MEASUREMENTS OF NANOMATERIALS IN ENVIRONMENTALLY RELEVANT WATER MATRICES USING LIQUID NEBULIZATION/DIFFERENTIAL MOBILITY ANALYSIS

A liquid nebulization-differential mobility analysis methodology was evaluated for the measurement of the size distribution and quantitative mass concentration of nanomaterials in environmentally relevant aqueous media. The analysis time is 8min, and the method requires little routine sample preparation and less than 8mL of sample. The method can be used for rapid, direct analysis of nanomaterials in aqueous media with a particular application to dose verification in ecotoxicology studies, analysis of manufacturing process waste streams, and raw material analysis. Twelve reference materials having a diameter traceable to the National Institute of Standards and Technology were spiked into 6 different aqueous matrices that included drinking water, groundwater, industrial wastewater, as well as the algae and daphnia media used in ecotoxicology testing. Measurement of the diameter of a reference material was within the expected range for the reference material. Individual response factors for each reference material were determined in each medium and the accuracy and precision of the concentration measurements evaluated. In ecotoxicology test media, measurements of the concentration of nanoparticles having diameter30nm, had corresponding accuracies and precisions of 103% and 7%, respectively. Over 28d 86% of the samples had concentrations within 20% of the initial concentration. The method limit of quantification depended primarily on matrix complexity and particle diameter; the limit of quantification ranged from 0.01mg/L to 3g/L. Environ Toxicol Chem 2015;34:833-842. (c) 2014 SETAC