Page 36 of NMR Sampling Tubes, Supplies & Accessories by Wilmad Labglass

doty susceptibility plugs for nmr microsampling · easier to use than the glass alternative · can be used with a wider range of solvents · use them with existing tubes · lower in cost than glass · less fragile than susceptibility-altered glass microtubes traditionally sample sizes were 3-5 times the height of the probe r coil all magnetic field distortions caused by magnetic susceptibility discontinuities at the upper air-sample and lower glass-sample interfaces were far from the sensitive probe r coil region small samples diluted to larger traditional volumes 1 ml yield poor nmr spectra in high field spectrometers through magnetic susceptibility matching of the sample solvent doty susceptibility plugs allow the sample to be substantially concentrated by extending out the air-sample/glass sample interfaces far enough away from the r coil region to remove the magnetic field distortions doty susceptibility plugs are provided as sets of two positioning rod and collar are provided as a set and ordered separately from the plug set the upper face of both plugs has a thread that lets you firmly attach a positioning rod the upper plug is held in the tube by the positioning rod the rod in turn is held by a collar that rests on top of the tube a special sealing collar equipped with two o-rings can be ordered separately for long term storage of samples where solvent evaporation can alter results the sealing collar is used to replace the standard positioning collar on the rod magnetic susceptibilities within 5 of each other can be considered to be matched resolution is less affected by larger mismatches when the magnetic susceptibilities are of greater magnitude high resolution nmr spectra can be obtained in vt experiments by using doty susceptibility plugs to reduce the resolution loss associated with thermal gradients advantages of doty susceptibility plugs · designed for use in wilmad thin wall nmr sample tubes 7 8 inch length · eliminate glass tube breakage · designed for easier air bubble removal product numbers with a v have vent grooves along the outer surface for easier bubble removal and for use with viscous samples/solvents · may be removed from the sample tube with minimal sample loss 1-2 after spectra are obtained and then used with other samples 30 www.wilmad-labglass.com 36

[close]