Determination of dimethyl fumarate in desiccant and mouldproof agents using ultrasound-assisted extraction gas chromatography with electron-capture detection.

A fast, simple, low cost, and high throughput method has been developed for the determination of dimethyl fumarate (DMF) in desiccant and anti-mould agents employed for protecting clothes, footwear and accessories from humidity and mould. The procedure is based on ultrasound-assisted extraction followed by GC-microECD analysis. The method was conveniently optimized, and the analyte was efficiently extracted from the samples in only 5 min using such a low volume of solvent (ethyl acetate) as 1 mL. Simultaneous extractions could be carried out in also 5 min without loosing efficiency. The method has been validated showing good linearity and selectivity. Precision was satisfactory with RSD of 4-5%. Recovery was evaluated in two real samples at different DMF concentration levels and was >90% in all cases. Limit of detection and quantification were at the ng g(-1) level. The proposed procedure was applied to the determination of DMF in several desiccant and anti-mould samples. Although most of them were labelled as "silica gel" all the samples tested with the exception of three presented important amounts of DMF, many of them at the high microg g(-1) level. The presence and the high concentrations of this allergenic fungicide in desiccant and anti-mould sachets employed in many consumer products, such as clothes and footwear, should be a matter of concern.