New nanoscale reference material to be known as P25
The National Institute of Standards and Technology (NIST) has issued a new nanoscale reference material for use in a wide range of environmental, health and safety studies of industrial nanomaterials. The new NIST reference material is a sample of commercial titanium dioxide powder commonly known as “P25.”
NIST standard reference materials (SRMs) are typically samples of industrially or clinically important materials that have been carefully analyzed by NIST. They are provided with certified values for certain key properties so that they can be used in experiments as a known reference point.
Nanoscale titanium dioxide powder may well be the most widely manufactured and used nanomaterial in the world, and, not coincidentally, it is also one of the most widely studied (Fig. 1). In the form of larger particles, titanium dioxide is a common white pigment. As nanoscale particles, the material is widely used as a photocatalyst, a sterilizing agent and an ultraviolet blocker (in sunscreen lotions, for example).
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Fig. 1. The nanoscale crystalline
structure of titanium dioxide in
NIST SRM 1898 (color added
for clarity). |
“Titanium dioxide is not considered highly toxic and, in fact, we don’t certify its toxicity,” said NIST chemist Vincent Hackley. “But it’s a representative industrial nanopowder that you could include in an environmental or toxicity study. It’s important in such research to include measurements that characterize the nanomaterial you’re studying—properties like morphology, surface area and elemental composition. We’re providing a known benchmark.”
The new titanium dioxide reference material is a mixed phase, nanocrystalline form of the chemical in a dry powder. To assist in its proper use, NIST has developed protocols for properly preparing samples for environmental or toxicological studies.
The new SRM also is particularly well suited for use in calibrating and testing analytical instruments that measure specific surface area of nanomaterials by the widely used Brunauer-Emmett-Teller gas sorption method. HP