Studies For Detection Of Atrazine Based On Gold Nanoparticles Modified The Electrochemical Immunosensors

In this work, the ability of the different size gold nanoparticles (GNPs) for enhancing the electrochemical signal was investigated, and the optimal size of GNPs is selected to structure a new detection method based on electrochemical immunosensor using GNPs for directly atrazine detection. All experiments were performed using a conventional three-electrode system (a gold electrode as the working electrode, a platinumwire as the auxiliary electrode, and a saturated calomel electrode (SCE) as the reference electrode). In addition, the direct method of the electrochemical immunosensor and the liquid chromatography tandem mass spectrometry (LC-MS/MS, GB/T23816-2009) was used to detect atrazine comparing with the new method. The results imply that this new method own the feature of simple and fast, high sensitive and selectivity. The main results as follows:(1) The four different sizes of GNPs were synthesized by the sodium citrate chemical reduction method. The results of the TEM and UV indicated that the sizes of GNPs are uniformity and have good dispersibility, the average diameter of prepared GNPs are about17(±0.14) nm24(±3.78) nm28(±0.78) nm30(±2.05) nm, respectively.(2) The new method of monolayer GNPs modified electrochemical immunosensor to detect atrazine was structured. The results indicate that the28nm GNPs offered the strongest electrochemical signal, the linear range is0.05ng/mL-0.5ng/mL, and the limit of detection is0.016ng/mL. In addition, the proposed immunosensor exhibite high selectivity, stability and sensitive.(3) The direct method of the electrochemical immunosensors for detection atrazine was studied, which there was no GNPs modified on the surface of gold electrode. The results demonstrate that the linear range is0.2ng/mL-0.5ng/mL, and the limit of detection is0.099ng/mL. Compared to the new method for detection atrazine, the direct method is inferior to the proposed new method in sensitive, selectivity and stability.(4) The GB/T23816-2009method of LC-MS/MS was used to detect atrazine. The results indicate that the linear range is0.976ng/mL-1000ng/mL, and the limit of quantitation is0.488ng/mL. A comparison of the proposed electrochemical immunosensors and LC-MS/MS two methods imply that the proposed electrochemical immunosensor own more superiority.