Optimizing microwave assisted acid digestion conditions for trace analysis of engineered Ag nanoparticles in different samples followed by ICP-MS

Engineered Ag nanoparticles can enter soils, sediments and other geological samples through various sources and pathways such as the application of fertilizers and plant protection products, biosolids, the irrigation of sewage water or the flooding of floodplains [1]. According to a material flow analysis from a life-cycle perspective of engineered nanoparticles-containing products, an increasing soil exposure to Ag nanoparticles has to be expected [2]. Silver nanoparticles are considered to have a cumulative impact on environmental and human health [3]. Nowadays, there are different techniques used for Ag nanoparticles determination in geological samples as reviewed elsewhere [3]. Most of them are expensive, time consumption and low throughput. In current study, an efficient sensitive, and quick Ag nanoparticle analysis was accomplished by using microwave-assisted acid digestion followed by Inductively Coupled Plasma – Mass Spectroscopy (ICP-MS). The digestion technique requires short times to completion and optimally requires only 0.1 g of sample. This method was optimized in soil and sediments in terms of recovery, repeatability, limit of detection and linear dynamic range. A detection limit of 0.6 ng mL-1 was obtained for Ag nanoparticles after Microwave assisted acid digestion, and a wide linear range of 2.0 - 1000 ng mL-1 with the relative standard deviation (RSD) was 3.4%. The method was successfully applied to soil and sediment samples