Magnetic molecularly imprinted polymer prepared by microwave heating for confirmatory determination of chloramphenicol in chicken feed using high-performance liquid chromatography-tandem mass spectrometry.

A magnetic molecularly imprinted polymer (MMIP) for chloramphenicol was prepared using a surface-imprinted and microwave-heating-induced polymerization method. The surfaces of the magnetic particles were first double-bond functionalized with 3-(trimethoxysilyl)propyl methacrylate (gamma-MPS), followed by the copolymerization of 4-vinyl pyridine (4-VP) and trimethylolpropane trimethacrylate (TRIM) in the presence of chloramphenicol as a template and 1,1-azobis(cyclohexane-carbonitrile) (ABCN) as an initiator in a mixture of dimethyl sulfoxide and water with microwave heating at 80 degrees C. The magnetic polymer possesses supraparamagnetic properties and was used to concentrate and cleanup chicken feed extract, followed by chromatographic separation using a Lichrospher (R) 100 RP C8 column and detection with two multi-reaction monitoring transitions at m/z 321 -> 152 and m/z 321 -> 257. The mean recoveries obtained at two spiking levels were in the range of 94.6-100% The relative intra- and inter-day standard deviations were in the range of 1.4-2.6% and 5.1-5.7%, respectively. The detection limit of the method was 0.12 mu g kg(-1). This confirmatory method was successfully applied to determine chloramphenicol in chicken feed samples

Degradation products of profenofos as identified by high-field FTICR mass spectrometry: Isotopic fine structure approach.

This study was performed to identify the degradation products of profenofos “a phenyl organothiophosphate insecticide” in raw water (RW) collected from the entry point of Metropolitan Water Works Authority “Bangkaen, Thailand” and ultrapure water (UPW) with and without TiO2 under simulated sunlight irradiation. Degradation of profenofos was followed with ultrahigh performance liquid chromatography (UHPLC) and follows pseudo first-order kinetic. Accordingly, high-field FTICR mass spectrometry coupled to an electrospray ionization source was used to reveal the degradation routes of profenofos and the isotopic fine structures (IFS) elucidations to approve the chemical structures of its degradation products. More degradation products were detected in UPW as compared to RW. Consequently, two main degradation pathways namely (i) interactive replacements of bromine and hydrogen by hydroxyl functional groups and (ii) rupture of PO, PS, CBr and CCl bonds were observed. None interactive replacement of chlorine by hydroxyl functional group was detected. Accordingly, mechanistical pathways of the main degradation products were established

Prenylfuranocoumarin-HMGA-flavonol glucoside conjugates and other constituents of the fruit peels of <em>Citrus hystrix</em> and their anticholinesterase activity.

Sixteen compounds including dihydroxy prenylfuranocoumarins/3-hydroxy-3-methylglutaric acid conjugates and dihydroxy prenylfuranocoumarins/3-hydroxy-3-methylglutaric acid/1-O-flavonyl-&beta;-d-glucopyranoside conjugates, together with other dihydroxyprenylfuranocoumarins conjugates, were isolated from the ethyl acetate extract of the fruit peels of Citrus hystrix. Some of the isolates were evaluated for their cholinesterase inhibitory activity, but only one compound possessing a 3-O-&beta;-d-glucopyranosyl-3,5,7,4&#39;-tetrahydroxy-6,8,3&#39;-trimethoxyflavonol nucleus in the prenylfuranocoumarin-HMGA conjugate showed strong activity