Anaerobic adhesives metal analysis

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. 

To study methods of sample preparation for metal analysis of anaerobic adhesives the following laboratory-prepared adhesives containing the usual additives and spiked with and without metals were used for comparison ... 

Table 6.8 Results of analysis of metal for metal content of Type A and Type B anaerobic adhesives after sample preparation using microwave acid digestion...

Trace metal analysis of anaerobic adhesives is best carried out using destructive techniques because of the high concentration of fillers and thickening agents added. These additives tend to interfere with trace metals from background noise, peak blooming, and the extent of dilution may exceed the detection limits and particle sizes may be too large to nebulise an anaerobic solution into the sample introduction orifice of the ICP-OES. 

Metal Analysis of Chemical Raw Materials Used to Manufacture Anaerobic Adhesives... 

Where specification of the metal is considered to be important, polarographic analysis may be utilized. In the case of primers based on oil-soluble iron salts for use with anaerobic adhesives, the Fe /Fe ratio may be determined by differential pulse polarography in a supporting electrolyte based on ammonium pyrophosphate buffer adjusted to pH 9.0. The iron(II) form is known to be significantly more effective than the iron(III) form in the redox-based curing process. 

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