Flow field-flow fractionation hyphenated with inductively coupled plasma mass spectrometry: a robust technique for characterization of engineered elemental metal nanoparticles in the environment

Due to the increased applications of engineered elemental metal nanoparticles (EMNPs) in recent years, increased attention has been devoted to their release into the environment. EMNPs pose potential risks to living organisms, including human beings. Hence, the characterization of EMNPs in the environment has gained significant importance. Among the various techniques reported for the characterization of EMNPs, on-line coupling of flow field-flow fractionation with inductively coupled plasma mass spectrometry (F4-ICPMS) has been well established for the simultaneous separation, identification, and quantification of EMNPs, especially in the complex matrices of environmental samples. Thus, this review focuses on the specific advantages of the F4 method, especially the asymmetrical F4 (AF4) and hollow fiber F4 (HF5) methods, in the separation of EMNPs, the general development of AF4-ICPMS and HF5-ICPMS techniques, and recent advances in the application of these hyphenated techniques in examining the occurrence and transformation of EMNPs in the environment. Finally, several perspectives on these techniques have been put forward.