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A fast, simple and efficient ultrahigh-performance liquid chromatography-fluorescence detection (UPLC-FLD) method for the determination of residues of albendazole (ABZ) and its three metabolites, albendazole sulfone (ABZ-SO2), albendazole sulfoxide (ABZ-SO), and albendazole-2-aminosulfone (ABZ-2NH2-SO2), in pig and poultry muscle (chicken, duck and goose) was established. The samples were extracted with ethyl acetate, and the extracts were further subjected to cleanup by utilizing a series of liquid–liquid extraction (LLE) steps. Then, extracts were purified by OASIS® PRiME hydrophilic-lipophilic balance (HLB) solid-phase extraction (SPE) cartridges (60 mg/3 mL). The target compounds were separated on an ACQUITY UPLC® BEH C18 (2.1 mm × 100 mm, 1.7 μm) chromatographic column, using a mobile phase composed of 31% acetonitrile and 69% aqueous solution (containing 0.2% formic acid and 0.05% triethylamine). The limits of detection (LODs) and limits of quantification (LOQs) of the four target compounds in pig and poultry muscle were 0.2–3.8 µg/kg and 1.0–10.9 µg/kg, respectively. The recoveries were all above 80.37% when the muscle samples were spiked with the four target compounds at the LOQ, 0.5 maximum residue limit (MRL), 1.0 MRL, and 2.0 MRL levels. The intraday relative standard deviations (RSDs) were less than 5.11%, and the interday RSDs were less than 6.29%.

A method for the simultaneous determination of robenidine, halofuginone, lasalocid, monensin, nigericin, salinomycin, narasin, and maduramicin residues in eggs by liquid chromatography&ndash, tandem mass spectrometry (LC&ndash, MS/MS) was developed. The sample preparation method used a combination of liquid&ndash, liquid extraction (LLE) and solid-phase extraction (SPE) technology to extract and purify these target compounds from eggs. The target compounds were separated by gradient elution using high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography (UPLC). Tandem mass spectrometry was used to quantitatively and qualitatively analyze the target compounds via electrospray ionization (ESI+) and multiple reaction monitoring mode. The HPLC&ndash, MS/MS and UPLC&ndash, MS/MS methods were validated according to the requirements defined by the European Union and the Food and Drug Administration. The limits of detection and limits of quantification of the eight coccidiostats in eggs were 0.23&ndash, 0.52 &micro, g/kg and 0.82&ndash, 1.73 &micro, g/kg for HPLC&ndash, MS/MS, and 0.16-0.42 &micro, g/kg and 0.81-1.25 &micro, g/kg for UPLC&ndash, MS/MS, respectively. The eggs were spiked with four concentrations of the eight coccidiostats, and the HPLC&ndash, MS/MS average recoveries were all higher than 71.69% and 72.26%, respectively. Compared with the HPLC&ndash, MS/MS method, utilizing UPLC&ndash, MS/MS had the advantages of low reagent consumption, a short detection time, and high recovery and precision. Finally, the HPLC&ndash, MS/MS methods were successfully applied to detect eight coccidiostats in 40 eggs.

An innovative study on the qualitative identification and quantitative determination of spectinomycin and lincomycin residues in poultry (chicken, duck, and goose) muscles and pork using gas chromatography-tandem mass spectrometry (GC–MS/MS) was conducted. The samples were extracted and separated with accelerated solvent extraction (ASE) and then purified and enriched by solid-phase extraction (SPE). Then, the obtained residues were derivatized with 200 μL bis(trimethylsilyl) trifluoroacetamide (BSTFA) for 60 min at 75 °C, and the derivative products were injected into a GC–MS/MS system. Under the optimized conditions, the limits of detection (LODs) and limits of quantification (LOQs) of spectinomycin and lincomycin in samples were 2.5–4.6 μg/kg and 5.7–7.6 μg/kg, respectively, the targets’ recoveries were 79.7 %–94.2 %, the determination coefficients were 0.9992−0.9998, and the relative standard deviations (RSDs) were 1.2 %–3.5 %. The method revealed good linearity, and the parameters met the European Union requirements for the detection of veterinary drug residues. Poultry muscles and pork were procured from local stores for actual sample testing, confirming the feasibility and practicability of this method. Therefore, this study established an ASE-SPE-GC–MS/MS method to detect spectinomycin and lincomycin residues in animal-derived food.

A simple, rapid and novel method for the detection of residues of thiamphenicol (TAP), florfenicol (FF) and its metabolite, florfenicol amine (FFA), in poultry eggs by ultra-performance liquid chromatography-fluorescence detection (UPLC-FLD) was developed. The samples were extracted with acetonitrile-ammonia (98:2, v/v) using accelerated solvent extraction (ASE) and purified by manual degreasing with acetonitrile-saturated n-hexane. The target compounds were separated on an ACQUITY UPLC&reg, BEH C18 (2.1 mm &times, 100 mm, 1.7 &mu, m) chromatographic column using a mobile phase composed of 0.005 mol/L NaH2PO4, 0.003 mol/L sodium lauryl sulfate and 0.05% trimethylamine, adjusted to pH 5.3 &plusmn, 0.1 by phosphoric acid and acetonitrile (64:36, v/v). The limits of detection (LODs) and limits of quantification (LOQs) of the three target compounds in poultry eggs were 1.8&ndash, 4.9 &micro, g/kg and 4.3&ndash, 11.7 &micro, g/kg, respectively. The recoveries of the three target compounds in poultry eggs were above 80.1% when the spiked concentrations of three phenicols were the LOQ, 0.5 maximum residue limit (MRL), 1.0 MRL and 2.0 MRL. The intraday relative standard deviations (RSDs) were less than 5.5%, and the interday RSDs were less than 6.6%. Finally, this new detection method was successfully applied to the quantitative analysis of TAP, FF and FFA in 150 commercial poultry eggs.

A method based on accelerated solvent extraction (ASE) coupled with gas chromatography tandem mass spectrometry (GC-MS/MS) was developed for the quantitative analysis of spectinomycin and lincomycin in poultry egg (whole egg, albumen and yolk) samples. In this work, the samples were extracted and purified using an ASE350 instrument and solid-phase extraction (SPE) cartridges, and the parameters of the ASE method were experimentally optimized. The appropriate SPE cartridges were selected, and the conditions for the derivatization reaction were optimized. After derivatization, the poultry egg (whole egg, albumen and yolk) samples were analyzed by GC-MS/MS. This study used blank poultry egg (whole egg, albumen and yolk) samples to evaluate the specificity, sensitivity, linearity, recovery and precision of the method. The linearity (5.6&ndash, 2000 &mu, g/kg for spectinomycin and 5.9&ndash, 200 &mu, g/kg for lincomycin), correlation coefficient (&ge, 0.9991), recovery (80.0%&ndash, 95.7%), precision (relative standard deviations, 1.0%&ndash, 3.4%), limit of detection (2.3&ndash, 4.3 &mu, g/kg) and limit of quantification (5.6&ndash, 9.5 &mu, g/kg) of the method met the requirements for EU parameter verification. Compared with traditional liquid&ndash, liquid extraction methods, the proposed method is fast and consumes less reagents, and 24 samples can be processed at a time. Finally, the feasibility of the method was evaluated by testing real samples, and spectinomycin and lincomycin residues in poultry eggs were successfully detected.

A method for the simultaneous analysis of amoxicillin (AMO), amoxicillin metabolites, and ampicillin residues in edible chicken muscle, liver, and kidney samples via high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI/MS/MS) was developed and verified. The extraction and purification procedures involved the extraction of the sample using a liquid-liquid extraction method with acetonitrile to eliminate the proteins. The chicken tissue extract was then injected directly onto an HPLC column coupled to a mass spectrometer with an ESI(+) source. The HPLC-ESI/MS/MS method was validated according to specificity, sensitivity, linearity, matrix effects, precision, accuracy, decision limit, detection capability, and stability, as defined by the European Union and Food and Drug Administration. The linearity was desirable, and the determination coefficients (r2 values) ranged from 0.9968 and 0.9999. The limits of detection and limits of quantification were 0.10&ndash, 2.20 &mu, g/kg and 0.30&ndash, 8.50 &mu, g/kg, respectively. The decision limits were 57.71&ndash, 61.25 &mu, g/kg, and the detection capabilities were 65.41&ndash, 72.50 &mu, g/kg, and the recoveries of the four target analytes exceeded 75% at the limits of quantification and exceeded 83% at 25, 50, and 100 &mu, g/kg (n = 6 at each level), confirming the reliability of this method for determining these analytes and providing a new detection technology. For real sample analysis, this experiment tested 30 chicken tissue samples, only one chicken muscle, liver, and kidney sample were contaminated with 5.20, 17.45, and 7.33 &mu, g/kg of AMO values, respectively, while other target compounds were not detected in the 30 tested chicken tissue samples.