Comparison of trimethoprim molecularly imprinted polymers in bulk and in sphere as the sorbent for solid-phase extraction and extraction of trimethoprim from human urine and pharmaceutical tablet and their determination by high-performance liquid chromato

Two types of trimethoprim molecularly imprinted polymers in bulk and sphere (by suspension polymerisation) were prepared and used as sorbents for solid-phase extraction. By comparing adsorption of trimethoprim in different solvents, desorption with ratio of ethanol and N,N-dimethylformamide, acetic acid and ratio of methanol and trifluoroacetic acid, we find that molecularly imprinted polymers in bulk are better at selectivity and adsorptive capacity than in sphere. Moreover specific surface area and pore volume of molecularly imprinted polymers in bulk are about twice than in sphere. But these two types of polymers may both enrich and separate trimethoprim from the human urine and the pharmaceutical tablet successfully. The linear range of trimethoprim is 1–100 nmol ml−1 and the limited detection is 0.1 nmol ml−1.