Simultaneous determination of multiple organotin compounds in fish oil by GC-MS following method development and...

(1) Background: Given the contamination risks of organotin compounds (OTCs) in fish oil and their potential threat to consumer health, this study addresses the analytical challenges posed by complex matrices and OTC degradation. A highly efficient and sensitive gas chromatography-mass spectrometry (GC-MS) method was established and optimized. This method enables the simultaneous qualitative and quantitative determination of multiple OTCs, providing reliable technical support for the quality and safety monitoring of dietary supplements. (2) Methods: After cryogenic extraction, sorbent cleanup, and derivatization with sodium tetraethylborate, samples were subjected to n-hexane extraction and further purification usiss identification and quantified using the internal standard method. This approach significantly improved separation efficiency and detection throughput through systematic optimization of pretreatment and instrumental conditions. (3) Results: Results showed that using 3% acetic acid-acetonitrile for the extraction of 0.5 g spiked fish oil improved efficiency by over 20% compared to single solvents. A dual-stage cleanup using 0.2 g HCC18 combined with a Florisil column provided optimal delipidation, with recoveries remaining above 80%. The nine organotins exhibited good linearity (R² ≥ 0.99) in the range of 2.0-750.0 μg/L. The limits of detection (LOD) and quantification (LOQ) were 0.151-0.439 μg/kg and 0.453-1.317 μg/kg, respectively. Spiked recoveries ranged from 81.1% to 105% with RSDs of 0.99-5.73%. (4) Conclusions: This study significantly enhanced the performance of GC-MS for detecting organotin compounds in fish oil by introducing a systematically optimized dual-stage cleanup strategy combining HCC18 and Florisil. This approach effectively eliminated lipid interference, thereby improving accuracy and sensitivity. Method validation demonstrated the method's reliability and practicality. These findings provide a high-sensitivity, anti-interference detection solution for the dietary supplement industry, holding significant public health implications for reducing consumer exposure to neurotoxic substances.