Nanotechnologies―Size distribution and concentration measurement of inorganic nanoparticles in aqueous media―Single particle inductively coupled plasma mass spectrometry
GB/T 42732-2023 Nanotechnologies - Size distribution and concentration measurement of inorganic nanoparticles in aqueous media - Single particle inductively coupled plasma mass spectrometry
1 Scope
This document specifies a method for the detection of nanoparticles in aqueous suspensions and characterization of the particle number and particle mass concentration and the number-based size distribution using ICP-MS in a time-resolved mode to determine the mass of individual nanoparticles and ionic concentrations.
The method is applicable for the determination of the size of inorganic nanoparticles (e.g. metal and metal oxides like Au, Ag, TiO2 , BVO4 , etc.), with size ranges of 10 nm to 100 nm (and larger particles up to 1 000 nm to 2000 nm) in aqueous suspensions. Metal compounds other than oxides (e.g. sulfides, etc.), metal composites or coated particles with a metal core can be determined if the chemical composition and density are known. Particle number concentrations that can be determined in aqueous suspensions range from 106 particles/L to 109 particles/L which corresponds to mass concentrations in the range of approximately 1 ng/L to 1000 ng/L (for 60 nm Au particles). Actual numbers depend on the type of mass spectrometer used and the type of nanoparticle analysed.
In addition to the particle concentrations, ionic concentrations in the suspension can also be determined. Limits of detection are comparable with standard ICP-MS measurements. Note that nanoparticles with sizes smaller than the particle size detection limit of the spICP-MS method may be quantified as ionic.
The method proposed in this document is not applicable for the detection and characterization of organic or carbon-based nanoparticles like encapsulates, fullerenes and carbon nanotubes (CNT). In addition, it is not applicable for elements other than carbon and that are difficult to determine with ICP-MS. Reference [12] gives an overview of elements that can be detected and the minimum particle sizes that can be determined with spICP-MS.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/TS 80004-1, Nanotechnologies - Vocabulary - Part 1: Core terms
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/TS 80004-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
——IEC Electropedia: available at http:// www .electropedia .org/
——ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
nanoparticle
nano-object with all three external dimensions in the nanoscale
[SOURCE: ISO/TS 80004-2:2015, modified]
3.2
aqueous suspension
particle suspension whose suspending phase is composed of water
3.3
inductively coupled plasma mass spectrometry; ICP-MS
analytical technique comprising a sample introduction system, an inductively coupled plasma source for ionization of the analytes, a plasma/vacuum interface and a mass spectrometer comprising an ion focusing, separation and detection system
3.4
dwell time
time during which the ICP-MS detector collects and integrates pulses
Note: Following integration, the total count number per dwell time is registered as one data point, expressed in counts, or counts per second.
3.5
transport efficiency
particle transport efficiency
nebulization efficiency
ratio of the number of particles or mass of solution entering the plasma to the number of particles or mass of solution aspirated to the nebulizer
3.6
particle number concentration
number of particles divided by the volume of a suspension, e.g. particles/L
3.7
particle mass concentration
total mass of the particles divided by the volume of a sample, e.g. ng/L
3.8
number-based particle size distribution
list of values that defines the relative amount by numbers of particles present according to size
4 Abbreviated terms
spICP-MS single particle inductively coupled plasma mass
