Determination of carbon-based engineered nanoparticles in marketed fish by microwave-assisted extraction and liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry

An optimized method for the determination of two major carbon-based engineered nanoparticles (C₆₀ and C₇₀) in marketed fish samples is described. The method involves the use of microwave-assisted extraction (MAE) coupled with liquid chromatography - tandem mass spectrometry with atmospheric pressure photoionization (LC-APPI-MS/MS). Factors affecting the extraction efficiency of the analytes from fish samples were optimized by a central composite design method. The optimal extraction temperature and time for MAE were found to be 233 °C for 22 min, and the extraction solution was composed of toluene and acetone in a ratio of 4.64:1. The limits of quantitation (LOQs) were 0.1 and 0.05 ng/g for C₆₀ and C₇₀, respectively. The precision for these analytes at two spiked levels, as indicated by relative standard deviations (RSDs), were less than 10% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was between 85 and 98%. The method was further validated based on EU Commission Decision 2002/657/EC, including a decision limit (CCα) and detection capability (CCβ) for marketed fish samples. A high throughput and reliable MAE technique coupled with LC-APPI-MS/MS was developed to determine two major carbon-based ENPs, C₆₀ and C₇₀, in marketed fish samples. The developed method provides good precision, a wide range of linearity, and detection limits at the sub-ng/g level when analyzing fish samples.