Sequential hollow-fiber liquid phase microextraction for the determination of rosiglitazone and metformin hydrochloride (anti-diabetic drugs) in biological fluids.

A new analytical method for the simultaneous determination of the antidiabetic drugs rosiglitazone (ROS) and metformin hydrochloride (MH) with marked differences in their affinity towards organic solvents (log P of 2.4 and -1.43, respectively) was developed.

Hollow fiber liquid phase microextraction with in situ derivatization for the determination of trace amounts of metformin hydrochloride (anti-diabetic drug) in biological fluids.

A three phase hollow fiber liquid-phase microextraction with in situ derivatization (in situ HF-LPME) followed by high-performance liquid chromatography-ultraviolet detection (HPLC-UV) method was developed for the trace determination of metformin hydrochloride (MH) in biological fluids. A new derivatization agent pentafluorobenzoyl chloride (PFBC) was used. Several parameters that affect the derivatization and extraction efficiency were studied and optimized (i.

Investigation of crystal structure influence on spectroscopic and photoluminescent properties of terbium-picrate triethylene glycol complex.

The [Tb(Pic)(2)(H(2)O)(EO3)](Pic)·0.5(EO3) complex, for which EO3 and Pic stand for triethylene glycol and picrate anion, respectively, was successfully prepared and characterized. The Tb(III) complex was crystallized in triclinic structure with space group P1¯.

A 4-hydroxy-N'-[(E)-(2-hydroxyphenyl)methylidene]benzohydrazide-based sorbent material for the extraction-HPLC determination of biogenic amines in food samples.

A sorbent material based on a newly synthesized hydrazone ligand, 4-hydroxy-N'-[(E)-(2-hydroxyphenyl)methylidene]benzohydrazide was prepared by immobilizing the ligand into a silica sol-gel matrix. The capability of the sorbent material for the extraction of seven biogenic amines (BAs), i.e.

Determination of underivatized long chain fatty acids using RP-HPLC with capacitively coupled contactless conductivity detection.

A reversed-phase high-performance liquid chromatographic method with capacitively coupled contactless conductivity detector (C(4)D) has been developed for the separation and the simultaneous determination of five underivatized long chain fatty acids (FAs), namely myristic, palmitic, stearic, oleic, and linoleic acids. An isocratic elution mode using methanol/1mM sodium acetate (78:22, v/v) as mobile phase with a flow rate of 0.6 mL min(-1) was used.

Extraction of biogenic amines using sorbent materials containing immobilized crown ethers.

Three sorbent materials (A18C6-MS, DA18C6-MS and AB18C6-MS) based on the crown ether ligands, 1-aza-18-crown-6, 1,4,10,13-tetraoxa-7,16-diazacyclo octadecane and 4'-aminobenzo-18-crown-6, respectively, were prepared by the chemical immobilization of the ligand onto mesoporous silica support. The sorbents were characterized by FT-IR, scanning electron microscopy-energy dispersive X-ray microanalysis, elemental analysis and nitrogen adsorption-desorption test. The applicability of the sorbents for the extraction of biogenic amines by the batch sorption method was extensively studied and evaluated as a function of pH, biogenic amines concentration, contact time and reusability.

Coordination of Ce(III) and Nd(III) with pentaethylene glycol in the presence of picrate anion: spectroscopic and X-ray structural studies.

(1)H NMR evidence for direct coordination between the Ln(III) ion and the oxygen atoms of the pentaethylene glycol (EO5) ligand and the picrate anion (Pic) in [Ln(Pic)(2)(EO5)][Pic] {Ln=Ce and Nd} complexes are confirmed by single X-ray diffraction. No dissociation of Ln-O bonds in dimethyl sulfoxide-d solution was observed in NMR studies conducted at different temperatures ranging 25-100 degrees C. The Ln(III) ion was chelated to nine oxygen atoms from the EO5 ligand in a hexadentate manner and the two Pic anions in each bidentate and monodentate modes.

In situ derivatization hollow fibre liquid-phase microextraction for the determination of biogenic amines in food samples.

Hollow fibre liquid-phase microextraction with in situ derivatization using dansyl chloride has been successfully developed for the high-performance liquid chromatography-ultraviolet (HPLC-UV) determination of the biogenic amines (tryptamine, putrescine, cadaverine, histamine, tyramine, spermidine) in food samples. Parameters affecting the performance of the in situ derivatization process such as type of extraction solvent, temperature, extraction time, stirring speed and salt addition were studied and optimized. Under the optimized conditions (extraction solvent, dihexyl ether; acceptor phase, 0.

Determination of quinocide as impurity in primaquine tablets by capillary zone electrophoresis.

A capillary zone electrophoretic method has been developed and validated for the determination of the impurity quinocide (QC) in the antimalarial drug primaquine (PQ). Different buffer additives such as native cyclodextrins and crown ethers were evaluated. Promising results were obtained when either beta-cyclodextrin (beta-CD) or 18-crown-6 ether (18C6) were used.

Enantioselective analysis of primaquine and its impurity quinocide by capillary electrophoresis.

A capillary electrophoretic (CE) method for the baseline separation of the enantiomers of primaquine diphosphate (PQ) and quinocide (QC) (a major contaminant) in pharmaceutical formulations is proposed. Both components were separated under the following conditions: 50 mm tris phosphate buffer (pH 3.0) containing 15 mm hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) as background electrolyte; applied voltage, 16 kV; capillary temperature, 25 degrees C; detection wavelength, 254 nm; hydrostatic injection, 10 s.

Development of a capillary electrophoresis method for the enantioselective estimation of primaquine in pharmaceutical formulations.

A capillary electrophoresis (CE) method has been developed that allows the separation and estimation of primaquine enantiomers using hydroxypropyl-gamma-cyclodextrin (HP-gamma -CD) as a chiral selector. The influence of chemical and instrumental parameters on the separation, such as type and concentration of CD, buffer concentration, buffer pH, applied voltage, capillary temperature, and injection time, were investigated. Good separation of the racemic mixture of primaquine was achieved using a fused-silica capillary (52.

Tris(nitrato-κO,O')bis-(1,10-phenanthroline-κN,N')holmium(III).

In the title compound, [Ho(NO(3))(3)(C(12)H(8)N(2))(2)], the ten-coordinate Ho(III) ion is chelated by four N atoms from two phenanthroline (phen) ligands and six O atoms from three bidentate nitrate groups. The environment around the Ho atom can be described as a distorted bicapped square anti-prism. Two phenanthroline ligands form a dihedral angle of 43.

Dibenzo-18-crown-6-picric acid-water (1/2/3).

In the crown ether ring of the title compound, C(20)H(24)O(6)·2C(6)H(3)N(3)O(7)·3H(2)O, the O-C(H(2))-C(H(2))-O torsion angles indicate a gauche conformation of the ethyl-eneoxy units, while the C-O-C-C torsion angles indicate planarity of these segments; the dihedral angle between the two benzene rings is 44.53 (13)°. In both picric acid mol-ecules, one of the nitro groups is twisted away from the attached ring.

Aqua-dipicrato(tetra-ethyl-ene glycol)gadolinium(III) picrate methanol hemisolvate.

THE ASYMMETRIC UNIT OF THE TITLE COMPOUND [SYSTEMATIC NAME: aqua-bis(2,4,6-trinitro-phenolato)(3,6,9-trioxaundecane-1,11-diol)gadolinium(III) 2,4,6-trinitro-phenolate methanol hemi-solvate], [Gd(C(6)H(2)N(3)O(7))(2)(C(8)H(18)O(5))(H(2)O)](C(6)H(2)N(3)O(7))·0.5CH(4)O, contains two crystallographically independent Gd(III) complex cations with two uncoordinated picrate anions and one methanol mol-ecule. Each Gd(III) atom has nine coordination sites occupied by five O atoms of tetra-ethyl-ene glycol as a penta-dentate ligand, one O atom of a water mol-ecule and three O atoms of the two picrate anions as bidentate and monodentate ligands.

Flow injection determination of anisidine value in palm oil samples using a triiodide potentiometric detector.

A flow injection analysis (FIA) procedure for the determination of anisidine value (AV) in palm olein using a triiodide detector is described. Undiluted oil sample and chloramine-T reagent were added to a reaction chamber, and reaction was accelerated by applying a short vortex action (typically for 30 s). After allowing the emulsified oil phase to be separated from the aqueous phase (bottom layer), an aliquot of the aqueous phase (containing unreacted chloramine-T) was aspirated into a carrier stream that contained I(-) where the chloramine-T oxidized the I- to form I3(-) which was finally detected by a flow-through triiodide potentiometric detector.

Sequential flow injection determination of chlorine species using a triiodide-selective electrode detector.

A flow injection analysis (FIA) method for the determination of four residual chlorine species, namely combined available chlorine (CAC), free available chlorine (FAC), total available chlorine (TAC) and chlorite (ClO2-) was developed using a flow-through triiodide-selective electrode as a detector. An important strategy of speciation studies utilized the kinetic discrimination of reactions between the CAC and FAC with Fe2+, which was applied to the speciation of FAC, CAC and TAC. The speciation of available chlorine species and chlorite (an oxychlorine species) was achieved by using the same set-up, but using flow streams of different pH.

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 ion-exchanger and bis(2-ethylhexyl)adipate (BEHA), or trioctylphosphate (TOP) or dioctylphenylphosphonate (DOPP) as plasticizing solvent mediator. All electrodes produced good quality characteristics such as Nernstian- and rapid responses, and are minimally interfered with by the alkali and alkaline earth metal ions tested.

Simultaneous determination of preservatives (benzoic acid, sorbic acid, methylparaben and propylparaben) in foodstuffs using high-performance liquid chromatography.

A reversed-phased HPLC method that allows the separation and simultaneous determination of the preservatives benzoic (BA) and sorbic acids (SA), methyl- (MP) and propylparabens (PP) is described. The separations were effected by using an initial mobile phase of methanol-acetate buffer (pH 4.4) (35:65) to elute BA, SA and MP and changing the mobile phase composition to methanol-acetate buffer (pH 4.