Simultaneous determination of melamine and related compounds by hydrophilic interaction liquid chromatography-electrospray mass spectrometry

Isolation of 2 simazine-degrading bacteria and development of a microbial agent for bioremediation of simazine pollution

Simazine was one of the most commonly used herbicides and was widely used to control broadleaf weeds in agriculture and forestry. Its widespread use had caused wide public concern for its high ecological toxicity. In order to remove simazine residues, 2 strains capable of effectively degrading simazine were isolated from the soil and named SIMA-N5 and SIMA-N9. SIMA-N5 was identified as Bacillus licheniformis by 16SrRNA sequence analysis, and SIMA-N9 was Bacillus altitudinis. According to the degradation ratio of simazine in a certain period of time, the degradation ability of different strains was evaluated. The degradation efficiency of simazine (5 mg/L) by SIMA-N9 could reach about 98% in 5d, and the strain SIMA-N5 could reach 94% under the same conditions. In addition, the addition of Pennisetum rhizosphere soil during the process of degrading simazine by strain SIMA-N9 could effectively improve the degradation efficiency. The strain SIMA-N9 has been developed as a microbial agent for the bioremediation of simazine contamination in soil. The new microbial agent developed by using SIMA-N9 has achieved satisfactory application effects. Based on the research results already obtained in this study, it was considered that strain SIMA-N9 and its live bacterial agent could play an important role in bioremediation of simazine pollution. This study could not only provide a set of solutions to the simazine pollution, but also provide a reference for the treatment of other pesticide pollution.

Interlaboratory validation of an LC-MS/MS method for the determination of melamine and cyanuric acid in animal feed

Melamine and cyanuric acid have been mixed illegally into food and feed to increase the nitrogen content, which results in deceptively high protein contents. As a consequence, a maximum level for melamine of 2.5 mg kg-1 feed was established by the European Union under Directive 2002/32/EC. The Technical Committee (TC) 327 of the European Committee for Standardisation (CEN) commissioned the standardisation of a method for the analysis of melamine and cyanuric acid in animal feed. One main task in the standardisation process is the performance of a full international collaborative trial, which is described in this paper. After performing a pre-trial study, in the main study eight different feed samples with different concentration levels of melamine and/or cyanuric acid were distributed as double-blind samples to 13 participants. The minimum criterion of eight laboratories submitting results per sample is fulfilled for melamine but only partly for cyanuric acid. The evaluation showed for both analytes a Horwitz ratio (HorRat) well below 2, and meets the requirements stated in the appropriate international protocols. The results demonstrated that the method seems to be suitable for the analysis of melamine and cyanuric acid in animal feed.