The application of pseudo template molecularly imprinted polymer to the solid‐phase extraction of cyromazine and its metabolic melamine from egg and milk

Abstract

The combination of molecularly imprinted polymer with high performance liquid chromatography has been developed to determine cyromazine and its metabolic melamine in some samples. However, the potential risk of template leakage used in molecularly imprinted polymer is a major disadvantage. To solve this problem, 2-(4,6-diamino-1,3,5-triazin-2-ylamino) ethanethiol disulfide, a molecule that shares the similar imprinting sites with cyromazine and melamine, was selected as pseudo template to prepare molecularly imprinted polymer. Methacrylic acid, ethylene glycol dimethyl acrylate and toluene were selected as functional monomer, crosslinker and porogen, respectively. The molecular recognition property and binding capability of cyromazine and melamine were evaluated by adsorption test and Scatchard analysis. The results showed that the molecularly imprinted polymer based on pseudo template had more excellent affinity and selectivity for cyromazine and melamine. The resulting molecularly imprinted polymer was used as a solid-phase extraction material to enrich cyromazine and melamine in egg and milk samples for high performance liquid chromatography analysis. The solid-phase extraction process was carefully optimized. It was found that when different concentration of cyromazine and melamine standards were spiked into samples, satisfactory recovery rate of cyromazine and melamine were obtained as 85.6-98.8% with relative standard deviation <5.5%.

Rapid and selective screening of melamine in bovine milk using molecularly imprinted matrix solid-phase dispersion coupled with liquid chromatography-ultraviolet detection

“…Based on the signal-to-noise ratio of 3 and 10, the LOD and LOQ for MEL was 0.05 g g −1 and 0.16 g g −1 , respectively. Comparison with previously reported methods, the MI-MSPD-HPLC method significantly reduced the complicated pretreatment procedure while shortens the analysis time and reduces the consumption of toxic organic solvents [8,9,13,32,33].…”

Determination of melamine in aquaculture feed samples based on molecularly imprinted solid‐phase extraction

“…So far, several papers also described the determination of MEL in various foods and environmental matrices, such as beverage products [24], swine kidney [25], strawberry [26], egg [27], royal jelly [28], and so on. MEL has been presented as a trace contaminant in nitrogen supplements used in animal feeds, however, there have been few reports on the analysis of MEL in aquaculture feed.…”

Synthesis of a Molecularly Imprinted Polymer for Melamine Analysis in Milk by HPLC with Diode Array Detection

“…Yang et al [27] and Wang et al [21], describe an extraction in a Soxhlet apparatus for 48 hours with a mixture of methanol:acetic acid (9:1, v/v), however nothing is said about solvent regeneration nor determination of the amount template that is being extracted. Meanwhile, Wang et al [19] used a mixture of methanol:acetic acid (7:3, v/v) with control of the released template by UV spectrophotometry at a wavelength of 240 nm.…”

“…MIPs have also been reported in the analysis of melamine in milk samples, mainly by the MISPE methodology [19][20][21][22]. Table 1 resumes the polymerization conditions considered in the synthesis of melamine selective polymers.…”

“…Table 1 resumes the polymerization conditions considered in the synthesis of melamine selective polymers. Bulk polymerisation [21][22][23] stands out as the most common procedure, however this methodology leads to irregular particles in size and shape as a consequence of the mechanical procedures applied to the resulting polymer [10]. In order to overcome these drawbacks some authors followed the suspension protocol which allows the synthesis of homogeneous beads with controlled size [19,20].…”