毛细管电泳-电致化学发光法测定土壤中的多抗霉素B

以稀土铕离子(Ⅲ)掺杂的类普鲁士蓝膜(Eu-PB)修饰铂电极为工作电极,采用毛细管电泳-电致化学发光法(CE-ECL)对土壤中的多抗霉素B进行检测.分别对毛细管电泳分离条件和电致化学发光检测条件进行优化,并探讨了体系产生电致化学发光的机理.在优化实验条件下,多抗霉素B可在4 min内得到分离,其ECL强度值与多抗霉素B...

Determination of Polyoxin B in Soils by Capillary Electrophoresis with Electrochemiluminescence Detection

On the basis of a chemically modified platinum electrode by europium(Ⅲ)-doped Prussian blue analogue film(Eu-PB) as a working electrode,a rapid and sensitive method for the determination of polyoxin B was established using capillary electrophoresis coupled with electrochemiluminescence detection(CE-ECL).Parameters related to the separation and detection were discussed and optimized.The possible mechanism of ECL was briefly discussed.Under the optimized conditions(ECL detection potential at 1.27 V,electrokinetic injection for 10 s at 8.5 kV,16 kV as the separation voltage,20 mmol/L pH 8.5 phosphate buffer containing 16 % acetonitrile as running buffer),polyoxin B was separated within 4 min,and the ECL intensity was in proportion to logarithm of polyoxin B concentration over the range of 1.0×10-4-5.0×10-4 g/L and 5.0×10-4-5.0×10-2 g/L with a detection limit(3σ) of 9.2×10-5 g/L.The relative standard deviations(RSDs) of intra-day and inter-day ECL intensity and migration time were all less than 5.0%.The proposed method was successfully applied in the determination of polyoxin B absorbed in three kinds of soils(e.g.bentonite,kaolinite and loess) with the recoveries of 92%-104%.The results also showed that the adsorption rate of polyoxin B in soils for 2 h was 89.0% for bentonite,45.5% for kaolinite and 40.4% for loess,respectively,indicating that the adsorption capacity of polyoxin B in different soils was bentonite>kaolinite>loess.The possible reason was related to the characteristics,specific surface area and cation exchange capacity(CEC) of soils.