ProFlow nano-liquid chromatography with a graphene oxide-functionalized monolithic nano-column for the simultaneous determination of chloramphenicol and chloramphenicol glucuronide in foods

Optimization, validation, and application of a liquid chromatography-tandem mass spectrometry method for the determination of 47 banned drug and related chemical residues in livestock urine using graphitized carboxyl multi-walled carbon nanotubes-based QuEChERS extraction

The establishment of an efficient method for the analysis of drug residues in animal urine facilitates the real-time monitoring of drugs used in the production of animal-derived food. A modified QuEChERS extraction-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the determination of 47 banned drug and related chemical residues in livestock urine. The sample was extracted with acetonitrile by converting the acid-base environment. The sample cleanup effects of seven solid phase extraction cartridges and two EMR-Lipid products were compared, and three materials, including graphitized carboxyl multi-walled carbon nanotubes (MWCNTs), PSA, and C18, were selected as QuEChERS adsorbents from 24 materials. All analytes showed good linearity, with correlation coefficients (R2) greater than 0.9936. Low limits of quantification could be obtained, ranging from 0.2 to 5.5 ng/mL. The average recoveries at low, medium, and high spiked levels were in the range of 70.8-114.9 %, with intra-day precision ranging from 2.4 % to 11.2 % and inter-day precision ranging from 4.5 % to 16.1 %. Swine urine and bovine urine samples collected from different farms were effectively analyzed using the developed method, and metronidazole was detected in three swine urine samples.

Recent Trends in Graphene-Based Sorbents for LC Analysis of Food and Environmental Water Samples

This review provides an overview of recent advancements in applying graphene-based materials as sorbents for liquid chromatography (LC) analysis. Graphene-based materials are promising for analytical chemistry, including applications as sorbents in liquid chromatography. These sorbents can be functionalized to produce unique extraction or stationary phases. Additionally, graphene-based sorbents can be supported in various materials and have consequently been applied to produce various devices for sample preparation. Graphene-based sorbents are employed in diverse applications, including food and environmental LC analysis. This review summarizes the application of graphene-based materials in food and environmental water analysis in the last five years (2019 to 2023). Offline and online sample preparation methods, such as dispersive solid phase microextraction, stir bar sorptive extraction, pipette tip solid phase extraction, in-tube solid-phase microextraction, and others, are reviewed. The review also summarizes the application of the columns produced with graphene-based materials in separating food and water components and contaminants. Graphene-based materials have been reported as stationary phases for LC columns. Graphene-based stationary phases have been reported in packed, monolithic, and open tubular columns and have been used in LC and capillary electrochromatography modes.

Nano-Liquid Chromatography with a New Monolithic Column for the Analysis of Coenzyme Q10 in Pistachio Samples

Coenzyme Q10 (CoQ10) is a vital substance found throughout body. It helps convert food into energy and is eaten small amounts in foods. CoQ10 has gained great interest in recent years as a potential candidate for the treatment of various diseases. The content of CoQ10 in food samples is a crucial quality index for foods. Therefore, the development of sensitive separation and quantification method for determining the amount of CoQ10 in various samples, especially in foods, is an important issue, especially for food nutrition. In this study, a new, miniaturized monolithic column was developed and applied for the determination of CoQ10 in pistachio samples by nano-liquid chromatography (nano-LC). The monolithic column with a 50 µm i.d. was prepared by in situ polymerization using laurylmethacrylate (LMA) as the main monomer and ethylene dimethacrylate (EDMA) as the crosslinker. Methanol (MeOH) and polyethyleneglycol (PEG) were used as porogenic solvents. The final monolithic column was characterized by using scanning electron microscopy (SEM) and chromatographic analyses. The monolithic column with a 50 µm i.d. was applied to the analysis of CoQ10 in pistachio samples in nano-LC. This analytical method was validated by means of sensitivity, linearity, precision, recovery, and repeatability. The LOD and LOQ values were 0.05 and 0.48 µg/kg, respectively. The developed method using the monolithic column was optimized to achieve very sensitive analyses of CoQ10 content in the food samples. The applicability of the method was successfully demonstrated by the analysis of CoQ10 in pistachio samples.