina, triptamina dan 2-fenileilamina dikembangkan menggunakan elektroforesis rerambut (CE) dengan pengesanan kekonduksian tanpa sentuh kupel teraruh (C4D). The main focus of the research is to develop new analytical methods for the determination of (i) biogenic amines and (ii) antidiabetic drug, metformin.A new method for the determination of eight biogenic amines namely histamine, putrescine, cadaverine, tyramine, spermine, spermidine, tryptamine, an 2- phenylethylamine was developed using capillary electrophoresis (CE) with capacitively coupled contactless conductivity (C40) detection

Tetracaine – selective electrodes with polymer membranes and their application in pharmaceutical formulation control

The construction and electrochemical response characteristics of poly(vinyl chloride) (PVC) membrane electrodes for tetracaine hydrochloride (TCH) are described. The sensing membranes incorporating ion-association complexes of tetracaine cation with phosphotungstic acid (PTA) or phosphomolybdic acid (PMA) or Sodium tetraphenyl borate (NaTPB) as electroactive materials and di-n-butyl phthalate (DBPH) or tri-n-butyl phosphate (TBP) as a plasticizer in PVC matrixes were evaluated. The results obtained show the electrodes based on PTA or PMA as electroactive compounds and DBPH as plasticizer with a fast, stable and near-Nernstian response over a wide concentration range (1 × 10−5–5 × 10−2 M), with cationic slopes of 55.02 and 52.05 mV decade−1 over a pH range of (2.5–6.5). The electrodes show good discrimination of tetracaine from several inorganic cations and sugars. The electrodes were successfully applied for the determination of tetracaine in pharmaceutical formulations