Surface-enhanced Raman Spectroscopy Detection Of Pesticides Residual Based On Gold Nanorod Array Substrate

Pesticide residual in food was threatening the health of people,and its determination is important.However,the traditional methods tend to be time-consuming and cost-spending,so an accurate,sensitive and cheap way was needed.Surface-enhanced Raman spectroscopy?SERS?was potential to meet the requirement.This thesis was aimed to establish a method for the rapid determination of pesticide in apple.Firstly,we fabricated a gold nanorods?GNR?array with a good enhance factor and reproducibility,and then applied it to the SERS determination of thiabendazole?TBZ?,finally,mixture of TBZ and thiram were detected by SERS for quantification.The main contents and conclusions are as follows:?1?Fabrication and characterization of the GNR array SERS substrate.GNRs was prepared through seed-mediated method and then applied for the fabrication of GNR vertical array according to a self-assembly mechanism.The process was charactered and optimized by UV-vis spectroscopy,SEM and size measurement.The results indicated:for the GNR synthesis,increasement of the AgNO₃ could improve the uniformity of GNR,while seed solution can influence the ratio of GNRs;ratio of GNRs and the interfacial property of Si wafers can influence the formation of GNR array.Finally,GNR with a ratio of 2.3 and a hydrophilic silicon slide was adapted for the fabrication of GNR array,whose enhance factor?EF?and RSD for R6G determination were 2.1×10⁵ and 17.10%,and the area was about 400?m².?2?SERS determination of thiabendazole?TBZ?by the GNR array.Firstly,the characteristic peaks of TBZ was identified and the peak at 1008 cm^-11 was applied for the quantification of TBZ in the range of 0.1¹0 mg/L,the standard curve was y=279.8x+102.3,with a determination coefficient?DC?of 0.993 and detection of limitation?LOD?of 0.071 mg/L.The quantification of TBZ in apple was carried out following the standard curve,and its results were compared with HPLC's,good correlation was achieved with a linear coefficient of 0.9999.Considering the influence of extraction method and food matrix,compensation factor?CF?of2.16 was calculated and gained a recovery of 95.23%¹19.85.?3?SERS determination of the mixture of pesticides on the GNR array.Standard curve of y=480.25x+199.54 was acquired according to the peak at 1382 cm^-1 of thiram in the range of0.1¹0 mg/L,with a DC of 0.983 and LOD of 0.087 mg/L.TBZ and thiram were quantified by the standard curve and the recovery was 80.92%⁹2.31%and 67.69%⁹7.62%.And then,a self-modeling mixture analysis?SMA?method was adopted to decrease the influence of the Raman signal between TBZ and thiram,and the recovery turned to 71.61%⁹0.36%and 62.95%⁸9.41%.Finally,TBZ in apple spiked by mixture of TBZ and thiram was quantified based on SMA and CF,add the recovery was 94.95%¹00.02%?...