Current trends in analytical strategies for the chromatographic determination of nitrofuran metabolites in food samples. An update since 2012.

Nitrofurans (NFs) are synthetic broad-spectrum antibacterial and antiparasitic drugs, which recently were extensively used in veterinary practice. In the body of animals, NFs are converted into carcinogenic and mutagenic metabolites that can be accumulated in foods of animal origin having an adverse effect on human health. Therefore, NFs are currently banned in animal husbandry and aquaculture of many countries. However, the data from monitoring the quality of food products indicate that, despite the prohibitions established by the law, they still are used not only in the developing countries but also in the European Union, due to their high antibacterial activity, low cost, and accessibility. Thus, it is of great importance for human health to develop reliable and sensitive analytical methods for monitoring NF metabolites in animal-derived foods. The objective of this review is to summarize the pretreatment strategies and chromatographic methods that have been reported during the last decade for the determination of NF metabolites in food samples, and to outline the future trends with an emphasis on the novel solutions in this area.

Determination of nitrofuran metabolites in honey using a new derivatization reagent, magnetic solid-phase extraction and LC-MS/MS.

In this study, 5-nitro-2-furaldehyde (5-NFA) was proposed as a new derivatizing agent for nitrofuran metabolites. It reacts with nitrofuran metabolites producing the parent nitrofurans (furazolidone, furaltadone, nitrofurantoin, and nitrofurazone). Magnetic hypercrosslinked polystyrene (HCP/Fe3O4) was first used for magnetic solid phase extraction (MSPE) clean-up before the determination of nitrofuran metabolite derivatives in honey via LC-MS/MS. Main parameters affecting the derivatization and MSPE efficiency were investigated in detail and the optimal conditions were found. The method was validated using honey spiked with the four metabolites at 1, 2 and 200 µg kg-1. Recoveries of >85% were achieved for the all analytes. The matrix calibration curve was fitted with the correlation coefficient (R2) > 0.99 in the range of 1-200 µg kg-1. Precision values expressed as relative standard deviation (RSD) were <12% and <15% for intra-day and inter-day precision, respectively. The limits of detection (LODs) for the nitrofuran metabolites were of 0.1-0.3 µg kg-1 and the limits of quantitation (LOQs) were of 0.3-1.0 µg kg-1. The proposed LC-MS/MS method was applied to the analysis of real honey samples.

Facile synthesis of magnetic hypercrosslinked polystyrene and its application in the magnetic solid-phase extraction of sulfonamides from water and milk samples before their HPLC determination.

In this study, a novel magnetic solid-phase extraction (MSPE) sorbent, magnetic hypercrosslinked polystyrene (HCP/Fe3O4), was prepared and used for preconcentration of four sulfonamides (sulfamethoxypyridazine, sulfamethazine, sulfamethoxazole and sulfachloropyridazine) from natural water and milk samples. This material was prepared by sorption of pre-synthesized Fe3O4 nanoparticles (NPs) onto HCP. A number of sorbents with varying Fe3O4NPs content were prepared, and their structural, magnetic and sorption properties were studied. Various experimental parameters affecting the extraction efficiencies such as the amount of the magnetic nanocomposite, extraction time, pH of the sample solution and desorption conditions were studied and optimized. Under the optimal conditions, a convenient and efficient method for the determination of sulfonamides in water and milk samples was developed by combining MSPE and high-performance liquid chromatography with amperometric detection. The results showed that the recoveries of these compounds were in the range of 84-105% with the relative standard deviations ranging between 3% and 10%; the limit of detection were in the range of 0.21-0.33 ng mL(-1) for water and 2.0-2.5 ng mL(-1) for milk.

Determination of the total content of some sulfonamides in milk using solid-phase extraction coupled with off-line derivatization and spectrophotometric detection.

A simple screening method for isolation and determination of the total content of some sulfonamides in milk using solid-phase extraction and a color reaction is described. This procedure is based on SPE of sulfonamides on hypercrosslinked polystyrene, elution with acetonitrile and off-line derivatization with p-dimethylaminocinnamaldehyde in acetonitrile followed by spectrophotometric determination. The reaction produces intense violet-red color and can be easily used both for quantitation of sulfonamides using spectrophotometry and for naked-eye semi-quantitative estimation. Maximum absorption of the reaction product was determined at 540 nm. The Lambert-Beer's law was obeyed in the range of 0.07-3.0 µg mL(-1) in eluate, with the squared correlation coefficient (R(2)) of 0.9875-0.9995, and the relative standard deviation (RSD) of 3-4%. The limits of SAs detection using preconcentration were of 0.02-0.03 µg mL(-1). The proposed method can be recommended as a routine screening method for quantitation of sulfonamides in milk.

Recent advances in sample preparation techniques and methods of sulfonamides detection - A review.

Sulfonamides (SAs) have been the most widely used antimicrobial drugs for more than 70 years, and their residues in foodstuffs and environmental samples pose serious health hazards. For this reason, sensitive and specific methods for the quantification of these compounds in numerous matrices have been developed. This review intends to provide an updated overview of the recent trends over the past five years in sample preparation techniques and methods for detecting SAs. Examples of the sample preparation techniques, including liquid-liquid and solid-phase extraction, dispersive liquid-liquid microextraction and QuEChERS, are given. Different methods of detecting the SAs present in food and feed and in environmental, pharmaceutical and biological samples are discussed.