Non-extractable additives

The use of moulded films for the direct measurement of additives by IR and UV spectroscopy has been described [1, 5]. While problems can exist with interferences from other additives present, for certain applications it is a quick method of analysis. It can be particularly useful in analysing for additives that are difficult to extract, although in such cases the calibration of standards may present a problem. 

The determination of the oligomeric HALS Tinuvin 622 by its saponification with tetrabutylammonium hydroxide (during the precipitation of the polymer) to form a diol and its subsequent quantification by HPLC has been reported [17]. 

---