NMR Spectroscopy

Buying guide

Price here spans a wider gap than on any single category page, because the set runs from a sealed benchtop instrument to a superconducting floor system with its cooling and siting. Listings start at EUR 1 and reach EUR 266.971. The low end is not a working spectrometer so much as a part, an accessory or a probe; a complete benchtop unit sits well above it, and the superconducting systems account for the top of the range, where the field strength and the magnet itself carry most of the cost. When weighing a used unit against a new one, the clearest fact is price: 80 percent of the listings are used, and used and refurbished units are listed below new. What that saving is worth depends on the magnet. A permanent magnet changes little with age, so a shielded benchtop unit carries a modest condition risk. A superconducting magnet is a different question, because its value sits in a cooled state that has to be maintained, and here the specifics belong to the individual listing. Warranty is often possible and is arranged in consultation for the specific listing, so the terms are read there rather than assumed from the price. Parts, including probes and sample hardware, can be sourced via Questpair. Across the set, the figure that matters is less the headline number than which part of the work it buys: a console, a probe and a magnet are priced as separate things even when they arrive as one instrument.

Types of NMR Spectroscopy

NMR spectroscopy draws on a short list of equipment: a spectrometer built around a magnet, the probe and sample hardware that sit inside it, a console that drives the pulses and reads the signal, and the analytical instruments that sit alongside it when a structure needs more than one technique to pin down. The work is not a single sequence so much as a set of stages that repeat per sample, and these are them.

Which magnet does the work set?

The magnet is the decision everything else answers to. Benchtop spectroscopy uses a permanent magnet, typically in the 40 to 100 MHz range, sealed and shielded enough to sit on an ordinary bench without a dedicated room. These suit reaction monitoring, teaching and routine identity checks, where resolving power matters less than having a result in minutes beside the fume hood. The superconducting systems are a different proposition. Field strengths from 300 MHz upward need a cooled magnet, which means liquid helium and nitrogen, periodic refills and a siting survey for stray field. The higher the field, the finer the signal separation, which is what structural elucidation of a complex molecule turns on. A lab choosing between the two is really choosing between a self-contained instrument and a facility.

Preparing and loading the sample

Between the magnet and the result sits the sample. For solution-state work the compound goes into a thin-walled tube in a deuterated solvent, and the choice of solvent is not incidental: it sets the lock signal the instrument uses to hold the field steady, and it leaves residual peaks that have to be read around. Tube quality matters more than it looks, because a tube that is out of round or dirty degrades the shim and widens every line on the spectrum. On the superconducting systems an autosampler feeds tubes in sequence, which is where throughput comes from; on a benchtop unit loading is usually by hand, one tube at a time.

How do the stages constrain each other?

This is where a single-category view falls short. A high-field magnet buys resolution, but it also sets the probe that can go inside it, the sample volume that probe wants, and the console bandwidth needed to excite the wider range of frequencies that comes with the field. Push the field up and the siting, cooling and running cost rise with it, so the resolution a project genuinely needs, rather than the most it could have, is the honest starting point. Where one technique leaves a structure ambiguous, a mass spectrometer settles the molecular weight and a chromatography step confirms the sample was pure going in, which is why these sit in the catalogue beside the spectrometers rather than apart from them.

Reading the result

The signal the console records is a decay in time, and it only becomes a spectrum after processing. That step is part of the instrument, not an afterthought: phasing, baseline correction and integration are where a clean acquisition is either preserved or spoiled. A benchtop unit ships this as a closed software package; a research system gives more control and expects more from the operator.