The calibration and measuring methods applied in the previous chapters can also be transferred to other low energetic β-nuclides like 63Ni, 90Sr and 241Pu from the nuclear fission activities. However, as these usually appear jointly together with each other, e.g. in waste water analysis or decommission activities, a chemical separation step has to be introduced. Extraction Chromatography both as filters or column materials plays a dominant role (e.g. Ni, Fe, Sr, Tc) as well for U and Pu, and is therefore described in this chapter.
Since more than twenty years, also selective disk filters for different radionuclides are commercially available. Bonded silica sorbents are known to be commonly used for the solid phase extraction of analytes from complex sample matrices. A variety of functional groups, such as crown ethers, can be bonded to the silica surface to provide selective interactions.
Strontium and Radium RAD Disks have been introduced for the determination of radioactive Strontium and Radium in aqueous samples. However, Lead is as well retained by both filters and can be analyzed separately by its slightly different complexing properties, as has already been shown in chapter 220.127.116.11. The fast sample extraction procedure for Sr is described in 2.3.2.
Additionally, Plastic Scintillator Microspheres are introduced for the determination of Sr, Pb (2.3.3.) and Tc (2.3.14.).
A recently developped method using the TDCR counting technique is outlined for the relevant electron capture nuclides 55Fe and 41Ca from decommissioning activities.