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An accurate, fast, economic and simple method to determine carotenoids, tocopherols, retinol and cholesterol in lyophilised samples of ovine milk, muscle and liver and raw samples of fat, which are difficult to lyophilise, is sought. Those analytes have been studied in animal tissues to trace forage feeding and unhealthy contents. The sample treatment consisted of mild overnight saponification, liquid-liquid extraction, evaporation with vacuum evaporator and redissolution. The quantification of the different analytes was performed by the use of ultra-high performance liquid chromatography with diode-array detector for carotenoids, retinol and cholesterol and fluorescence detector for tocopherols. The retention times of the analytes were short and the resolution between analytes was very high. The limits of detection and quantification were very low. This method is suitable for all the matrices and analytes and could be adapted to other animal species with minor changes. [ABSTRACT FROM AUTHOR]

In this study a simple and fast multi-class method for the determination of veterinary drugs in bovine liver, kidney and muscle was developed. The method employed acetonitrile for extraction followed by clean-up with EMR-Lipid® sorbent and trichloracetic acid. Tests indicated that the use of TCA was most effective when added in the final step of the clean-up procedure instead of during extraction. Different sorbents were tested and optimized using central composite design and the analytes determined by ultra-high-performance liquid chromatographic-tandem mass spectrometry (UHPLC-MS/MS). The method was validated according the European Commission Decision 2002/657 presenting satisfactory results for 69 veterinary drugs in bovine liver and 68 compounds in bovine muscle and kidney. The method was applied in real samples and in proficiency tests and proved to be adequate for routine analysis. Residues of abamectin, doramectin, eprinomectin and ivermectin were found in samples of bovine muscle and only ivermectin in bovine liver. [ABSTRACT FROM AUTHOR]

• A high affinity monoclonal antibody against gentamicin was produced successfully by hybridoma technology. • The specificity of monoclonal antibody was evaluated using 6 analogous compounds of gentamicin. • A sensitive indirect competitive CLEIA for gentamicin was developed based on the monoclonal antibody. • The developed icCLEIA in our study showed higher sensitivity and specificity than those immunoassay methods for gentamicin in previous literature reports. To determine gentamicin residues in animal tissues, a monoclonal antibody (Mab) was produced and a sensitive indirect competitive chemiluminescent enzyme immunoassay (icCLEIA) was developed. At first, gentamicin was conjugated with bovine serum albumin as immunogens which were used to immunize BALB/c mice. Then, an anti-gentamicin Mab was prepared by hybridoma technology. Finally, a sensitive icCLEIA was developed with an 50% inhibition concentration (IC 50) of 0.067 ng/mL for gentamicin. The limit of detection of the icCLEIA was 0.002 ng/mL. The cross reactivity of the Mab with structural analogues were<0.01%. The recoveries of gentamicin ranged from 80 to 101% and coefficient of variation was <6.4% in pork and fish samples. Samples were detected by UPLC-MS/MS for evaluating reliability of the icCLEIA. The results suggested that the prepared anti-gentamicin Mab can be used for rapid and convenient immunoassays to detect gentamicin residues in animal tissues. [ABSTRACT FROM AUTHOR]

Abstract: A simple, fast and reliable method to quantify, simultaneously, 3,4-dihydroxyphenylglycol (DHPG), hydroxytyrosol (HT) and tyrosol (Ty) extracted and purified successfully from olive oil by-product, called alperujo, in animal plasma and tissues samples has been developed using a high-performance liquid chromatographic (HPLC) method with UV–Vis detection. Extraction of compounds is based on solid-phase extraction for plasma and homogenisation with zirconia beads and centrifugation for tissues. Calibration curves were linear for all three phenols at a relatively low concentration range (0.05–50μg/mL). This method has acceptable accuracy (91–95% in plasma and 63–100% in tissues), precision (1.11–8.26% intra-day and 0.32–9.5% inter-day) and sensitivity for detecting low concentrations of these phenols in small plasma volumes and several animal tissues such as liver, heart, kidney, muscle, testes, white adipose tissue (WAT) and brain. [Copyright &y& Elsevier]

[Display omitted] • A UHPLC-MS/MS method suitable for the analysis MACs in 17 animal-derived foods. • d -SPE based on MWCNTs is time-efficient and cost-effective. • A human medicine and an unapproved veterinary drug were detected in real egg samples. • 1The first two authors contributed equally to this work. A simple and reliable analytical method was developed for the simultaneous determination of 11 macrolides in swine, chicken, bovine, and sheep tissues (muscle, liver, kidney, and fat), as well as eggs. Samples were extracted using a mixture of acetonitrile, ethyl acetate, and methanol; dispersive solid-phase extraction purification was then performed using multi-walled carbon nanotubes as the sorbent. The analytes were separated through ultra-high performance liquid chromatography and detected by electrospray ionization on a triple quadrupole mass spectrometer. The average recoveries ranged from 83.5% to 111.4%; the corresponding intra-day and inter-day relative standard deviations were less than 13.6% and 16.4%, respectively. The limit of detection and quantification of the eggs were 0.1–0.6 and 2.0 μg/kg, respectively. For other tissues, the limits of detection and quantification were 0.1–2.0 μg/kg and 5.0 μg/kg, respectively. The proposed method was successfully employed for the analysis of real samples to demonstrate its applicability. [ABSTRACT FROM AUTHOR]

• The first direct spectrofluorimetric analysis of SAL and MAD without pre-derivatization. • A simple hydrothermal synthesis and characterization of highly fluorescent N,S-CQDs. • N,S-CQDs as fluorescent nanosensors for analysis of SAL and MAD in six raw matrices. • Determination of cited drugs based on quantitative fluorescence quenching of N,S-CQDs. • Method validation in accordance to ICH guidelines was performed. A simple green hydrothermal method was proposed for synthesis of highly fluorescent nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) using citric acid and thiosemicarbazide. The produced N,S-CQDs were subjected to extensive spectroscopic characterization and applied as fluorescent nanosensors for the sensitive spectrofluorimetric determination of salinomycin and maduramicin directly without prior derivatization for the first time. The obtained N,S-CQDs showed strong emission band at 430 nm after excitation at 360 nm. The native fluorescence of N,S-CQDs was found to be quenched by the addition of increased concentrations of each drug. Method validation revealed a wide linear relationship between the fluorescence quenching of N,S-CQDs and the concentration of each drug in the range of 10.0–300.0 μM with detection limits of 2.07 μM and 1.34 μM for salinomycin and maduramicin, respectively. The developed method has been efficiently applied for estimation of analytes in six raw matrices with high recoveries. [ABSTRACT FROM AUTHOR]