Hi Liam Kelleher , I´m also interested on these Raman devices, and I had done some tests, mainly to study their capabilities in combination with SERS substrates. At the moment I have tested the Bruker and B&WTeek systems, with bad results (no signal or very low one at best). The Anton Paar spectrometer is being used by Isabel Pastoriza's group at Vigo University, they have a EU project and Anton Paar is a industrial partner. They also deal with SERS sensors in combination with that handheld raman. The project involves the detection of toxic gases, so the challenge is big.

All these systems are mainly designed to deal with raw materials in factories. They also have an use identifiying chemicals in pharmaceutical preparations or for drug identification in customs. The good thing is that they can perform the analysis without removing the sample from the container, making it easy and fast the process. They rely on normal Raman signal excited by a red or IR laser in all the cases I have seen at least (632nm or 1064 diode lasers). Most of them, for instance Bruker and Anton-Paar include a library of standards, which is clearly useful. All of them include some adapter head to hold a spectroscopy cell or a vial. The B&Wtek include a fiber optics guide that finish in a handheld head that allows to reach tiny or very localized areas. This head includes a lens with 10mm focal distance that is encased in a stainless steel tube so that you just have to place the tube in contact with the sample and the focal distance is there. Many groups working with art or conservation of artworks use this equipment successfully. The one I tried was the I-Raman Plus, it is a portable device, but still quite bulky, thought the fiber optics guide lets you bring the laser light and detection to the areas of interest easily. This device needs a laptop to visualize the spectra, new versions include a screen that simplifies the things.

Handheld instruments that show the spectra are more useful, from my point of view, but most of them require a external device to visualize the data.

About the issues with SERS substrates, I think the main problem is the lack of control of the focal distance and the lack of microscope objectives to focus the laser and collect the Raman signal (the Numerical Aperture). Focusing would be difficult when you have to hold the instrument with your hands, so using objectives would be useless unless you can keep the instrument stable (mecanically holded). Note that my SERS substrates are solid structures, and the problems refered could be avoided when you deal with plasmonic nanoparticles in solution, where the place you focus your beam is not so relevant.

Hope it helps.

Thank you Manuel Gómez for all the details, I had wondered if they would work well or not! I think the larger I-Raman Plus might work well for my needs, but I need to iron out the exact requirements first. It's for polymer work, so fingers crossed the signal will be manageable to obtain!

Hi Liam Kelleher yesterday in our laboratory there was a sales manager from Bruker who showed a new Bravo device with two laser excitation wavelengths, and it records a signal up to 3200 cm-1. A colleague took a spectrum of his skin (a signal with a low signal-to-noise ratio), in his words the spectrum was very good. I can also recommend the company Enspectr (https://enspectr.com/), they have portable Raman analyzers at different wavelengths of 532, 785, and 1064 nm with better results compared to B&W Tek, they seem to be cheaper if such a question takes place.