Quantitative Analysis Of Thiophene Sulfur In Gasoline Using Surface Enhanced Raman Spectrum On Solid Nano-silver Surface

The automotive industry developed rapidly with the growing of economic, but the increasing of the vehicle emissions and environment pollutions came along with it. The sulfur in gasoline is one of the major pollutants in vehicle emissions, the combustion products of it have great harm for the environment and human health. So it is becoming particularly urgent to detect the content of sulfur in gasoline accurately. Surface-enhanced Raman spectroscopy has been widely developed with the application of nanotechnology. It solved the issue of Raman spectroscopy of weak detection signal and low sensitivity at the same time.In this thesis, nano-silver sol and nano-silver pieces were prepared by different methods.This paper studied the enhancement of different preparation conditions on thiophene sulfur in simulated gasoline and quantitative analysis of the thiophene sulfur in gasoline used in car.Several different advanced techniques such as UV, SEM and TEM were used to get an ideal preparation: scan potential-0.35 V ~ +0.35 V, scan rate 5 mV/s, number of scan 2 times in Cyclic Voltanmetry, electrolyte solution concentration 0.1 mol·L-1, step potential 0.25 V, step time 10 s, optimize surfactant contention 1.0×10-4 mol·L-1 in Step Potential Method. The simulated gasoline was taken Raman spectral scanning using nano-silver pieces for the enhance substrate. The enhancement of relative peak height and relative peak area was explored by taking 1000 cm-1 and 1398 cm-1 characteristic peak as the object. For the 1000cm-1 peak, the maximum enhancement were 71 times and 4780 times to the relative peak height and relative peak area. For the 1398 cm-1 peak, the maximum enhancement were 161 times and 3740 times to the relative peak height and relative peak area. The different sulfur content of simulated gasoline were taken Raman spectral scanning by taking nano-silver pieces for the enhance substrate. For the 1000 cm-1 peak, thiophene sulfur in 100 mg·kg-1 ~1000 mg·kg-1, the linear correlation coefficient R2 were 0.9912 and 0.9826 between relativepeak height, relative peak area and sulfur content. For the 1398 cm-1 peak, thiophene sulfur in1 mg·kg-1 ~ 100 mg·kg-1, the linear correlation coefficient R2 were 0.7332 and 0.9880 between relative peak height, relative peak area and sulfur content. The thiophene sulfur of gasoline used in car was analysis by the linear correlation between the relative peak area and the sulfur content of the 1398 cm-1. The predictive value is 31.79,the relative error is 10.30 %.The recovery was 100% ~ 110%, within the error range by the recovery experiments.The experiment is the frist time to detect the thiophene sulfur content in gasoline by nano-silver piece active substrates combined with surface enhanced Raman spectroscopy and has some accesses. The processing meyhod is simple on Raman spectra, therefore, it can be combined with the chemometrics method to detect the thiophene sulfur content of variety of gasolines and has a further exploration on the stability and reproducibility of the active substrates in the following work.