Destructive sample preparation methods adhesives

Table 6.4 Results of comparison of destructive sample preparation methods for the determination of the concentration of Nb in cyanoacrylate adhesive, in /ig/mlippm)...

Sample preparation of anaerobic adhesives for metal content is an important step, be it by destructive or non-destructive methods. Inactive metal salts are added directly to anaerobic formulations as fillers or for thixotropic reasons. Generally, active transition metals are not added directly to anaerobic adhesives but are prepared as activators in aerosol solvents to be applied to inactive surfaces as part B of an adhesive formulation. In the majority of cases trace metal analysis of anaerobic adhesives is only required for batches with problematic stability and is best done using destructive methods. 

Table 6.27 Results of analysis of polyurethane (PU) adhesives spiked with 0.1 % organometallic catalysts using destructive methods ashing, microwave acid digestion and bomb combustion methods of sample preparation...

With certain exceptions, cyanoacrylate monomer formulations containing additives e.g. rubbers, high-density neutral resins, silicon dioxide, etc., may hinder accurate and precise analysis using dilution methods. In such cases it may be necessary to prepare samples using destructive techniques, particularly where the levels are very low. Solvent selection for dilution of cyanoacrylate adhesive must be compatible for the entire journey of the sample solution from sample vessel to torch. Failure to do this could cause the cyanoacrylate to polymerise locally and block the entire sample transport system in ICP-OES and can cause serious damage requiring expensive replacements. The solvents suggested in the above dilution methods were found to be satisfactory. 

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