Although these methods for the characterisation of such kind ofproducts are valuable and necessary, there is still the problem thatthe sample has to be sent to a laboratory for analysis. Inspectors andcustoms are often confronted with products, in which they supposethe presence of illegal whitening agents and therefore block them atports and airports until analysis of the samples. When the product is found to be within specifications the blockage of the products represents a significant financial loss for the companies. Therefore easy to use screening methods that can be used on the inspection site itself would be very useful.