Determination of 2,8-dichlorodibenzo-p-dioxin in toothpaste and mouthwash consumer products using GC-MS.

A gas chromatography-mass spectrometry (GC-MS) method was developed for the identification and quantification of 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD) in toothpaste and mouthwash consumer products. Liquid-liquid extraction and solid-phase extraction were used in the sample preparation. The limit of detection was 0.96 ng/g in toothpaste and 0.83 ng/g in mouthwash. The accuracy represented by relative errors was less than 12.5%. The intra-day and inter-day precision, which are represented by the relative standard deviation values, were within 11.2 and 10.6%, respectively. The method was successfully applied to analyze 2,8-DCDD in toothpaste and mouthwash products, as well as that from the photo-degradation of triclosan spiked in both sample matrix.