Development of method for simultaneous determination of plasticizers in plastic food packaging by gas chromatography

Abstract

An analytical method has been developed for the simultaneous determination of plasticizers belonging to the classes of phthalates, adipates, sebacates, azelates, phosphates, glycolate, citrates, and trimellitates which are often present in plastic food packaging. Sample extraction consists of solvent dissolution, precipitation, centrifugation, and concentration steps before analysis by gas chromatography with flame ionization detector (GC-FID). The developed analytical procedure makes possible the simultaneous determination of 20 compounds in common plastic materials for food packaging industry, namely dimethyl phthalate, diethyl phthalate, diisopropyl phthalate, di-n-propyl phthalate, diisobutyl phthalate, di-n-butyl phthalate, dipentyl phthalate, din- butyl sebacate, acetyl-tri-n-butyl citrate, butylphthalyl butyl glycolate, butylbenzyl phthalate, dihexyl phthalate, di-2-ethylhexyl adipate, tri-2-ethylhexyl phosphate, dichlorohexyl phthalate, di-2-ethylhexyl phthalate, tri-n-butyl trimellitate, di-2- ethylhexyl azelate, di-n-octyl phthalate and tri-2-ethylhexyl trimellitate within 35 minutes of gas chromatographic separation. Performance characteristics of the method such as linearity range, detection and quantification limit, specificity, trueness and precision were studied and were found to be within the acceptable limit for each plasticizer type. With the limit of detection between 0.61 to 2.88 mg/kg, the method was successfully applied to the determination of plasticizers in plastic food packaging made of polyvinyl chloride, polyvinylidene chloride, polystyrene and polycarbonate. The method was found to be reliable, not labor intensive, suitable for general use and offer considerable time savings over the individual methods available to date. Thus, the proposed method could be used by many agencies including industries’ own quality control laboratories and enforcement authorities in charge with ensuring plastic food packaging meet applicable regulations.