While 5mm NMR tubes are the default size for solution NMR, several alternatives are available. For those with less sample 3mm, 1.7mm, and 1mm NMR tubes are available. The 1.7mm and 1mm NMR tubes really require a microprobe with reduced diameter coils, but 3mm tubes can be used in a 5mm probe. With our 1.7mm probe out of action I purchased a 3mm spinner and ran some spectra to compare the fill volumes of 5mm and 3mm tubes in our 5mm BBI probe.
