Determination of Melamine in Fertilizer by IC

IC was applied to the determination of melamine in fertilizer. The sample was extracted ultrasonically with a mixture of NH3·H2O+CH3OH+H2O (2+7+1). After centrifuging, the extract was evaporated to dryness by N2-blowing, and the residue was dissolved with 3 mmol·L-1 methylsulfonic acid solution. Dionex IonPac R SCS1 columns were used both as separation and guard columns and a mixture of acetonitrile and 3 mmol·L-1 methylsulphonic acid solution (15+85) was used as eluent. Melamine was detected by non-suppressed conductivity detector. The linearity range of melamine was between 1.00-1 000 mg·L-1. The detection limit was 5 mg·kg-1 and the limit of quantification was 15 mg·kg-1. Values of recovery found by standard addition method were in the range of 79.3%-116% and RSD′s (n=6) were in the range of 3.4%-13%.