Metsulfuron-methyl molecularly imprinted polymer(MIP)-coated stir bar was prepared for sorptive extraction of sulfonylurea herbicides in complex samples.The MIP-coating was about 21.3 μm thickness with the relative standard deviation(RSD) of 4.4%(n=10).It was homogeneous and porous with good thermal stability and chemical stability.The extraction capability of the MIP-coating was 2.8 times over that of the non-imprinted polymer(NIP)-coating in hexane.The MIP-coating exhibited selective adsorption ability to the template and its analogues.The extraction conditions,including extraction solvent,desorption solvent,extraction time,desorption time and stirring speed,were optimized.A method for the determination of six sulfonylurea herbicides by MIP-coated stir bar sorptive extraction coupled with high performance liquid chromatography(HPLC) was developed.The linear range was 10―200 μg/L and the detection limits were within a range of 2.0―3.3 μg/L.It was also applied to the analysis of sulfonylurea herbicides in spiked river water,soil and rice samples.
A novel chemiluminescence(CL)reaction was based on the oxidizing reaction of luminol by the trivalent copper-periodate complex(K5[Cu(HIO6)2],DPC)in alkaline medium.The CL intensity could be enhanced in the presence of amikacin sulfate(AKS).A new CL method was developed for the determination of AKS by coupling with flow injection(FI)technology.Because of the distinctive oxidative effect of DPC,the luminol-based CL reaction could occur at a low concentration of 107M.The relative CL intensity was proportional to the concentration of AKS in the range of 4.0 109–4.0 106g/mL with the detection limit of 1.2 109g/mL.The relative standard deviation was 2.1%for 8.0 109g/mL AKS(n 9).The proposed method was successfully applied to the direct determination of AKS at the level of ng/mL in serum samples.The recovery varied from 97.0%to 106.3%.A possible mechanism of the CL reaction was discussed in detail by relating to the CL kinetic characteristics and electrochemical activities of the oxidant DPC.
