Graphene-functionalized melamine sponges for microextraction of sulfonamides from food and environmental samples

The study describes the functionalization of melamine sponges with graphene and its use as an adsorbent for the microextraction of sulfonamides from food and environmental samples. The graphene-functionalized melamine sponge (GMeS) was prepared by an easy, one-step procedure, which complies with the principles of green chemistry and is proved advantageous over previously described methods. The applicability of the GMeS in extraction procedures was studied and an analytical method for the determination of sulfonamides in milk, eggs and lake water was developed and validated according to SANCO/12571/2013 guideline. The developed method was highly accurate and reproducible, while the limits of quantification were found to be relatively low (0.31-0.91μgkg^-1, 0.96-1.32μgkg^-1 and 0.10-0.29μgL^-1 in the case of milk, eggs and lake water respectively). Furthermore, matrix effects were absent in all cases, since the microextraction procedure serves also as a clean-up step. The low cost of synthesis, the environmentally friendly conditions, the efficiency and high extraction recoveries are some additional advantages of the proposed procedure. To the best of our knowledge, this is the first time that a GMeS is prepared in a straightforward way and used for analytical purposes.