The purity of nanodiamond (ND) is of great importance for the characterization of the properties of ND. Unfortunately, there is a lack of the information on presence of elemental impurities in ND, which was connected for many years with the absence of the sensitive and robust methods for the analysis of this type of nanocarbon material.
Recently, a novel simple, rapid, sensitive and accurate method for the determination of metal impurities in detonation ND, based upon the direct aspiration of aqueous suspensions of nanodiamond into a sector field inductively coupled plasma mass spectrometer (ICP-MS) was developed. This method of direct analysis was capable of the quantification of more than 30 elements at concentration levels of 10-8 wt. %, with acceptable levels of precision and accuracy, from an aqueous suspension of just 0.1 mg mL-1 DND.
The further application of ICP-MS method to the analysis of more than 20 commercial samples allowed identification of possible sources for the contamination of various DND samples during their processing. The careful of reasons for the contamination and elimination of them caused a significant improvement in the existing technology of their purification. As a results the content of 28 most common elemental impurities in ND was dropped to the level of 0.05 mass %.
This work was supported by grants from the Australian Research Council to ACROSS (DP110102046) and CSL (LE0989539).