DETERMINATION OF FORMALDEHYDE IN FINGER-PAINTS FOR CHILDREN USE BY SFE COMBINED WITH SPECTROPHOTOMETRIC AND CHROMATOGRAPHIC TECHNIQUES

A new method to determine formaldehyde in finger-paints for children use is presented, including the optimisation of the supercritical fluid extraction (SFE) variables and the comparison between three different detection techniques. The selection of SFE conditions has been carried out by using a factorial design of 4 factors in 2 level (24). Three different detection techniques, ultraviolet-visible (UV-V) spectrophotometry, gas chromatography with flame ionisation detection (GC-FID) and gas chromatography coupled to mass spectrometry (GC-MS) have been used. A study of the linearity and limit of detection for the quantification of formaldehyde as a product of the Hantzsch reaction has been also carried out for each detection technique. Accuracy and precision in the determination of the formaldehyde content in real samples obtained with the addition of known quantities of formaldehyde to the paint previous to the analysis, were compared to the direct determination of formaldehyde in a finger-paint without any fortification.