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Abstract The widespread use of sulfonamides can result in the residue of sulfonamides in the foods of animal origin that are the major concerns of consumers and regulatory bodies due to their adverse reaction such as the development of antibiotic resistance. A rapid and efficient multi-residue analytical method was developed to screen and confirm 31 sulfonamides in livestock samples in a single run, using ultra-high-performance liquid chromatography combined with comprehensive mass spectrometric approaches. In this study, a novel sample preparation procedure was used, based on a modified QuEChERS method (Quick, Easy, Cheap, Effective, Rugged, and Safe). The linearity, sensitivity, accuracy, and precision of the method were validated according to the Codex guidelines. The response of the detector was linear for each target compound over a wide concentration range, with a correlation coefficient (r2) greater than 0.98. The limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.3 to 5 ng g −1 and from 1 to 19 ng g −1 and the average recoveries (%) for three laboratories ranged from 85 to 109% with a CV (n = 5) below 22%. The applicability of this screening method was verified using real livestock samples. The proposed analytical method achieves identification and quantification of target sulfonamides at trace levels in a short analysis time. None of the samples contained residues that exceeded the maximum residue limit (MRL).

Abstract In this study, an analysis method was established for the quantification of residues of halquinol and its metabolites in livestock and fishery products using liquid chromatography–tandem mass spectrometry (LC–MS/MS). We selected beef, pork (muscle and fat), chicken, egg, milk, flat fish, eel, and shrimp as target samples for validation of the method owing to them being typical livestock and fishery products. Validation of the developed analysis method was performed using liquid chromatography–tandem mass spectrometry (LC–MS/MS) at three concentration levels (0.5, 1, and 2 × the maximum residue limits) following the Codex Alimentarius (CODEX) guidelines (CAC/GL 71–2009). For all samples, correlation coefficients (R2) exceeded 0.99, recoveries ranged between 75.59 and 119.36%, and coefficients of variation (CV) ranged between 1.39 and 28.66%, thus satisfying CODEX guidelines. In addition, inter-laboratory validation was conducted, and the resulting recoveries and CVs satisfied the CODEX guidelines; LOQ was established as 10 μg kg–1 for pig muscle and 5 μg kg–1 for the other samples. Therefore, the analysis method developed in this study can accurately and precisely screen for and quantify halquinol and its metabolites in livestock and fishery products.

Background: There are two methods for quantifying methylmercury (MeHg) in fish using GC–electron capture detection (ECD): AOAC INTERNATIONAL Official Method 988.11 and the Korean Food Code (KFC) method. Both of these methods consume a large amount of chemicals and require long pretreatment times because of several complicated MeHg extraction steps. Objective: In this study, a new method for the simple and rapid determination of MeHg in fish has been developed. The method is based on the investigation of oxygen combustion– gold amalgamation using a direct mercury analyzer (DMA) after the complete removal of MeHg by organic extraction and back-extraction to an aqueous medium. Methods: The DMA is suitable for the analysis of both solid and liquid materials and has a good detection limit. The developed method was validated by comparing the MeHg recoveries (%) of both certified reference materials and the market-purchased fish samples with the MeHg concentration obtained using the KFC method. Results: The following parameters pertaining to the developed method were established: detection limit, 1.02 μg/kg; LOQ, 3.09 μg/kg; linearity (r), 0.9998; range, 0.1–300 μg/kg; and recovery, 95–97%. Conclusions: Our method is a promising alternative by virtue of its much simpler and faster sample pretreatment procedure, with a MeHg recovery as high as that of the KFC method. Highlights: The developed method enables the simultaneous analysis of total Hg and MeHg with only DMA equipment. [ABSTRACT FROM AUTHOR]