Simultaneous determination of tylosin and josamycin residues in muscles, liver, eggs and milk by MLC with a monolithic column and time-programmed UV detection: application to baby food and formulae

Functionalized monolithic columns: Recent advancements and their applications for high-efficiency separation and enrichment in food and medicine

The chromatographic column is the core of a high-performance liquid chromatography (HPLC) system, and must have excellent separation efficiency and selectivity. Therefore, functional modification materials for monolithic columns have been rapidly developed. This study is a systematic review of the recently reported functionalized monolithic columns. In particular, the study reviews the types of functional monomers under different modification conditions, as well as the separation and detection techniques combined with chromatography, and their development prospects. In addition, the applications of functionalized monolithic columns in food analysis, biomedicine, and the analysis of active ingredient of Chinese herbal medicines in recent years are also discussed. Also reviewed are the functionalized monolithic columns for qualitative and quantitative analysis. It provided a reference for further development and application of organic polymer monolithic columns.

Analytical capabilities of micellar liquid chromatography and application to residue and contaminant analysis: A review

Green chemistry is the use of chemistry to reduce or eliminate the use of generation of feedstocks, products, by-products, solvents, reagents, etc. that are hazardous to human health or the environment. One of the branches of green chemistry is micellar liquid chromatography. Micellar liquid chromatography is a reversed-phase liquid chromatographic mode with mobile phases containing a surfactant above its critical micellar concentration. The applications of micellar liquid chromatography for the determination of numerous compounds in pharmaceutical formulation, biological samples, food, environmental samples, and feeds have been growing rapidly. Micellar liquid chromatography technique has several advantages over other chromatographic techniques. Its main advantage is the small amount of organic modifiers used such as acetonitrile and methanol and the safety and recyclability of the mobile phase. In our work, we discuss the development of "green chemistry" and present what micellar liquid chromatography is. This article presents application methods with the use of micellar liquid chromatography for analysis on antibacterial substances, melamine, biogenic amines, plant protection products, flavonoids, as well as peptides in biological matrices such as milk, eggs, tissues, honey, and feed.

High throughput detection of antibiotic residues in milk by time-resolved fluorescence immunochromatography based on QR code

Herein, we have successfully established a novel, rapid, and simple lateral-flow immunoassay based on time-resolved fluorescence and biotin-streptavidin to detect the residues of various antibiotics in milk. The fluorescence signal and sensitivity of immunochromatography were enhanced through biotinylated antibody coupled with streptavidin europium microspheres. Moreover, due to the use of a QR Code and fluorescent reader, quantitative detection and real-time data uploading can be achieved. Under the optimal conditions, the various antibiotic residues were detected in the milk samples. The results showed that the limits of detection of tylosin, lincomycin and doxycycline were 0.10, 0.06, and 0.27 ng/mL, respectively. The recoveries of the spiked milk samples were 88.9%~127%, with coefficients of variation less than 11%, and the test strip can be stored at room temperature for 12 months. This study shows that the proposed time-resolved fluorescence immunoassay is sensitive, rapid and reliable, and has the potential to be used for detection of veterinary antibiotic residues in food safety fields.

Pharmacokinetics, tissue residues, and ex vivo pharmacodynamics of tylosin against Mycoplasma anatis in ducks

The pharmacokinetics of tylosin were investigated in 3 groups of ducks (n = 6). They received a single dose of tylosin (50 mg/kg) by intravenous (IV), intramuscular (IM), and oral administrations, respectively. Plasma samples were collected at various time points to 24 hr post-administration to evaluate tylosin concentration over time. Additionally, tylosin residues in tissues and its withdrawal time were assessed using 30 ducks which received tylosin orally (50 mg/kg) once daily for 5 consecutive days. After IV administration, the volume of distribution, elimination half-life, area under the plasma concentration-time curve, and the total body clearance were 7.07 ± 1.98 L/kg, 2.04 hr, 19.47 µg hr/ml, and 2.82 L hr^-1  kg^-1 , respectively. After IM and oral administrations, the maximum plasma concentrations were 3.70 and 2.75 µg/ml achieved at 1 and 2 hr, and the bioavailability was 93.95% and 75.77%, respectively. The calculated withdrawal periods of tylosin were 13, 8, and 5 days for kidney, liver, and muscle, respectively. For the pharmacodynamic profile, the minimum inhibitory concentration for tylosin against M. anatis strain 1,340 was 1 µg/ml. The calculated optimal oral dose of tylosin against M. anatis in ducks based on the ex vivo pharmacokinetic/pharmacodynamic modeling was 61 mg kg^-1  day^-1 .

Presence of emerging contaminants in baby food

Food safety becomes imperative when it aims to protect infants. The objective of this study was to investigate the presence of emerging contaminants of which some act as endocrine-disruptors in baby food. Persistent organic pollutants (POPs), perfluoroalkyl substances (PFASs), parabens and antibiotics were analysed in 112 baby food of different categories (meat, fish, vegetables, fruit, cheese). As regard POPs, PFASs and antibiotics, no residues were detected, while one sample showed methyl-paraben (4.14 ng g^-1), whereas another three contained propyl-paraben (median 1.70 ng g^-1). Special attention must be paid on parabens metabolites, as 4-hydroxybenzoic acid, the principal parabens metabolite, was detected in all samples (median 176.7 ng g^-1). It may be present as a degradation product, but also, it can be released from vegetables and fruits during food processing. It is recommended to collect more data on natural vs non-natural occurrence of parabens and metabolites to evaluate the exposure of sensitive population vs ADI published by the European Food Safety Authority and European Medicines Agency.