Evaluation of the combination of micellar electrokinetic capillary chromatography with sweeping and cation selective exhaustive injection for the determination of 5-nitroimidazoles in egg samples

Construction of hydrophilic hypercrosslinked polymer based on natural kaempferol for highly effective extraction of 5-nitroimidazoles in environmental water, honey and fish samples

A series of novel hydroxyl-functional hypercrosslinked polymers (named as HCPs-Kae) were fabricated using natural and environmentally benign kaempferol as monomer via one-step Friedel-Crafts reaction. The prepared HCP-Kae1-24 h exhibited large surface area, good hydrophilicity and excellent adsorption performance to 5-nitroimidazoles (5-NDZs). Thus, by applying HCP-Kae1-24 h as a solid-phase extraction adsorbent, a sensitive method was developed for enrichment of 5-NDZs including metronidazole, ronidazole, secnidazole, dimetridazole and ornidazole prior to high performance liquid chromatography analysis. Under the optimum conditions, good linearities were achieved in the range of 0.10-100.0 ng mL^-1 for water, 1.3-500.0 ng g^-1 for honey, and 1.7-100.0 ng g^-1 for fish meat. The detection limits of the method were 0.03-0.05 ng mL^-1, 0.4-1.0 ng g^-1, 0.5-1.0 ng g^-1 for water, honey and fish meat, respectively. High method recovery was obtained in the range of 84-118% with relative standard deviations lower than 8.9%. The established method was successfully applied to the detection of 5-NDZs in environmental water, honey and fish samples. This work provides a new strategy for constructing hydroxyl-functional HCPs by using natural resource as robust adsorbent for adsorption/extraction applications.

Advances in the Analysis of Veterinary Drug Residues in Food Matrices by Capillary Electrophoresis Techniques

In the last years, the European Commission has adopted restrictive directives on food quality and safety in order to protect animal and human health. Veterinary drugs represent an important risk and the need to have sensitive and fast analytical techniques to detect and quantify them has become mandatory. Over the years, the availability of different modes, interfaces, and formats has improved the versatility, sensitivity, and speed of capillary electrophoresis (CE) techniques. Thus, CE represents a powerful tool for the analysis of a large variety of food matrices and food-related molecules with important applications in food quality and safety. This review focuses the attention of CE applications over the last decade on the detection of different classes of drugs (used as additives in animal food or present as contaminants in food products) with a potential risk for animal and human health. In addition, considering that the different sample preparation procedures have strongly contributed to CE sensitivity and versatility, the most advanced sample pre-concentration techniques are discussed here.

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2016-2018)

One of the most cited limitations of capillary and microchip electrophoresis is the poor sensitivity. This review continues to update this series of biannual reviews, first published in Electrophoresis in 2007, on developments in the field of online/in-line concentration methods in capillaries and microchips, covering the period July 2016-June 2018. It includes developments in the field of stacking, covering all methods from field-amplified sample stacking and large-volume sample stacking, through to isotachophoresis, dynamic pH junction, and sweeping. Attention is also given to online or in-line extraction methods that have been used for electrophoresis.

Recent progress of sample stacking in capillary electrophoresis (2016-2018)

Electrophoretic sample stacking comprises a group of capillary electrophoretic techniques where trace analytes from the sample are concentrated into a short zone (stack). This paper is a continuation of our previous reviews on the topic and brings a survey of more than 120 papers published approximately since the second quarter of 2016 till the first quarter of 2018. It is organized according to the particular stacking principles and includes chapters on concentration adjustment (Kohlrausch) stacking, on stacking techniques based on pH changes, on stacking in electrokinetic chromatography and on other stacking techniques. Where available, explicit information is given about the procedure, electrolyte(s) used, detector employed and sensitivity reached. Not reviewed are papers on transient isotachophoresis which are covered by another review in this issue.