Fluorescence rejection in Raman spectra of Syncrude Sweet Blend distillation fractions

Sequentially Shifted Excitation Raman Spectroscopy: Novel Algorithm and Instrumentation for Fluorescence-Free Raman Spectroscopy in Spectral Space

“…[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] The varied nature of fluorescence backgrounds has resulted in limited success for the first three methods; however, shifted excitation methods are gaining widespread use due to their successful application for any sample. In the most simplistic implementation, only two laser wavelengths are used for excitation.…”

“…In this case, the only way to extract the Raman data is to take a difference of the two spectra, and hence the technique is often referred to as SERDS (shifted excitation Raman difference spectroscopy). [25][26][27][28][29][30][31][32][33][40][41][42] The result of SERDS is spectral data in the derivative form. More recently, it has been demonstrated that by using externalgrating tuned lasers in constant sweep mode, the signal-tonoise (S/N) of the Raman derivative signal can be significantly enhanced due to the presence of more than two excitation wavelengths.…”

“…More recently, it has been demonstrated that by using externalgrating tuned lasers in constant sweep mode, the signal-tonoise (S/N) of the Raman derivative signal can be significantly enhanced due to the presence of more than two excitation wavelengths. [30][31][32][33][34]42 Despite the impressive results, the true Raman spectra are not generated, and as with SERDS, there is significant difficultly in reconstructing the Raman spectra from the derivative data. In addition, the instrumentation is large and expensive, thus limiting some of the main advantages of dispersive Raman spectroscopy.…”

“…In general, these methods can be separated into four categories: algorithm-based baseline correction methods, 5–12 sampling optics and geometries, 13–15 time gating methods, 16–21 and shifted excitation methods. 22–41 The varied nature of fluorescence backgrounds has resulted in limited success for the first three methods; however, shifted excitation methods are gaining widespread use due to their successful application for any sample. In the most simplistic implementation, only two laser wavelengths are used for excitation.…”