IDENTIFICATION AND ANALYSIS OF POLYMER ADDITIVES USING PACKED-COLUMN SUPERCRITICAL-FLUID CHROMATOGRAPHY WITH APCI MASS-SPECTROMETRIC DETECTION

Packed-column supercritical fluid chromatography (pSFC) with detection using atmospheric pressure chemical ionisation (APCI) mass spectromet ry (MS) provides a versatile method for the detection and quantificati on of 20 polymer additives, including-common antioxidants, light stabi lisers and slip agents. Using MS with APCI in both positive and negati ve ion modes both molecular mass data and informative fragmentation pa tterns were obtained. The pSFC-MS technique was-shown to be linear ove r a wide concentration range (0.05-25 mu g ml(-1)) and picogram limits of detection with positive ion APCI (single ion monitoring) were dete rmined for Tinuvin 327 (68 pg) and Irganox 1010 (390 pg): The correspo nding figures for negative ion APCI were 150 and 470 pg, respectively. Standard mixtures of additives could be separated in less than 15 min with a high degree of resolution. Experiments on additives extracted from polyethylene confirmed these observations, and it was possible no t only to identify a number of the additives, but also, in the case of the antioxidant Irgafos 168, an oxidation product.