Tuning and matching is the process of optimizing the frequency and resistance of the probe to suit your sample. Our probes need to be tuned and matched manually by turning the rods at the bottom of the probes. With the 1.7 mm probe the sample volume is small enough that the tuning and matching does not vary much from sample to sample and you can get away without doing it. For the 5 mm probe, however, the larger volume results in a significant difference in the tuning and matching when switching between aqueous and organic solvents. To automate data acquisition, ideally we would use an automated tune and match module to enable the computer to adjust the rods, but these are expensive. As a workaround we could just skip the tuning and matching and accept a loss in sensitivity. I decided to measure the loss in sensitivity by acquiring spectra of organic solvents when the probe was tuned and matched for an aqueous sample.
