Fully automated multianalyte determination of different classes of pesticides,at picogram per litre levels in water,by on-line solid-phase extraction–liquid chromatography–electrospray–tandem mass spectrometry

This paper reports the development of a fully automated method for the multianalyte determination of twenty pesticides belonging to different classes (triazines, phenylureas, organophosphates, anilines, acidic, propanil, and molinate) in natural and treated waters. The method, based on on-line solid-phase extraction–liquid chromatography–electrospray–tandem mass spectrometry, is highly sensitive (limits of detection between 0.004 and 2.8 ng L^–1), precise (relative standard deviations between 2.0 and 12.1%), reliable (two selected reaction-monitoring transitions are monitored per compound), rapid (45 min per sample), and simple. The application of this method to the monitoring of the target compounds in a waterworks revealed the presence of the pesticides investigated at concentrations up to 516 and 82 ng L^–1 (total pesticide concentration) in river water and ground water, respectively, used as sources, and their gradual removal through the purification process.Dedicated to the memory of Wilhelm Fresenius     

Development and single-laboratory validation of a new gas chromatographic multi-pesticide method of analysis of commercial emulsifiable concentrate formulations containing alachlor, chlorpyrifos methyl, fenthion and trifluralin as active ingredients

A multi-pesticide (MP) method was developed and single-laboratory validated for the quality control of commercial pesticide products containing alachlor, chlorpyrifos methyl, fenthion and trifluralin as active ingredients (a.i.). A capillary gas chromatographic system with flame ionization detection (FID) and a programmable temperature vaporising split injector was used. The performance characteristics (specificity, linearity, precision and repeatability) of the method satisfied international acceptability criteria.     

Salting-out homogeneous liquid-liquid microextraction for the determination of azole drugs in human urine: Validation using total error concept

A salting-out homogeneous liquid-liquid microextraction was proposed for the quantification of four azole drugs in human urine prior to high-performance liquid chromatography analysis. The procedure involved the mixing of the sample with acetonitrile in appropriate volumes followed by the addition of sodium sulfate solution in order to facilitate phase separation. The parameters influencing the extraction performance were studied and optimized using a two-step experimental design. The analytical procedure was thoroughly validated using the accuracy profiles as a graphical decision-making tool. The β-expectation tolerance intervals did not exceed the acceptance criteria of ±15% meaning that 95% of future results will be included in the defined bias limits. The limits of detection of the procedure were satisfactory, ranging between 0.01 and 0.03 μg/mL. The mean analytical bias in the spiking levels was satisfactory and ranged between –10.3 and 4.2% while the relative standard deviation was lower than 5.6%. Monte-Carlo simulations followed by capability analysis were employed to investigate the ruggedness of the sample preparation protocol. The developed method offers advantages compared to previously reported approaches for the same type of analysis including extraction efficiency and scaling down of the sample volume and extraction time.     

Photoluminescence and electroluminescence by gallium(III) complexes of N-salicylidene-o-aminophenol and its derivatives

N-salicylidene-o-aminophenol and two of its derivatives bearing either an electron-donating methyl group or an electron-withdrawing Br group were used as ligands for the synthesis of three Ga(III) complexes. The complexes involved the participation of one acetylacetonate and one ethanol or methanol molecule. The geometry of the dianion of the Schiff base in the complexes is planar while photoluminescence data showed that photoluminescence intensity was extensively increased upon complex formation. Complexes emitted ligand-centered luminescence by ligand-centered excitation. Substituent groups broadly modified emission maximum. These substitutions can be exploited to tune light emission by the complex. All three complexes were used for the construction of electroluminescence devices and all emitted electroluminescence. Both photoluminescence and electroluminescence emission was enhanced in the case of substituted Schiff bases.     

Crocins from Crocus sativus L. in the Management of Hyperglycemia. In Vivo Evidence from Zebrafish

Diabetes mellitus is a disease characterized by persistent high blood glucose levels and accompanied by impaired metabolic pathways. In this study, we used zebrafish to investigate the effect of crocins isolated from Crocus sativus L., on the control of glucose levels and pancreatic β-cells. Embryos were exposed to an aqueous solution of crocins and whole embryo glucose levels were measured at 48 h post-treatment. We showed that the application of crocins reduces zebrafish embryo glucose levels and enhances insulin expression. We also examined whether crocins are implicated in the metabolic pathway of gluconeogenesis. We showed that following a single application of crocins and glucose level reduction, the expression of phosphoenolpyruvate carboxykinase 1 (pck1), a key gene involved in glucose metabolism, is increased. We propose a putative role for the crocins in glucose metabolism and insulin management.     

Synthesis and structure of N-salicylidene-o-aminophenolato gallium(III) complexes

The reactions of Ga(acac)₃ with N-salicylidene-o-aminophenol (saphH₂) and its 5-methyl (5MesaphH₂) and 5-bromo (5BrsaphH₂) derivatives in alcohols afforded the complexes [Ga(acac)(saph)(EtOH)] (1), [Ga(acac)(5Mesaph)(MeOH)] (2) and [Ga(acac)(5Brsaph)(EtOH)] (3), respectively, in good yields. The crystal structures of 1 and 2 have been solved by single-crystal X-ray crystallography. All three complexes are mononuclear with the Ga^III atoms being surrounded by a dianionic tridentate Schiff base ligand, one bidentate acac⁻ ligand and a terminal alcohol molecule. Characteristic IR data are discussed in terms of the nature of bonding and the structures of the three complexes.     

Lithium-7, sodium-23, and cesium-133 NMR and far infrared study of alkali complexes with C222-dilactam in various solvents

Nuclear magnetic resonances of alkali nuclei,⁷Li,²³Na, and¹³³Cs, as well as far infrared measurements are used to study alkali complexes of a bicyclic diazapolyoxa ligand—the dilactam of cryptand C222. Measurements were carried out in pyridine, tetrahydrofuran, acetonitrile, nitromethane, dimethylformamide, and aqueous solutions. The complexing ability of the dilactam is similar to, but weaker than, that of the cryptand C222. The limiting chemical shifts of the complexed cations were solvent-dependent, indicating incomplete enclosure of the cation by the ligand. Formation constants of Li⁺ and Cs⁺ complexes were calculated from the chemical-shift dependence on the ligand/metal ion mole ratio.     

Synthesis,characterization and crystal structure of a novel mononuclear peroxotungsten(VI) complex with an acetone peroxide ligand

A new mononuclear peroxo complex of tungsten of the formula (gu)₂[WO(O₂)₂CO(O)₂(CH₃)₂](CH₃)₂CO (where gu⁺ = guanidinium ion, CN₃H₆⁺ion) has been synthesized and characterized by infrared, Raman, and ¹H NMR spectroscopies. The crystal structure of (gu)₂[WO(O₂)₂CO(O)₂(CH₃)₂](CH₃)₂CO determined by X-ray diffraction indicates that the side-on peroxo groups and the bidentate acetone peroxide ligand bind the W(VI) centre leading to an hepta coordination mode. The guanidinium ion occurring as a counterion and the hydrogen-bound interactions stabilize the complexes. The stability of the complex in aqueous solution was determined by Raman and NMR spectroscopies.