This essentially is supported by the capability of the Raman technique to probe materials directly through packaging material. Hence, a variety of expensive and time consuming sections of a conventional material release process can be omitted, e.g. statistical extraction in a sampling booth for a laboratory based testing. Next to the shortening of the release chain handheld devices can push the limits towards 100 % inspection minimizing the risk to miss a harmful container which is enabled by a fast analysis in just a few seconds.

All this sounds outstanding but why handheld or mobile Raman systems are not found at every goods receipt despite being well recognized on the market? The answer is pretty easy – no technique can offer an all-in-one solution and has its specific limitations and susceptibilities. During the Raman analysis a laser beam is emitted onto the material of interest and only the backscattered light which has changed its color due to a non-destructive interaction with the sample is analyzed. Despite the unquestionable fact that the information acquired is highly selective as it can be interpreted like a unique fingerprint, it is obvious that the portion of light which needs to be measured by the instrument is of very low intensity. Therefore, intense lasers are required causing a potential thread to the operator’s eyesight and requiring the compliance to laser safety regulations. Furthermore, the weak Raman signals are often accompanied by interfering signals, i.e. mostly fluorescence, which decrease the significance of results or even prevent reasonable measurements to be generated.

This is an excerpt of current challenges which need to be addressed in order to take advantage of the capabilities of the Raman technique. BRAVO (Bruker RAman Verification Optics) from Bruker addresses before mentioned limitations of conventional handheld Raman instrumentation. With its patented Sequentially Shifted Excitation (SSETM) BRAVO offers the first active fluorescence mitigation within a handheld Raman instrument in order to extend the performance with respect to selectivity, sensitivity and the range of materials to be analyzed. Figure 1 for example shows spectra of sodium alginate acquired with BRAVO (blue) and a conventional dispersive instrument using 785 nm excitation (red). Here it is obvious that in the red spectrum most of the signal does not include information desired for material verification. Only the “bumps” superimposed onto the slope represents the chemical information. On the contrary the spectrum acquired using the SSETM technique (blue) yields relevant chemical information maintaining a superior signal quality. Thus, the absence of non-information-bearing signals in combination with DuoLASERTM excitation forms the basis for the most unambiguous verification of materials on a very large spectral range from 300 to 3200 cm-1 including the CH-stretching region.

A further aspect worth to look into is the ease of use as handheld systems are not operated by scientists typically. This gets even more important with respect to an operation compliant to regulations like 21 CFR Part 11. BRAVO offers a unique workflow on a large touchscreen display with the most utmost ease of use and as a laser class 1M product the highest safety standard.

By Dr. Felix Fromm, Bruker Optik GmbH
Application Manager Handheld Raman