Improved matrix purification using a graphene oxide-coated melamine sponge for UPLC-MS/MS-based determination of 37 veterinary drugs in milks.

A rapid and highly sensitive method was established for the analysis of 37 veterinary drug residues in milk using a modified QuEChERS method based on a reduced graphene oxide-coated melamine sponge (rGO@MeS) coupled with UPLC-MS/MS. Under optimal chromatographic and mass spectrometric conditions, the effects of different dehydrated salts (MgSO and NaSO) and metal chelating agents (NaEDTA) on extraction efficiency were first investigated. Next, the influence of a dynamic and static purification mode was evaluated in terms of drug recoveries.

Effects of lactic acid bacteria on antioxidant activity in vitro and aroma component of tea.

tea is a popular functional health drink in Asian countries, but its unique herbal aroma is difficult for consumers to accept. The effects of four lactic acid bacteria strains (, , and ) fermentation on the physicochemical property, antioxidant activity in vitro and aroma component of leaves were studied. Within the four strains, the sample by fermentation showed the higher concentrations of chlorogenic acid, geniposidic acid and stronger antioxidant activity in vitro.

A modified QuEChERS method based on a reduced graphene oxide-coated melamine sponge for multiresidue analysis of veterinary drugs in mutton by UPLC-MS/MS.

The development of different matrix adsorbents is a research focus in the multiresidue analysis of veterinary drugs in foods. In this study, a novel elastic matrix adsorbent based on a reduced graphene oxide-coated melamine sponge was prepared and applied in matrix purification for the simultaneous determination of 52 veterinary drugs in mutton by UPLC-MS/MS. Efficient and convenient matrix removal was achieved through simple soaking and squeezing.

A facile fluorescent sensor based on nitrogen-doped carbon dots derived from for highly selective and visual detection of iodide and pH.

Sensitive and visual analysis of iodide (I) and pH is significant in environmental and food applications. Herein, we present a facile fluorescent sensor for highly selective and visual detection of I and pH based on nitrogen-doped carbon dots derived from (NCDs-LM). The NCDs-LM-based fluorescent sensor showed a good linear relationship to I concentrations, and the detection limit was calculated as 20 nmol L.

Application of silanized melamine sponges in matrix purification for rapid multi-residue analysis of veterinary drugs in eggs by UPLC-MS/MS.

Fast and convenient matrix purification is an important prerequisite for high-throughput analysis of drug multiresidues in food. In this study, a silanized melamine sponge was prepared and first applied in the rapid determination of multiclass veterinary drugs in eggs by ultrahigh-performance liquid chromatography-tandem mass spectrometry. Within five seconds, fast, convenient and efficient matrix separation could be achieved through simple soaking and squeezing.

Development of a modified quick, easy, cheap, effective, rugged, and safe method based on melamine sponge for multi-residue analysis of veterinary drugs in milks by ultra-performance liquid chromatography tandem mass spectrometry.

The purpose of this study was to develop a modified QuEChERS method based on melamine sponge for rapid determination of multi-class veterinary drugs in milks by UPLC-MS/MS. Through simple infiltration and extrusion, fast and convenient matrix purification could be achieved within several seconds, and there was no need of extra phase separation operations. Good linearity with correlation coefficient (R) ≥0.

Magnetic porous aromatic framework with a core-shell structure as a sorbent for rapid extraction of phenols and their quantitation in urine by HPLC-UV.

A porous aromatic framework (PAF) is shown to be a viable sorbent for the adsorption of phenols. To overcome the difficulty of quick adsorption and enrichment by phenols from the matrix, a sorbent material consisting of porous aromatic framework magnetic nanoparticles (PAF MNPs) with a core-shell structure was fabricated by an in situ growth method. The PAF MNP sorbent was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and other techniques.

Antioxidant epoxydon and benzolactone derivatives from the insect-associated fungus sp.

One new epoxydon ester () and a new benzolactone derivative (), along with four known compounds (-), were isolated from the insect-associated fungus sp. Their structures were confirmed by extensive MS and NMR spectroscopic analysis and their absolute configurations were determined by a combination of modified Mosher method and Mo(OCOCH)-induced electronic circular dichroism (ECD) experiments. Compounds and were revealed to have potent antioxidant activities, which were approximate to the potency of the positive control trolox.