Supercritical fluid chromatography antioxidants

Wieboldt, R.C. Kempfert, K.D. Dahymple, D.L. Analysis of antioxidants in polyethylene using supercritical fluid extraction/supercritical fluid chromatography and infrared detection. Appl. Spectrosc. 1990, 44, 1028-1034. 

In supercritical fluid chromatography (SFC), a supercritical fluid, usually carbon dioxide, is used. An SFC column resembles a GC column or a packed LC column. The operating temperature is lower than that in GC, which makes it more suitable for the analysis of thermally labile compounds. Another advantage is that water is not present and this is particularly valuable for the analysis of phosphatic antioxidants. In addition, high molecular mass antioxidants can be analyzed with SFC. SFC and FTIR have been used for the analysis of light stabilizers (UV absorbers) and antioxidants [43]. The eluted compounds were deposited on a KBr window after they had passed through a capillary restrictor. The hmit of detection was aroimd 100 ng. 

Antioxidant and antiozonant types most commonly used are aromatic amines or phenolics, though others are also employed, and can be determined using a variety of techniques such as UV-visible spectrophotometry, FTIR, near-infrared spectroscopy, TEC, GC (if the material can be volatilized), supercritical fluid chromatography, and HPLC. Identification of unknown antioxidants requires a separation technique like chromatography followed by mass spectrometry, NMR, ETIR, X-ray crystallography, etc. Standardized TEC methods are given in ASTM D3156 and... 

Ramirez, P., Senorans, F.J., Ibanez, E., and Reglero, G. 2004. Separation of rosemary antioxidant compounds by supercritical fluid chromatography on coated packed capillary columns. Journal of chromatography. A, 7057(1-2), 241-5. 

MS can also be coupled with supercritical fluid chromatography (SFC, see VI.F). The four tocopherols have been separated on capillary columns and identified by MS in commercial antioxidant samples and deodorizer distillates (172). 

An example of the medicinal plant is Rosmarinus officinalis which has chemical components that has significant antioxidant activity [3-6]. Carvalho, Jr. et al., [6] obtained Rosmarinus officinalis extracts via supercritical extraction with CO2 (CO2-SFE) with high antioxidant activity and identified camphor, 1,8-cineole, camosic acid and rosmarinic acid, moreover studied changes in the production scale of extracts. Vincent et al., [7] isolated, by supercritical fluid chromatography, camosic acid (over 80% by mass) from extracts obtained via SFE Rosmarinus officinalis. Camphor, 1,8-cineole, camphene, bomeol, myrcene and a-pinene can be identified as major compounds in extracts via CO2-SFE Spanish sage [8]. 

Purification of poloxamers has been extensively investigated due to their use in medical applications, the intention often being to remove potentially toxic components. Supercritical fluid fractionation and liquid fractionation have been used successfully to remove low-molecular weight impurities and antioxidants from poloxamers. Gel filtration, high-performance liquid chromatography (HPLC), and ultrafiltration through membranes are among the other techniques examined [5]. 

Ibanez E, Cifuentes A, Crego AL, Senorans FJ, Cavero S, Reglero G. Combined use of supercritical fluid extraction, micellar electrokinetic chromatography and reverse phase high performance liquid chromatography for the analysis of antioxidants from rosemary Rosmarinus officinalis L.). J Agric Food Chem 2000 48 4060-4065. 

See also Dioxins. Extraction Solvent Extraction Principles Supercritical Fluid Extraction. Food and Nutritional Analysis Antioxidants and Preservatives Pesticide Residues Mycotoxins Packaging Materials. Gas Chromatography Overview. Hormones Steroids. 

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