This paper presents experimental results highlighting the useful range of parameters (wavelength, spot size, substrate type) effective in detection limit of materials such as Methylene Blue (MB) by Raman spectroscopy.
A variety of spectroscopic techniques have been used for material and/or structural identifications, diagnostics, etc. [1-3]. Among them, Raman spectroscopy has been opening many and new interesting applications in the field of biology, non-destructive testing, and medical science, etc. [4-5]. However, one of the challenges with Raman spectroscopy is to identify the detection limits of probe molecules by it. The question therefore arises how one might increase the detection limit of a material using Raman spectroscopy.
In this study, Methylene Blue (MB) in both solution and solid form is used as a probe molecule to determine detection limit of it by Raman spectroscopy. Under different conditions, the detection limit of MB has been found by Raman spectrometer and results have been compared together. Moreover, methods for improving detection limit of this analyte have been discussed and tested to find the optimum conditions under which the minimum number of molecules can be detected. Furthermore, in order to enhance the accuracy of the results, methods for increasing signal to noise ratio have been utilized and discussed. The results demonstrate that how factors such as substrate type, laser spot size, wavelength and material phase play important roles in detection limit of this molecule by Raman spectroscopy. Detailed analysis of the measurements will be presented.