Disperse dyes are low molecular weight synthetic dyes. The primary application of disperse dyes is in consumer products such as textiles, paper, toys, etc. Several of the dyes have been found to induce an allergic response as a result of prolonged exposure to the skin. The presence of azo groups in the structure of some dyes provides the possibility for them to be converted to potential or known carcinogenic aromatic amines.
The existence of these dyes in consumer products has led to increased awareness of the potential harmful effects to consumer health. Legislation controlling the use of several of these dyes was introduced in Germany in 1996. This led to the development of the DIN 54231 standard procedure which describes a method for the analysis of disperse dyes that employs high performance liquid chromatography (HPLC) or thin layer chromatography (TLC) with either ultraviolet (UV), mass spectrometry (MS), or densitometry detection.
In this application note, we present the analysis of 9 disperse dyes using the standard DIN 54231 procedure with a combination of UV and mass detection, and a dual-flow path liquid chromatography system capable of emulating HPLC or UHPLC separations.
The addition of mass detection as a complementary analytical detection technique enhances confidence in compound detection and identification. The inclusion of the mass detector allowed increased information to be derived from the analysis including confirmation of impurity peaks in specific dye samples.