Using LEGO Blocks for the Evaluation of Fluorescence Avoidance and Mitigation in Handheld Raman Spectrometers

In a previous paper, we proposed the use of a set of colored LEGO blocks as "standard" samples for the evaluation of fluorescence avoidance and mitigation schemes in Raman spectroscopy, as well as for use to evaluate the instruments' performance on dark samples. The purpose of this paper is to establish that this set of LEGO blocks does represent a good test case for fluorescence avoidance and mitigation when using handheld Raman spectrometers, and for the ability to record Raman spectra from dark samples. The performance of ten different instruments, operating using different exciting lines (785, 830/852, and 1064 nm), and different data processing schemes, are compared. The combination of a series of colored blocks (white, yellow, red, and blue), and successively darker tone blocks (white, gray, and black) do challenge these instruments, and shed light on the ways that their manufacturers have optimized these instruments in specific areas and for different purposes.