Search results for "FATE"

Exploiting 1,4-naphthoquinone and 3-iodo-1,4-naphthoquinone motifs as anion binding sites by hydrogen or halogen-bonding interactions

2019

We describe here the utilization of 1,4-naphthoquinone and 3-iodo-1,4-naphthoquinone motifs as new anion binding sites by hydrogen- or halogen-bonding interactions, respectively. These binding sites have been integrated in bidentate ester based receptors. Emission experiments reveal that both receptors selectively recognize sulfate anions, which induced a remarkable increase of a new emission band attributed to the formation of π-stacking interactions between two 1,4-naphthoquinone units. Absorption spectroscopy and mass spectrometry indicate the disruption of the ester group of the 1,4-naphthoquinone based receptor in the presence of HP2O73−, H2PO4−, F−, AcO− and C6H5CO2− and in the haloge…

2009

Abstract. Systematic laboratory experiments were performed to investigate quantification of various species with two versions of the Aerodyne Aerosol Mass Spectrometer, a Quadrupole Aerosol Mass Spectrometer (Q-AMS) and a compact Time-of-Flight Aerosol Mass Spectrometer (c-ToF-AMS). Here we present a new method to continuously determine the detection limits of the AMS analyzers during regular measurements, yielding detection limit (DL) information under various measurement conditions. Minimum detection limits range from 0.03 μg m−3 (nitrate, sulfate, and chloride) up to 0.5 μg m−3 (organics) for the Q-AMS. Those of the c-ToF-AMS are found between 0.003 μg m−3 (nitrate, sulfate) and 0.03 μg …

Determination of thyreostatics in animal feed by micellar electrokinetic chromatography

1999

The determination of the thyreostatics 2-thiouracil, its derivatives (4-methyl-2-thiouracil, 4-propyl-2-thiouracil and 4-phenyl-2-thiouracil) and methimazole in manufactured dried animal feed by micellar electrokinetic chromatography (MEKC) is described. A 99 +/- 5% extraction yield at the 20 micrograms g-1 level (n = 8) was achieved by shaking the milled fodder with methanol-1 M NaOH (80 + 20). Aliquots of the supernatant were injected in a 75 microns x 33.5 cm uncoated silica capillary using pressure; separation was performed at 23 degrees C with 15 kV (positive polarity) in a background electrolyte (BGE) containing 40 mM sodium dihydrogenphosphate, 50 mM sodium dodecyl sulfate and 15 mM …

Analysis of post-harvest fungicides by micellar electrokinetic chromatography.

2001

A method based on solid-phase extraction (SPE) and micellar electrokinetic chromatography (MEKC) was developed for the simultaneous determination of carbendazim, imazalil, methylthiophanate, O-phenylphenol, prochloraz, procimidone, thiabendazole and triadimefon residues in grape, lettuce, orange and tomato. Selectivity and resolution were studied changing the pH and the concentration of the buffer, the type and concentration of surfactant and the methanol content in the mobile phase. A buffer consisting of 4 mM borate with 75 mM sodium cholate (pH 9.2) gave the best results. The recoveries of the fungicides in spiked fruit and vegetable samples ranged from 30 to 105%, and the limits of dete…

RAPID LIQUID CHROMATOGRAPHIC DETERMINATION OF TETRACYCLINES IN ANIMAL FEEDS USING A SURFACTANT SOLUTION AS MOBILE PHASE

2002

ABSTRACT A chromatographic procedure was developed for the determination of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), doxycycline (DC) and minocycline (MINO) in animal feeds. Clear analyte-rich extracts were obtained using a 1 : 1 acetonitrile/water mixture buffered at pH 3. The extracts were injected into a conventional unprotected C18 chromatographic column and eluted with a mobile phase of 0.05 M sodium dodecyl sulfate/5% 1-butanol/0.01 M oxalic acid at pH 3. Good resolution was achieved for the five compounds, whereas OTC and TC coeluted with an optimized aqueous-organic mobile phase of methanol/acetonitrile/0.01 M oxalic acid at pH 3. Mean recoveries from spike…

Determination of amitraz and its transformation products in pears by ethyl acetate extraction and liquid chromatography-tandem mass spectrometry.

2008

A method has been developed for identification and quantification of the acaricide amitraz and its transformation products, 2,4-dimethylaniline (DMA), 2,4-dimethylformamidine (DMF) and N-2,4-dimethylphenyl-N-methylformamidine (DMPF) in pears. The analytes were extracted using ethyl acetate and anhydrous sodium sulphate. Analysis was performed by liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) in the positive ion mode using a triple quadrupole (QqQ) instrument. Two precursor-product ion transitions were monitored for each compound in the selected reaction monitoring (SRM) mode. The method was validated with pears taken from the orchard before the amitraz treatment …

Zinc removal in anaerobic sulphate-reducing liquid substrate process

2002

Abstract Zinc and sulphate removal from synthetic wastewater was investigated by using four laboratory parallel upflow-mode reactors (referred as R1 to R4; R1 contained carriers to retain biomass, whereas R2–R4 were operated as suspended reactors). All reactors were inoculated with anaerobically digested cow manure. R1 and R2 were first fed with glucose- and sulphate-containing feed for 48 days after which all four reactors were fed with wastewater containing 50 mg l−1 of zinc in R1–R3 and 200 mg l−1 in R4 and operated for 96 days. In all reactors, hydraulic retention time, organic loading rate, and sulphate load were 5–6 d, 0.2–0.4 kg COD m−3 d−1 and 3.3–3.8 g SO4 l−1 d−1, respectively, wh…

A fugacity model assessment of ibuprofen, diclofenac, carbamazepine, and their transformation product concentrations in an aquatic environment

2018

An updated version of FATEMOD, a multimedia fugacity model for environmental fate of organic chemicals, was set up to assess environmental behaviour of three pharmaceuticals in northern Lake Päijänne, Finland. Concentrations of ibuprofen, diclofenac, and carbamazepine were estimated at various depths at two sites: near a wastewater treatment plant and 3.5 km downstream the plant. When compared with environmental sampling data from corresponding depths and sites, the predicted concentrations, ranging from nanograms to hundreds of nanograms per litre, were found to be in good agreement. Weather data were utilised with the model to rationalise the effects of various environmental parameters on…

Purification of Large Cytosolic Proteases for In Vitro Assays: 20S and 26S Proteasomes

2012

Proteasomes are the main cytosolic proteases responsible for generating peptides for antigen processing and presentation in the MHC (major histocompatibility complex) class-I pathway. Purified 20S and 26S proteasomes have been widely used to study both specificity and efficiency of antigen processing. Here, we describe the purification of active human 20S and 26S proteasomes from human erythrocytes by DEAE-ion exchange chromatography, ammonium sulfate precipitation, glycerol density gradient centrifugation, and Superose-6 size exclusion chromatography and their characterization using fluorogenic substrates and specific inhibitors.

Neue chemotherapeutisch-aktive 4-trifluormethylpyrimidine

1993

Abstract Condensation of N -(2-hydroxyethyl)- N -methylguanidine sulfate with various β-diketonesbearing 1,1,1-trifluoromethyl substituents leads to 2-[ N -(2-hydroxyethyl)-methylamino]-4-trifluoromethylpyrimidine derivatives. These compounds exhibit antimycotic, trichomonazide and anti-HIV properties.